SimpleModal breaks ASP.Net Postbacks

Question

I'm using jQuery and SimpleModal in an ASP.Net project to make some nice dialogs for a web app. Unfortunately, any buttons in a modal dialog can no longer execute their postbacks, which is not really acceptable.

There is one source I've found with a workaround, but for the life of me I can't get it to work, mostly because I am not fully understanding all of the necessary steps.

I also have a workaround, which is to replace the postbacks, but it's ugly and probably not the most reliable. I would really like to make the postbacks work again. Any ideas?

UPDATE: I should clarify, the postbacks are not working because the Javascript used to execute the post backs has broken in some way, so nothing happens at all when the button is clicked.

Answer 1

Both of you were on the right track. What I realized is that SimpleModal appends the dialog to the body, which is outside ASP.Net's <form>, which breaks the functionality, since it can't find the elements.

To fix it, I just modified the SimpleModal source to append eveything to 'form' instead of 'body'. When I create the dialog, I also use the persist: true option, to make sure the buttons stay through opening and closing.

Thanks everyone for the suggestions!

UPDATE: Version 1.3 adds an appendTo option in the configuration for specifying which element the modal dialog should be appended to. Here are the docs.

Answer 2

All standard ASP.NET postbacks work by calling a __doPostBack javascript method on the page. That function submits the form (ASP.NET only really likes one form per page) which includes some hidden input field in which all the viewstate and other goodness lives.

On the face of it I can't see anything in SimpalModal that would screw up your page's form or any of the standard hidden inputs, unless the contents of that modal happened to come from a HTTP GET to an ASP.NET page. That would result in two ASP.NET forms being rendered into one DOM and would would almost certainly screw up the __doPostBack function.

Have you considered using the ASP.NET AJAX ModalPopup control?

Answer 3

Web browsers will not POST any disabled or hidden form elements.

So what's happening is:

1. The user clicks on a button in your dialog.
2. The button calls SimpleModal's close() method, hiding the dialog and the button
3. The client POSTs the form (without the button's ID)
4. The ASP.NET framework can't figure out which button was clicked
5. Your server-side code doesn't get executed.

The solution is to do whatever you need to do on the client (closing the dialog in this case) and then call __doPostback() yourself.

For example (where "dlg" is the client-side SimpleModal dialog reference):

btn.OnClientClick = string.Format("{0}; dlg.close();",
                        ClientScript.GetPostBackEventReference(btn, null));

That should hide the dialog, submit the form, and call whatever server-side event you have for that button.

@Dan

All standard ASP.NET postbacks work by calling a __doPostBack javascript method on the page.

asp:Buttons do not call __doPostback() because HTML input controls already submit the form.

Answer 4

got caught out by this one - many thanks to tghw and all the other contributors on the appendto form instead of body fix. (resolved by attributes on the 1.3 version)

btw: If anyone needs to close the dialog programmatically from .net - you can use this type of syntax

private void CloseDialog()
{
    string script = string.Format(@"closeDialog()");
    ScriptManager.RegisterClientScriptBlock(this, typeof(Page), UniqueID, script, true);
}

where the javascript of closedialog is like this....

    function closeDialog() {
        $.modal.close();
    }