Calling an old OLE component from C#

Question

I have a very old (VC++ 5.0) proprietary DLL which I need to use from C# (Visual Studio 2010). The example specifies that to access this component I need to call CreateDispatch("application") which indicates towards OLE.

The following is the example code (C++):

IComponentServer Server;
Server.CreateDispatch("Component.Server");

I added a Reference through Visual Studio to the TLB file I have, and I can import its namespace successfully, but IComponentServer does not have any method called CreateDispatch.

What is the right approach to create the instance of an OLE component through C#?

Answer 1

MFC's CreateDispatch creates COM objects based on a CLSID or ProgId string. You can instantiate COM objects directly from C# code.

Assuming the Visual Studio reference gives you Interop.Component.dll:

IComponentServer server = new Interop.Component.ServerClass();

Answer 2

If you have either the CLSID or ProgID you can use the following set of methods.

var type = Type.GetTypeFromProgID(progIdString);
var obj = Activator.CreateInstance(type);
var server = (IComponentServer)obj;