Question

I’m developing an asp.net application and I need to call a confirm dialog box on the code behind. And after that, I need to get the user’s click (if he clicked at OK or Cancel).

If he clicked the OK button of the dialog, I must continue to running the code where I stopped before call the dialog.

To solve this problem I thought in put at the aspx an input of type button, and set it’s style to visibility:hide. So, when the users click on the OK button the programm will call this hidden button which calls a method that will continue the job stopped.

I’ll post my code, I expect it might help.

The code below is on my code behind, and it calls the confirm dialog.

System.Web.UI.
    ScriptManager.RegisterClientScriptBlock(this, GetType(), "__Mensagem", "if (confirm('" + CustomMessage + "')){document.getElementById(\'<%=btnSave.ClientID%>\').click();}", true); 

The code below is on my aspx, it’s the “hidden” button.

<input style="visibility:hidden;" id="btnSave" runat="server" onclick="btnSave_Click"/>

I don’t know why isn’t working. The error that I receive after click on the button OK of the confirm dialog box is the following: Erro em tempo de execução do Microsoft JScript: ‘document.getElementByID(…)’ é nulo ou não é um objeto

I’m from Brazil so the error is in portuguese, a translation to english it’s something like this:

“A runtime error occurred on Microsoft JScript ‘document.getElementByID(…)’ is null or is not an object”

I give a look at the html code of the page and I notice that the button isn’t there.

Maybe it’s because I’m using an UpdatePanel, but when I removed it (just for tests, I must use the Update Panel), the same error is showed, and in this time the button were on the page’s html code.

Answer 1

I solved the problem replacing the part

document.getElementById(\'<%=btnSave.ClientID%>\').click();

by

$(\"#ctl00_body_btnSave\").click();

I also replace the input element by an asp:Button.

Give a look how my code is on my code behind now:

System.Web.UI.
    ScriptManager.RegisterClientScriptBlock(this, GetType(), "__Mensagem", "if (confirm('" + CustomMessage+ "')){$(\"#" + btnSave.ClientID + "\").click();}", true);

And on my aspx:

<asp:Button id="btnSave" Width="0px" Text="" runat="server" onclick="btnSave_Click"/>

The use of Widht=”0px” and Text=”” to hidden the button isn’t recommended, but I used because it won’t cause me problems. It’s recommended the use of a CssClass which make it hide.

So, if the user confirm the operation, the even btnSave_Click is called.

Thanks for all the answers.