The base type is the type from which the current type directly inherits. object is the only type that does not have a base type, therefore null is returned as the base type of object.

Interfaces inherit from zero or more base interfaces; therefore, this property returns null if the Type object represents an interface. The base interfaces can be determined with Type.GetInterfaces or Type.FindInterfaces(System.Reflection.TypeFilter, object).

If the current Type represents a constructed generic type, the base type reflects the generic arguments. For example, consider the following declarations:

code reference: System.Type.BaseType#1

For the constructed type C<int> (C(Of Integer) in Visual Basic), the Type.BaseType property returns B<int>.

If the current Type represents a type parameter of a generic type definition, Type.BaseType returns the class constraint, that is, the class the type parameter must inherit. If there is no class constraint, Type.BaseType returns object.

This property is read-only.

The following example demonstrates using the Type.BaseType property.

using System;
class TestType {
 public static void Main() {
 Type t = typeof(int);
 Console.WriteLine("{0} inherits from {1}", t,t.BaseType);
 }
}

The output is

System.Int32 inherits from System.ValueType