cast class into another class or convert class to another

Question

my question is shown in this code   I have class like that   public class  maincs     public int a    public int b    public int c    public int d      public class  sub1     public int a    public int b    public int c      public void methoda  sub1 model      maincs mdata   new maincs   a   model a   b   model b   c  model c             is there is a way to directly cast class sub1 into main like that       mdata    maincs  model

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I tried to use the Cast Extension  see https   stackoverflow com users 247402 stacker  in a situation where the Target Type contains a Property that is not present in the Source Type   It did not work  I m not sure why   I refactored to the following extension that did work for my situation  public static T Casting lt T gt  this Object source        Type sourceType   source GetType        Type targetType   typeof T       var target    Activator CreateInstance targetType  false       var sourceMembers   sourceType GetMembers            Where x   gt  x MemberType     MemberTypes Property           ToList        var targetMembers   targetType GetMembers            Where x   gt  x MemberType    MemberTypes Property           ToList        var members   targetMembers          Where x   gt  sourceMembers              Select y   gt  y Name                   Contains x Name        PropertyInfo propertyInfo      object value      foreach  var memberInfo in members                propertyInfo   typeof T  GetProperty memberInfo Name           value   source GetType   GetProperty memberInfo Name  GetValue source  null           propertyInfo SetValue target  value  null             return  T target     Note that I changed the name of the extension as the Name Cast conflicts with results from Linq   Hat tip https   stackoverflow com users 2093880 usefulbee

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You have already defined the conversion  you just need to take it one step further if you would like to be able to cast  For example    public class sub1       public int a      public int b      public int c       public static explicit operator maincs sub1 obj                maincs output   new maincs     a   obj a  b   obj b  c   obj c            return output            Which then allows you to do something like   static void Main         sub1 mySub   new sub1        maincs myMain    maincs mySub

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By using following code you can copy any class object to another class object for same name and same type of properties   public class CopyClass            lt summary gt          Copy an object to destination object  only matching fields will be copied          lt  summary gt           lt typeparam name  T  gt  lt  typeparam gt           lt param name  sourceObject  gt An object with matching fields of the destination object lt  param gt           lt param name  destObject  gt Destination object  must already be created lt  param gt      public static void CopyObject lt T gt  object sourceObject  ref T destObject                    If either the source  or destination is null  return         if  sourceObject    null    destObject    null              return               Get the type of each object         Type sourceType   sourceObject GetType            Type targetType   destObject GetType                 Loop through the source properties         foreach  PropertyInfo p in sourceType GetProperties                              Get the matching property in the destination object             PropertyInfo targetObj   targetType GetProperty p Name                   If there is none  skip             if  targetObj    null                  continue                   Set the value in the destination             targetObj SetValue destObject  p GetValue sourceObject  null   null                       Call Method Like   ClassA objA   new ClassA    ClassB objB   new ClassB     CopyClass CopyObject objOfferMast  ref objB     It will copy objA into objB

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What he wants to say is     If you have two classes which share most of the same properties you can cast an object from class a to class b and automatically make the system understand the assignment via the shared property names    Option 1  Use reflection   Disadvantage   It s gonna slow you down more than you think   Option 2  Make one class derive from another  the first one with common properties and other an extension of that   Disadvantage  Coupled  if your re doing that for two layers in your application then the two layers will be coupled   Let there be   class customer       public string firstname   get  set        public string lastname   get  set        public int age   get  set      class employee       public string firstname   get  set        public int age   get  set         Now here is an extension for Object type   public static T Cast lt T gt  this Object myobj        Type objectType   myobj GetType        Type target   typeof T       var x   Activator CreateInstance target  false       var z   from source in objectType GetMembers   ToList           where source MemberType    MemberTypes Property select source       var d   from source in target GetMembers   ToList           where source MemberType    MemberTypes Property select source      List lt MemberInfo gt  members   d Where memberInfo   gt  d Select c   gt  c Name          ToList   Contains memberInfo Name   ToList        PropertyInfo propertyInfo      object value      foreach  var memberInfo in members                propertyInfo   typeof T  GetProperty memberInfo Name           value   myobj GetType   GetProperty memberInfo Name  GetValue myobj null            propertyInfo SetValue x value null                return  T x        Now you use it like this   static void Main string   args        var cus   new customer        cus firstname    John       cus age   3      employee emp    cus Cast lt employee gt         Method cast checks common properties between two objects and does the assignment automatically

