Hi Rashid,
You can use Row command event of grid view. I have put the row command event in your grid. you are having p_id and u_id . get that ids at row command and the save it to database. retrieve from database when you want.
<asp:GridView ID="Grid1" runat="server" BackColor="#DEBA84"
BorderColor="#DEBA84" BorderStyle="None" BorderWidth="1px" CellPadding="3"
CellSpacing="2" Width="90%" Height="10%"
AutoGenerateColumns="False"
AllowPaging="True" AllowSorting="True" PageSize="5"
onpageindexchanging="Grid1_PageIndexChanging"
onrowediting="Grid1_RowEditing" onrowupdating="Grid1_RowUpdating" OnRowCommand="Grid1_RowCommand"
DataKeyNames ="P_id, U_id" >