GetTextBoxCurrentLine - Determine the current line in a multiline TextBox control

<System.Runtime.InteropServices.DllImport("user32")> Shared Function _
    SendMessage(ByVal hWnd As Integer, ByVal wMsg As Integer, _
    ByVal wParam As Integer, ByVal lParam As Integer) As Integer
End Function

' Determine the current line in a multiline TextBox control
' Example: MessageBox.Show(GetTextBoxCurrentLine(TextBox1))

Function GetTextBoxCurrentLine(ByVal tb As TextBox) As Integer
    Const EM_LINEFROMCHAR As Integer = &HC9
    Return SendMessage(tb.Handle.ToInt32(), EM_LINEFROMCHAR, -1, 0) + 1
End Function