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There are some great answers here  I just wanted to add a little bit of type checking here as we cannot assume that if properties exist with the same name  that they are of the same type  Here is my offering  which extends on the previous  very excellent answer as I had a few little glitches with it   In this version I have allowed for the consumer to specify fields to be excluded  and also by default to exclude any database   model specific related properties       public static T Transform lt T gt  this object myobj  string excludeFields   null                   Compose a list of unwanted members         if  string IsNullOrWhiteSpace excludeFields               excludeFields   string Empty          excludeFields    string IsNullOrEmpty excludeFields    excludeFields         excludeFields          excludeFields       nameof DBTable ID    nameof DBTable InstanceID    nameof AuditableBase CreatedBy    nameof AuditableBase CreatedByID    nameof AuditableBase CreatedOn              var objectType   myobj GetType            var targetType   typeof T           var targetInstance   Activator CreateInstance targetType  false               Find common members by name         var sourceMembers   from source in objectType GetMembers   ToList                                     where source MemberType    MemberTypes Property                                   select source          var targetMembers   from source in targetType GetMembers   ToList                                     where source MemberType    MemberTypes Property                                   select source          var commonMembers   targetMembers Where memberInfo   gt  sourceMembers Select c   gt  c Name               ToList   Contains memberInfo Name   ToList                Remove unwanted members         commonMembers RemoveWhere x   gt  x Name InList excludeFields             foreach  var memberInfo in commonMembers                        if     PropertyInfo memberInfo  CanWrite  continue               var targetProperty   typeof T  GetProperty memberInfo Name               if  targetProperty    null  continue               var sourceProperty   myobj GetType   GetProperty memberInfo Name               if  sourceProperty    null  continue                  Check source and target types are the same             if  sourceProperty PropertyType Name    targetProperty PropertyType Name  continue               var value   myobj GetType   GetProperty memberInfo Name   GetValue myobj  null               if  value    null  continue                  Set the value             targetProperty SetValue targetInstance  value  null                     return  T targetInstance

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var obj     account Retrieve Email  hash    AccountInfoResponse accountInfoResponse   new AccountInfoResponse     if  obj    null                      accountInfoResponse       JsonConvert     DeserializeObject lt AccountInfoResponse gt      JsonConvert SerializeObject obj        image description

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Using this code you can copy any class object to another class object for same name and same type of properties   JavaScriptSerializer JsonConvert   new JavaScriptSerializer     string serializeString   JsonConvert Serialize objectEntity   objectViewModel objVM   JsonConvert Deserialize lt objectViewModel gt  serializeString

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You could change your class structure to   public class maincs   sub1      public int d      public class sub1      public int a     public int b     public int c      Then you could keep a list of sub1 and cast some of them to mainc

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You can provide an explicit overload for the cast operator   public static explicit operator maincs sub1 val        var ret   new maincs     a   val a  b   val b  c   val c        return ret      Another option would be to use an interface that has the a  b  and c properties and implement the interface on both of the classes   Then just have the parameter type to methoda be the interface instead of the class

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Use JSON serialization and deserialization  using Newtonsoft Json   Class1 obj1   new Class1    Class2 obj2   JsonConvert DeserializeObject lt Class2 gt  JsonConvert SerializeObject obj1      Or  public class Class1       public static explicit operator Class2 Class1 obj                return JsonConvert DeserializeObject lt Class2 gt  JsonConvert SerializeObject obj             Which then allows you to do something like Class1 obj1   new Class1    Class2 obj2    Class2 obj1

[c#] cast class into another class or convert class to another

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