public class AbsoluteFile  
{  
       public event EventHandler FinishDeleteFileEvent = null;  
       public event EventHandler FinishDeleteFolderEvent = null;  
       public event EventHandler DeleteErrorEvent = null;  
       public string ErrorString = string.Empty;  
       public void DoAbsoluteDeleteFile(object filePath)  
       {  
           try  
           {  
               string filename = filePath.ToString();  
               if (string.IsNullOrEmpty(filename))  
               {  
                   return;  
               }  
               if (File.Exists(filename))  
               {  
                   File.SetAttributes(filename, FileAttributes.Normal);  
                   double sectors = Math.Ceiling(new FileInfo(filename).Length / 512.0);  
                   byte[] dummyBuffer = new byte[512];  
                   RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();  
                   FileStream inputStream = new FileStream(filename, FileMode.Open);  
                   inputStream.Position = 0;  
                   for (int sectorsWritten = 0; sectorsWritten < sectors; sectorsWritten++)  
                   {  
                       rng.GetBytes(dummyBuffer);  
                       inputStream.Write(dummyBuffer, 0, dummyBuffer.Length);  
                       sectorsWritten++;  
                   }  
                   inputStream.SetLength(0);  
                   inputStream.Close();  
                   DateTime dt = new DateTime(2049, 1, 1, 0, 0, 0);  
                   File.SetCreationTime(filename, dt);  
                   File.SetLastAccessTime(filename, dt);  
                   File.SetLastWriteTime(filename, dt);  
                   File.Delete(filename);  
                   WipeDone();  
               }  
           }  
           catch (Exception e)  
           {  
               WipeError(e);  
           }  
       }  
       public void DoDeleteFolder(object folder)  
       {  
           string folderPath = folder.ToString();  
           if (string.IsNullOrEmpty(folderPath))  
           {  
               return;  
           }  
           DirectoryInfo direct = new DirectoryInfo(folderPath);  
           FileSystemInfo[] filesystem = direct.GetFileSystemInfos();  
           if (filesystem == null || filesystem.Length == 0)  
           {  
               direct.Delete();  
           }  
           else  
           {  
               foreach (FileSystemInfo fileItem in filesystem)  
               {  
                   if (fileItem is FileInfo)  
                   {  
                       this.DoAbsoluteDeleteFile(fileItem.FullName);  
                   }  
                   else  
                   {  
                       DoDeleteFolder(fileItem.FullName);  
                   }  
               }  
           }  
           if (this.FinishDeleteFolderEvent != null)  
           {  
               this.FinishDeleteFolderEvent(this, null);  
           }  
       }  
       private void WipeError(Exception e)  
       {  
           if (DeleteErrorEvent != null)  
           {  
               ErrorString = e.Message;  
               DeleteErrorEvent(this, null);  
           }  
       }  
       private void WipeDone()  
       {  
           if (FinishDeleteFileEvent != null)  
           {  
               FinishDeleteFileEvent(this, null);  
           }  
       }  
}

public partial class Form1 : Form  
{  
       private Thread dfileThread = null;  
       private string fileObjectPath = string.Empty;  
       private bool isFile = true;  
       public delegate void DefaulEventDelegate(object sender, EventArgs e);  
       public Form1()  
       {  
           InitializeComponent();  
       }  
       private void btnSelectFile_Click(object sender, EventArgs e)  
       {  
           isFile = true;  
          this.openFileDialog1 = new OpenFileDialog();  
          openFileDialog1.Multiselect = true;  
          openFileDialog1.Title = "請選擇文件";  
          openFileDialog1.Filter = "所有文件(*.*)|*.*";  
          if (openFileDialog1.ShowDialog() == DialogResult.OK)  
           {  
              this.txtFilePath.Text = openFileDialog1.FileName;  
           }  
          fileObjectPath = this.txtFilePath.Text.Trim();  
       }  
       private void btnSelectFolder_Click(object sender, EventArgs e)  
       {  
           isFile = false;  
           this.folderBrowserDialog1  = new FolderBrowserDialog();  
           folderBrowserDialog1.Description = "請選擇文件路徑";  
           if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)  
           {  
               this.txtFolder.Text = folderBrowserDialog1.SelectedPath;  
           }  
           fileObjectPath = this.txtFolder.Text.Trim();  
       }  
       private void btnAbsoluteDelete_Click(object sender, EventArgs e)  
       {  
           this.lblHint.Visible = true;  
           if(string.IsNullOrEmpty(fileObjectPath))  
           {  
               MessageBox.Show("請選擇要粉碎的文件和文件夾！");  
               return;  
           }  
           AbsoluteFile dfile = new AbsoluteFile();  
           dfile.DeleteErrorEvent += new EventHandler(Dfile_DeleteErrorEvent);  
           if (isFile)  
           {  
               dfile.FinishDeleteFileEvent += new EventHandler(Dfile_FinishDeleteFileEvent);  
               dfileThread = new Thread(new ParameterizedThreadStart(dfile.DoAbsoluteDeleteFile));  
               dfileThread.IsBackground = true;  
               dfileThread.Start(fileObjectPath);  
           }  
           else  
           {  
               dfile.FinishDeleteFolderEvent += new EventHandler(Dfile_FinishDeleteFolderEvent);  
               dfileThread = new Thread(new ParameterizedThreadStart(dfile.DoDeleteFolder));  
               dfileThread.IsBackground = true;  
               dfileThread.Start(fileObjectPath);  
           }  
           this.lblHint.Text = @"正在刪除...";  
       }  
       void Dfile_DeleteErrorEvent(object sender, EventArgs e)  
       {  
           if (!this.InvokeRequired)  
           {  
               MessageBox.Show((sender as AbsoluteFile).ErrorString);  
           }  
           else  
           {  
               this.BeginInvoke(new DefaulEventDelegate(Dfile_DeleteErrorEvent), new object[] { sender, e });  
           }  
       }  
       void Dfile_FinishDeleteFolderEvent(object sender, EventArgs e)  
       {  
           if (!this.InvokeRequired)  
           {  
               this.lblHint.Visible = false;  
               MessageBox.Show("刪除完畢！");  
           }  
           else  
           {  
               this.BeginInvoke(new DefaulEventDelegate(Dfile_FinishDeleteFolderEvent),new object[] { sender,e });  
           }  
       }  
       void Dfile_FinishDeleteFileEvent(object sender, EventArgs e)  
       {  
           if (!this.InvokeRequired)  
           {  
               this.lblHint.Visible = false;  
               MessageBox.Show("刪除完畢！");  
           }  
           else  
           {  
               this.BeginInvoke(new DefaulEventDelegate(Dfile_FinishDeleteFileEvent), new object[] { sender, e });  
           }  
       }  
}