Monday, April 11, 2011

How to get the namespace alias operator :: to work under C#?

I've come up against the unlikely scenario when I reference two external assemblies that both have the same namespace and type names. When I try to use the type, the compiler throws an error that it cannot resolve which one I want to use.

I see that C# offers a mechanism to use aliases for references. You can even specify these aliases via the Property window of a reference in Visual Studio 2008. How do I use this alias in my code? As I understand, I should be using the :: operator, but it fails with the following error:

CS0432 - Alias not found

The usual . operator fails as well.

In the output window I see that the compiler gets the alias passed correctly in its command line.

Any pointers on what I may be able to try next are greatly appreciated.

From stackoverflow
  • extern alias alias1;
    using alias1::Namespace;
    

    HTH, Kent

    RandomNickName42 : This can be used for a method to workaround around CS0433 ( C# compiler error ). http://msdn.microsoft.com/en-us/library/64wh5743(VS.100).aspx
    RandomNickName42 : I just noticed, it's 1 error number from "Gortok's" question here, funny.
  • Try this:

    extern alias asm1;
    extern alias asm2;
    
    namespace Client
    {
        class Program
        {
            static void Main(string[] args)
            {
                asm1.MyNs.MyClass mc1 = null;
                asm2.MyNs.MyClass mc2 = null;
            }
        }
    }
    

    And add global,asm1 to the project reference for assembly1 and global,asm2 for assembly2

  • I think you need to use an extern alias. Anson Horton has a good blog on this problem and how to use extern alias to fix it.

  • When you reference some assembly in project it has default alias "global". When you add another alias for that assembly, e.g. "global, AssemblyA", you will reference it like this:

    using SomeTypeAlias = AssemblyA::Company.Product.SomeType;
    

    or:

    void SomeMethod(AssemblyA::Company.Product.SomeType someType) { ... }
    

0 comments:

Post a Comment