Friend Assemblies in C#
- by Tim Long
I'm trying to create some 'friend assemblies' using the [InternalsVisibleTo()] attribute, but I can't seem to get it working. I've followed Microsoft's instructions for creating signed friend assemblies and I can't see where I'm going wrong. So I'll detail my steps here and hopefully someone can spot my deliberate mistake...?
Create a strong name key and extract the public key, thus:
sn -k StrongNameKey
sn -p public.pk
sn -tp public.pk
Add the strong name key to each project and enable signing.
Create a project called Internals and a class with an internal property:
namespace Internals
{
internal class ClassWithInternals
{
internal string Message { get; set; }
public ClassWithInternals(string m)
{
Message = m;
}
}
}
Create another project called TestInternalsVisibleTo:
namespace TestInternalsVisibleTo
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
var c = new Internals.ClassWithInternals("Test");
Console.WriteLine(c.Message);
}
}
}
Edit the AssemblyInfo.cs file for the Internals project, and add teh necessary attribute:
[assembly: AssemblyTitle("AssemblyWithInternals")]
[assembly: AssemblyDescription("")]
[assembly: AssemblyConfiguration("")]
[assembly: AssemblyCompany("Microsoft")]
[assembly: AssemblyProduct("Internals")]
[assembly: AssemblyCopyright("Copyright © Microsoft 2010")]
[assembly: AssemblyTrademark("")]
[assembly: AssemblyCulture("")]
[assembly: ComVisible(false)]
[assembly: Guid("41c590dc-f555-48bc-8a94-10c0e7adfd9b")]
[assembly: AssemblyVersion("1.0.0.0")]
[assembly: AssemblyFileVersion("1.0.0.0")]
[assembly: InternalsVisibleTo("TestInternalsVisibleTo PublicKey=002400000480000094000000060200000024000052534131000400000100010087953126637ab27cb375fa917c35b23502c2994bb860cc2582d39912b73740d6b56912c169e4a702bedb471a859a33acbc8b79e1f103667e5075ad17dffda58988ceaf764613bd56fc8f909f43a1b177172bc4143c96cf987274873626abb650550977dcad1bb9bfa255056bb8d0a2ec5d35d6f8cb0a6065ec0639550c2334b9")]
And finally... build!
I get the following errors:
error CS0122: 'Internals.ClassWithInternals' is inaccessible due to its protection level
error CS1729: 'Internals.ClassWithInternals' does not contain a constructor that takes 1 arguments
error CS1061: 'Internals.ClassWithInternals' does not contain a definition for 'Message' and no extension method 'Message' accepting a first argument of type 'Internals.ClassWithInternals' could be found (are you missing a using directive or an assembly reference?)
Basically, it's as if I had not used the InternalsVisibleTo attrbute. Now, I'm not going to fall into the trap of blaming the tools, so what's up here? Anyone?
