dropdownlist的OnSelectedIndexChanged怎么用确认窗口？

我想在dropdownlist选择时弹出确认窗口，但总是不行，我试了button却可以，不知为什么，
dropdownlist1.Attributes.Add("OnSelectedIndexChanged", "return confirm('Are you sure to change this line');")
button1.Attributes.Add("onclick", "return confirm('delete this line');")

8 个解决方案

#1

你可以直接在OnSelectedIndexChanged这个事件的代码里写

#2

怎么写呢

#3

在事件处理中写上这个代码

#4

it is not as simple as you would think, play with the following code:

<form runat="server">
<asp:DropDownList id=DropDownList1 runat=server OnSelectedIndexChanged="TestSel" AutoPostBack="true">
  <asp:ListItem Text="a" Value="0" />
  <asp:ListItem Text="b" Value="1" />
  <asp:ListItem Text="c" Value="2" />
  <asp:ListItem Text="d" Value="3" />
</asp:DropDownList>
</form>
<script language="C#" runat="server">
void TestSel(Object sender, EventArgs e)
{
  DropDownList ddl = (DropDownList)sender;
  Response.Write(ddl.SelectedItem.Value);
}
</script>
<%=DateTime.Now%>
<script language="javascript">
var nOld = -1;
var fnOldChange = null;
function testConfirm()
{
  return confirm('are you sure?');
}

function newChange()
{
  var ret = testConfirm();
  if (ret)
  {
if(fnOldChange != null)
fnOldChange();
else
nOld = event.srcElement.selectedIndex;
  }
  else
  {
if (nOld != -1)
event.srcElement.selectedIndex = nOld;
  }
}

function window.onload()
{
  var e = document.getElementById("DropDownList1");
  fnOldChange = e.onchange;
  e.onchange = newChange;
  nOld = e.selectedIndex;
}
</script>

#5

行是行，不过能不能全在后台写呢？我的dropdownlist 是动态产生的，放在datagrid中，所以最好是全在codebehind中，不知怎么写，谢了 saucer

#6

而且，我在datagrid中会有多个dropdownlist，例如10个，那这句 var e = document.getElementById("DropDownList1"); 怎么改

#7

这段代码能运行，给你借鉴。
private void Page_Load(object sender, System.EventArgs e)
{
// 在此处放置用户代码以初始化页面
StringBuilder script=new StringBuilder();
script.Append("<script language=javascript>\n");
script.Append("function OnSelectChange()\n");
script.Append("{\n");
script.Append("alert('你的选择是：'+document.all.DropDownList1.options[document.all.DropDownList1.selectedIndex].text);\n");
script.Append("\n}\n</script>");

RegisterClientScriptBlock("OnSelectIndexChange",script.ToString());
DropDownList1.Attributes.Add("OnChange","OnSelectChange()");
}

#8

for dropdownlists in a datagrid, you probably need to do the following (didn't test, so it might not work), of course, if you want to make them code behind, go ahead, it is not difficult:

<script language="javascript">
var nOldIndices = null;
var fnOldChange = null;
function testConfirm()
{
  return confirm('are you sure?');
}

function newChange()
{
  var ret = testConfirm();
  //find the index, here is a dumb but simple way, you could get the TD and then TR and get its rowIndex

  var e = event.srcElement;
  var selects = document.all("YourDataGrid").all.tags("SELECT");
  var i;
  for (i=0; i < selects.length; i++)
  {
        if (selects[i] == e)
           break;
  }

  var nIndex = i;

  if (ret)
  {
if(fnOldChange[nIndex] != null)
fnOldChange[nIndex]();
else
nOldIndices[nIndex] = e.selectedIndex;
  }
  else
  {
if (nOldIndices[nIndex] != -1)
e.selectedIndex = nOldIndices[nIndex];
  }
}

function window.onload()
{
  var selects = document.all("YourDataGrid").all.tags("SELECT");
  nOldIndices = new Array(selects.length);
  fnOldChange = new Array(selects.length);
  for(var i=0; i < nOldIndices.length; i++)
  {
    fnOldChange[i] = selects[i].onchange;
    selects[i].onchange = newChange;
    nOldIndices[i] = selects[i].selectedIndex;
  }
}
</script>

#1