ASP.NET GridView SortedAscendingHeaderStyle does not work

Question

My SortedAscendingHeaderStyle and SortedDescendingHeaderStyle is not working at all

<asp:GridView ID="grdProducts" runat="server" CssClass="grid" AllowPaging="True" AllowSorting="True" PageSize="100" EmptyDataText="No data to show"
              onrowdatabound="grdProducts_RowDataBound"  onrowediting="grdProducts_RowEditing" onsorting="grdProducts_Sorting" AutoGenerateEditButton="True">
  <AlternatingRowStyle CssClass="even" />
  <SortedAscendingHeaderStyle ForeColor="White" CssClass="sorted" />
  <SortedDescendingHeaderStyle CssClass="sorted desc" />
</asp:GridView>

Rows are sorted correctly when headers are clicked, but when I inspect the header using FireBug, it only shows: (this is when sorted ascending)

<th scope="col">
  <a href="javascript:__doPostBack('ctl00$body$ctl00$grdProducts','Sort$Namekey')">Namekey</a>
</th>

ForeColor and CssClass are not set at all.

Anyone has any idea what I am doing wrong?

EDIT: My C# code behind

  protected void grdProducts_Sorting(object sender, GridViewSortEventArgs e)
  {
    if ((string)ViewState["SortColumn"] == e.SortExpression)
      ViewState["SortDirection"] = ((string)ViewState["SortDirection"] == "") ? " DESC" : "";
    else
    {
      ViewState["SortColumn"] = e.SortExpression;
      ViewState["SortDirection"] = "";
    }
  }

  protected override void OnPreRender(EventArgs e)
  {
    BindGrid();
    base.OnPreRender(e);
  }

  private void BindGrid()
  {
    string query = "SELECT ... ORDER BY " + ViewState["SortColumn"] + ViewState["SortDirection"];

    DataTable dt = SqlFunctions.Select(query);
    grdProducts.DataSource = dt;
    grdProducts.DataBind();
  }

Answer 1

I'm not sure if SortedDescendingHeaderStyle works without code if you're not using an asp:SQLDataSource as your GridView data source. But a little coding can get you there.

You need to apply the CSS style manually to the header cell. You can do it in the Sorting event.

protected void grdProducts_Sorting(object sender, GridViewSortEventArgs e)
{
   if ((string)ViewState["SortColumn"] == e.SortExpression)
   {
      ViewState["SortDirection"] = ((string)ViewState["SortDirection"] == "") ? " DESC" : "";
      grdProducts.HeaderRow.Cells[GetColumnIndex( e.SortExpression )].CssClass = "AscendingHeaderStyle";
   }
   else
   {
      ViewState["SortColumn"] = e.SortExpression;
      ViewState["SortDirection"] = "";
      grdProducts.HeaderRow.Cells[GetColumnIndex( e.SortExpression )].CssClass = "DescendingHeaderStyle";
   }
   BindGrid();
}




private int GetColumnIndex( string SortExpression )
{
    int i = 0;
    foreach( DataControlField c in gvwCustomers.Columns )
    {
        if( c.SortExpression == SortExpression )
            break;
        i++;
    }
    return i;
}

Answer 2

I don't have enough rep to comment on the accepted answer. When I tried applying the solution, it would sort properly, but did not apply the CSS class to what was eventually rendered.

In my case, invoking DataBind() on my grid AFTER sorting my DataSource (List) and assigning it as the grid's DataSource, but BEFORE setting the CssClass did the trick. Figured I'd share in case someone else encountered something similar.