I didn't use the control in one of my projects for 2 weeks and now when I tried to upload I ran into an 500 Internal Server Error and the "Upload failed" string in Silverlight control.
I went on to investigate and installed ELMAH into the project to figure out the 500 Internal Server Error is actually this:
System.Web.HttpException (0x80004005): The URL-encoded form data is not valid. ---> System.InvalidOperationException: Operation is not valid due to the current state of the object.
at System.Web.HttpValueCollection.FillFromEncodedBytes(Byte bytes, Encoding encoding)
Of course, I investigated further and figured there was a MS security bulletin on the number of POSTed form entries in ASP.NET. I checked my updates and figured out this KB article update was installed a few day after I implemented the MVC sample (posting
I found out this supposed solution but it makes no difference for me:
<add key="aspnet:MaxHttpCollectionKeys" value="1000000"></add>
Do you have any idea what else I could try to fix this? Do you think the SL control could be changed to not POST such a large number of items (if that's even the root cause of this problem)?