Question

I want to DataBind between those two controls in xaml how I do so ?

 <MenuItem Header="_Log" IsCheckable="True"/>

 <TextBox Name="_commandsRichTextBox" ,Visibility="Collapsed"/>

And I wrote a converter:

class BoolToVisibilityConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (targetType != typeof(Visibility))
                throw new InvalidOperationException("The target must be a Visibility");

            return (bool)value ? Visibility.Visible : Visibility.Collapsed;    

        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }

And I now have an issue to connect everything.

Thanks for helper .

Answer 1

There already is a converter for that: BooleanToVisibilityConverter

<Window.Resources>
    <BooleanToVisibilityConverter x:Key="converter"/>
</Window.Resources>
<!-- ... -->
<MenuItem Name="mi" Header="_Log" IsCheckable="True"/>
<TextBox Name="_commandsRichTextBox" Visibility="{Binding IsChecked, ElementName=mi, Converter={StaticResource converter}}"/>

I would only recommend binding from control to control if you can be sure that the data stays in the view, otherwise create a bindable property and just bind both controls to that, the MenuItem will change the value and the TextBox will react.