Question

I am working on an add-on component that needs to play nice with other similar add-ons. There is a 3rd party component that decided to implement the functionality a little differently than the default.

What I am trying to do is call an overload of a method that only the 3rd party component has, like this:

Select Case True
    Case TypeOf provider Is 3rdParty.Provider
        result = DirectCast(provider, 3rdParty.Provider).GetNames(method, True)
    Case Else
        result = provider.GetNames(method)
End Select

Unfortunately, the DLL that contains 3rdParty.Provider is optional, so this code will give compile errors if it is not present. How can I accomplish the same thing but make it safe to run whether the 3rdParty.Provider.dll is present or not?

Answer 1

After some trial and error and going through several MSDN docs and forum posts, I was able to piece together the following solution:

Dim t As Type = Type.GetType("3rdParty.Provider, 3rdParty.Provider")
Select Case True
    Case Object.ReferenceEquals(provider.GetType(), t)
        result = Convert.ChangeType(provider, t).GetNames(method, True)
    Case Else
        result = provider.GetNames(method)
End Select

I tested removing the 3rd party DLL reference from my project and this works without a hitch and calls the default GetNames in that case without any exceptions or compile errors.