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radConfirm button postback

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Dennis asked on 16 Nov 2009, 03:31 PM

This is probably simple but I'm not seeing why this won't work. I have button on a form declared as:

    
            <asp:button ID="CancelButton" runat="server" OnClick="CancelButton_Click" Text="Cancel" CssClass="btnNormal" OnClientClick="CancelTrainingSessionDialog(this); return false;"/>

At the top of the content control, I have this:

    
            <telerik:RadWindowManager ID="RadWindowManager1" runat="server">  
        
                        </telerik:RadWindowManager> 
        
            <telerik:RadCodeBlock ID="JavascriptRadCodeBlock" runat="server">  
        
             <script type="text/javascript">  
        
                 var cancelMessage = "Are you sure";  
        
                 var cancelTitle = "Cancel Title";  
        
                 function CancelTrainingSessionDialog(cancelButton) {  
        
                     radconfirm(cancelMessage, CancelTrainingSessionCallback);  
        
                 }  
        
                 function CancelTrainingSessionCallback(arg, cancelButton) {  
        
                     if (arg == true) {              
        
                         document.getElementById("CancelButton").click();     
        
                     }  
        
                 }  
        
             </script> 
        
            </telerik:RadCodeBlock>

Basically, I want the button to display the confirm and if the result is true, then I would like to process the code behind for the cancel button.
However, when I run this, and click OK in the confirmation dialog box, I get "Microsoft JScript runtime error: 'document.getElementById(...)' is null or not an object".

Any ideas on how to resolve this?
Thanks,
Dennis

13 Answers, 1 is accepted

answered on 17 Nov 2009, 03:23 PM

Princy and Georgi, thank you both for your help.

Georgi,
I have changed my callback method to closely resemble the one you suggested in this forum posting (http://www.telerik.com/community/forums/aspnet-ajax/window/radconfirm.aspx) dated Jul 6. Here is what my function looks like now:

    
             function CancelTrainingSessionCallback(arg, cancelButton) {  
        
                     if (arg == true) {  
        
                         document.getElementById("<%= CancelButton.ClientID %>").click();  
        
                        }

When I the confirm appears, clicking cancel dismisses it appropriately. Clicking OK does nothing (no errors, but the confirmation window continues to display).

Any thoughts as to why this isn't working?

Accepted

answered on 24 Nov 2009, 11:52 AM

Hi Dennis,

I just answered your support ticket and sent you the solution - the project helped me a lot to understand what was going on :)

For convenience I am pasting my reply below:

Thank you very much for the sample project - now I see what the problem is. I was under the impression that the button that you click programatically is a hidden button on the page that you use to execute the server-side function that you want, but now I see that this is actually the same button (Cancel).
What happens with your current code is:

You click on the button and the radconfirm dialog appears
You click OK in the confirm dialog which calls the client callback function
The client callback function programatically clicks that same Cancel button again
The radconfirm dialog appears again, because the button's OnClientClick is executed for the second time.

To avoid that loop, I suggest to use one of the following approaches:
Note: In both cases I changed the OnClientClick event handler to return the result from the JavaScript function and I cancel the postback there.
e.g.

<asp:Button ID="CancelButton" runat="server" OnClick="CancelButton_Click" Text="Cancel"

CssClass="btnNormal" OnClientClick="return CancelTrainingSessionDialog(this);" />

Approach #1 - Use ajaxRequestWithTarget with the RadAjaxPanel

var cancelMessage = "Are you sure";

var cancelTitle = "Cancel Title";

function CancelTrainingSessionDialog(cancelButton)

{

radconfirm(cancelMessage, CancelTrainingSessionCallback);

//cancel the postback here

return false;

}

function CancelTrainingSessionCallback(arg, cancelButton)

{

if (arg == true)

{

//document.getElementById("<%= CancelButton.ClientID %>").click();

var panel = $find("<%=TrainingQuestionsAjaxPanel.ClientID%>");

panel.ajaxRequestWithTarget("<%= CancelButton.UniqueID %>", "")

}

Approach #2 - use __doPostBack() instead of Ajax request: