The problem happens for "large" files. I re-produced it for files as small as 123,260 bytes (123 kilobytes!) even when FileSelect.MaxFileSize=223260 or MaxFileSize=int.MaxValue!
Is this by design in the FileSelect component to not support files greater than a hundred kilobytes, or am I doing something wrong? There is nothing in the documentation warning about such tiny file limits.
I can upload files of any size when I add this line to the code. It of course is a hack and the real problem is in the design of FileSelect and should be fixed there.
options.MaximumReceiveMessageSize = null;
Was this setting enabled by the Telerik engineers who tested the control? Because it is not in the default VS project and anyone creating a vanilla VS project and using FileSelect will not be able to use it with anything > 10-20kb or so :/
Another problem: (sometimes?) even when the file is uploaded successfully using all-default code, the uploaded file cannot be re-written because it remains locked despite the upload process finishing successfully. There is a place in the Telerik code that is opening the destination file and NOT disposing it properly.