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copied!<p>Unusually if you really need this and don't mind throwing too much infrastructure at the problem, you can use <code>ldvirtftn</code> and <code>calli</code>.</p> <p>It seems very strange to me as that's what I thought was what a delegate did behind the scene basically do the following...</p> <pre><code>public class MyAction{ public virtual void Invoke(SomeClass @this) { ldarg.1 dup ldvirtftn SomeClass.GenericMethod<Int32> calli void *(argument) ret } </code></pre> <p><code>Ldvirtftn</code> does a look up to figure out the function pointer to be invoked for this particular method. If you use a non-virtual generic method the performance is about the same as a delegate bound to the same function. And if it is a virtual generic method its about twice as slow, that said its still works so that's quite an improvement.<br> I created this using reflection.emit and it seems to work just fine and it can invoke a closed virtual generic method. Unfortunately, unlike a delegate this type is bound to a specific method. However, quite a pain in the butt is that the runtime doesn't allow you to create a dynamic method that uses <code>ldvirtftn</code>,<code>ldftn</code>, or <code>calli</code> opcode. </p> <pre><code> public class SomeType { public virtual void DoNothing<T>() { Console.WriteLine(typeof(T)); } } public abstract class MyAction { public abstract void Invoke(SomeType type); } public static void Main(string[] args) { TypeBuilder builder = AppDomain.CurrentDomain .DefineDynamicAssembly(new AssemblyName(MethodBase.GetCurrentMethod().DeclaringType.Name), AssemblyBuilderAccess.RunAndCollect) .DefineDynamicModule("Module").DefineType("MyType", TypeAttributes.AnsiClass | TypeAttributes.AutoClass | TypeAttributes.Class | TypeAttributes.Public | TypeAttributes.Sealed, typeof (MyAction)); var ilgen = builder.DefineMethod("Invoke", MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.Final | MethodAttributes.Virtual, CallingConventions.HasThis, typeof (void), new[] {typeof (SomeType)}).GetILGenerator(); ilgen.Emit(OpCodes.Ldarg_1); ilgen.Emit(OpCodes.Dup); ilgen.Emit(OpCodes.Ldvirtftn, typeof (SomeType).GetMethod("DoNothing").MakeGenericMethod(typeof (int))); ilgen.Emit(OpCodes.Calli, SignatureHelper.GetMethodSigHelper(CallingConventions.HasThis, typeof (void))); ilgen.Emit(OpCodes.Ret); MyAction action = Activator.CreateInstance(builder.CreateType()) as MyAction; action.Invoke(new SomeType()); } </code></pre> <p>If you are okay with code generation you can use expression trees or dynamicmethod to just invoke the method. It's a little slower than a direct delegate but we're talking a tiny overhead. </p>

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