plus,   
I can get DataValueField by sender.get_value(), and how to get the value in a whole field.

Codes Template:


public class ReceivingSheetDropDownItemTemplate : ITemplate
   {
       Boolean IsCompany { get; set; }
       Boolean IsName{get;set;}
       Boolean IsPhone{get;set;}
       Boolean IsMobile{get;set;}
       Boolean IsAddress{get;set;}
       public ReceivingSheetDropDownItemTemplate(Boolean isCompany = true, Boolean isName = true, Boolean isPhone = true, Boolean isMobile = true, Boolean isAddress = true)
       {
           IsCompany =isCompany;
           IsName =isName;
           IsPhone = isPhone;
           IsMobile = isMobile;
           IsAddress = isAddress;
       }
       public void InstantiateIn(Control container)
       {
           if (IsCompany || IsName || IsPhone || IsMobile || IsAddress)
           {
               HtmlTable table = new HtmlTable();
               HtmlTableRow titleRow = new HtmlTableRow();
               HtmlTableRow dataRow = new HtmlTableRow();
               titleRow.Attributes.Add("class", "title");
               table.Attributes.Add("class", "DropTable");
 
               if (IsCompany)
               {
                   AddBindItem(container, titleRow, "CompanyName", dataRow, "CompanyName");
               }
 
               if (IsName)
               {
                   AddBindItem(container, titleRow, "Name", dataRow, "Name");
               }
 
               if (IsPhone)
               {
                   AddBindItem(container, titleRow, "Phone", dataRow, "Phone");
               }
 
               if (IsMobile)
               {
                   AddBindItem(container, titleRow, "Mobile", dataRow, "Mobile");
               }
 
               if (IsAddress)
               {
                   AddBindItem(container, titleRow, "Address", dataRow, "Address");
               }
               table.Controls.Add(titleRow);
               table.Controls.Add(dataRow);
               container.Controls.Add(table);
           }
       }
       private void AddBindItem(Control container, HtmlTableRow titleRow, String strTitle, HtmlTableRow dataRow, String strContactName)
       {
           HtmlTableCell cellTitle = new HtmlTableCell();
           cellTitle.InnerHtml = strTitle;
           titleRow.Cells.Add(cellTitle);
 
           HtmlTableCell cellData = new HtmlTableCell();
           Label lab = new Label();
           lab.Text = (string)DataBinder.Eval((container as Telerik.Web.UI.AutoCompleteBox.DropDownItem).DataItem, strContactName);
           cellData.Controls.Add(lab);
           dataRow.Controls.Add(cellData);
 
       }
 
       public void RadAutoCompleteBox_DropDownTemplateNeeded(object sender, AutoCompleteDropDownItemEventArgs e)
       {
           e.Item.Template = new ReceivingSheetDropDownItemTemplate();
       }



page logic:


protected void Page_Load(object sender, EventArgs e)
        {
            BindAutoCompleteBox();
        }
 
        private void BindAutoCompleteBox()
        {
            rAutoReceiveCompany.DropDownTemplateNeeded += new  ReceivingSheetDropDownItemTemplate().RadAutoCompleteBox_DropDownTemplateNeeded;
            rAutoReceiveCompany.DataSource = new BLL.BaseInfo.ReceiveCompany().GetIsReceiveCompany(true);
            rAutoReceiveCompany.DataTextField = "CompanyName";
            rAutoReceiveCompany.DataValueField = "CompanyName";
        }



 UI :
<tk:RadAutoCompleteBox ID="rAutoDeliverCompany" runat="server" Filter="StartsWith" TextSettings-SelectionMode="Single" AllowCustomEntry="true" InputType="Text"></tk:RadAutoCompleteBox>