实现思路：需要在下拉框的onchage客户端事件做相关处理，并且需要在页面放置一个hidvalue放置下拉框改变之前的索引值，用于
在客户取消后回滚到之前选项。如果确定那么直接让下拉框进行提交 __doPostBack(“下拉框ID”,''); 具体实现代码如下：
aspx:
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
<script language="javascript">
function SelectedChange(ctl)
{
if(confirm("确认提交后台数据吗?") == false)
{
ctl.selectedIndex = document.getElementById('HidLastSelect').value;
return false;
}
else
{
document.getElementById('HidLastSelect').value = ctl.selectedIndex;
_doPostBack(''+ ctl.ClientID +'','');
}
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
<asp:ListItem>All</asp:ListItem>
<asp:ListItem>1</asp:ListItem>
<asp:ListItem>2</asp:ListItem>
</asp:DropDownList>
</div>
<input type="hidden" id="HidLastSelect" value="0" runat="server" />
</form>
</body>
</html>
cs:
public partial class Default3 : System.Web.UI.Page {
protected void Page_Load(object sender, EventArgs e) {
DropDownList1.Attributes.Add("onchange", "return SelectedChange(this)");
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) {
Response.Write("changed");
}
}