onkeydown

function LetterUpperCase(event, flag,obj)//keypress
{
if (flag) {
var evt = event || window.event;
var nKeyCode = evt.keyCode || evt.which;
var sInput = obj.value;
if (nKeyCode >= 65 && nKeyCode <= 90) {
obj.value = sInput + String.fromCharCode(nKeyCode);
return false;
} else {
return true;
}
}

this.Attributes.Add("onkeydown", string.Format("return LetterUpperCase(event,{0},this);", this.UpperCase ? "true" : "false")); 会取消keypress事件

this.Attributes.Add("onkeydown", string.Format("LetterUpperCase(event,{0},this);", this.UpperCase ? "true" : "false")); 不会取消keypress事件