YUI dialog upload file problem

[Gee Bee]

Hi,

Im really hoping someone can help here - what im trying to do is have a form upload a file using AJAX with the YUI Dialog widget. The form is submited to an asp.net MVC application and all seems to work fine until the Json string is returned - IE7 then pops up a security warning box instead of processing the returned json encoded string. My js code is;

var dialog = new YAHOO.widget.Dialog("newFile",
							{
							    width: "30em",
							    fixedcenter: true,
							    visible: true,
							    constraintoviewport: true,
							    modal: true,
							    buttons: [{ text: "Submit", handler: PopupSubmit, isDefault: true },
								          { text: "Cancel", handler: PopupClose}]
							});

    dialog.setBody('<form id="uploadFile" enctype="multipart/form-data" method="post" action="/File/Upload">' +
			                '<label for="uploadedFile">File:</label> <input type="file" id="uploadedFile" name="uploadedFile" />' +
			                '<input type="hidden" name="assignToId" value="123" />' +
		                    '</form>')
    dialog.setHeader("Add a new File");

    dialog.callback.upload = processNewFile;
    dialog.render(document.body);

[Dharma]

What's the warning IE7 gives you?

[Gee Bee]

File Downlad - Security Warning

Do you want to save this file, or find a program onine to open it?
Name: 335d4fe3
Type: Unknown File Type

I also get this warning with Firefox

[Gee Bee]

Ok so it's been a while but today I went back to the problem and sorted it.

The problem is that if you use (as i did) the method Json(object data) in the base MVC Controller class it will return a json encoded string with the content type set to "application/json" - which is fine except that if you upload a file the browser expects you to return HTML.

All I've done to fix this is use the overloaded method Json(object data, string contentType), and set its value to something like;

Json(myData, "text/html");

and its fixed the problem.
Maybe this will help someone else too.