File uploads not working within jQuery UI Dialog

Question

So I have a rather odd issue that I wanted to see if anyone has some insight into.

I have a page in which I display a grid of files that have been uploaded to our server. The toolbar for the grid provides them with the ability to upload more files. When they click the "Add File" button on the toolbar, a jQuery UI Dialog modal window appears with a simple file upload control in it. After they select a file, they click the "Upload" button on the Dialog which submits the underlying form for uploading. Also note that because I'm using asp.net, there is only one form on the page so I'm not submitting the wrong form.

Now... when I attempt to look for uploaded files on the backend, no files are uploaded. What's worse, if I move the upload control out of the dialog div and use it straight from the page without a dialog, the uploads work fine.

This leads me to believe that even though I am defining the div that will become my dialog within the main form to allow it to submit with a postback, jQuery is somehow moving it or disassociating it from the form.

Is this possible? Or is there something else I may be missing? I can't seem to find any documentation that says either way. Thanks in advance!

Answer 1

You need to move the dialog to inside the form.

var dialog = $("#dialog").dialog({
  autoOpen: false,
  height: 300,
  width: 350,
  modal: true,
  buttons: {
    "Upload": function() {
      __doPostBack('uploadfile', '');
      $( this ).dialog( "close" );
    },
    Cancel: function() {
      $(this).dialog("close");
    }
  }
});

dialog.parent().appendTo($("form:first"));

Answer 2

You're right. Dialog moves its content outside of its form, and appends it to body. Probably to gain better control of the DOM, to make sure it always displays in the center, above everything else, and is not contained in some absolutely positioned DIV or so...