Kann mir jemand bei diesem Fehler helfen ?

"ListView2.Form1.ListViewItemSorter.get" ist nicht als abstrakt oder extern deklariert und muss daher einen Text deklarieren.

using System;

using System.Collections;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

using System.IO;

using System.Diagnostics;


namespace ListView2

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();


            string[] drives = Directory.GetLogicalDrives();

            TreeNode node;

            foreach (string drv in drives)

            {

                node = treeView1.Nodes.Add(drv);

                if (node.Text == "A:\\")

                {

                    node.ImageIndex = 0;

                    node.SelectedImageIndex = 0;

                    continue;

                }


                AllSubDirectories(node);

                if (drv == "C:\\")


                    treeView1.SelectedNode = node;                   

            }

        }


        private void AllSubDirectories(TreeNode node)

        {

            DirectoryInfo[] arrDirInfo;

            DirectoryInfo dirinfo = new DirectoryInfo(node.FullPath);


            try

            {

                arrDirInfo = dirinfo.GetDirectories();

            }

            catch

            {

                return;

            }

            foreach (DirectoryInfo info in arrDirInfo)

            {

                node.Nodes.Add(info.Name);

            }

        }


        private void treeView1_BeforeExpand(object sender, TreeViewCancelEventArgs e)

        {

            foreach (TreeNode node in e.Node.Nodes)

            {

                AllSubDirectories(node);

            }

        }


        private TreeNode activeNode;


        private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)

        {

            activeNode = e.Node;

            this.GetAllDirAndFileInfos(); 

        }


        private void GetAllDirAndFileInfos() 

        {  

        listView1.Items.Clear();  

        ListViewItem item;  

        DirectoryInfo dirInfo =   

        new DirectoryInfo(treeView1.SelectedNode.FullPath);  

        try 

        {  

        foreach(DirectoryInfo dir in dirInfo.GetDirectories()) 

           {  

            item = listView1.Items.Add(" " + dir.Name, 1);  

            item.SubItems.Add("");  

            item.SubItems.Add(dir.LastWriteTime.ToString());  

           }  


        foreach(FileInfo file in dirInfo.GetFiles()) 

            {  

               item = listView1.Items.Add(file.Name, 2);  

               item.SubItems.Add(file.Length.ToString());  

               item.SubItems.Add(file.LastWriteTime.ToString());

               string fileAttributes = "";

               if ((file.Attributes & FileAttributes.Archive) != 0)

                   fileAttributes += "A";

               if ((file.Attributes & FileAttributes.Hidden) != 0)

                   fileAttributes += "H";

               if ((file.Attributes & FileAttributes.ReadOnly) != 0)

                   fileAttributes += "R";

               if ((file.Attributes & FileAttributes.System) != 0)

                   fileAttributes += "S";

               item.SubItems.Add(fileAttributes);

           }

       }

       catch

       {

           return;

       }

   }


        private void listView_ItemActivate(object sender, EventArgs e)

        {

            foreach (ListViewItem item in listView1.SelectedItems)

            {

                string path = treeView1.SelectedNode.FullPath;

                path = path + "\\" + item.Text;


                FileInfo fileInfo = new FileInfo(path);

                if (0 != (fileInfo.Attributes | FileAttributes.Directory))

                {

                    foreach (TreeNode node in activeNode.Nodes)

                    {

                        if (item.Text.Trim() == node.Text.Trim())

                        {

                            treeView1.SelectedNode = node;

                            treeView1.SelectedNode.Expand();

                            activeNode = node;

                            treeView1.Refresh();

                            return;

                        }

                    }

                }

                else

                {

                    try

                    {

                        Process.Start(path);

                    }

                    catch { return; }

                }

            }

        }




        private void schließenToolStripMenuItem_Click(object sender, EventArgs e)

        {

            this.Close();

        }


        private void löschenToolStripMenuItem_Click(object sender, EventArgs e)

        {

            OpenFileDialog dlgFileOpen = new OpenFileDialog();

            dlgFileOpen.Title = "Öffnen";

            dlgFileOpen.ShowDialog();

        }


        private void schließenToolStripMenuItem_Click_1(object sender, EventArgs e)

        {

            this.Close();

        }



        public class ListViewComparer : IComparer  //Sortieren der Colums

        {

            private int col;

            private SortOrder order;

            public ListViewComparer(int col, SortOrder order)

            {

                this.col = col;

                this.order = order;

            }

            public int Compare(object x, object y)

            {

                ListViewItem item1, item2;

                item1 = (ListViewItem)x;

                item2 = (ListViewItem)y;

                if (this.order == SortOrder.Ascending)

                    return item1.SubItems[col].Text.CompareTo(item2.SubItems[col].Text);

                else

                    return

                  item2.SubItems[col].Text.CompareTo(item1.SubItems[col].Text);

            }

        }




        public IComparer ListViewItemSorter { get; set;} 


        private void Dateiname_ColumnClick(object sender, ColumnClickEventArgs e)

        {


            if (Dateiname.ListView.Sorting == SortOrder.Ascending)

            {

                Dateiname.ListView.Sorting = SortOrder.Descending;

                Dateiname.ListViewItemSorter =

                   new ListViewComparer(e.Column, SortOrder.Descending);

            }

            else

            {

                Dateiname.ListView.Sorting = SortOrder.Ascending;

                Dateiname.ListViewItemSorter =

                   new ListViewComparer(e.Column, SortOrder.Ascending);

            }

        }



      }

} 

Kann Geclosed werden der Fehler lag an ListView