title: ASP.Net display progress on long running task
body: <p>I have a button on a page that posts the page back to the server and generates a file that gets sent to the client. This process can sometimes take a few minutes to generate the file and I'd like to display some type of progress to the client. </p>
  
  <p>I currently have the long running process in a background thread and when the button is clicked, some javascript runs that hits a webservice every X seconds and returns a string of the progress (it's generating a PPTX so something like 'Completed slides X of Y').</p>
  
  <p>What's happening is when the page posts back, it keeps any of the webservice calls from being hit. Kind of like the long running process is still keeping the code from doing anything else even though it's in a background thread. I've run this locally and if I put a breakpoint in the webservice, it never gets hit until the process completes.</p>
  
  <p>How can I modify this to report back some information to the client on the process?</p>