Are you familiar with the following C# compilation error: “CS0104: ClassA is an ambiguous reference between Namespace1.ClassA and Namespace2.ClassA“? It happens when your program contains using directives for two namespaces and your code references a name that appears in both namespaces.

Lets work with a concrete example:

Have you ever tried using  the "Using" statement with a method and not a class?

We all have done the following:

   1: using(StreamReader s = new StreamReader(@"c:\Test.txt"))

   2: {

   3:     // Do stuff

   4: }

Whether you know it or not, the compiler translates that code to the following: