CS0246: The type or namespace name 'Dictionary' could not be found and CS0305: Using the generic type 'System.Collections.Generic.IDictionary' requires '2' type arguments

I had a piece of C# vendor code to install for authentication:

IDictionary userInfo = new Dictionary();
userInfo.Add(Agent.TOKEN_SUBJECT, sAMAccountName);
userInfo.Add(“domain”, domain);

Kept getting errors:

CS0246: The type or namespace name 'Dictionary' could not be found

CS0305: Using the generic type 'System.Collections.Generic.IDictionary' requires '2' type arguments

Turns out the vendor did not specify which classes to include, so I had to do a bit of digging.  I found some posts that said Dictionary was no longer being used in .NET 2.0 (not sure about that).  To resolve this, make sure you import the following in order to instantiate a Dictionary object with 2 params:

using System;
using System.Collections;
using System.Collections.Generic;

ASP.NET, .NET 2.0