Visual Basic

<br />
Public Function TrapKey(ByVal KCode As String) As Boolean<br />
Try<br />
If KCode < 48 Or KCode > 57 Then TrapKey = True<br />
'Add these if you want to allow commas, dots and such: And KCode <> 46 And KCode <> 8 And KCode <> 44<br />
Catch Ex As Exception<br />
Msgbox(Ex.message)<br />
End Try<br />
End Function<br />

Private Sub MyTextBox_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles MyTextBox.KeyPress<br />
e.Handled = TrapKey(Asc(e.KeyChar))<br />
End Sub

Imports System
Imports System.IO
Imports System.Security.AccessControl



Module DirectoryExample

    Sub Main()
        Try
            Dim DirectoryName As String = "TestDirectory"

            Console.WriteLine("Adding access control entry for " + DirectoryName)

            ' Add the access control entry to the directory.
            AddDirectorySecurity(DirectoryName, "MYDOMAIN\MyAccount", FileSystemRights.ReadData, AccessControlType.Allow)

            Console.WriteLine("Removing access control entry from " + DirectoryName)

            ' Remove the access control entry from the directory.
            RemoveDirectorySecurity(DirectoryName, "MYDOMAIN\MyAccount", FileSystemRights.ReadData, AccessControlType.Allow)

            Console.WriteLine("Done.")
        Catch e As Exception
            Console.WriteLine(e)
        End Try

        Console.ReadLine()

    End Sub


    ' Adds an ACL entry on the specified directory for the specified account.
    Sub AddDirectorySecurity(ByVal FileName As String, ByVal Account As String, ByVal Rights As FileSystemRights, ByVal ControlType As AccessControlType)
        ' Create a new DirectoryInfoobject.
        Dim dInfo As New DirectoryInfo(FileName)

        ' Get a DirectorySecurity object that represents the 
        ' current security settings.
        Dim dSecurity As DirectorySecurity = dInfo.GetAccessControl()

        ' Add the FileSystemAccessRule to the security settings. 
        dSecurity.AddAccessRule(New FileSystemAccessRule(Account, Rights, ControlType))

        ' Set the new access settings.
        dInfo.SetAccessControl(dSecurity)