<code><font color=green>'benötigte API-Funktionen und Konstanten</font>
Private Declare Function SendMessage Lib "user32" Alias _
  "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As _
  Long, ByVal wParam As Long, lParam As Any) As Long
 
Private Const EM_LINEFROMCHAR = &HC9
 
<font color=green>'Ermittelt die aktuelle Zeile des Eingabecursors innerhalb 
'einer (Richt-)Textbox. Einfach das Handle der (Rich-)Textbox übergeben.</font>
Public Function GetCurrentLine(hWnd As Long) As Long
  GetCurrentLine = SendMessage(hWnd, EM_LINEFROMCHAR, -1, ByVal 0&) + 1
End Function</code>

<code>Private Sub RichTextBox1_SelChange()
  lblZeile.Caption = GetCurrentLine(RichTextBox1.hWnd)
End Sub</code>