Check if a class is derived from a generic class

Question

I have a generic class in my project with derived classes   public class GenericClass lt T gt    GenericInterface lt T gt       public class Test   GenericClass lt SomeType gt        Is there any way to find out if a Type object is derived from GenericClass   t IsSubclassOf typeof GenericClass lt  gt      does not work

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JaredPar s code works but only for one level of inheritance   For unlimited levels of inheritance  use the following code  public bool IsTypeDerivedFromGenericType Type typeToCheck  Type genericType        if  typeToCheck    typeof object                 return false            else if  typeToCheck    null                return false            else if  typeToCheck IsGenericType  amp  amp  typeToCheck GetGenericTypeDefinition      genericType                return true            else               return IsTypeDerivedFromGenericType typeToCheck BaseType  genericType

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Type  type   myclass GetType    PropertyInfo    propertyInfos    type GetProperties    Boolean  test    propertyInfos 0  PropertyType GetGenericTypeDefinition       typeof List lt  gt

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EnocNRoll - Ananda Gopal  s answer is interesting  but in case an instance is not instantiated beforehand or you want to check with a generic type definition  I d suggest this method    public static bool TypeIs this Type x  Type d        if null  d            return false             for var c   x  null  c  c c BaseType            var a   c GetInterfaces             for var i   a Length  i-- gt  0                 var t   i lt 0   c   a i                if t  d  t IsGenericType amp  amp t GetGenericTypeDefinition    d                    return true                                     return false      and use it like    var b   typeof char    TypeIs typeof IList lt  gt        true   There are four conditional cases when both t to be tested  and d are generic types and two cases are covered by t  d which are  1 neither t nor d is a generic definition or  2  both of them are generic definitions  The rest cases are one of them is a generic definition  only when d is already a generic definition we have the chance to say a t is a d but not vice versa    It should work with arbitrary classes or interfaces you want to test  and returns what as if you test an instance of that type with the is operator

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Try this code  static bool IsSubclassOfRawGeneric Type generic  Type toCheck        while  toCheck    null  amp  amp  toCheck    typeof object             var cur   toCheck IsGenericType   toCheck GetGenericTypeDefinition     toCheck          if  generic    cur                return true                    toCheck   toCheck BaseType            return false

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Try this code  static bool IsSubclassOfRawGeneric Type generic  Type toCheck        while  toCheck    null  amp  amp  toCheck    typeof object             var cur   toCheck IsGenericType   toCheck GetGenericTypeDefinition     toCheck          if  generic    cur                return true                    toCheck   toCheck BaseType            return false

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Building on the excellent answer above by fir3rpho3nixx and David Schmitt  I have modified their code and added the ShouldInheritOrImplementTypedGenericInterface test  last one             lt summary gt          Find out if a child type implements or inherits from the parent type          The parent type can be an interface or a concrete class  generic or non-generic           lt  summary gt           lt param name  child  gt  lt  param gt           lt param name  parent  gt  lt  param gt           lt returns gt  lt  returns gt      public static bool InheritsOrImplements this Type child  Type parent                var currentChild   parent IsGenericTypeDefinition  amp  amp  child IsGenericType   child GetGenericTypeDefinition     child           while  currentChild    typeof object                         if  parent    currentChild    HasAnyInterfaces parent  currentChild                   return true               currentChild   currentChild BaseType    null  amp  amp  parent IsGenericTypeDefinition  amp  amp  currentChild BaseType IsGenericType                                   currentChild BaseType GetGenericTypeDefinition                                     currentChild BaseType               if  currentChild    null                  return false                    return false             private static bool HasAnyInterfaces Type parent  Type child                return child GetInterfaces   Any childInterface   gt                                var currentInterface   parent IsGenericTypeDefinition  amp  amp  childInterface IsGenericType                       childInterface GetGenericTypeDefinition                         childInterface                   return currentInterface    parent                               Test      public void ShouldInheritOrImplementNonGenericInterface                 Assert That typeof FooImplementor               InheritsOrImplements typeof IFooInterface    Is True               Test      public void ShouldInheritOrImplementGenericInterface                 Assert That typeof GenericFooBase               InheritsOrImplements typeof IGenericFooInterface lt  gt     Is True               Test      public void ShouldInheritOrImplementGenericInterfaceByGenericSubclass                 Assert That typeof GenericFooImplementor lt  gt                InheritsOrImplements typeof IGenericFooInterface lt  gt     Is True               Test      public void ShouldInheritOrImplementGenericInterfaceByGenericSubclassNotCaringAboutGenericTypeParameter                 Assert That new GenericFooImplementor lt string gt    GetType                InheritsOrImplements typeof IGenericFooInterface lt  gt     Is True               Test      public void ShouldNotInheritOrImplementGenericInterfaceByGenericSubclassNotCaringAboutGenericTypeParameter                 Assert That new GenericFooImplementor lt string gt    GetType                InheritsOrImplements typeof IGenericFooInterface lt int gt     Is False               Test      public void ShouldInheritOrImplementNonGenericClass                 Assert That typeof FooImplementor               InheritsOrImplements typeof FooBase    Is True               Test      public void ShouldInheritOrImplementAnyBaseType                 Assert That typeof GenericFooImplementor lt  gt                InheritsOrImplements typeof FooBase    Is True               Test      public void ShouldInheritOrImplementTypedGenericInterface                 GenericFooImplementor lt int gt  obj   new GenericFooImplementor lt int gt             Type t   obj GetType             Assert IsTrue t InheritsOrImplements typeof IGenericFooInterface lt int gt              Assert IsFalse t InheritsOrImplements typeof IGenericFooInterface lt String gt

User · Answer

You can try this extension      public static bool IsSubClassOfGenericClass this Type type  Type genericClass Type t                return type IsSubclassOf genericClass MakeGenericType new     t

