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Use DefinePInvokeMethod method to create a PInvoke method

using System; using System.Text; using System.Reflection; using System.Reflection.Emit; using System.Runtime.InteropServices; public class Example {     public static void Main()     {         AssemblyName asmName = new AssemblyName("MyTest");                    AssemblyBuilder dynamicAsm = AppDomain.CurrentDomain.DefineDynamicAssembly(asmName,AssemblyBuilderAccess.RunAndSave);         ModuleBuilder dynamicMod = dynamicAsm.DefineDynamicModule(asmName.Name, asmName.Name + ".dll");         TypeBuilder tb = dynamicMod.DefineType("MyType",TypeAttributes.Public | TypeAttributes.UnicodeClass);         MethodBuilder mb = tb.DefinePInvokeMethod(             "MyCount",             "Kernel32.dll",             MethodAttributes.Public | MethodAttributes.Static | MethodAttributes.PinvokeImpl,             CallingConventions.Standard,             typeof(int),             Type.EmptyTypes,             CallingConvention.Winapi,             CharSet.Ansi);         mb.SetImplementationFlags(mb.GetMethodImplementationFlags() | MethodImplAttributes.PreserveSig);         Type t = tb.CreateType();         MethodInfo mi = t.GetMethod("MyCount");         Console.WriteLine(mi.Invoke(null, null));         Console.WriteLine(asmName.Name + ".dll");         dynamicAsm.Save(asmName.Name + ".dll");     } }