Code For itemtemplate
<asp:linkbutton id="LinkButton3" runat="server" commandname="passid" commandargument="<%# Bind("Id") %>" text='Select' xmlns:asp="#unknown"></asp:linkbutton>
protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
if (e.CommandName == "passid")
{
Session["id"] = e.CommandArgument.ToString();
Response.Redirect("yourpage.aspx?id=" + Session["id"].ToString() + "");
}
}
OR
use aref tag On that select button
<a href='yourpage.aspx?id=<%# Eval("Id") %>'">
<asp:Label ID="Label1" runat="server" Text="Select" ></asp:Label>
</a>