Ben

<telerik:RadAjaxManager ID="RadAjaxManager1" runat="server">
            <AjaxSettings>
                <telerik:AjaxSetting AjaxControlID="RadGridOpenItems">
                    <UpdatedControls>
                        <telerik:AjaxUpdatedControl ControlID="RadGridOpenItems" />
                    </UpdatedControls>
                </telerik:AjaxSetting>
                <telerik:AjaxSetting AjaxControlID="RadGridOpenItems">
                    <UpdatedControls>
                        <telerik:AjaxUpdatedControl ControlID="RadGridOpenItems" />
                    </UpdatedControls>
                </telerik:AjaxSetting>
              
            </AjaxSettings>
        </telerik:RadAjaxManager>
<telerik:RadComboBox ID="RadComboBox1" runat="server"
                MarkFirstMatch="True" EnableLoadOnDemand="True" AutoPostBack="true" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
 <telerik:RadCodeBlock ID="RadCodeBlock1" runat="server">

            <script type="text/javascript">
                function RowDblClick(sender, eventArgs) {
                    sender.get_masterTableView().editItem(eventArgs.get_itemIndexHierarchical());
                }
            </script>

        </telerik:RadCodeBlock>

<telerik:RadGrid ID="RadGridOpenItems" runat="server" DataSourceID="SqlDataSourcePwOpenItems" AllowMultiRowEdit="true"
         ShowStatusBar="True" GridLines="None" OnItemUpdated="RadGrid1_ItemUpdated" OnItemInserted="RadGrid1_ItemInserted"
        AllowFilteringByColumn="false" AllowPaging="True" OnItemDeleted="RadGrid1_ItemDeleted"  
    AllowSorting="True" Skin="Vista" AllowAutomaticDeletes="True"  
        AllowAutomaticInserts="True" AllowAutomaticUpdates="True"
        AutoGenerateColumns="False" ShowGroupPanel="false" >
        <ClientSettings Scrolling-AllowScroll="True" AllowColumnsReorder="True" ReorderColumnsOnClient="True">
                <Selecting AllowRowSelect="True" />
                <Scrolling AllowScroll="True" UseStaticHeaders="True" FrozenColumnsCount="0" SaveScrollPosition="True" />
                <Resizing AllowColumnResize="True" />
                <ClientEvents OnRowDblClick="RowDblClick" />

                <Selecting AllowRowSelect="True"></Selecting>
                <Scrolling AllowScroll="True" UseStaticHeaders="True"></Scrolling>
                <Resizing AllowColumnResize="True"></Resizing>
        </ClientSettings>
        <MasterTableView DataSourceID="SqlDataSourcePwOpenItems"
            AllowPaging="True" AllowSorting="True" CommandItemDisplay="Top"
             EditMode="InPlace" DataKeyNames="PWOPENITEMS_ID" AllowAutomaticDeletes="true">
                <CommandItemSettings ExportToPdfText="Export to Pdf"></CommandItemSettings>
 
 
        <RowIndicatorColumn>
            <HeaderStyle Width="20px"></HeaderStyle>
        </RowIndicatorColumn>

        <ExpandCollapseColumn>
            <HeaderStyle Width="20px"></HeaderStyle>

        </ExpandCollapseColumn>
      
       
<%--Gridview Columns--%>   
    <Columns>
        <telerik:GridEditCommandColumn UniqueName="EditCommandColumn"
            ButtonType="imagebutton" >
            <HeaderStyle Width="35px" />
        </telerik:GridEditCommandColumn>

        <telerik:GridClientDeleteColumn ConfirmText="Are you sure you want to delete the selected row?"
              HeaderStyle-Width="35px" ButtonType="ImageButton" UniqueName="column1" >

        <HeaderStyle Width="35px"></HeaderStyle>
          </telerik:GridClientDeleteColumn>

        <telerik:GridTemplateColumn DataField="OPCODE" HeaderText="OPCODE"
            SortExpression="OPCODE" UniqueName="OPCODE" AllowFiltering="false">
            <HeaderStyle Width="120px" />
<%--Convert to uppercase--%>        
            <EditItemTemplate>
                <asp:TextBox id="txtOpcode" runat="server" Text='<%# Bind("OPCODE") %>' MaxLength="3"
                    Onkeyup="javascript:this.value = this.value.toUpperCase();"></asp:TextBox>
            </EditItemTemplate>
                <ItemTemplate>
                    <asp:Label id="lblOpcode" runat="server" Text='<%# Eval("OPCODE") %>'></asp:Label>
                </ItemTemplate>
        </telerik:GridTemplateColumn>
 .
 .column2, column3,...
 .

 </Columns>

        <EditFormSettings FormCaptionStyle-HorizontalAlign="Center">
       
            <EditColumn UniqueName="EditCommandColumn1"></EditColumn>
        </EditFormSettings>
    </MasterTableView>
</telerik:RadGrid>

 asp:sqlDataSource here
Update command, select command, insert command, delete command is here
update, insert, and delete parameters here.