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It seems to me that this implementation works in more cases  generic class and interface with or without initiated parameters  regardless of the number of child and parameters    public static class ReflexionExtension       public static bool IsSubClassOfGeneric this Type child  Type parent                if  child    parent              return false           if  child IsSubclassOf parent               return true           var parameters   parent GetGenericArguments            var isParameterLessGeneric     parameters    null  amp  amp  parameters Length  gt  0  amp  amp                parameters 0  Attributes  amp  TypeAttributes BeforeFieldInit     TypeAttributes BeforeFieldInit             while  child    null  amp  amp  child    typeof object                         var cur   GetFullTypeDefinition child               if  parent    cur     isParameterLessGeneric  amp  amp  cur GetInterfaces   Select i   gt  GetFullTypeDefinition i   Contains GetFullTypeDefinition parent                     return true              else if   isParameterLessGeneric                  if  GetFullTypeDefinition parent     cur  amp  amp   cur IsInterface                                        if  VerifyGenericArguments GetFullTypeDefinition parent   cur                           if  VerifyGenericArguments parent  child                               return true                                    else                     foreach  var item in child GetInterfaces   Where i   gt  GetFullTypeDefinition parent     GetFullTypeDefinition i                            if  VerifyGenericArguments parent  item                               return true               child   child BaseType                     return false             private static Type GetFullTypeDefinition Type type                return type IsGenericType   type GetGenericTypeDefinition     type             private static bool VerifyGenericArguments Type parent  Type child                Type   childArguments   child GetGenericArguments            Type   parentArguments   parent GetGenericArguments            if  childArguments Length    parentArguments Length              for  int i   0  i  lt  childArguments Length  i                    if  childArguments i  Assembly    parentArguments i  Assembly    childArguments i  Name    parentArguments i  Name    childArguments i  Namespace    parentArguments i  Namespace                      if   childArguments i  IsSubclassOf parentArguments i                            return false           return true            Here are my 70 76 test cases    TestMethod  public void IsSubClassOfGenericTest         Assert IsTrue typeof ChildGeneric  IsSubClassOfGeneric typeof BaseGeneric lt  gt       1        Assert IsFalse typeof ChildGeneric  IsSubClassOfGeneric typeof WrongBaseGeneric lt  gt       2        Assert IsTrue typeof ChildGeneric  IsSubClassOfGeneric typeof IBaseGeneric lt  gt       3        Assert IsFalse typeof ChildGeneric  IsSubClassOfGeneric typeof IWrongBaseGeneric lt  gt       4        Assert IsTrue typeof IChildGeneric  IsSubClassOfGeneric typeof IBaseGeneric lt  gt       5        Assert IsFalse typeof IWrongBaseGeneric lt  gt   IsSubClassOfGeneric typeof ChildGeneric2 lt  gt       6        Assert IsTrue typeof ChildGeneric2 lt  gt   IsSubClassOfGeneric typeof BaseGeneric lt  gt       7        Assert IsTrue typeof ChildGeneric2 lt Class1 gt   IsSubClassOfGeneric typeof BaseGeneric lt  gt       8        Assert IsTrue typeof ChildGeneric  IsSubClassOfGeneric typeof BaseGeneric lt Class1 gt       9        Assert IsFalse typeof ChildGeneric  IsSubClassOfGeneric typeof WrongBaseGeneric lt Class1 gt      10        Assert IsTrue typeof ChildGeneric  IsSubClassOfGeneric typeof IBaseGeneric lt Class1 gt      11        Assert IsFalse typeof ChildGeneric  IsSubClassOfGeneric typeof IWrongBaseGeneric lt Class1 gt      12        Assert IsTrue typeof IChildGeneric  IsSubClassOfGeneric typeof IBaseGeneric lt Class1 gt      13        Assert IsFalse typeof BaseGeneric lt Class1 gt   IsSubClassOfGeneric typeof ChildGeneric2 lt Class1 gt      14        Assert IsTrue typeof ChildGeneric2 lt Class1 gt   IsSubClassOfGeneric typeof BaseGeneric lt Class1 gt      15        Assert IsFalse typeof ChildGeneric  IsSubClassOfGeneric typeof ChildGeneric     16        Assert IsFalse typeof IChildGeneric  IsSubClassOfGeneric typeof IChildGeneric     17        Assert IsFalse typeof IBaseGeneric lt  gt   IsSubClassOfGeneric typeof IChildGeneric2 lt  gt      18        Assert IsTrue typeof IChildGeneric2 lt  gt   IsSubClassOfGeneric typeof IBaseGeneric lt  gt      19        Assert IsTrue typeof IChildGeneric2 lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt  gt      20        Assert IsFalse typeof IBaseGeneric lt Class1 gt   IsSubClassOfGeneric typeof IChildGeneric2 lt Class1 gt      21        Assert IsTrue typeof IChildGeneric2 lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt Class1 gt      22        Assert IsFalse typeof IBaseGeneric lt Class1 gt   IsSubClassOfGeneric typeof BaseGeneric lt Class1 gt      23        Assert IsTrue typeof BaseGeneric lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt Class1 gt      24        Assert IsFalse typeof IBaseGeneric lt  gt   IsSubClassOfGeneric typeof BaseGeneric lt  gt      25        Assert IsTrue typeof BaseGeneric lt  gt   IsSubClassOfGeneric typeof IBaseGeneric lt  gt      26        Assert IsTrue typeof BaseGeneric lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt  gt      27        Assert IsFalse typeof IBaseGeneric lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt Class1 gt      28        Assert IsTrue typeof BaseGeneric2 lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt Class1 gt      29        Assert IsFalse typeof IBaseGeneric lt  gt   IsSubClassOfGeneric typeof BaseGeneric2 lt  gt      30        Assert IsTrue typeof BaseGeneric2 lt  gt   IsSubClassOfGeneric typeof IBaseGeneric lt  gt      31        Assert IsTrue typeof BaseGeneric2 lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt  gt      32        Assert IsTrue typeof ChildGenericA  IsSubClassOfGeneric typeof BaseGenericA lt   gt      33        Assert IsFalse typeof ChildGenericA  IsSubClassOfGeneric typeof WrongBaseGenericA lt   gt      34        Assert IsTrue typeof ChildGenericA  IsSubClassOfGeneric typeof IBaseGenericA lt   gt      35        Assert IsFalse typeof ChildGenericA  IsSubClassOfGeneric typeof IWrongBaseGenericA lt   gt      36        Assert IsTrue typeof IChildGenericA  IsSubClassOfGeneric typeof IBaseGenericA lt   gt      37        Assert IsFalse typeof IWrongBaseGenericA lt   gt   IsSubClassOfGeneric typeof ChildGenericA2 lt   gt      38        Assert IsTrue typeof ChildGenericA2 lt   gt   IsSubClassOfGeneric typeof BaseGenericA lt   gt      39        Assert IsTrue typeof ChildGenericA2 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof BaseGenericA lt   gt      40        Assert IsTrue typeof ChildGenericA  IsSubClassOfGeneric typeof BaseGenericA lt ClassA  ClassB gt      41        Assert IsFalse typeof ChildGenericA  IsSubClassOfGeneric typeof WrongBaseGenericA lt ClassA  ClassB gt      42        Assert IsTrue typeof ChildGenericA  IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      43        Assert IsFalse typeof ChildGenericA  IsSubClassOfGeneric typeof IWrongBaseGenericA lt ClassA  ClassB gt      44        Assert IsTrue typeof IChildGenericA  IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      45        Assert IsFalse typeof BaseGenericA lt ClassA  ClassB gt   IsSubClassOfGeneric typeof ChildGenericA2 lt ClassA  ClassB gt      46        Assert IsTrue typeof ChildGenericA2 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof BaseGenericA lt ClassA  ClassB gt      47        Assert IsFalse typeof ChildGenericA  IsSubClassOfGeneric typeof ChildGenericA     48        Assert IsFalse typeof IChildGenericA  IsSubClassOfGeneric typeof IChildGenericA     49        Assert IsFalse typeof IBaseGenericA lt   gt   IsSubClassOfGeneric typeof IChildGenericA2 lt   gt      50        Assert IsTrue typeof IChildGenericA2 lt   gt   IsSubClassOfGeneric typeof IBaseGenericA lt   gt      51        Assert IsTrue typeof IChildGenericA2 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt   gt      52        Assert IsFalse typeof IBaseGenericA lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IChildGenericA2 lt ClassA  ClassB gt      53        Assert IsTrue typeof IChildGenericA2 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      54        Assert IsFalse typeof IBaseGenericA lt ClassA  ClassB gt   IsSubClassOfGeneric typeof BaseGenericA lt ClassA  ClassB gt      55        Assert IsTrue typeof BaseGenericA lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      56        Assert IsFalse typeof IBaseGenericA lt   gt   IsSubClassOfGeneric typeof BaseGenericA lt   gt      57        Assert IsTrue typeof BaseGenericA lt   gt   IsSubClassOfGeneric typeof IBaseGenericA lt   gt      58        Assert IsTrue typeof BaseGenericA lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt   gt      59        Assert IsFalse typeof IBaseGenericA lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      60        Assert IsTrue typeof BaseGenericA2 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      61        Assert IsFalse typeof IBaseGenericA lt   gt   IsSubClassOfGeneric typeof BaseGenericA2 lt   gt      62        Assert IsTrue typeof BaseGenericA2 lt   gt   IsSubClassOfGeneric typeof IBaseGenericA lt   gt      63        Assert IsTrue typeof BaseGenericA2 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt   gt      64        Assert IsFalse typeof BaseGenericA2 lt ClassB  ClassA gt   IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      65        Assert IsFalse typeof BaseGenericA lt ClassB  ClassA gt   IsSubClassOfGeneric typeof ChildGenericA2 lt ClassA  ClassB gt      66        Assert IsFalse typeof BaseGenericA2 lt ClassB  ClassA gt   IsSubClassOfGeneric typeof BaseGenericA lt ClassA  ClassB gt      67        Assert IsTrue typeof ChildGenericA3 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof BaseGenericB lt ClassA  ClassB  ClassC gt      68        Assert IsTrue typeof ChildGenericA4 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericB lt ClassA  ClassB  ClassC gt      69        Assert IsFalse typeof ChildGenericA3 lt ClassB  ClassA gt   IsSubClassOfGeneric typeof BaseGenericB lt ClassA  ClassB  ClassC gt      68-2        Assert IsTrue typeof ChildGenericA3 lt ClassA  ClassB2 gt   IsSubClassOfGeneric typeof BaseGenericB lt ClassA  ClassB  ClassC gt      68-3        Assert IsFalse typeof ChildGenericA3 lt ClassB2  ClassA gt   IsSubClassOfGeneric typeof BaseGenericB lt ClassA  ClassB  ClassC gt      68-4        Assert IsFalse typeof ChildGenericA4 lt ClassB  ClassA gt   IsSubClassOfGeneric typeof IBaseGenericB lt ClassA  ClassB  ClassC gt      69-2        Assert IsTrue typeof ChildGenericA4 lt ClassA  ClassB2 gt   IsSubClassOfGeneric typeof IBaseGenericB lt ClassA  ClassB  ClassC gt      69-3        Assert IsFalse typeof ChildGenericA4 lt ClassB2  ClassA gt   IsSubClassOfGeneric typeof IBaseGenericB lt ClassA  ClassB  ClassC gt      69-4        Assert IsFalse typeof bool  IsSubClassOfGeneric typeof IBaseGenericB lt ClassA  ClassB  ClassC gt      70        Classes and interfaces for testing    public class Class1     public class BaseGeneric lt T gt    IBaseGeneric lt T gt      public class BaseGeneric2 lt T gt    IBaseGeneric lt T gt   IInterfaceBidon     public interface IBaseGeneric lt T gt      public class ChildGeneric   BaseGeneric lt Class1 gt      public interface IChildGeneric   IBaseGeneric lt Class1 gt      public class ChildGeneric2 lt Class1 gt    BaseGeneric lt Class1 gt      public interface IChildGeneric2 lt Class1 gt    IBaseGeneric lt Class1 gt       public class WrongBaseGeneric lt T gt      public interface IWrongBaseGeneric lt T gt       public interface IInterfaceBidon      public class ClassA     public class ClassB     public class ClassC     public class ClassB2   ClassB     public class BaseGenericA lt T  U gt    IBaseGenericA lt T  U gt      public class BaseGenericB lt T  U  V gt      public interface IBaseGenericB lt ClassA  ClassB  ClassC gt      public class BaseGenericA2 lt T  U gt    IBaseGenericA lt T  U gt   IInterfaceBidonA     public interface IBaseGenericA lt T  U gt      public class ChildGenericA   BaseGenericA lt ClassA  ClassB gt      public interface IChildGenericA   IBaseGenericA lt ClassA  ClassB gt      public class ChildGenericA2 lt ClassA  ClassB gt    BaseGenericA lt ClassA  ClassB gt      public class ChildGenericA3 lt ClassA  ClassB gt    BaseGenericB lt ClassA  ClassB  ClassC gt      public class ChildGenericA4 lt ClassA  ClassB gt    IBaseGenericB lt ClassA  ClassB  ClassC gt      public interface IChildGenericA2 lt ClassA  ClassB gt    IBaseGenericA lt ClassA  ClassB gt       public class WrongBaseGenericA lt T  U gt      public interface IWrongBaseGenericA lt T  U gt       public interface IInterfaceBidonA

