Banding data form sharepoint list and library with using Group and fields into drop down in Infopath 2010

Please see the code

sing Microsoft.Office.InfoPath;
using System;
using System.Xml;
using System.Xml.XPath;
using Microsoft.SharePoint;

namespace SetValueToDropdownListInfoPathFromChoiceField
{
    public partial class FormCode
    {
        // NOTE: The following procedure is required by Microsoft InfoPath.
        // It can be modified using Microsoft InfoPath.
        public void InternalStartup()
        {
            EventManager.FormEvents.Loading += new LoadingEventHandler(FormEvents_Loading);
        }

        public void FormEvents_Loading(object sender, LoadingEventArgs e)
        {
            AddStatus();
        }

        public void AddStatus()
        {
            try
            {
                SPSite site = new SPSite("http://win-67038mbkel7");
                SPWeb web = site.OpenWeb();
                SPList list = web.Lists["Tasks"];
                SPFieldMultiChoice spFieldMultiChoice = (SPFieldMultiChoice)list.Fields["Status"];
                XPathNavigator nav = this.CreateNavigator().SelectSingleNode("/my:myFields/my:GroupStatus",
                    this.NamespaceManager);
                for (int item = 0; item < spFieldMultiChoice.Choices.Count; item++)
                {
                    XPathNavigator newNode = null;
                    newNode = nav.Clone();
                    newNode.SelectSingleNode("/my:myFields/my:GroupStatus/my:Displayname",
                        this.NamespaceManager).
                        SetValue(spFieldMultiChoice.Choices[item].ToString());
                    newNode.SelectSingleNode("/my:myFields/my:GroupStatus/my:Value",
                        this.NamespaceManager).
                        SetValue(spFieldMultiChoice.Choices[item].ToString());
                    nav.InsertAfter(newNode);
                    newNode = null;
                }
                nav.DeleteSelf();
                nav = null;
            }
            catch
            {

            }
        }
    }
}