How to Folder Lock and Unlock (Vb.net)

The following code shows you how to lock and unlock the browsed folder.
For this you have to first browse the folder and then lock it. This namespaces is used to achieve this : 

Imports System.Security.AccessControl

Imports System.Security.AccessControl

Imports System.IO

Private Sub btnBrowse_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnBrowse.Click

        With FolderBrowserDialog1

            If .ShowDialog() = DialogResult.OK Then

                TextBox1.Text = .SelectedPath

            End If

        End With

End Sub

Private Sub btnLock_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLock.Click

    Dim fs As FileSystemSecurity = File.GetAccessControl(TextBox1.Text)

    fs.AddAccessRule(New FileSystemAccessRule(Environment.UserName, FileSystemRights.FullControl, AccessControlType.Deny))

    File.SetAccessControl(TextBox1.Text, fs)

End Sub

Private Sub btnUnLock_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnUnLock.Click

    Dim fs As FileSystemSecurity = File.GetAccessControl(TextBox1.Text)

    fs.RemoveAccessRule(New FileSystemAccessRule(Environment.UserName, FileSystemRights.FullControl, AccessControlType.Deny))

    File.SetAccessControl(TextBox1.Text, fs)

End Sub