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JaredPar s code works but only for one level of inheritance   For unlimited levels of inheritance  use the following code  public bool IsTypeDerivedFromGenericType Type typeToCheck  Type genericType        if  typeToCheck    typeof object                 return false            else if  typeToCheck    null                return false            else if  typeToCheck IsGenericType  amp  amp  typeToCheck GetGenericTypeDefinition      genericType                return true            else               return IsTypeDerivedFromGenericType typeToCheck BaseType  genericType

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I worked through some of these samples and found they were lacking in some cases  This version works with all kinds of generics  types  interfaces and type definitions thereof   public static bool InheritsOrImplements this Type child  Type parent        parent   ResolveGenericTypeDefinition parent        var currentChild   child IsGenericType                              child GetGenericTypeDefinition                                child       while  currentChild    typeof  object                 if  parent    currentChild    HasAnyInterfaces parent  currentChild               return true           currentChild   currentChild BaseType    null                         amp  amp  currentChild BaseType IsGenericType                              currentChild BaseType GetGenericTypeDefinition                                currentChild BaseType           if  currentChild    null              return false            return false     private static bool HasAnyInterfaces Type parent  Type child        return child GetInterfaces            Any childInterface   gt                        var currentInterface   childInterface IsGenericType                   childInterface GetGenericTypeDefinition                     childInterface               return currentInterface    parent                 private static Type ResolveGenericTypeDefinition Type parent        var shouldUseGenericType   true      if  parent IsGenericType  amp  amp  parent GetGenericTypeDefinition      parent          shouldUseGenericType   false       if  parent IsGenericType  amp  amp  shouldUseGenericType          parent   parent GetGenericTypeDefinition        return parent      Here are the unit tests also   protected interface IFooInterface      protected interface IGenericFooInterface lt T gt       protected class FooBase      protected class FooImplementor       FooBase  IFooInterface      protected class GenericFooBase       FooImplementor  IGenericFooInterface lt object gt        protected class GenericFooImplementor lt T gt        FooImplementor  IGenericFooInterface lt T gt         Test  public void Should inherit or implement non generic interface         Assert That typeof FooImplementor           InheritsOrImplements typeof IFooInterface    Is True       Test  public void Should inherit or implement generic interface         Assert That typeof GenericFooBase           InheritsOrImplements typeof IGenericFooInterface lt  gt     Is True       Test  public void Should inherit or implement generic interface by generic subclass         Assert That typeof GenericFooImplementor lt  gt            InheritsOrImplements typeof IGenericFooInterface lt  gt     Is True       Test  public void Should inherit or implement generic interface by generic subclass not caring about generic type parameter         Assert That new GenericFooImplementor lt string gt    GetType            InheritsOrImplements typeof IGenericFooInterface lt  gt     Is True       Test  public void Should not inherit or implement generic interface by generic subclass not caring about generic type parameter         Assert That new GenericFooImplementor lt string gt    GetType            InheritsOrImplements typeof IGenericFooInterface lt int gt     Is False       Test  public void Should inherit or implement non generic class         Assert That typeof FooImplementor           InheritsOrImplements typeof FooBase    Is True       Test  public void Should inherit or implement any base type         Assert That typeof GenericFooImplementor lt  gt            InheritsOrImplements typeof FooBase    Is True

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Reposted due to a massive rewrite   JaredPar s code answer is fantastic  but I have a tip that would make it unnecessary if your generic types are not based on value type parameters   I was hung up on why the  is  operator would not work  so I have also documented the results of my experimentation for future reference   Please enhance this answer to further enhance its clarity    TIP   If you make certain that your GenericClass implementation inherits from an abstract non-generic base class such as GenericClassBase  you could ask the same question without any trouble at all like this   typeof Test  IsSubclassOf typeof GenericClassBase       IsSubclassOf    My testing indicates that IsSubclassOf   does not work on parameterless generic types such as   typeof GenericClass lt  gt     whereas it will work with   typeof GenericClass lt SomeType gt     Therefore the following code will work for any derivation of GenericClass lt    assuming you are willing to test based on SomeType   typeof Test  IsSubclassOf typeof GenericClass lt SomeType gt      The only time I can imagine that you would want to test by GenericClass lt   is in a plug-in framework scenario     Thoughts on the  is  operator  At design-time C  does not allow the use of parameterless generics because they are essentially not a complete CLR type at that point   Therefore  you must declare generic variables with parameters  and that is why the  is  operator is so powerful for working with objects   Incidentally  the  is  operator also can not evaluate parameterless generic types   The  is  operator will test the entire inheritance chain  including interfaces     So  given an instance of any object  the following method will do the trick   bool IsTypeof lt T gt  object t        return  t is T       This is sort of redundant  but I figured I would go ahead and visualize it for everybody     Given   var t   new Test      The following lines of code would return true   bool test1   IsTypeof lt GenericInterface lt SomeType gt  gt  t    bool test2   IsTypeof lt GenericClass lt SomeType gt  gt  t    bool test3   IsTypeof lt Test gt  t     On the other hand  if you want something specific to GenericClass  you could make it more specific  I suppose  like this   bool IsTypeofGenericClass lt SomeType gt  object t        return  t is GenericClass lt SomeType gt        Then you would test like this   bool test1   IsTypeofGenericClass lt SomeType gt  t

