[Solved] Sorting in ASP.Net GridView is not working

Hi,

I have problem using Paging and Sorting in ASP.Net GridView example Paging and Sorting in ASP.Net GridView example.

I don't have error in my code below, but the sorting not working.

Please help me

<asp:GridView ID="gvProducts" runat="server" AutoGenerateColumns="false"
AllowPaging="true" AllowSorting="true" OnSorting="OnSorting"
OnPageIndexChanging="OnPageIndexChanging" PageSize="10">
    <Columns>
        <asp:TemplateField HeaderText="Progr" SortExpression="Progr"
            ItemStyle-CssClass="ddl_Class_new" ItemStyle-HorizontalAlign="Center">
               <ItemTemplate>
                  <asp:HyperLink ID="hlProgr" runat="server"
                     Text='<%# Eval("Progr") %>'
                     NavigateUrl='<%# (String.IsNullOrEmpty(Eval("Progr").ToString()) ? "" :
                     String.Format("sEdit.aspx?spID={0}&sp={1}",
                     MaP.Base64ForUrlEncode(Eval("pID").ToString().ToUpper()),
                     MaP.Base64ForUrlEncode(Eval("Progr").ToString().ToUpper())))%>'
                     onclick="javascript:w=window.open(this.href, 'pID',
                     'left=150,top=150,width=1800,height=1800,toolbar=0,resizable=0');
                     return false;"
                     CssClass="linkbutton">
                  </asp:HyperLink>
               </ItemTemplate>
           </asp:TemplateField>
    </Columns>
</asp:GridView>

 protected void Page_Load(object sender, EventArgs e)
 {
     if (!Page.IsPostBack)
     {
         BindData();
     }
 }
 
 private void BindData(string sortExpression = null)
 {
     gvProducts.DataSource = RetrieveProducts();
     gvProducts.DataBind();
 }
 
 private string SortDirection
 {
     get { return ViewState["SortDirection"] != null ? ViewState["SortDirection"].ToString() : "ASC"; }
     set { ViewState["SortDirection"] = value; }
 }
 
 protected void OnSorting(object sender, GridViewSortEventArgs e)
 {
     BindData(e.SortExpression);
 }
 
 private DataSet RetrieveProducts(string sortExpression = null)
 {
     if (!String.IsNullOrEmpty(MaP.Container.tname))
     {
         DataTable dt = new DataTable();
         DataSet ds = new DataSet();
 
         using (MySqlConnection myConnectionString =
           new MySqlConnection(ConfigurationManager.ConnectionStrings["cn"].ConnectionString))
         {
             using (MySqlCommand cmd =
                 new MySqlCommand("sp_select_gv", myConnectionString))
             {
                 cmd.CommandTimeout = 2147483;
                 cmd.Connection.Open();
                 cmd.CommandType = CommandType.StoredProcedure;
                 cmd.Parameters.Clear();
 
                 MTparameters(cmd);
 
                 MySqlDataAdapter adapter =
                      new MySqlDataAdapter(cmd);
 
                 adapter.Fill(ds);
 
                 if (ds.Tables.Count > 0)
                 {
                     if (sortExpression != null)
                     {
                         DataView dv = dt.AsDataView();
                         this.SortDirection = this.SortDirection == "ASC" ? "DESC" : "ASC";
 
                         dv.Sort = sortExpression + " " + this.SortDirection;
                         gvProducts.DataSource = dv;
                     }
                     else
                     {
                         gvProducts.DataSource = dt;
                     }
 
                     dt = ds.Tables[0];
                 }
             }
         }
 
         return ds;
     }
     else
     {
         Page.ClientScript.RegisterStartupScript(this.GetType(), "Alert", "alert('No good');" +
             "window.location='https://google.com';", true);
         return null;
     }
 }
 
 protected void OnPageIndexChanging(object sender, GridViewPageEventArgs e)
 {
     gvProducts.PageIndex = e.NewPageIndex;
     BindData();
 }