Type GetType namespace a b ClassName returns null

Question

This code   Type GetType  namespace a b ClassName     returns null   and I have in the usings   using namespace a b    Update   The type exists  it s in a different class library  and i need to get it by string name

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Dictionary lt string  Type gt  typeCache      public static bool TryFindType string typeName  out Type t        lock  typeCache            if   typeCache TryGetValue typeName  out t                 foreach  Assembly a in AppDomain CurrentDomain GetAssemblies                      t   a GetType typeName                   if  t    null                      break                            typeCache typeName    t     perhaps null                     return t    null

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if your class is not in current assambly you must give qualifiedName and this code shows how to get qualifiedname of class  string qualifiedName   typeof YourClass  AssemblyQualifiedName    and then you can get type with qualifiedName  Type elementType   Type GetType qualifiedName

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You can also get the type without assembly qualified name but with the dll name also  for example   Type myClassType   Type GetType  TypeName DllName      I had the same situation and it worked for me  I needed an object of type  DataModel QueueObject  and had a reference to  DataModel  so I got the type as follows   Type type   Type GetType  DataModel QueueObject DataModel      The second string after the comma is the reference name  dll name

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I am opening user controls depending on what user controls the user have access to specified in a database  So I used this method to get the TypeName     Dim strType As String   GetType Namespace ClassName  AssemblyQualifiedName ToString Dim obj As UserControl   Activator CreateInstance Type GetType strType     So now one can use the value returned in strType to create an instance of that object

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Try this method  public static Type GetType string typeName        var type   Type GetType typeName       if  type    null  return type      foreach  var a in AppDomain CurrentDomain GetAssemblies                  type   a GetType typeName           if  type    null              return type            return null

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Make sure that the comma is directly after the fully qualified name  typeof namespace a b ClassName  AssemblyName    As this wont work  typeof namespace a b ClassName  AssemblyName    I was stumped for a few days on this one

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If the assembly is referenced and the Class visible    typeof namespace a b ClassName    GetType returns null because the type is not found  with typeof  the compiler may help you to find out the error

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If the assembly is part of the build of an ASP NET application  you can use the BuildManager class   using System Web Compilation     BuildManager GetType typeName  false

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Try using the full type name that includes the assembly info  for example   string typeName     MyCompany MyApp MyDomain MyClass  Version 1 0 0 0  Culture neutral  PublicKeyToken null   Type myClassType   Type GetType typeName     I had the same situation when I was using only the the namesspace classname to get the type of a class in a different assembly and it would not work   Only worked when I included the assembly info in my type string as shown above

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I cheated    Since the types I want to create  by name  are all in In a dll I control  I just put a static method in the dll in the assembly that takes a simple name  and calls type GetType from that context and returns the result   The original purpose was so that the type could be specified by name in configuration data    I ve since change the code so that the user specified a format to process    The format handler classes implement a interface that determines if the type can parse the specified format    I then use reflection to find types that implement the interface  and find one that handles the format    So now the configuration specifies a format name  a not a specific type   The reflection code can look at adjacent dlls and load  them so I have a sort poor man s plug-in architecture

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When I have only the class name I use this   Type obj   AppDomain CurrentDomain GetAssemblies   SelectMany t   gt  t GetTypes    Where t   gt  String Equals t Name   viewModelName  StringComparison Ordinal   First

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This solution above seems to be the best to me  but it didn t work for me  so I did it as follows   AssemblyName assemblyName   AssemblyName GetAssemblyName HttpContext Current Server MapPath     Bin  AnotherAssembly dll     string typeAssemblyQualifiedName   string Join        MyNamespace MyType   assemblyName FullName    Type myType   Type GetType typeAssemblyQualifiedName     The precondition is that you know the path of the assembly  In my case I know it because this is an assembly built from another internal project and its included in our project s bin folder   In case it matters I am using Visual Studio 2013  my target  NET is 4 0  This is an ASP NET project  so I am getting absolute path via HttpContext  However  absolute path is not a requirement as it seems from MSDN on AssemblyQualifiedNames

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For me  a     was the key  This is my class it is a nested one     namespace PortalServices   public class PortalManagement   WebService       public class Merchant              and this line of code worked   Type type   Type GetType  PortalServices PortalManagement Merchant

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Type GetType  namespace qualified TypeName   only works when the type is found in either mscorlib dll or the currently executing assembly   If neither of those things are true  you ll need an assembly-qualified name   Type GetType  namespace qualified TypeName  Assembly Name

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As Type GetType String  need the Type AssemblyQualifiedName you should use Assembly CreateQualifiedName String  String    string typeName    MyNamespace MyClass      Type FullName string assemblyName    MyAssemblyName      MyAssembly FullName or MyAssembly GetName   Name string assemblyQualifiedName   Assembly CreateQualifiedName assemblyName   typeName   Type myClassType   Type GetType assemblyQualifiedName     The Version  Culture and PublicKeyToken are not required for assemblyName that s why you can use MyAssembly GetName   Name   About Type GetType String        If the type is in the currently executing   assembly or in Mscorlib dll  it is sufficient to supply the type name   qualified by its namespace

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If it s a nested Type  you might be forgetting to transform a   to a    Regardless  typeof  T  FullName will tell you what you should be saying  EDIT  BTW the usings  as I m sure you know  are only directives to the compiler at compile time and cannot thus have any impact on the API call s success   If you had project or assembly references  that could potentially have had influence - hence the information isnt useless  it just takes some filtering

[c#] Type.GetType("namespace.a.b.ClassName") returns null

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