CommandName 有关问题

CommandName 问题
三个按扭,定义了三个CommandName,分别为a,b,c功能代码如下
 protected void Button1_Click(object sender, EventArgs e)
  {
  if (((Button)sender).CommandName == "a")
  {
  Response.Write("a");
  }
  if (((Button)sender).CommandName == "b")
  {
  Response.Write("b");
  }
  if (((Button)sender).CommandName == "c")
  {
  Response.Write("c");
  }
  }
问题:在点CommandName为a时要显示结果,其它两个就没反应,望高手指点

------解决方案--------------------------------------------------------
Button1.Click+=new EventHandler(Button1_Click);
Button2.Click+=new EventHandler(Button1_Click);
Button3.Click+=new EventHandler(Button1_Click);