JS中C＃var的asp.net值

Question

I have a simple JS pop up "are you sure..." window, along with a dropdownlist and asp:button . What I want when I click the button is to get this message:

"Are you sure you want to perform <%= ACTION %>?"

where ACTION is a string coming from dropdownlist.SelectedItem.Text.

The following does not seem to work:

OnClientClick="return confirm('Are you sure you want to perform <%= ACTION %>? );

It actually just prints the <%= ACTION %> instead of the value.

I have also tried:

function testMe() {
    return confirm('Are you sure you want to perform ' + document.getElementById('<%= hfAction.ClientID %>').value + '?');
}

OnClientClick="testMe();"

But the above causes postback regardless of clicking cancel or OK .

Which is the correct usage?

Answer 1

You can't use server tags inside of server control declarations. Set the OnClientClick script in the code behind when initialising the object.

mybutton.OnClientClick 
    = string.format("return confirm('Are you sure you want to perform {0}?');", ACTION);

Answer 2

Try this:

<asp:DropDownList runat="server" ID="ACTION">
    <asp:ListItem>Action 1</asp:ListItem>
    <asp:ListItem>Action 2</asp:ListItem>
</asp:DropDownList>

<script type="text/javascript">
    function ExecuteConfirm() {
        var ddlId = '<%= ACTION.UniqueID %>';
        var action = $("#" + ddlId + " option:selected").text();
        return confirm('Are you sure you want to perform ' + action + ' ?');
    }
</script>

<asp:Button runat="server" Text="Button" OnClientClick="return ExecuteConfirm();" />

Answer 3

Sorry, my last answer was complete garbage (didn't think before posting). What about this (you're almost right)?

function testMe() {
    var val = document.getElementById('<%= hfAction.ClientID %>').value;
    return confirm('Are you sure you want to perform ' + val + '?');
}

OnClientClick="return testMe();"

You just missed the return on the OnClientClick.