How to: Register a Component for COM Interop
The Register for COM interop project property specifies whether your managed application will expose a COM object (a COM-callable wrapper) that allows a COM object to interact with your managed application.
The Register for COM interop property is set on the Compile page of the Visual Basic Project Designer or the Build page of the C# Project Designer. This property is not available for Windows Application or Console Application projects.
To register a component for COM interop
With a project selected in Solution Explorer, on the Project menu, click Properties.
Click the Compile tab in Visual Basic. Click the Build tab in C#.
Select the Register for COM interop check box.