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Type.BaseType Property

Gets the type from which the current Type directly inherits.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

Public MustOverride ReadOnly Property BaseType As Type

Property Value

Type: System.Type
The Type from which the current Type directly inherits, or Nothing if the current Type represents the Object class or an interface.



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 Nothing is returned as the base type of Object.

Interfaces inherit from zero or more base interfaces; therefore, this property returns Nothing 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:

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.

The following example demonstrates using the BaseType property.

Imports System

Class TestType

    Public Shared Sub Main()
        Dim t As Type = GetType(Integer)
        Console.WriteLine("{0} inherits from {1}.", t, t.BaseType)
    End Sub 'Main
End Class 'TestType

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.

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
            derived = derived.BaseType
            If derived IsNot Nothing Then 
               Console.WriteLine("   {0}", derived.FullName)
            End If    
         Loop While derived IsNot Nothing
   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

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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