post back issue

i have the following code, i have a method named bindgrid(),
when i call this method with
if (postback==false) bindgrid();
i dont any problem

but if i do it only like bindgrid on page load event
so my button command does not work and also my edit command in gridview
does not work , although its working with is postbak ==false ,
but can you please tell me that where is the actual problem ,,

thanks  , my code is bellow


<asp:ScriptManager ID="ScriptManager1" runat="server">
             </asp:ScriptManager>
    <asp:UpdatePanel id ="upanel" runat ="server">
    <ContentTemplate>
    
    <asp:GridView  ID="GridView1" runat="server"
      &nbs ...