WPF Breadcrumb Folder TextBox

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using QuickZip.UserControls.Breadcrumb.Framework;
using System.Windows.Media;

namespace QuickZip.UserControls.Breadcrumb.Presenter
{
    public class BreadcrumbCorePresenter : PresenterBase<View.BreadcrumbCoreView>
    {
        private bool _trailDirEnabled = false;
        internal BreadcrumbItemBase _root;        

        public BreadcrumbItemBase Root { get { return _root; } } 
        //public BreadcrumbItemBase SelectedItem { get { return View.LastNonTailItem; } }
        public string SelectedPath { get { return View.SelectedFolder; } }
        public string SelectedDisplayPath { get { return View.LastNonTailItem.FolderDisplayPath; } set { ChangeFolder(BreadcrumbItemBase.PathType.ptDisplay, value); } }
        public ImageSource Icon { get { return View.LastNonTailItem.Icon; } }
        public bool TrailDirEnabled { set { _trailDirEnabled = value; } }

        internal void ChangeFolder(BreadcrumbItemBase.PathType pt, string folderPath)
        {
            //if (!View.GetRootLoaded()) return;

            /* Can only trace path using display path, so convert first. */
            if (pt == BreadcrumbItemBase.PathType.ptFolder)
                folderPath = Root.ConvertPath(pt, folderPath);
            if (folderPath.StartsWith(Root.DisplayName))
                folderPath = folderPath.Substring(Math.Min(Root.DisplayName.Length + 1, folderPath.Length));

            /* Do the rest */

            /* TrailDir */
            BreadcrumbItemBase newFolder = Root.LookupFolder(pt, folderPath);
            if (View.SelectedPresenter == newFolder) return;

            if (newFolder != null &&  _trailDirEnabled && newFolder.FolderLevel > 0 && newFolder != null && newFolder.IsVisible && View.LastItem.HasParent(newFolder))
            {
                BreadcrumbItemBase[] hierarchy = View.LastItem.Hierarchy;
                for (int i = 0; i < View.LastItem.FolderLevel + 1; i++)                
                    hierarchy[i].IsTrailDir = false;
                hierarchy[newFolder.FolderLevel].ClearSelection();
                for (int i = newFolder.FolderLevel + 1; i <= View.LastItem.FolderLevel; i++)
                    hierarchy[i].IsTrailDir = true;
            }
            else
            /* */
            {
                Root.ClearSelection();
                Root.ExpanderClear();
                if (folderPath == null) { View.ClearAll(); } // Null -> Select Root
                else
                {
                    string[] folderSplit = folderPath.Split(new char[] { '\\' }, StringSplitOptions.RemoveEmptyEntries);                    
                    string current;
                    BreadcrumbItemBase currentPresenter = Root;
                    View.ClearAfterIndex(folderSplit.Length); //It wont be displayed anyway, remove them.       

                    for (int i = 0; i < folderSplit.Length; i++)
                    {
                        current = folderSplit[i].EndsWith(":") ? folderSplit[i] + "\\" : folderSplit[i]; // e.g. C: ---> C:\
                        string next = i + 1 < folderSplit.Length ? folderSplit[i + 1] : ""; // next select path                    

                        if (View.Count > i && (current == View.GetItem(i).DisplayName || current.TrimEnd('\\') == View.GetItem(i).FolderName)) //Check if the path is exists and same
                        {
                            //Ignore it, already constructed
                            View.GetItem(i).ClearSelection(); //Reset select folder
                            View.GetItem(i).IsTrailDir = false;
                        }
                        else
                        {
                            //Construct it.
                            View.ClearAfterIndex(i);
                            BreadcrumbItemBase nextPresenter = currentPresenter[BreadcrumbItemBase.PathType.ptDisplay, current];
                            if (nextPresenter == null)
                                throw new ArgumentException("Path not found");
                            else
                                if (next != "") nextPresenter.SelectedDisplayFolder = next;
                            nextPresenter.IsTrailDir = false;
                            this.View.AddItem(nextPresenter);
                        }
                        currentPresenter = View.GetItem(i);
                    }

                     
                }
            }
            Root.ShowDisplayName = View.Count == 0;

            View.SelectedFolder = Root.ConvertPath(BreadcrumbItemBase.PathType.ptDisplay, folderPath);
            View.SelectedPresenter = View.LastNonTailItem;
            

            //OnPropertyChanged("SelectedItem");
            //OnPropertyChanged("SelectedPath");
            OnPropertyChanged("SelectedDisplayPath");
            OnPropertyChanged("Icon");
        }

        

        public BreadcrumbCorePresenter(View.BreadcrumbCoreView view)
            : base(view)
        {
        }


        internal void SetRootItem(BreadcrumbItemBase newRoot)
        {
            View.SetRootItem(newRoot);
            OnPropertyChanged("Icon");
        }
    }
}