Limiting text entered to two lines

My idea to create a second XamTextEditor did not work - I realized that I didn't have access to the LineCount property unless I was getting an event on the underlying textbox. Suggestion: can you in future features of NetAdvantage for WPF provide the LineCount property in the XamTextEditor? Alternatively, is there any way I could get the line count directly from a XamTextEditor today?

Instead, I tried out another idea of adding a character to the already typed string and then checking the LineCount. This way, I can stop the user from typing the next character that would cause the LineCount to be greater than 2.

This worked and I copy the code below - I also took care of not allowing paste (CTRL-V, this should be ok in our case) and some other stuff:

<Window.Resources>
     <ControlTemplate x:Key="XamTextEditorControlTemplate3" TargetType="{x:Type igEditors:XamTextEditor}">
     <Border x:Name="MainBorder" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}">
       <TextBox Background="#00FFFFFF" BorderBrush="#00FFFFFF" BorderThickness="0,0,0,0" Foreground="{TemplateBinding Foreground}" HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}" Padding="{TemplateBinding Padding}" VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}" ContextMenu="{TemplateBinding ContextMenu}" x:Name="PART_FocusSite" MaxLength="{Binding Path=ValueConstraint.MaxLength, Mode=OneWay, RelativeSource={RelativeSource TemplatedParent}}" Text="{Binding Path=Text, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}, UpdateSourceTrigger=PropertyChanged}" TextAlignment="{TemplateBinding TextAlignmentResolved}" TextWrapping="{TemplateBinding TextWrapping}" HorizontalScrollBarVisibility="{TemplateBinding HorizontalScrollBarVisibility}" IsReadOnly="{TemplateBinding ReadOnly}" VerticalScrollBarVisibility="{TemplateBinding VerticalScrollBarVisibility}" AcceptsReturn="True" MaxLines="2"/>
     </Border>
     <ControlTemplate.Triggers>
       <Trigger Property="IsInEditMode" Value="True">
        <Setter Property="IsTabStop" Value="False"/>
       </Trigger>
     </ControlTemplate.Triggers>
     </ControlTemplate>
</Window.Resources>

  Private Sub OnKeyUpOrDown(ByVal sender As Object, ByVal e As System.Windows.Input.KeyEventArgs)
    Dim iLineCount As Integer = 0
    Dim oTextBox As TextBox
    Dim sText1 As String = ""
    Dim sText2 As String = ""
    Dim iCaretPosition As Integer = 0

    If TypeOf sender Is TextBox Then
      oTextBox = CType(sender, TextBox)
      iCaretPosition = oTextBox.SelectionStart

      If e.Key = Input.Key.Enter And oTextBox.LineCount > 1 Then ' Do not allow a third line
        e.Handled = True
      ElseIf e.Key = Key.V And Keyboard.Modifiers = ModifierKeys.Control Then ' Do not allow Paste
        e.Handled = True
      ElseIf e.Key = Key.Tab Or e.Key = Key.Back Or e.Key = Key.CapsLock Or e.Key = Key.Delete _
             Or e.Key = Key.Left Or e.Key = Key.Right Or e.Key = Key.Down Or e.Key = Key.End Or e.Key = Key.Up Or e.Key = Key.RightShift _
             Or e.Key = Key.LeftShift Or e.Key = Key.PageDown Or e.Key = Key.PageUp Or e.Key = Key.Home Then
        e.Handled = False
      Else
        sText1 = oTextBox.Text
        sText2 = sText1 + "A" ' I add one more character to check if we are going to go over two lines when the next key is pressed
        oTextBox.Text = sText2

        iLineCount = oTextBox.LineCount
        If iLineCount > 2 Then e.Handled = True

        oTextBox.Text = sText1 ' Restore the original value

        Try
          oTextBox.SelectionStart = iCaretPosition ' Restore the original caret position (when we set the value back it was reset to the first character)
        Catch ex As Exception ' just in case there are no characters
        End Try
      End If
    End If
  End Sub