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It might be overkill but I use extension methods like the following   They check interfaces as well as subclasses   It can also return the type that has the specified generic definition   E g  for the example in the question it can test against generic interface as well as generic class   The returned type can be used with GetGenericArguments to determine that the generic argument type is  SomeType         lt summary gt      Checks whether this type has the specified definition in its ancestry       lt  summary gt     public static bool HasGenericDefinition this Type type  Type definition        return GetTypeWithGenericDefinition type  definition     null          lt summary gt      Returns the actual type implementing the specified definition from the     ancestry of the type  if available  Else  null       lt  summary gt  public static Type GetTypeWithGenericDefinition this Type type  Type definition        if  type    null          throw new ArgumentNullException  type        if  definition    null          throw new ArgumentNullException  definition        if   definition IsGenericTypeDefinition          throw new ArgumentException               The definition needs to be a GenericTypeDefinition    definition         if  definition IsInterface          foreach  var interfaceType in type GetInterfaces                if  interfaceType IsGenericType                  amp  amp  interfaceType GetGenericTypeDefinition      definition                  return interfaceType       for  Type t   type  t    null  t   t BaseType          if  t IsGenericType  amp  amp  t GetGenericTypeDefinition      definition              return t       return null

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Added to  jaredpar s answer  here s what I use to check for interfaces   public static bool IsImplementerOfRawGeneric this Type type  Type toCheck        if  toCheck GetTypeInfo   IsClass                return false             return type GetInterfaces   Any interfaceType   gt                var current   interfaceType GetTypeInfo   IsGenericType                       interfaceType GetGenericTypeDefinition     interfaceType          return current    toCheck             public static bool IsSubTypeOfRawGeneric this Type type  Type toCheck        return type IsInterface             IsImplementerOfRawGeneric type  toCheck            IsSubclassOfRawGeneric type  toCheck       Ex   Console WriteLine typeof IList lt  gt   IsSubTypeOfRawGeneric typeof IList lt int gt         true

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EnocNRoll - Ananda Gopal  s answer is interesting  but in case an instance is not instantiated beforehand or you want to check with a generic type definition  I d suggest this method    public static bool TypeIs this Type x  Type d        if null  d            return false             for var c   x  null  c  c c BaseType            var a   c GetInterfaces             for var i   a Length  i-- gt  0                 var t   i lt 0   c   a i                if t  d  t IsGenericType amp  amp t GetGenericTypeDefinition    d                    return true                                     return false      and use it like    var b   typeof char    TypeIs typeof IList lt  gt        true   There are four conditional cases when both t to be tested  and d are generic types and two cases are covered by t  d which are  1 neither t nor d is a generic definition or  2  both of them are generic definitions  The rest cases are one of them is a generic definition  only when d is already a generic definition we have the chance to say a t is a d but not vice versa    It should work with arbitrary classes or interfaces you want to test  and returns what as if you test an instance of that type with the is operator

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JaredPar   This did not work for me if I pass typeof type lt    as toCheck   Here s what I changed   static bool IsSubclassOfRawGeneric Type generic  Type toCheck        while  toCheck    typeof object             var cur   toCheck IsGenericType   toCheck GetGenericTypeDefinition     toCheck            if  cur IsGenericType  amp  amp  generic GetGenericTypeDefinition      cur GetGenericTypeDefinition                  return true                    toCheck   toCheck BaseType            return false

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Reposted due to a massive rewrite   JaredPar s code answer is fantastic  but I have a tip that would make it unnecessary if your generic types are not based on value type parameters   I was hung up on why the  is  operator would not work  so I have also documented the results of my experimentation for future reference   Please enhance this answer to further enhance its clarity    TIP   If you make certain that your GenericClass implementation inherits from an abstract non-generic base class such as GenericClassBase  you could ask the same question without any trouble at all like this   typeof Test  IsSubclassOf typeof GenericClassBase       IsSubclassOf    My testing indicates that IsSubclassOf   does not work on parameterless generic types such as   typeof GenericClass lt  gt     whereas it will work with   typeof GenericClass lt SomeType gt     Therefore the following code will work for any derivation of GenericClass lt    assuming you are willing to test based on SomeType   typeof Test  IsSubclassOf typeof GenericClass lt SomeType gt      The only time I can imagine that you would want to test by GenericClass lt   is in a plug-in framework scenario     Thoughts on the  is  operator  At design-time C  does not allow the use of parameterless generics because they are essentially not a complete CLR type at that point   Therefore  you must declare generic variables with parameters  and that is why the  is  operator is so powerful for working with objects   Incidentally  the  is  operator also can not evaluate parameterless generic types   The  is  operator will test the entire inheritance chain  including interfaces     So  given an instance of any object  the following method will do the trick   bool IsTypeof lt T gt  object t        return  t is T       This is sort of redundant  but I figured I would go ahead and visualize it for everybody     Given   var t   new Test      The following lines of code would return true   bool test1   IsTypeof lt GenericInterface lt SomeType gt  gt  t    bool test2   IsTypeof lt GenericClass lt SomeType gt  gt  t    bool test3   IsTypeof lt Test gt  t     On the other hand  if you want something specific to GenericClass  you could make it more specific  I suppose  like this   bool IsTypeofGenericClass lt SomeType gt  object t        return  t is GenericClass lt SomeType gt        Then you would test like this   bool test1   IsTypeofGenericClass lt SomeType gt  t

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Reposted due to a massive rewrite   JaredPar s code answer is fantastic  but I have a tip that would make it unnecessary if your generic types are not based on value type parameters   I was hung up on why the  is  operator would not work  so I have also documented the results of my experimentation for future reference   Please enhance this answer to further enhance its clarity    TIP   If you make certain that your GenericClass implementation inherits from an abstract non-generic base class such as GenericClassBase  you could ask the same question without any trouble at all like this   typeof Test  IsSubclassOf typeof GenericClassBase       IsSubclassOf    My testing indicates that IsSubclassOf   does not work on parameterless generic types such as   typeof GenericClass lt  gt     whereas it will work with   typeof GenericClass lt SomeType gt     Therefore the following code will work for any derivation of GenericClass lt    assuming you are willing to test based on SomeType   typeof Test  IsSubclassOf typeof GenericClass lt SomeType gt      The only time I can imagine that you would want to test by GenericClass lt   is in a plug-in framework scenario     Thoughts on the  is  operator  At design-time C  does not allow the use of parameterless generics because they are essentially not a complete CLR type at that point   Therefore  you must declare generic variables with parameters  and that is why the  is  operator is so powerful for working with objects   Incidentally  the  is  operator also can not evaluate parameterless generic types   The  is  operator will test the entire inheritance chain  including interfaces     So  given an instance of any object  the following method will do the trick   bool IsTypeof lt T gt  object t        return  t is T       This is sort of redundant  but I figured I would go ahead and visualize it for everybody     Given   var t   new Test      The following lines of code would return true   bool test1   IsTypeof lt GenericInterface lt SomeType gt  gt  t    bool test2   IsTypeof lt GenericClass lt SomeType gt  gt  t    bool test3   IsTypeof lt Test gt  t     On the other hand  if you want something specific to GenericClass  you could make it more specific  I suppose  like this   bool IsTypeofGenericClass lt SomeType gt  object t        return  t is GenericClass lt SomeType gt        Then you would test like this   bool test1   IsTypeofGenericClass lt SomeType gt  t

