WPF RTL (Right-to-Left) Support

Implement bidirectional text and mirrored layouts for RTL languages.

1. RTL Languages

Language	Culture Code	Direction
Arabic	ar-SA, ar-EG	RTL
Hebrew	he-IL	RTL
Persian (Farsi)	fa-IR	RTL
Urdu	ur-PK	RTL

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2. Setting FlowDirection

2.1 Window Level

<!-- Left-to-Right (default) -->
<Window FlowDirection="LeftToRight"
        Title="My Application">

<!-- Right-to-Left -->
<Window FlowDirection="RightToLeft"
        Title="التطبيق">

2.2 Element Level

<Window FlowDirection="RightToLeft">
    <StackPanel>
        <!-- Inherits RTL from parent -->
        <TextBlock Text="مرحبا بالعالم"/>

        <!-- Override to LTR for specific content -->
        <TextBlock FlowDirection="LeftToRight"
                   Text="user@example.com"/>
    </StackPanel>
</Window>

2.3 Resource-Based

<Window FlowDirection="{DynamicResource AppFlowDirection}">

<!-- In ResourceDictionary -->
<FlowDirection x:Key="AppFlowDirection">RightToLeft</FlowDirection>

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3. Dynamic FlowDirection

3.1 Based on Culture

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        SetFlowDirection();
    }

    private void SetFlowDirection()
    {
        var culture = Thread.CurrentThread.CurrentUICulture;
        FlowDirection = culture.TextInfo.IsRightToLeft
            ? FlowDirection.RightToLeft
            : FlowDirection.LeftToRight;
    }
}

3.2 Language Switching

public void SwitchLanguage(string cultureName)
{
    var culture = new CultureInfo(cultureName);

    Thread.CurrentThread.CurrentCulture = culture;
    Thread.CurrentThread.CurrentUICulture = culture;

    // Update FlowDirection
    Application.Current.MainWindow.FlowDirection =
        culture.TextInfo.IsRightToLeft
            ? FlowDirection.RightToLeft
            : FlowDirection.LeftToRight;
}

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4. Mirroring Behavior

4.1 What Gets Mirrored

Element	Mirrored
Text alignment	✅
StackPanel Horizontal	✅
Grid columns	✅
Margins/Padding	✅
ScrollBar position	✅
Menu items	✅

4.2 What Should NOT Be Mirrored

<!-- Images (logos, icons) -->
<Image Source="logo.png" FlowDirection="LeftToRight"/>

<!-- Phone numbers -->
<TextBlock FlowDirection="LeftToRight" Text="+1-234-567-8900"/>

<!-- Email addresses -->
<TextBlock FlowDirection="LeftToRight" Text="user@example.com"/>

<!-- Numbers in specific format -->
<TextBlock FlowDirection="LeftToRight" Text="12345"/>

<!-- Progress bars -->
<ProgressBar FlowDirection="LeftToRight" Value="75"/>

<!-- Sliders -->
<Slider FlowDirection="LeftToRight" Value="50"/>

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5. Bidirectional Text

5.1 Mixed Content

<!-- Arabic text with English -->
<TextBlock>
    <Run Text="مرحبا "/>
    <Run FlowDirection="LeftToRight" Text="John"/>
    <Run Text=" كيف حالك؟"/>
</TextBlock>

5.2 TextBlock with Mixed Direction

<TextBlock FlowDirection="RightToLeft">
    السعر: <Run FlowDirection="LeftToRight">$99.99</Run>
</TextBlock>

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6. Layout Considerations

6.1 Grid Layout

<!-- RTL: Column 0 appears on right -->
<Grid FlowDirection="RightToLeft">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto"/>  <!-- Right side in RTL -->
        <ColumnDefinition Width="*"/>
        <ColumnDefinition Width="Auto"/>  <!-- Left side in RTL -->
    </Grid.ColumnDefinitions>

    <TextBlock Grid.Column="0" Text="الاسم:"/>
    <TextBox Grid.Column="1"/>
    <Button Grid.Column="2" Content="حفظ"/>
</Grid>

6.2 DockPanel

<!-- RTL: DockPanel.Dock="Left" appears on right -->
<DockPanel FlowDirection="RightToLeft">
    <Button DockPanel.Dock="Left" Content="القائمة"/>  <!-- Right side -->
    <TextBlock Text="المحتوى"/>
</DockPanel>

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7. Testing RTL

// Force RTL for testing (even on LTR system)
public partial class App : Application
{
    protected override void OnStartup(StartupEventArgs e)
    {
        // Test with Arabic culture
        var culture = new CultureInfo("ar-SA");
        Thread.CurrentThread.CurrentCulture = culture;
        Thread.CurrentThread.CurrentUICulture = culture;

        base.OnStartup(e);
    }
}

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8. Common Pitfalls

Issue	Solution
Icons look wrong	Set FlowDirection="LeftToRight" on Image
Numbers reversed	Wrap in Run with LTR
Progress bar wrong	Set FlowDirection="LeftToRight"
Checkbox text spacing	Check Margin/Padding

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9. References

• Bidirectional Features - Microsoft Docs
• FlowDirection - Microsoft Docs