protected void btnFind_Click(object sender, EventArgs e)
{
        Parameter p = SqlDataSource2.SelectParameters["CategoryID"];
        SqlDataSource2.SelectParameters.Remove(p);
        SqlDataSource2.SelectParameters.Add("CategoryID", DropDownList1.SelectedValue);
        DataView d = (DataView)SqlDataSource2.Select(DataSourceSelectArguments.Empty);
        lblResult.Text = d.Count.ToString();
}