C# using alias as type parameter in other using alias

Question

I\'m trying to define a pair of type aliases at the top of my C# program. This is a short example of what I\'m trying to do:

using System;
using System.Colle         


        

Answer 1

Check documentation for this question:

https://msdn.microsoft.com/en-us/library/aa664765(v=vs.71).aspx

It says:

The order in which using-alias-directives are written has no significance, and resolution of the namespace-or-type-name referenced by a using-alias-directive is not affected by the using-alias-directive itself or by other using-directives in the immediately containing compilation unit or namespace body. In other words, the namespace-or-type-name of a using-alias-directive is resolved as if the immediately containing compilation unit or namespace body had no using-directives. In the example

namespace N1.N2 {}
namespace N3
{
   using R1 = N1;         // OK
   using R2 = N1.N2;      // OK
   using R3 = R1.N2;      // Error, R1 unknown
}

the last using-alias-directive results in a compile-time error because it is not affected by the first using-alias-directive.

Technically, you cannot do it same namespace, but if you do alias in namespace 1, and do alias for this alias in a nested namespace, it will work:

namespace N1
{
    namespace N12 { }
}

namespace N2
{
    using R1 = N1;

    namespace N2
    {
        using R2 = R1.N12;
    }
}

I am not really sure it's worth using aliases in your specific example, consider using them as rare as you can, mostly for resolving namespace conflicts.