Question

I’m using the latest release of IKVM to ‘compile’ a Java .jar file into a .NET DLL. That all worked fine, and now I’m trying to reference the DLL in a .NET 3.5 C# project.

In my C# project, I’ve created an static ‘StringExtensions’ class with an extension method on string.

For some reason this seemed to work yesterday, but today, I’m getting a build error on my extension class (not sure how this worked yesterday…).

Missing compiler required member System.Runtime.CompilerServices.ExtensionAttribute..ctor 

And a build warning as well:

The predefined type 'System.Runtime.CompilerServices.ExtensionAttribute' is defined in multiple assemblies in the global alias; using definition from 'c:\TEMP\IKVM.Runtime.dll' 

I discovered that both IKVM.Runtime.dll and System.Core.dll (3.5 version) have the same type: ‘System.Runtime.CompilerServices.ExtensionAttribute’

Since the namespace is the same, how can I get this to compile with the System.Core version of ExtensionAttribute (or how can I fix this)?

Thanks

Answer 1

If you target .Net 2.0 you can only create extension methods if you define this attribute yourself. This works great until you move to .Net 3.5.

I don’t know ‘IKVM’ but the only real fix is to ask them to remove the attribute and target 3.5.