这是一个比较通用的方法,可以用在网站的很多地方,建议大家Copy回去,欢迎大家提供更好的方法
public static void TieButton(Page page, Control TextBoxToTie,
Control ButtonToTie)
{
  // 初始化Jscript,实现原理是向客户端发送特定Jscript
  // ps.这种方法在其他地方也用得很多
  string jsString = "";
  // 检查输入框对应的事件按纽
  if (ButtonToTie is LinkButton)
  {
    jsString = "if ((event.which && event.which == 13) ||
(event.keyCode && event.keyCode == 13)) {"
        + page.ClientScript.GetPostBackEventReference
(ButtonToTie, "").Replace(":", "$") + ";return false;} else return true;";
  }
  else if (ButtonToTie is ImageButton)
  {
    jsString = "if ((event.which && event.which == 13) ||
(event.keyCode && event.keyCode == 13)) {"
        + page.ClientScript.GetPostBackEventReference
(ButtonToTie, "").Replace(":", "$") + ";return false;} else return true;";
  }
  else
  {
    jsString = "if ((event.which && event.which == 13) ||
(event.keyCode && event.keyCode == 13)) {document."
        + "forms[0].elements['" + ButtonToTie.UniqueID.Replace
(":", "_") + "'].click();return false;} else return true; ";
  }
  // 把 jscript 附加到输入框的onkeydown属性

  if (TextBoxToTie is HtmlControl)
  {
    ((HtmlControl)TextBoxToTie).Attributes.Add("onkeydown", jsString);
  }
  else if (TextBoxToTie is WebControl)
  {
    ((WebControl)TextBoxToTie).Attributes.Add("onkeydown", jsString);
  }
}