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ComClassAttribute Class

The ComClassAttribute attribute instructs the compiler to add metadata that allows a class to be exposed as a COM object.

<System.AttributeUsage(System.AttributeTargets.Class, _
   Inherited := False, AllowMultiple := False)> _
Public NotInheritable Class ComClassAttribute
   Inherits System.Attribute


Use ComClassAttribute to simplify the process of creating COM components from Visual Basic .NET. COM objects are considerably different from .NET assemblies, and without the ComClassAttribute, you need to follow a number of steps to generate a COM object from Visual Basic .NET. For classes marked with ComClassAttribute, the compiler performs many of these steps automatically.


To run this example, create a new Class Library application and add the following code to a class module.

<ComClass(ComClass1.ClassId, ComClass1.InterfaceId, ComClass1.EventsId)> _
Public Class ComClass1
   ' Use the Region directive to define a section named COM Guids. 
#Region "COM GUIDs"
   ' These  GUIDs provide the COM identity for this class 
   ' and its COM interfaces. You can generate 
   ' these guids using guidgen.exe
    Public Const ClassId As String = "7666AC25-855F-4534-BC55-27BF09D49D46"
    Public Const InterfaceId As String = "54388137-8A76-491e-AA3A-853E23AC1217"
    Public Const EventsId As String = "EA329A13-16A0-478d-B41F-47583A761FF2"
#End Region

   Public Sub New()
   End Sub

   Function AddNumbers(ByVal X As Integer, ByVal Y As Integer)
      AddNumbers = X + Y
   End Function
End Class
Note   This attribute simplifies the creation of COM objects. To create a COM object, you must compile the project with the Register for COM Interop option selected in the Build section of the Configuration Properties dialog.


Namespace: Microsoft.VisualBasic

Assembly: Microsoft Visual Basic .NET Runtime (in Microsoft.VisualBasic.dll)

See Also

Attributes | Applying Interop Attributes | ComClassAttribute Class Members | Walkthrough: Creating COM Objects with Visual Basic .NET | VBFixedArrayAttribute Class | VBFixedStringAttribute Class | Attributes Used in Visual Basic .NET | System.Runtime.InteropServices Namespace | Declaring Variables for Random File Access