How to Lock Folder in C#

[Costas]

using NTFS permissions

//source - http://stackoverflow.com/a/21728004
using System.IO;
using System.Security.AccessControl;

private void btnBrowse_Click(object sender, EventArgs e)
{

   if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
   {
        // Select the folder to lock
        textBox1.Text = folderBrowserDialog1.SelectedPath;
   }

}

private void btnLock_Click(object sender, EventArgs e)
{
  try
     {

      string folderPath = textBox1.Text;
      string adminUserName = Environment.UserName;// getting your adminUserName
      DirectorySecurity ds = Directory.GetAccessControl(folderPath);
      FileSystemAccessRule fsa = new FileSystemAccessRule(adminUserName, FileSystemRights.FullControl, AccessControlType.Deny)    
      ds.AddAccessRule(fsa);
      Directory.SetAccessControl(folderPath, ds);
      MessageBox.Show("Locked");
     }
     catch (Exception ex)
     {
        MessageBox.Show(ex.Message);
     }       
}

private void btnUnLock_Click(object sender, EventArgs e)
{
   try
      {
     string folderPath = textBox1.Text;
     string adminUserName = Environment.UserName;// getting your adminUserName
     DirectorySecurity ds = Directory.GetAccessControl(folderPath);
     FileSystemAccessRule fsa = new FileSystemAccessRule(adminUserName,FileSystemRights.FullControl, AccessControlType.Deny)    
     ds.RemoveAccessRule(fsa);
     Directory.SetAccessControl(folderPath, ds);
     MessageBox.Show("UnLocked");
     }
     catch (Exception ex)
     {
        MessageBox.Show(ex.Message);
     } 
}

kids - http://itknowledgeexchange.techtarget.com/itanswers/folder-lock/