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Added to  jaredpar s answer  here s what I use to check for interfaces   public static bool IsImplementerOfRawGeneric this Type type  Type toCheck        if  toCheck GetTypeInfo   IsClass                return false             return type GetInterfaces   Any interfaceType   gt                var current   interfaceType GetTypeInfo   IsGenericType                       interfaceType GetGenericTypeDefinition     interfaceType          return current    toCheck             public static bool IsSubTypeOfRawGeneric this Type type  Type toCheck        return type IsInterface             IsImplementerOfRawGeneric type  toCheck            IsSubclassOfRawGeneric type  toCheck       Ex   Console WriteLine typeof IList lt  gt   IsSubTypeOfRawGeneric typeof IList lt int gt         true

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Here s a little method I created for checking that a object is derived from a specific type   Works great for me   internal static bool IsDerivativeOf this Type t  Type typeToCompare        if  t    null  throw new NullReferenceException        if  t BaseType    null  return false       if  t BaseType    typeToCompare  return true      else return t BaseType IsDerivativeOf typeToCompare

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JaredPar s code works but only for one level of inheritance   For unlimited levels of inheritance  use the following code  public bool IsTypeDerivedFromGenericType Type typeToCheck  Type genericType        if  typeToCheck    typeof object                 return false            else if  typeToCheck    null                return false            else if  typeToCheck IsGenericType  amp  amp  typeToCheck GetGenericTypeDefinition      genericType                return true            else               return IsTypeDerivedFromGenericType typeToCheck BaseType  genericType

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Try this code  static bool IsSubclassOfRawGeneric Type generic  Type toCheck        while  toCheck    null  amp  amp  toCheck    typeof object             var cur   toCheck IsGenericType   toCheck GetGenericTypeDefinition     toCheck          if  generic    cur                return true                    toCheck   toCheck BaseType            return false

User · Answer

Try this code  static bool IsSubclassOfRawGeneric Type generic  Type toCheck        while  toCheck    null  amp  amp  toCheck    typeof object             var cur   toCheck IsGenericType   toCheck GetGenericTypeDefinition     toCheck          if  generic    cur                return true                    toCheck   toCheck BaseType            return false

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This can all be done easily with linq   This will find any types that are a subclass of generic base class GenericBaseType       IEnumerable lt Type gt  allTypes   Assembly GetExecutingAssembly   GetTypes         IEnumerable lt Type gt  mySubclasses   allTypes Where t   gt  t BaseType    null                                                               amp  amp  t BaseType IsGenericType                                                              amp  amp  t BaseType GetGenericTypeDefinition      typeof GenericBaseType lt   gt

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JaredPar s code works but only for one level of inheritance   For unlimited levels of inheritance  use the following code  public bool IsTypeDerivedFromGenericType Type typeToCheck  Type genericType        if  typeToCheck    typeof object                 return false            else if  typeToCheck    null                return false            else if  typeToCheck IsGenericType  amp  amp  typeToCheck GetGenericTypeDefinition      genericType                return true            else               return IsTypeDerivedFromGenericType typeToCheck BaseType  genericType

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Reposted due to a massive rewrite   JaredPar s code answer is fantastic  but I have a tip that would make it unnecessary if your generic types are not based on value type parameters   I was hung up on why the  is  operator would not work  so I have also documented the results of my experimentation for future reference   Please enhance this answer to further enhance its clarity    TIP   If you make certain that your GenericClass implementation inherits from an abstract non-generic base class such as GenericClassBase  you could ask the same question without any trouble at all like this   typeof Test  IsSubclassOf typeof GenericClassBase       IsSubclassOf    My testing indicates that IsSubclassOf   does not work on parameterless generic types such as   typeof GenericClass lt  gt     whereas it will work with   typeof GenericClass lt SomeType gt     Therefore the following code will work for any derivation of GenericClass lt    assuming you are willing to test based on SomeType   typeof Test  IsSubclassOf typeof GenericClass lt SomeType gt      The only time I can imagine that you would want to test by GenericClass lt   is in a plug-in framework scenario     Thoughts on the  is  operator  At design-time C  does not allow the use of parameterless generics because they are essentially not a complete CLR type at that point   Therefore  you must declare generic variables with parameters  and that is why the  is  operator is so powerful for working with objects   Incidentally  the  is  operator also can not evaluate parameterless generic types   The  is  operator will test the entire inheritance chain  including interfaces     So  given an instance of any object  the following method will do the trick   bool IsTypeof lt T gt  object t        return  t is T       This is sort of redundant  but I figured I would go ahead and visualize it for everybody     Given   var t   new Test      The following lines of code would return true   bool test1   IsTypeof lt GenericInterface lt SomeType gt  gt  t    bool test2   IsTypeof lt GenericClass lt SomeType gt  gt  t    bool test3   IsTypeof lt Test gt  t     On the other hand  if you want something specific to GenericClass  you could make it more specific  I suppose  like this   bool IsTypeofGenericClass lt SomeType gt  object t        return  t is GenericClass lt SomeType gt        Then you would test like this   bool test1   IsTypeofGenericClass lt SomeType gt  t

