Get all inherited classes of an abstract class

Question

I have an abstract class   abstract class AbstractDataExport           public string name          public abstract bool ExportData        I have classes which are derived from AbstractDataExport   class XmlExport   AbstractDataExport       new public string name    XmlExporter       public override bool ExportData                             class CsvExport   AbstractDataExport       new public string name    CsvExporter       public override bool ExportData                               Is it possible to do something like this   Pseudocode    foreach  Implementation imp in Reflection GetInheritedClasses AbstractDataExport        AbstractDataExport derivedClass   Implementation CallConstructor        Console WriteLine derivedClass name      with an output like  CsvExporter XmlExporter      The idea behind this is to just create a new class which is derived from AbstractDataExport so i can iterate through all implementations automatically and add for example the names to a Dropdown-List  I just want to code the derived class without changing anything else in the project  recompile  bingo   If you have alternative solutions  tell em   Thanks

User · Accepted Answer

This is such a common problem  especially in GUI applications  that I m surprised there isn t a BCL class to do this out of the box  Here s how I do it   public static class ReflectiveEnumerator       static ReflectiveEnumerator            public static IEnumerable lt T gt  GetEnumerableOfType lt T gt  params object   constructorArgs  where T   class  IComparable lt T gt                List lt T gt  objects   new List lt T gt             foreach  Type type in              Assembly GetAssembly typeof T   GetTypes                Where myType   gt  myType IsClass  amp  amp   myType IsAbstract  amp  amp  myType IsSubclassOf typeof T                           objects Add  T Activator CreateInstance type  constructorArgs                      objects Sort            return objects            A few notes    Don t worry about the  cost  of this operation - you re only going to be doing it once  hopefully  and even then it s not as slow as you d think  You need to use Assembly GetAssembly typeof T   because your base class might be in a different assembly   You need to use the criteria type IsClass and  type IsAbstract because it ll throw an exception if you try to instantiate an interface or abstract class  I like forcing the enumerated classes to implement IComparable so that they can be sorted  Your child classes must have identical constructor signatures  otherwise it ll throw an exception  This typically isn t a problem for me

User · Answer

typeof AbstractDataExport  Assembly tells you an assembly your types are located in  assuming all are in the same    assembly GetTypes   gives you all types in that assembly or assembly GetExportedTypes   gives you types that are public   Iterating through the types and using type IsAssignableFrom   gives you whether the type is derived

User · Answer

It may not be the elegant way but you can iterate all classes in  the assembly and invoke  Type IsSubclassOf AbstractDataExport   for each one

User · Answer

Assuming they are all defined in the same assembly  you can do   IEnumerable lt AbstractDataExport gt  exporters   typeof AbstractDataExport       Assembly GetTypes        Where t   gt  t IsSubclassOf typeof AbstractDataExport    amp  amp   t IsAbstract       Select t   gt   AbstractDataExport Activator CreateInstance t

[c#] Get all inherited classes of an abstract class

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