Imports System.Windows.Forms
Imports System.Drawing
Imports System.ComponentModel
 
Public Class MaskedTextBox
    Inherits TextBox
 
    Dim KeyAscii As Integer
    Private _Mask As String
 
    <Description("Gibt das Format an. (z.B. ##.##.#### oder ##.####)"), _
    Category("Eingabe"), _
    DefaultValue(GetType(String), "##.##.####"), _
    Browsable(True)> _
    Public Property Mask() As String
        Get
            Return _Mask
        End Get
        Set(ByVal Value As String)
            _Mask = Value
            Me.Text = ""
        End Set
    End Property
 
    Protected Overrides Sub OnKeyPress(ByVal e As KeyPressEventArgs)
        If Mask = "" Then Exit Sub
        e.Handled = True
 
        KeyAscii = Asc(e.KeyChar)
        Dim NewText As String = Me.Text
        Dim del As Boolean = False
 
        Dim i As Integer
        If KeyAscii = 8 Then
            If Not NewText = "" Then
                If del = False Then
                    NewText = Microsoft.VisualBasic.Left(NewText, Len(NewText) _
                      - 1)
                    del = True
                End If
            End If
        Else
            If KeyAscii >= 32 And KeyAscii <= 126 Then
                For i = Me.SelectionStart To _Mask.Length - 1
                    Select Case _Mask.Chars(i)
                        Case CType("#", Char)
 
                            If Char.IsDigit(e.KeyChar) = True Then
                                NewText &= e.KeyChar.ToString()
                                Exit For
                            Else
                            End If
                        Case CType("$", Char)
 
                            If Char.IsLetter(e.KeyChar) = True Then
                                NewText &= e.KeyChar.ToString()
                                Exit For
                            End If
                        Case Else
 
                            NewText = NewText & _Mask.Chars(i)
 
                    End Select
                Next
            End If
        End If
 
        Me.Text = NewText
        Me.SelectionStart = Me.Text.Length
 
    End Sub
 
    Protected Overrides Sub OnKeyDown(ByVal e As KeyEventArgs)
        e.Handled = True
    End Sub
 
End Class