Code behind

namespace Ames5.Schedule
{
    public partial class PWOPENITEMS : System.Web.UI.Page
    {
       
        public string GetConnectionString()
        {

            //sets the connection string from web config file "ConnString"

            return System.Configuration.ConfigurationManager.ConnectionStrings["AMES5DB_TESTConnectionString"].ConnectionString;
        }

        protected void Page_Load(object sender, EventArgs e)
        {

            if (!Page.IsPostBack)
            {
                SqlConnection conn = new SqlConnection(GetConnectionString());
                SqlCommand cmd = new SqlCommand("Select DISTINCT OPCODE,FLEET,SUBFLEET from  PWOPENITEMS", conn);//query to get the distinct values.

                SqlDataAdapter sda = new SqlDataAdapter();
                sda.SelectCommand = cmd;
                DataSet ds = new DataSet();
                sda.Fill(ds, "tbl_data"); //nameing the table getting stored in DataSet as "tbl_data"

                string str1, str2, str3, str4;
                ArrayList MyDisplayList = new ArrayList();
                ArrayList MyValueList = new ArrayList();

                if (ds.Tables["tbl_data"].Rows.Count != 0)
                {
                    MyDisplayList.Add("ALL");
                    foreach (DataRow myRow in ds.Tables["tbl_data"].Rows)
                    {

                        str1 = myRow["OPCODE"].ToString();
                        str2 = myRow["FLEET"].ToString();
                        str3 = myRow["SUBFLEET"].ToString();
                        str4 = str1 + " " + str2 + " " + str3; //Concatinating three strings with space in between.

                        MyDisplayList.Add(str4);
                    }

                    RadComboBox1.DataSource = MyDisplayList;
                    RadComboBox1.DataBind();
                }
                else
                {
                    Response.Write("No Data");

                }

            }

           
            (RadAjaxManager.GetCurrent(this.Page) as RadAjaxManager).ResponseScripts.Add(string.Format("window['gridId'] = '{0}';", RadGridOpenItems.ClientID));

        }

        protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
        {
            SqlConnection con = new SqlConnection(GetConnectionString());
            if (RadComboBox1.SelectedItem.Text == "ALL")
            {
                string str = "SELECT * FROM PWOPENITEMS";
                SqlDataSourcePwOpenItems.SelectCommand=str;
               
                    RadGridOpenItems.DataBind();

            }
            else
            {
                string fullString = RadComboBox1.SelectedValue.ToString();

                string firstString = fullString.Substring(0, 3); //Extracting substring

                string middleString = fullString.Substring(3, 7); //Extracting substring

                string lastString = fullString.Substring(11, 1);

               
                string st = "SELECT * FROM PWOPENITEMS WHERE OPCODE = '" + firstString + "' AND FLEET = '" + middleString + "' AND SUBFLEET = '" + lastString + "'";
                SqlDataSourcePwOpenItems.SelectCommand = st;
             
                RadGridOpenItems.Rebind();

            }
        }

        protected void RadGrid1_ItemUpdated(object source, Telerik.Web.UI.GridUpdatedEventArgs e)
        {
            GridEditableItem item = (GridEditableItem)e.Item;
            String id = item.GetDataKeyValue("PWOPENITEMS_ID").ToString();

            if (e.Exception != null)
            {
                e.KeepInEditMode = true;
                e.ExceptionHandled = true;
                SetMessage("Product with ID " + id + " cannot be updated. Reason: " + e.Exception.Message);
            }
            else
            {
                SetMessage("Product with ID " + id + " is updated!");
            }
        }

        protected void RadGrid1_ItemInserted(object source, GridInsertedEventArgs e)
        {
            if (e.Exception != null)
            {
                e.ExceptionHandled = true;
                SetMessage("Item cannot be inserted. Reason: " + e.Exception.Message);
            }
            else
            {
                SetMessage("New item is inserted!");
            }
        }

        protected void RadGrid1_ItemDeleted(object source, GridDeletedEventArgs e)
        {
            GridDataItem dataItem = (GridDataItem)e.Item;
            String id = dataItem.GetDataKeyValue("PWOPENITEMS_ID").ToString();

            if (e.Exception != null)
            {
                e.ExceptionHandled = true;
                SetMessage("Product with ID " + id + " cannot be deleted. Reason: " + e.Exception.Message);
            }
            else
            {
                SetMessage("Product with ID " + id + " is deleted!");
            }
        }

        private void DisplayMessage(string text)
        {
            RadGridOpenItems.Controls.Add(new LiteralControl(string.Format("<span style='color:red'>{0}</span>", text)));
        }

        private void SetMessage(string message)
        {
            gridMessage = message;
        }

        private string gridMessage = null;
        protected void RadGrid1_DataBound(object sender, EventArgs e)
        {
            if (!string.IsNullOrEmpty(gridMessage))
            {
                DisplayMessage(gridMessage);
            }
        }

    }
}