如何在执行Response.Redirect之前显示/隐藏面板

I have a form that kicks off a Response.Redirect to download a file once complete. I also want to hide the form and show a 'thank you' panel before the redirect takes place, however it seems the asp.net engine just does the redirect without doing the 2 tasks before in the following code:I have a form that kicks off a Response.Redirec