Option Explicit
  Dim strText1 As String
 
 
Private Sub TextBox1_Change() 
  If IsNumeric(TextBox1.Text) Then
    If CDec(TextBox1.Text) <> CDec(Format(TextBox1.Text, "0.00")) Then
      TextBox1.Text = Format(TextBox1.Text, "0.00")
    Else
      TextBox1.Text = Replace(TextBox1.Text, ",", "", 1, -1, 1)
    End If
    strText1 = TextBox1.Text
  Else
    If Trim(TextBox1.Text) = "" Then
      TextBox1.Text = ""
      strText1 = ""
    Else
      TextBox1.Text = strText1
    End If
  End If
End Sub
 
Private Sub UserForm_Activate()
  TextBox1.ControlSource = "Tabelle1!$B$2"
  strText1 = TextBox1.Text
End Sub