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It seems to me that this implementation works in more cases  generic class and interface with or without initiated parameters  regardless of the number of child and parameters    public static class ReflexionExtension       public static bool IsSubClassOfGeneric this Type child  Type parent                if  child    parent              return false           if  child IsSubclassOf parent               return true           var parameters   parent GetGenericArguments            var isParameterLessGeneric     parameters    null  amp  amp  parameters Length  gt  0  amp  amp                parameters 0  Attributes  amp  TypeAttributes BeforeFieldInit     TypeAttributes BeforeFieldInit             while  child    null  amp  amp  child    typeof object                         var cur   GetFullTypeDefinition child               if  parent    cur     isParameterLessGeneric  amp  amp  cur GetInterfaces   Select i   gt  GetFullTypeDefinition i   Contains GetFullTypeDefinition parent                     return true              else if   isParameterLessGeneric                  if  GetFullTypeDefinition parent     cur  amp  amp   cur IsInterface                                        if  VerifyGenericArguments GetFullTypeDefinition parent   cur                           if  VerifyGenericArguments parent  child                               return true                                    else                     foreach  var item in child GetInterfaces   Where i   gt  GetFullTypeDefinition parent     GetFullTypeDefinition i                            if  VerifyGenericArguments parent  item                               return true               child   child BaseType                     return false             private static Type GetFullTypeDefinition Type type                return type IsGenericType   type GetGenericTypeDefinition     type             private static bool VerifyGenericArguments Type parent  Type child                Type   childArguments   child GetGenericArguments            Type   parentArguments   parent GetGenericArguments            if  childArguments Length    parentArguments Length              for  int i   0  i  lt  childArguments Length  i                    if  childArguments i  Assembly    parentArguments i  Assembly    childArguments i  Name    parentArguments i  Name    childArguments i  Namespace    parentArguments i  Namespace                      if   childArguments i  IsSubclassOf parentArguments i                            return false           return true            Here are my 70 76 test cases    TestMethod  public void IsSubClassOfGenericTest         Assert IsTrue typeof ChildGeneric  IsSubClassOfGeneric typeof BaseGeneric lt  gt       1        Assert IsFalse typeof ChildGeneric  IsSubClassOfGeneric typeof WrongBaseGeneric lt  gt       2        Assert IsTrue typeof ChildGeneric  IsSubClassOfGeneric typeof IBaseGeneric lt  gt       3        Assert IsFalse typeof ChildGeneric  IsSubClassOfGeneric typeof IWrongBaseGeneric lt  gt       4        Assert IsTrue typeof IChildGeneric  IsSubClassOfGeneric typeof IBaseGeneric lt  gt       5        Assert IsFalse typeof IWrongBaseGeneric lt  gt   IsSubClassOfGeneric typeof ChildGeneric2 lt  gt       6        Assert IsTrue typeof ChildGeneric2 lt  gt   IsSubClassOfGeneric typeof BaseGeneric lt  gt       7        Assert IsTrue typeof ChildGeneric2 lt Class1 gt   IsSubClassOfGeneric typeof BaseGeneric lt  gt       8        Assert IsTrue typeof ChildGeneric  IsSubClassOfGeneric typeof BaseGeneric lt Class1 gt       9        Assert IsFalse typeof ChildGeneric  IsSubClassOfGeneric typeof WrongBaseGeneric lt Class1 gt      10        Assert IsTrue typeof ChildGeneric  IsSubClassOfGeneric typeof IBaseGeneric lt Class1 gt      11        Assert IsFalse typeof ChildGeneric  IsSubClassOfGeneric typeof IWrongBaseGeneric lt Class1 gt      12        Assert IsTrue typeof IChildGeneric  IsSubClassOfGeneric typeof IBaseGeneric lt Class1 gt      13        Assert IsFalse typeof BaseGeneric lt Class1 gt   IsSubClassOfGeneric typeof ChildGeneric2 lt Class1 gt      14        Assert IsTrue typeof ChildGeneric2 lt Class1 gt   IsSubClassOfGeneric typeof BaseGeneric lt Class1 gt      15        Assert IsFalse typeof ChildGeneric  IsSubClassOfGeneric typeof ChildGeneric     16        Assert IsFalse typeof IChildGeneric  IsSubClassOfGeneric typeof IChildGeneric     17        Assert IsFalse typeof IBaseGeneric lt  gt   IsSubClassOfGeneric typeof IChildGeneric2 lt  gt      18        Assert IsTrue typeof IChildGeneric2 lt  gt   IsSubClassOfGeneric typeof IBaseGeneric lt  gt      19        Assert IsTrue typeof IChildGeneric2 lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt  gt      20        Assert IsFalse typeof IBaseGeneric lt Class1 gt   IsSubClassOfGeneric typeof IChildGeneric2 lt Class1 gt      21        Assert IsTrue typeof IChildGeneric2 lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt Class1 gt      22        Assert IsFalse typeof IBaseGeneric lt Class1 gt   IsSubClassOfGeneric typeof BaseGeneric lt Class1 gt      23        Assert IsTrue typeof BaseGeneric lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt Class1 gt      24        Assert IsFalse typeof IBaseGeneric lt  gt   IsSubClassOfGeneric typeof BaseGeneric lt  gt      25        Assert IsTrue typeof BaseGeneric lt  gt   IsSubClassOfGeneric typeof IBaseGeneric lt  gt      26        Assert IsTrue typeof BaseGeneric lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt  gt      27        Assert IsFalse typeof IBaseGeneric lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt Class1 gt      28        Assert IsTrue typeof BaseGeneric2 lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt Class1 gt      29        Assert IsFalse typeof IBaseGeneric lt  gt   IsSubClassOfGeneric typeof BaseGeneric2 lt  gt      30        Assert IsTrue typeof BaseGeneric2 lt  gt   IsSubClassOfGeneric typeof IBaseGeneric lt  gt      31        Assert IsTrue typeof BaseGeneric2 lt Class1 gt   IsSubClassOfGeneric typeof IBaseGeneric lt  gt      32        Assert IsTrue typeof ChildGenericA  IsSubClassOfGeneric typeof BaseGenericA lt   gt      33        Assert IsFalse typeof ChildGenericA  IsSubClassOfGeneric typeof WrongBaseGenericA lt   gt      34        Assert IsTrue typeof ChildGenericA  IsSubClassOfGeneric typeof IBaseGenericA lt   gt      35        Assert IsFalse typeof ChildGenericA  IsSubClassOfGeneric typeof IWrongBaseGenericA lt   gt      36        Assert IsTrue typeof IChildGenericA  IsSubClassOfGeneric typeof IBaseGenericA lt   gt      37        Assert IsFalse typeof IWrongBaseGenericA lt   gt   IsSubClassOfGeneric typeof ChildGenericA2 lt   gt      38        Assert IsTrue typeof ChildGenericA2 lt   gt   IsSubClassOfGeneric typeof BaseGenericA lt   gt      39        Assert IsTrue typeof ChildGenericA2 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof BaseGenericA lt   gt      40        Assert IsTrue typeof ChildGenericA  IsSubClassOfGeneric typeof BaseGenericA lt ClassA  ClassB gt      41        Assert IsFalse typeof ChildGenericA  IsSubClassOfGeneric typeof WrongBaseGenericA lt ClassA  ClassB gt      42        Assert IsTrue typeof ChildGenericA  IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      43        Assert IsFalse typeof ChildGenericA  IsSubClassOfGeneric typeof IWrongBaseGenericA lt ClassA  ClassB gt      44        Assert IsTrue typeof IChildGenericA  IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      45        Assert IsFalse typeof BaseGenericA lt ClassA  ClassB gt   IsSubClassOfGeneric typeof ChildGenericA2 lt ClassA  ClassB gt      46        Assert IsTrue typeof ChildGenericA2 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof BaseGenericA lt ClassA  ClassB gt      47        Assert IsFalse typeof ChildGenericA  IsSubClassOfGeneric typeof ChildGenericA     48        Assert IsFalse typeof IChildGenericA  IsSubClassOfGeneric typeof IChildGenericA     49        Assert IsFalse typeof IBaseGenericA lt   gt   IsSubClassOfGeneric typeof IChildGenericA2 lt   gt      50        Assert IsTrue typeof IChildGenericA2 lt   gt   IsSubClassOfGeneric typeof IBaseGenericA lt   gt      51        Assert IsTrue typeof IChildGenericA2 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt   gt      52        Assert IsFalse typeof IBaseGenericA lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IChildGenericA2 lt ClassA  ClassB gt      53        Assert IsTrue typeof IChildGenericA2 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      54        Assert IsFalse typeof IBaseGenericA lt ClassA  ClassB gt   IsSubClassOfGeneric typeof BaseGenericA lt ClassA  ClassB gt      55        Assert IsTrue typeof BaseGenericA lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      56        Assert IsFalse typeof IBaseGenericA lt   gt   IsSubClassOfGeneric typeof BaseGenericA lt   gt      57        Assert IsTrue typeof BaseGenericA lt   gt   IsSubClassOfGeneric typeof IBaseGenericA lt   gt      58        Assert IsTrue typeof BaseGenericA lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt   gt      59        Assert IsFalse typeof IBaseGenericA lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      60        Assert IsTrue typeof BaseGenericA2 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      61        Assert IsFalse typeof IBaseGenericA lt   gt   IsSubClassOfGeneric typeof BaseGenericA2 lt   gt      62        Assert IsTrue typeof BaseGenericA2 lt   gt   IsSubClassOfGeneric typeof IBaseGenericA lt   gt      63        Assert IsTrue typeof BaseGenericA2 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericA lt   gt      64        Assert IsFalse typeof BaseGenericA2 lt ClassB  ClassA gt   IsSubClassOfGeneric typeof IBaseGenericA lt ClassA  ClassB gt      65        Assert IsFalse typeof BaseGenericA lt ClassB  ClassA gt   IsSubClassOfGeneric typeof ChildGenericA2 lt ClassA  ClassB gt      66        Assert IsFalse typeof BaseGenericA2 lt ClassB  ClassA gt   IsSubClassOfGeneric typeof BaseGenericA lt ClassA  ClassB gt      67        Assert IsTrue typeof ChildGenericA3 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof BaseGenericB lt ClassA  ClassB  ClassC gt      68        Assert IsTrue typeof ChildGenericA4 lt ClassA  ClassB gt   IsSubClassOfGeneric typeof IBaseGenericB lt ClassA  ClassB  ClassC gt      69        Assert IsFalse typeof ChildGenericA3 lt ClassB  ClassA gt   IsSubClassOfGeneric typeof BaseGenericB lt ClassA  ClassB  ClassC gt      68-2        Assert IsTrue typeof ChildGenericA3 lt ClassA  ClassB2 gt   IsSubClassOfGeneric typeof BaseGenericB lt ClassA  ClassB  ClassC gt      68-3        Assert IsFalse typeof ChildGenericA3 lt ClassB2  ClassA gt   IsSubClassOfGeneric typeof BaseGenericB lt ClassA  ClassB  ClassC gt      68-4        Assert IsFalse typeof ChildGenericA4 lt ClassB  ClassA gt   IsSubClassOfGeneric typeof IBaseGenericB lt ClassA  ClassB  ClassC gt      69-2        Assert IsTrue typeof ChildGenericA4 lt ClassA  ClassB2 gt   IsSubClassOfGeneric typeof IBaseGenericB lt ClassA  ClassB  ClassC gt      69-3        Assert IsFalse typeof ChildGenericA4 lt ClassB2  ClassA gt   IsSubClassOfGeneric typeof IBaseGenericB lt ClassA  ClassB  ClassC gt      69-4        Assert IsFalse typeof bool  IsSubClassOfGeneric typeof IBaseGenericB lt ClassA  ClassB  ClassC gt      70        Classes and interfaces for testing    public class Class1     public class BaseGeneric lt T gt    IBaseGeneric lt T gt      public class BaseGeneric2 lt T gt    IBaseGeneric lt T gt   IInterfaceBidon     public interface IBaseGeneric lt T gt      public class ChildGeneric   BaseGeneric lt Class1 gt      public interface IChildGeneric   IBaseGeneric lt Class1 gt      public class ChildGeneric2 lt Class1 gt    BaseGeneric lt Class1 gt      public interface IChildGeneric2 lt Class1 gt    IBaseGeneric lt Class1 gt       public class WrongBaseGeneric lt T gt      public interface IWrongBaseGeneric lt T gt       public interface IInterfaceBidon      public class ClassA     public class ClassB     public class ClassC     public class ClassB2   ClassB     public class BaseGenericA lt T  U gt    IBaseGenericA lt T  U gt      public class BaseGenericB lt T  U  V gt      public interface IBaseGenericB lt ClassA  ClassB  ClassC gt      public class BaseGenericA2 lt T  U gt    IBaseGenericA lt T  U gt   IInterfaceBidonA     public interface IBaseGenericA lt T  U gt      public class ChildGenericA   BaseGenericA lt ClassA  ClassB gt      public interface IChildGenericA   IBaseGenericA lt ClassA  ClassB gt      public class ChildGenericA2 lt ClassA  ClassB gt    BaseGenericA lt ClassA  ClassB gt      public class ChildGenericA3 lt ClassA  ClassB gt    BaseGenericB lt ClassA  ClassB  ClassC gt      public class ChildGenericA4 lt ClassA  ClassB gt    IBaseGenericB lt ClassA  ClassB  ClassC gt      public interface IChildGenericA2 lt ClassA  ClassB gt    IBaseGenericA lt ClassA  ClassB gt       public class WrongBaseGenericA lt T  U gt      public interface IWrongBaseGenericA lt T  U gt       public interface IInterfaceBidonA

