WPF Resize Text In Control MouseWheelScroll Event

CodeBehind.cs

    private void MouseWheelScroll(object sender, MouseWheelEventArgs e)
    {
        if (Keyboard.Modifiers != ModifierKeys.Control)
            return;
        var delta = (e.Delta > 0) ? 2 : -2;
        var change = VM.MainFontSize + delta;
        if (change < 8)
            change = 8;
        VM.MainFontSize = change;
    }

VM.CS

    private double _MainFontSize;

    public double MainFontSize
    {
        get => _MainFontSize;
        set { _MainFontSize = value; OnPropertyChanged(nameof(MainFontSize)); }
    }

Window.Xaml

<TabItem Header="Tree" Width="100" Height="40">
    <TreeView x:Name="tView"  HorizontalAlignment="Stretch" FontSize="{Binding MainFontSize}" PreviewMouseWheel="MouseWheelScroll" />
</TabItem>
<TabItem Header="Text" Width="100" Height="40">
    <TextBox Text="{Binding JSONText}" PreviewMouseWheel="MouseWheelScroll" FontSize="{Binding MainFontSize}" />
</TabItem>