Get type name of T using reflection

Question

I have:

public class MyUserControl : WebUserControlBase <MyDocumentType>{...}

How do I get the TypeName of MyDocumentType if I'm in another class?

Answer 1

You can use something like this:

typeof(MyUserControl).BaseType.GetGenericArguments()[0]

Answer 2

There are plenty answers showing how to get the type of T if you know that the class derives directly from WebUserControlBase<T>. Here's how to do it if you want to be able to go up the hierarchy until you encounter the WebUserControlBase<T>:

var t = typeof(MyUserControl);
while (!t.IsGenericType
    || t.GetGenericTypeDefinition() != typeof(WebUserControlBase<>))
{
    t = t.BaseType;
}

And then go on to get T by reflecting on the generic type arguments of t.

Since this is an example and not production code, I 'm not handling the case where t represents a type that does not derive from WebUserControlBase<T> at all.

Answer 3

If you are on .NET 4.5:

typeof(MyUserControl).BaseType.GenericTypeArguments.First();

Answer 4

You can use Type.GetGenericArguments method.

Returns an array of Type objects that represent the type arguments of a generic type or the type parameters of a generic type definition.

Like

typeof(MyUserControl).BaseType.GetGenericArguments()[0]

Since return type of this method is System.Type[], the array elements are returned in the order in which they appear in the list of type arguments for the generic type.