C# interface static method call with generics

Try an extension method instead:

public interface IMyInterface
{
     string GetClassName();
}

public static class IMyInterfaceExtensions
{
    public static void PrintClassName<T>( this T input ) 
        where T : IMyInterface
    {
         Console.WriteLine(input.GetClassName());
    }
}

This allows you to add static extension/utility method, but you still need an instance of your IMyInterface implementation.

You can’t have interfaces for static methods because it wouldn’t make sense, they’re utility methods without an instance and hence they don’t really have a type.