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It might be overkill but I use extension methods like the following   They check interfaces as well as subclasses   It can also return the type that has the specified generic definition   E g  for the example in the question it can test against generic interface as well as generic class   The returned type can be used with GetGenericArguments to determine that the generic argument type is  SomeType         lt summary gt      Checks whether this type has the specified definition in its ancestry       lt  summary gt     public static bool HasGenericDefinition this Type type  Type definition        return GetTypeWithGenericDefinition type  definition     null          lt summary gt      Returns the actual type implementing the specified definition from the     ancestry of the type  if available  Else  null       lt  summary gt  public static Type GetTypeWithGenericDefinition this Type type  Type definition        if  type    null          throw new ArgumentNullException  type        if  definition    null          throw new ArgumentNullException  definition        if   definition IsGenericTypeDefinition          throw new ArgumentException               The definition needs to be a GenericTypeDefinition    definition         if  definition IsInterface          foreach  var interfaceType in type GetInterfaces                if  interfaceType IsGenericType                  amp  amp  interfaceType GetGenericTypeDefinition      definition                  return interfaceType       for  Type t   type  t    null  t   t BaseType          if  t IsGenericType  amp  amp  t GetGenericTypeDefinition      definition              return t       return null

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late to the game on this    i too have yet another permutation of JarodPar s answer   here s Type IsSubClassOf Type  courtesy of reflector       public virtual bool IsSubclassOf Type c                Type baseType   this          if    baseType    c                         while  baseType    null                                if  baseType    c                                        return true                                    baseType   baseType BaseType                            return false                    return false          from that  we see that it s not doing anything too cray cray and is similar to JaredPar s iterative approach  so far  so good   here s my version  disclaimer  not thoroughly tested  so lemme know if you find issues       public static bool IsExtension this Type thisType  Type potentialSuperType                              protect ya neck                    if  thisType    null    potentialSuperType    null    thisType    potentialSuperType  return false                         don t need to traverse inheritance for interface extension  so check do these first                    if  potentialSuperType IsInterface                        foreach  var interfaceType in thisType GetInterfaces                                  var tempType   interfaceType IsGenericType   interfaceType GetGenericTypeDefinition     interfaceType                   if  tempType    potentialSuperType                                        return true                                                                   do the concrete type checks  iterating up the inheritance chain  as in orignal                    while  thisType    null  amp  amp  thisType    typeof object                         var cur   thisType IsGenericType   thisType GetGenericTypeDefinition     thisType               if  potentialSuperType    cur                                return true                             thisType   thisType BaseType                    return false          basically this is just an extension method to System Type - i did this to intentionally limit the  thisType  Type to concrete Types  as my immediate usage is to LINQ query  where  predicates against Type objects   i m sure all you smart folks out there could bang it down to an efficient  all-purpose static method if you need to     the code does a few things the answer s code doesn t   open s it up to to general  extension  - i m considering inheritance  think classes  as well as implementation  interfaces   method and parameter names are changed to better reflect this  input null-validation  meah  input of same type  a class cannot extend itself   short-circuit execution if Type in question is an interface  because GetInterfaces   returns all implemented interfaces  even ones implemented in super-classes   you can simply loop through that collection not having to climb the inheritance tree   the rest is basically the same as JaredPar s code

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I worked through some of these samples and found they were lacking in some cases  This version works with all kinds of generics  types  interfaces and type definitions thereof   public static bool InheritsOrImplements this Type child  Type parent        parent   ResolveGenericTypeDefinition parent        var currentChild   child IsGenericType                              child GetGenericTypeDefinition                                child       while  currentChild    typeof  object                 if  parent    currentChild    HasAnyInterfaces parent  currentChild               return true           currentChild   currentChild BaseType    null                         amp  amp  currentChild BaseType IsGenericType                              currentChild BaseType GetGenericTypeDefinition                                currentChild BaseType           if  currentChild    null              return false            return false     private static bool HasAnyInterfaces Type parent  Type child        return child GetInterfaces            Any childInterface   gt                        var currentInterface   childInterface IsGenericType                   childInterface GetGenericTypeDefinition                     childInterface               return currentInterface    parent                 private static Type ResolveGenericTypeDefinition Type parent        var shouldUseGenericType   true      if  parent IsGenericType  amp  amp  parent GetGenericTypeDefinition      parent          shouldUseGenericType   false       if  parent IsGenericType  amp  amp  shouldUseGenericType          parent   parent GetGenericTypeDefinition        return parent      Here are the unit tests also   protected interface IFooInterface      protected interface IGenericFooInterface lt T gt       protected class FooBase      protected class FooImplementor       FooBase  IFooInterface      protected class GenericFooBase       FooImplementor  IGenericFooInterface lt object gt        protected class GenericFooImplementor lt T gt        FooImplementor  IGenericFooInterface lt T gt         Test  public void Should inherit or implement non generic interface         Assert That typeof FooImplementor           InheritsOrImplements typeof IFooInterface    Is True       Test  public void Should inherit or implement generic interface         Assert That typeof GenericFooBase           InheritsOrImplements typeof IGenericFooInterface lt  gt     Is True       Test  public void Should inherit or implement generic interface by generic subclass         Assert That typeof GenericFooImplementor lt  gt            InheritsOrImplements typeof IGenericFooInterface lt  gt     Is True       Test  public void Should inherit or implement generic interface by generic subclass not caring about generic type parameter         Assert That new GenericFooImplementor lt string gt    GetType            InheritsOrImplements typeof IGenericFooInterface lt  gt     Is True       Test  public void Should not inherit or implement generic interface by generic subclass not caring about generic type parameter         Assert That new GenericFooImplementor lt string gt    GetType            InheritsOrImplements typeof IGenericFooInterface lt int gt     Is False       Test  public void Should inherit or implement non generic class         Assert That typeof FooImplementor           InheritsOrImplements typeof FooBase    Is True       Test  public void Should inherit or implement any base type         Assert That typeof GenericFooImplementor lt  gt            InheritsOrImplements typeof FooBase    Is True

