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 exposing COM components from Visual Basic. COM objects are very different from .NET Framework assemblies; without the ComClassAttribute, you need to follow a number of steps to generate a COM object from Visual Basic. For classes marked with ComClassAttribute, the compiler performs many of these steps automatically.
This attribute simplifies the creation of COM objects. To expose a class as 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 box.
Although you can also expose a class created with Visual Basic as a COM object for unmanaged code to use, it is not a true COM object. For details, see COM Interoperability in .NET Framework Applications.
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() MyBase.New() End Sub Function AddNumbers(ByVal X As Integer, ByVal Y As Integer) AddNumbers = X + Y End Function End Class
Assembly: Visual Basic Runtime Library (in Microsoft.VisualBasic.dll)