Auto Button Click in Asp.net On Page Refresh

Reason is that the submitted data gets stored in viewstate and refreshing the page re-fires the click.

There are many possible solutions depending on what suits you:

1) Do a response.redirect to same page and it will remove cache and fresh page will load.

2) Use

Response.Cache.SetCacheability(HttpCacheability.NoCache);

in Page_Load event.

3) Use javascript like

document.onkeydown = function() 
{
           if(event.keyCode==116)
           {
               event.keyCode=0;
               event.returnValue = false;
           }
}

document.oncontextmenu = function() {event.returnValue = false;}