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How to Display RadDropDownList Dropdown Popup in AjaxControlToolkit ModalPopup Window
Updated on Oct 27, 2025
Environment
| Property | Value |
|---|---|
| Product | RadDropDownList for ASP.NET AJAX |
| Version | all |
Description
When using an AjaxControlToolkit modalpopup window, the RadDropDownList dropdown popup may not be displayed correctly.
Solution
To address this issue and ensure that the RadDropDownList dropdown popup is displayed correctly within the AjaxControlToolkit modalpopup window, you can follow these steps:
- Add the following JavaScript code to your page:
javascript
<script>
function popupOpening(sender, args) {
var popup = sender.get_dropDownElement();
setTimeout(function () {
popup.style.setProperty('z-index', '103000', 'important');
});
}
</script>
- Modify your RadDropDownList control by adding the
OnClientDropDownOpeningattribute and set it to thepopupOpeningJavaScript function:
html
<telerik:RadDropDownList ID="ddlMatch" runat="server" OnClientDropDownOpening="popupOpening">
<Items>
<telerik:DropDownListItem Value="1" Text="Item1" />
<telerik:DropDownListItem Value="2" Text="Item2" />
<telerik:DropDownListItem Value="3" Text="Item 3" />
</Items>
</telerik:RadDropDownList>
By implementing these steps, you will increase the z-index of the RadDropDownList dropdown popup, allowing it to be displayed correctly within the AjaxControlToolkit modalpopup window.