ModalPopupExtender, Object reference not set to an instance of an object error

Question

I am using an ASP button in a DataList control to pop up an AjaxPopupExtender. However the following error is being thrown:

Microsoft JScript runtime error: Sys.WebForms.PageRequestManagerServerErrorException: Object reference not set to an instance of an object.

Markup:

<asp:HiddenField ID="ModalPopUpHidden" runat="server" />
<cc1:ModalPopupExtender ID="mdlComments" runat="server"
    CancelControlID="btnCancelComment" PopupControlID="pnlComments" 
    TargetControlID="ModalPopUpHidden" PopupDragHandleControlID="PopupHeader"
    Drag="true" BackgroundCssClass="ModalPopupBG">
</cc1:ModalPopupExtender>
<asp:Panel ID="pnlComments" Style="display: none" runat="server">
    <div class="popup_Container">
        <div class="popup_Titlebar" id="PopupHeader">
            Comment
        </div>
        <div class="popup_Body">
            <asp:TextBox ID="txtPopupComment" runat="server" MaxLength="500"
                TextMode="MultiLine" Width="200" Height="200">
            </asp:TextBox>
        </div>
        <div class="popup_Buttons">
            <asp:Button id="btnSaveComment" type="button" value="Save" 
                runat="server" Text="Save" CommandName="SaveComment" />
            <input id="btnCancelComment" type="button" value="Cancel"/>         
        </div>
    </div>
</asp:Panel>

Code-Behind:

protected void dtListBids_ItemCommand(object source, DataListCommandEventArgs e)
{
    if (e.CommandName == "Comments")
    {
        AjaxControlToolkit.ModalPopupExtender mdlComments = 
            (AjaxControlToolkit.ModalPopupExtender)e.Item.FindControl("mdlComments");

        BidId = Convert.ToInt64(dtListBids.DataKeys[0]);
        mdlComments.Show();
    }
}

score 0 · Answer 1 · answered Oct 08 '12 at 04:50

0

The error you are getting is related to JavaScript due to failure of your AJAX call, exception at server-side.

Why don't you just debug your server-side code by setting breakpoints at the time of call to the server. By this activity you would exactly know where the exception has occurred.

answered Oct 08 '12 at 04:50

Furqan Safdar

16,260
13
59
93

I do and the ajax instance is not null. However on .Show() this error happens. – Sev Oct 08 '12 at 05:02
1

Then mdlComments variable must be null. And this means FindControl is unable to find the ModalPopupExtender control. Where have you placed ModalPopupExtender in the markup? – Furqan Safdar Oct 08 '12 at 07:09

score 0 · Accepted Answer · edited Oct 08 '12 at 05:36

0

I was able to resolve this by moving the markup in <li> tag next to the button that triggers this popup.

edited Oct 08 '12 at 05:36

ThiefMaster

310,957
84
592
636

answered Oct 08 '12 at 05:11

Sev

761
4
16
29

ModalPopupExtender, Object reference not set to an instance of an object error

2 Answers2