.Net(c#)采用“晚期绑定”方式调用DLL

private void menuItem3_Click(object sender, System.EventArgs e)
  {
   
   Assembly asm = Assembly.LoadFrom(@Application.StartupPath+@"/CrystalDLL.dll");
   Type mytype = asm.GetType("CrystalDLL.DLLClass");
   MethodInfo mi = mytype.GetMethod("OpenFrmQXSZ");
   object obj = Activator.CreateInstance(mytype);
   mi.Invoke(obj,new object[] {this});
  }