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Type.BaseType Property

  • Reference

Definition

Namespace:
System
Assembly:
System.Runtime.dll
Assembly:
mscorlib.dll
Assembly:
netstandard.dll
Source:
Type.CoreCLR.cs
Source:
Type.CoreCLR.cs
Source:
Type.CoreCLR.cs

Gets the type from which the current Type directly inherits.

public:
 abstract property Type ^ BaseType { Type ^ get(); };
public abstract Type? BaseType { get; }
public abstract Type BaseType { get; }
member this.BaseType : Type
Public MustOverride ReadOnly Property BaseType As Type

Property Value

Type

The Type from which the current Type directly inherits, or null if the current Type represents the Object class or an interface.

Implements

BaseType

Examples

The following example demonstrates using the BaseType property.

using namespace System;
void main()
{
   Type^ t = int::typeid;
   Console::WriteLine( "{0} inherits from {1}.", t, t->BaseType );
}

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

let t = typeof<int>
printfn $"{t} inherits from {t.BaseType}."

Class TestType
   
    Public Shared Sub Main()
        Dim t As Type = GetType(Integer)
        Console.WriteLine("{0} inherits from {1}.", t, t.BaseType)
    End Sub
End Class

The following example uses recursion to list the complete inheritance hierarchy of each class found in an assembly. The example defines a class named C that derives from a class named B, which, in turn, derives from a class named A.

using System;

public class Example
{
   public static void Main()
   {
      foreach (var t in typeof(Example).Assembly.GetTypes()) {
         Console.WriteLine("{0} derived from: ", t.FullName);
         var derived = t;
         do { 
            derived = derived.BaseType;
            if (derived != null) 
               Console.WriteLine("   {0}", derived.FullName);
         } while (derived != null);
         Console.WriteLine(); 
      } 
   }
}

public class A {} 

public class B : A
{}

public class C : B   
{}
// The example displays the following output:
//       Example derived from:
//          System.Object
//       
//       A derived from:
//          System.Object
//       
//       B derived from:
//          A
//          System.Object
//       
//       C derived from:
//          B
//          A
//          System.Object

type A() = class end 

type B() = inherit A()

type C() = inherit B()   

module Example =
    [<EntryPoint>]
    let main _ =
        for t in typeof<A>.Assembly.GetTypes() do
            printfn $"{t.FullName} derived from: "
            let mutable derived = t
            while derived <> null do
                derived <- derived.BaseType
                if derived <> null then 
                    printfn $"   {derived.FullName}"
            printfn ""
        0
// The example displays the following output:
//       Example derived from:
//          System.Object
//       
//       A derived from:
//          System.Object
//       
//       B derived from:
//          A
//          System.Object
//       
//       C derived from:
//          B
//          A
//          System.Object

Public Class Example
   Public Shared Sub Main()
      For Each t In GetType(Example).Assembly.GetTypes()
         Console.WriteLine("{0} derived from: ", t.FullName)
         Dim derived As Type = t
         Do 
            derived = derived.BaseType
            If derived IsNot Nothing Then 
               Console.WriteLine("   {0}", derived.FullName)
            End If   
         Loop While derived IsNot Nothing
         Console.WriteLine() 
      Next 
   End Sub
End Class

Public Class A 
End Class

Public Class B : Inherits A
End Class

Public Class C : Inherits B
End Class
' The example displays the following output:
'       Example derived from:
'          System.Object
'       
'       A derived from:
'          System.Object
'       
'       B derived from:
'          A
'          System.Object
'       
'       C derived from:
'          B
'          A
'          System.Object

Remarks

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 GetInterfaces or FindInterfaces.

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

generic<typename U> ref class B { };
generic<typename T> ref class C : B<T> { };

class B<U> { }
class C<T> : B<T> { }

type B<'U>() = class end
type C<'T>() = inherit B<'T>()

Class B(Of U)
End Class
Class C(Of T)
    Inherits B(Of T)
End Class

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

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

This property is read-only.

Applies to

See also