How to fix ambiguous reference errors?

Question

I have a web app that allows importing of contacts from Hotmail, Yahoo and GMail. I finally have it almost completed but since I added the importing of GMail, I am getting ambiguous reference errors and I am unsure how to fix them without breaking any code.

Here is a screen shot of the errors:

Answer 1

1. Try to use unique class names as much as possible. This will be the better solution in the end.

2. Write the entire namespace when referencing

   OAuth.OAuthBase a = new ...;
   Google.GData.Client.OAuthBase b = new ...;
   

3. Make an using alias for one or both:

   using n2 = OAuth;
   using      Google.GData.Client;
   
   n2.OAuthBase a = new ...; // referenced using namespace
   OAuthBase b = new ...;    // referenced through existing `using`