Forms Data Controls :: Gridview Display On Pageload Error

I m working on application that works similar to our email i.e when user enter his emailid and password his inbox should be display and those unread should be in bold and i have a treeview for inbox, sent, deleted .when inbox is selected the inbox detail should be displayed using gridview by default like in email the inbox data shoul be display on pageload so i have written databind code for grid view in page load event

protected
void Page_Load(object sender,
EventArgs e)
{
if (!IsPostBack)
{
Class1 obj =
new
Class1();
string toid = Context.User.Identity.Name;
obj.gridfill(gv, "select * from inbox inner join usermaster on inbox.userid=usermaster.userid where inbox.toid= '" + toid +
"'");
string id = Context.User.Identity.Name;
lblemaiid.Text = id;
Session["inbox"] =
"false";.........................................