User · Answer

Simple solution  just create and add a second  non-generic interface to the generic class   public interface IGenericClass      public class GenericClass lt T gt    GenericInterface lt T gt   IGenericClass       Then just check for that in any way you like using is  as  IsAssignableFrom  etc   if  thing is IGenericClass           Do work     Obviously only possible if you have the ability to edit the generic class  which the OP seems to have   but it s a bit more elegant and readable than using a cryptic extension method

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JaredPar   This did not work for me if I pass typeof type lt    as toCheck   Here s what I changed   static bool IsSubclassOfRawGeneric Type generic  Type toCheck        while  toCheck    typeof object             var cur   toCheck IsGenericType   toCheck GetGenericTypeDefinition     toCheck            if  cur IsGenericType  amp  amp  generic GetGenericTypeDefinition      cur GetGenericTypeDefinition                  return true                    toCheck   toCheck BaseType            return false

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You can try this extension      public static bool IsSubClassOfGenericClass this Type type  Type genericClass Type t                return type IsSubclassOf genericClass MakeGenericType new     t

User · Answer

Here s a little method I created for checking that a object is derived from a specific type   Works great for me   internal static bool IsDerivativeOf this Type t  Type typeToCompare        if  t    null  throw new NullReferenceException        if  t BaseType    null  return false       if  t BaseType    typeToCompare  return true      else return t BaseType IsDerivativeOf typeToCompare

User · Answer

This can all be done easily with linq   This will find any types that are a subclass of generic base class GenericBaseType       IEnumerable lt Type gt  allTypes   Assembly GetExecutingAssembly   GetTypes         IEnumerable lt Type gt  mySubclasses   allTypes Where t   gt  t BaseType    null                                                               amp  amp  t BaseType IsGenericType                                                              amp  amp  t BaseType GetGenericTypeDefinition      typeof GenericBaseType lt   gt

User · Answer

late to the game on this    i too have yet another permutation of JarodPar s answer   here s Type IsSubClassOf Type  courtesy of reflector       public virtual bool IsSubclassOf Type c                Type baseType   this          if    baseType    c                         while  baseType    null                                if  baseType    c                                        return true                                    baseType   baseType BaseType                            return false                    return false          from that  we see that it s not doing anything too cray cray and is similar to JaredPar s iterative approach  so far  so good   here s my version  disclaimer  not thoroughly tested  so lemme know if you find issues       public static bool IsExtension this Type thisType  Type potentialSuperType                              protect ya neck                    if  thisType    null    potentialSuperType    null    thisType    potentialSuperType  return false                         don t need to traverse inheritance for interface extension  so check do these first                    if  potentialSuperType IsInterface                        foreach  var interfaceType in thisType GetInterfaces                                  var tempType   interfaceType IsGenericType   interfaceType GetGenericTypeDefinition     interfaceType                   if  tempType    potentialSuperType                                        return true                                                                   do the concrete type checks  iterating up the inheritance chain  as in orignal                    while  thisType    null  amp  amp  thisType    typeof object                         var cur   thisType IsGenericType   thisType GetGenericTypeDefinition     thisType               if  potentialSuperType    cur                                return true                             thisType   thisType BaseType                    return false          basically this is just an extension method to System Type - i did this to intentionally limit the  thisType  Type to concrete Types  as my immediate usage is to LINQ query  where  predicates against Type objects   i m sure all you smart folks out there could bang it down to an efficient  all-purpose static method if you need to     the code does a few things the answer s code doesn t   open s it up to to general  extension  - i m considering inheritance  think classes  as well as implementation  interfaces   method and parameter names are changed to better reflect this  input null-validation  meah  input of same type  a class cannot extend itself   short-circuit execution if Type in question is an interface  because GetInterfaces   returns all implemented interfaces  even ones implemented in super-classes   you can simply loop through that collection not having to climb the inheritance tree   the rest is basically the same as JaredPar s code

User · Answer

Simple solution  just create and add a second  non-generic interface to the generic class   public interface IGenericClass      public class GenericClass lt T gt    GenericInterface lt T gt   IGenericClass       Then just check for that in any way you like using is  as  IsAssignableFrom  etc   if  thing is IGenericClass           Do work     Obviously only possible if you have the ability to edit the generic class  which the OP seems to have   but it s a bit more elegant and readable than using a cryptic extension method

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Type  type   myclass GetType    PropertyInfo    propertyInfos    type GetProperties    Boolean  test    propertyInfos 0  PropertyType GetGenericTypeDefinition       typeof List lt  gt

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Building on the excellent answer above by fir3rpho3nixx and David Schmitt  I have modified their code and added the ShouldInheritOrImplementTypedGenericInterface test  last one             lt summary gt          Find out if a child type implements or inherits from the parent type          The parent type can be an interface or a concrete class  generic or non-generic           lt  summary gt           lt param name  child  gt  lt  param gt           lt param name  parent  gt  lt  param gt           lt returns gt  lt  returns gt      public static bool InheritsOrImplements this Type child  Type parent                var currentChild   parent IsGenericTypeDefinition  amp  amp  child IsGenericType   child GetGenericTypeDefinition     child           while  currentChild    typeof object                         if  parent    currentChild    HasAnyInterfaces parent  currentChild                   return true               currentChild   currentChild BaseType    null  amp  amp  parent IsGenericTypeDefinition  amp  amp  currentChild BaseType IsGenericType                                   currentChild BaseType GetGenericTypeDefinition                                     currentChild BaseType               if  currentChild    null                  return false                    return false             private static bool HasAnyInterfaces Type parent  Type child                return child GetInterfaces   Any childInterface   gt                                var currentInterface   parent IsGenericTypeDefinition  amp  amp  childInterface IsGenericType                       childInterface GetGenericTypeDefinition                         childInterface                   return currentInterface    parent                               Test      public void ShouldInheritOrImplementNonGenericInterface                 Assert That typeof FooImplementor               InheritsOrImplements typeof IFooInterface    Is True               Test      public void ShouldInheritOrImplementGenericInterface                 Assert That typeof GenericFooBase               InheritsOrImplements typeof IGenericFooInterface lt  gt     Is True               Test      public void ShouldInheritOrImplementGenericInterfaceByGenericSubclass                 Assert That typeof GenericFooImplementor lt  gt                InheritsOrImplements typeof IGenericFooInterface lt  gt     Is True               Test      public void ShouldInheritOrImplementGenericInterfaceByGenericSubclassNotCaringAboutGenericTypeParameter                 Assert That new GenericFooImplementor lt string gt    GetType                InheritsOrImplements typeof IGenericFooInterface lt  gt     Is True               Test      public void ShouldNotInheritOrImplementGenericInterfaceByGenericSubclassNotCaringAboutGenericTypeParameter                 Assert That new GenericFooImplementor lt string gt    GetType                InheritsOrImplements typeof IGenericFooInterface lt int gt     Is False               Test      public void ShouldInheritOrImplementNonGenericClass                 Assert That typeof FooImplementor               InheritsOrImplements typeof FooBase    Is True               Test      public void ShouldInheritOrImplementAnyBaseType                 Assert That typeof GenericFooImplementor lt  gt                InheritsOrImplements typeof FooBase    Is True               Test      public void ShouldInheritOrImplementTypedGenericInterface                 GenericFooImplementor lt int gt  obj   new GenericFooImplementor lt int gt             Type t   obj GetType             Assert IsTrue t InheritsOrImplements typeof IGenericFooInterface lt int gt              Assert IsFalse t InheritsOrImplements typeof IGenericFooInterface lt String gt

[c#] Check if a class is derived from a generic class

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