Public Class frmPicTextBox
 
    Dim WithEvents pb As New PictureBox With _
          {.Parent = Me, .Dock = DockStyle.Fill}
    Dim WithEvents tb As New TextBox With _
          {.Parent = Me, .Dock = DockStyle.Fill, .Multiline = True}
 
 
    Dim cv As Boolean 'Sichtbarkeit des Cursors
    Dim WithEvents TIM As New Timer With _
          {.Interval = 500, .Enabled = True}
 
 
    Private Sub frmPicTextBox_KeyDown(sender As Object, _
        e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
 
        tb.Top = Me.Height 'Textbox bleibt unsichtbar
        tb.Focus()
    End Sub
 
 
 
    Private Sub frmPicTextBox_Load(sender As System.Object, _
        e As System.EventArgs) Handles MyBase.Load
 
        KeyPreview = True
    End Sub
 
 
    Private Sub tb_KeyUp(sender As Object, _
       e As System.Windows.Forms.KeyEventArgs) Handles tb.KeyUp
        pb.Invalidate() 
       'Textänderungen in der Picturebox anzeigen
    End Sub
 
 
    Private Sub TIM_Tick(sender As Object, _
        e As System.EventArgs) Handles TIM.Tick
        cv = Not cv
        pb.Invalidate() 'Cursor blinken lassen
    End Sub
 
 
    Private Sub pb_Paint(sender As Object, _
        e As System.Windows.Forms.PaintEventArgs) Handles pb.Paint
 
        Dim txt As String, c As String = " "
        If cv Then c = "|"
 
        'Text-Cursor einfügen         
        txt = tb.Text.Insert(tb.SelectionStart, c)
        Me.Text = tb.SelectionStart.ToString
 
        Using br As New SolidBrush(tb.ForeColor)
            e.Graphics.DrawString(txt, tb.Font, br, 0, 0)
        End Using
    End Sub
 
End Class