using System;

using System.Collections;

using System.Configuration;

using System.Data;

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;

namespace UsingDataKeys

{

    public partial class GridViewSelectionUsingDataKeys : System.Web.UI.Page

    {

        protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)

        {

            GridView1.SetRowValueValueByKey(DropDownList1.SelectedValue);

        }

    }

    public static class GridViewExtensions

    {

        public static void SetRowValueValueByKey(this GridView GridView, string DataKeyValue)

        {

            int intSelectedIndex = 0;

            int intPageIndex = 0;

            int intGridViewPages = GridView.PageCount;

            // Loop thru each page in the GridView

            for (int intPage = 0; intPage < intGridViewPages; intPage++)

            {

                // Set the current GridView page

                GridView.PageIndex = intPage;

                // Bind the GridView to the current page

                GridView.DataBind();

                // Loop thru each DataKey in the GridView

                for (int i = 0; i < GridView.DataKeys.Count; i++)

                {

                    if (Convert.ToString(GridView.DataKeys[i].Value) == DataKeyValue)

                    {

                        // If it is a match set the variables and exit

                        intSelectedIndex = i;

                        intPageIndex = intPage;

                        break;

                    }

                }

            }

            // Set the GridView to the values found

            GridView.PageIndex = intPageIndex;

            GridView.SelectedIndex = intSelectedIndex;

            GridView.DataBind();

        }

    }

}