C# Telerik RadGrid subtract one automatically from column quantity when I press refresh
<p>I am using a Telerik RadGrid in ASP.Net framework.  I create Buy procedure and when I press (Buy) it must subtract 1 from the column quantity.  It works correctly but if I press F5 or refresh, it continues subtracting 1 by 1.  Every refresh subtracts 1 from the quantity.  How can i prevent that?  <a href="http://i.stack.imgur.com/U0fts.jpg" rel="nofollow">image description here</a></p>
