Странное Наследие

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
 
namespace MyHandLib.Controls
{
    /// <summary>
    /// Interaction logic for Nav_InDirButtom.xaml
    /// </summary>
    public partial class Nav_InDirButton : UserControl
    {
        private Frame frame;
        public string Dir_Path { get; set; }
        public string Dir_Name { get; set; }
 
        public Nav_InDirButton(string Dir_Path)
        {
            InitializeComponent();
            DataContext = this;
            this.frame = (Frame)Application.Current.Resources["MainFrame"];
            this.Dir_Path = Dir_Path;
           
 
            Dir_Name = System.IO.Path.GetFileNameWithoutExtension(Dir_Path);
        }
 
        private void Button_Click(object sender, RoutedEventArgs e)
        {
         (((this.Parent as StackPanel).Parent as Grid).Parent as Nav_Bar).GoLevelDown(Dir_Path);
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.IO;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using Microsoft.Office.Interop.Excel;
using Excel = Microsoft.Office.Interop.Excel;
using MyHandLib.Controls;
 
namespace MyHandLib.Pages
{
    /// <summary>
    /// Interaction logic for Dir_Content.xaml
    /// </summary>
    public partial class Dir_Content : UserControl
    {
        public DirectoryInfo Dir_info;
        string datapath = @"C:SharePointsystemDataTable.xlsx";
        string[][] filesdata;
        string
     
 
        //fills the files data from excel
        public Dir_Content(string Dir_Path)
        {
            this.Dir_info = new DirectoryInfo(Dir_Path);
            InitializeComponent();
            Update(Dir_Path);
 
 
        }
 
        //Updates the Control-Shows current files if the current folder doesn't contain ant sub-folders
        public void Update(string Dir_Path)
        {
            Dir_info = new DirectoryInfo(Dir_Path);
            if (Dir_info.GetDirectories().Length == 0 && Dir_info.GetFiles().Length > 0)
            {
               // UI_Items.Background.Opacity = 0;
                filesdata = GetData();
                string[] arr = new string[6];
                arr[0] = "Ч¤ЧўЧ•ЧњЧЄ ЧђЧ—Ч–Ч§Ч”";
                arr[1] = "Ч©Чќ ЧЎЧ¤ЧЁ";
                arr[2] = "ЧЄЧ™ЧђЧ•ЧЁ";
                arr[3] = "ЧћЧЎ' ЧўЧ“Ч›Ч•Чџ";
                arr[4] = "ЧЄЧђЧЁЧ™Чљ  ЧЎЧ*Ч›ЧЁЧ•Чџ";
                arr[5] = "Ч™Ч©Ч™ЧћЧ™Ч•ЧЄ";
                UI_Items.Children.Add(new Item(arr));
 
                //adds files by filters(Folder or Name)
                foreach (FileInfo Dir_file in Dir_info.GetFiles())
                    foreach (string[] file in filesdata)
                        if (file[0] == Dir_info.Name && (file[1]+".pdf") == Dir_file.Name)
                            UI_Items.Children.Add(new Item(file, Dir_file.FullName,(this.Parent as System.Windows.Controls.Border)));
            }
            else
            {
                UI_Items.Children.Clear();
                // UI_Items.Background.Opacity = 1;
            }
        }
        //gets all written cells
        public string[][] GetData()
        {
           
            var excel = new Excel.Application();
            string Name = Path.GetDirectoryName(Dir_info.FullName);
            Workbook DataTable = (excel.Workbooks.Open(datapath) as Workbook);
            Worksheet ws = (DataTable.Worksheets[1] as Worksheet);
            string[][] files = new string[GetLastPos(ws) - 1][];
            for (int i = 0; i < files.Length; i++)
            {
                files[i] = new string[]{ ws.Cells[1][i + 1].Value2.ToString() , ws.Cells[2][i + 1].Value2.ToString(), ws.Cells[3][i + 1].Value2.ToString(), ws.Cells[4][i + 1].Value2.ToString(),
                    ws.Cells[5][i + 1].Value2.ToString(), ws.Cells[6][i + 1].Value2.ToString()};
            }
            DataTable.Close(0);
            excel.Quit();
            return files;
        }
 
        //get the last cell written cell in the current worksheet
        public int GetLastPos(Worksheet ws)
        {
            int i = 1;
            while (true)
            {
                if (ws.Cells[i, 1].Value == null)
                   return i;
                else
                    i++;
            }
        }
 
       
    }
}

public void GoLevelUp(string Dir_path, int Dir_Level)
        {
            Current_DirPath = Dir_path;
            Current_DirLevel = Dir_Level;
            this.UI_PreDir.Children.RemoveRange(Dir_Level, 20);
            this.UI_InDir.Children.RemoveRange(0, 50);
            foreach (string dir in Directory.GetDirectories(Dir_path))
            {
                if (Current_DirLevel <= 1 && dir.Split('\')[2].Equals("system"))
                    continue;
 
                UI_InDir.Children.Add(new Nav_InDirButton(dir));
            }
            ContentBorder.Child = content;
            content.Update(Dir_path);
        }
 
        //add an element to a dockpanel
        public void addToDock(DockPanel dockPanel, UIElement control, Dock dock)
        {
            DockPanel.SetDock(control, dock);
            dockPanel.Children.Add(control);
        }