protected void Button3_Click(object sender, EventArgs e)
    {
        try
        {
            Whitfieldcore wUser = new Whitfieldcore();
            for (int i = 0; i < Chkqualification.Items.Count; i++)
                {
                    if (Chkqualification.Items[i].Selected)
                        wUser.PopulateQualification(Convert.ToInt32(ViewState["EstNum"].ToString()), Convert.ToInt32(Chkqualification.Items[i].Value));
                }
            Response.Write("<script language='javascript'>parent.location.replace('Whitfield_estimation.aspx?EstNum=" + ViewState["EstNum"].ToString() + "');</script>");
         }

        catch (Exception exp)
        {
            Response.Write(exp.Message.ToString());
        }
    }