private void dt1_ValueChanged(object sender, EventArgs e)
        {
            SqlConnection con = new SqlConnection(dbclass.constring);
            string query = "SELECT * FROM tbl_customer  where Date=@Date";
            SqlCommand cmd = new SqlCommand(query, con);
            cmd.Parameters.AddWithValue("@Date", dt1.Value);
            SqlDataAdapter adp = new SqlDataAdapter(cmd);
            DataTable datatable = new DataTable();
            adp.Fill(datatable);
            this.Grid1.DataSource = AutoNumberedTable(datatable);
        }