Display special characters in WPF TextBox

Question

I have a string like [VIP], but textbox only shows it as [VIP]. How can i display this special characters atleast as squares like in browser? Tried to set multiple font families(<Setter Property="FontFamily" Value="Arial, Symbol"/>), but it does not work. I dont wanna use richtextbox because its hugely increase window rendering time.

upd: well, stackoverflow text renderer eating this characters too, so the string is "\u0001[\u0004VIP\u0001] "

Answer 1

I hope I understood your question well.

Add the attached property of the below to your project. it could converts "[" character to the "\u0001".

class CharacterConvertBehavior : DependencyObject
{
    public static bool GetConvertEnable(DependencyObject obj)
    {
        return (bool)obj.GetValue(ConvertEnableProperty);
    }

    public static void SetConvertEnable(DependencyObject obj, bool value)
    {
        obj.SetValue(ConvertEnableProperty, value);
    }

    // Using a DependencyProperty as the backing store for ConvertEnable.  This enables animation, styling, binding, etc...
    public static readonly DependencyProperty ConvertEnableProperty =
        DependencyProperty.RegisterAttached("ConvertEnable", typeof(bool), typeof(CharacterConvertBehavior), new PropertyMetadata(ConvertEnableChanged));


    private static void ConvertEnableChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var textBox = d as TextBox;

        if ((bool)e.NewValue == true)
            textBox.PreviewKeyDown += TextBox_ConvertHandler;
        else
            textBox.PreviewKeyDown -= TextBox_ConvertHandler;
    }


    #region Convert Handler
    private static void TextBox_ConvertHandler(object sender, KeyEventArgs e)
    {
        var textBox = sender as TextBox;

        if (e.Key == Key.Oem4)  // "["
        {
            string convertString = "\\u0001";
            TextCompositionManager.StartComposition(new TextComposition(InputManager.Current, textBox, convertString));

            e.Handled = true;
        }
    }
    #endregion
}

In this fashion, you could add the feature you want.

The above code could be used in the main project as shown below.

<Window x:Class="StackOverFlowAnswers.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:attached="clr-namespace:Parse.WpfControls.AttachedProperties"
        xmlns:local="clr-namespace:StackOverFlowAnswers"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.Resources>
        <Style x:Key="ConvertableTextBox" TargetType="TextBox">
            <Setter Property="attached:CharacterConvertBehavior.ConvertEnable" Value="True"/>
        </Style>
    </Window.Resources>

    <Grid>
        <TextBox Style="{StaticResource ConvertableTextBox}"/>
    </Grid>
</Window>