ASP.net c# Gridview sorting with custom template fields

Question

Hi all,

I can't seem to figure out how to sort my gridview with both databound AND custom fields.

The custom field look like this:

  <asp:Label ID="lblItems" runat="server" Text='<%# GetItems((int)DataBinder.Eval(Container.DataItem, "ObjectCategoryID"))%>' />

It calls for a function which shows how many item the given category has.

The sorting for the databounded fields work perfec but not the customfields. Im also looking for a generic method which works for all my gridviews.

Can someone help me in the right direction please? Below is my full customgrid code.

Thank you for your time

Kind regards, Mark

using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;
using System.Collections;

namespace CustomControls
{
    public class CustomGrid : GridView
    {
        public CustomGrid()
        {
              PageIndexChanging += CustomGrid_PageIndexChanging;
        }        

    private string ConvertSortDirectionToSql(SortDirection sortDirection)
    {
        string newSortDirection = String.Empty;

        switch (sortDirection)
        {
            case SortDirection.Ascending:
                newSortDirection = "ASC";
                break;

            case SortDirection.Descending:
                newSortDirection = "DESC";
                break;
        }

        return newSortDirection;
    }  

    protected void CustomGrid_PageIndexChanging(object sender, GridViewPageEventArgs e)
    {
        this.PageIndex = e.NewPageIndex;
        this.DataBind();
    }

    protected override void OnSorting(GridViewSortEventArgs e)
    {
        DataSet ds = (DataSet)System.Web.HttpContext.Current.Session["Source"];
        DataTable dataTable = ds.Tables[0];

        if (dataTable != null)
        {
            DataView dataView = new DataView(dataTable);


            if ((string)System.Web.HttpContext.Current.Session["Direction"] == "Asc")
            {
                dataView.Sort = e.SortExpression + " " + "ASC";
                System.Web.HttpContext.Current.Session["Direction"] = "Desc";
            }

            else if ((string)System.Web.HttpContext.Current.Session["Direction"] == "Desc")
            {
                dataView.Sort = e.SortExpression + " " + "DESC";
                System.Web.HttpContext.Current.Session["Direction"] = "Asc";
            }

            else
            {
                dataView.Sort = e.SortExpression + " " + "ASC";
                System.Web.HttpContext.Current.Session["Direction"] = "Desc";
            }

            this.DataSource = dataView;
            this.DataBind();
        }
    }

    protected override void OnInit(System.EventArgs e)
    {
        this.AllowSorting = true;
        this.AllowPaging = true;
        this.PagerSettings.Mode = PagerButtons.NumericFirstLast;
        this.AutoGenerateColumns = false;
        this.CssClass = "gv";
        this.RowStyle.CssClass = "gvRow";
        this.AlternatingRowStyle.CssClass = "gvAlternateRow";
        this.HeaderStyle.CssClass = "gvHeader";
        this.GridLines = GridLines.None;
        this.PagerStyle.CssClass = "gvPager";
        this.EmptyDataText = "<div style=\"width:100%;text-align:left;\">No data found</div>";
    }
}

}

enter code here

Answer 1

try to use capital letter -- ASC or DESC.

Answer 2

Make your you specify the SortExpression property on the template field

<asp:TemplateField HeaderText="Object Category ID" SortExpression="ObjectCategoryID">
<ItemTemplate>
    <asp:Label ID="lblItems" runat="server" Text='<%# GetItems((int)DataBinder.Eval(Container.DataItem, "ObjectCategoryID"))%>' />
</ItemTemplate>
</asp:TemplateField>