反射调用外部exe/dll

var filename = Server.MapPath(@"data/a.exe");
Assembly asm = System.Reflection.Assembly.LoadFile(filename);
Type type = asm.GetType("aaaa");
Object oper = Activator.CreateInstance(type);

object[] paras = new object[] { 'a','b'};
MethodInfo method = t.GetMethod("CreateSMS");
BindingFlags   flag   =   BindingFlags.Public   |   BindingFlags.Instance;

object result = method.Invoke(oper, flag, Type.DefaultBinder, paras, null);