Add a Breakpoints Margin

Environment

Product Version	2020.3.1130
Product	RadSyntaxEditor for WPF

Description

Make it possible to add breakpoints to the RadSyntaxEditor control.

Solution

1. Create a custom IndicatorsMargin<Ellipse> to hold the breakpoints collection as shown in Example 1.

Example 1: Creating a Custom IndicatorsMargin

public class BreakpointsMargin : IndicatorsMargin<Ellipse> 
{ 
    public BreakpointsMargin(RadSyntaxEditor syntaxEditor) 
        : base(syntaxEditor) 
    { 
        this.IndicatorBrush = new SolidColorBrush(Color.FromArgb(255, 210, 47, 47)); 
    } 
 
    protected override void UpdateIndicator(Ellipse ellipse, int lineNumber) 
    { 
        if (ellipse.Width != this.Editor.EditorFontSize) 
        { 
            ellipse.Width = this.Editor.EditorFontSize; 
        } 
 
        if (ellipse.Height != this.Editor.EditorFontSize) 
        { 
            ellipse.Height = this.Editor.EditorFontSize; 
        } 
 
        if (ellipse.Fill != this.IndicatorBrush) 
        { 
            ellipse.Fill = this.IndicatorBrush; 
        } 
    } 
} 

2. Add a BreakpointsMargin instance to the Margins collection of the control, register a LineHighlightTagger in the TaggersRegistry of the RadSyntaxEditor and define an appropriate TextFormatDefinition.

Example 2: Registering the LineHighlightTagger

public partial class MainWindow : Window 
{ 
    private BreakpointsMargin breakpointsMargin; 
    private LineHighlightTagger breakpointsTagger; 
 
    public MainWindow() 
    { 
        InitializeComponent();  
        using (StreamReader reader = new StreamReader("../../MainWindow.xaml.cs")) 
        { 
            this.syntaxEditor.Document = new TextDocument(reader); 
        } 
 
        var cSharpTagger = new CSharpTagger(this.syntaxEditor); 
        this.syntaxEditor.TaggersRegistry.RegisterTagger(cSharpTagger); 
 
        var foldingTagger = new CSharpFoldingTagger(this.syntaxEditor); 
        this.syntaxEditor.TaggersRegistry.RegisterTagger(foldingTagger); 
 
        this.breakpointsMargin = new BreakpointsMargin(this.syntaxEditor); 
        this.syntaxEditor.Margins.ScrollableLeft.Insert(0, breakpointsMargin); 
        this.breakpointsMargin.Indicators.CollectionChanged += OnIndicatorsCollectionChanged; 
 
        this.breakpointsTagger = new LineHighlightTagger(this.syntaxEditor, LineHighlightTagger.LineHighlightFormatDefinition); 
        this.syntaxEditor.TaggersRegistry.RegisterTagger(this.breakpointsTagger); 
 
        var breakpointBrush = this.breakpointsMargin.IndicatorBrush; 
        this.syntaxEditor.TextFormatDefinitions.AddLast(LineHighlightTagger.LineHighlightFormatDefinition, 
 new TextFormatDefinition(null, breakpointBrush, null, new Pen(breakpointBrush, 2))); 
    } 
 
    private void OnIndicatorsCollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e) 
    { 
        this.breakpointsTagger.HighlightLines(this.breakpointsMargin.Indicators); 
    } 
} 

Figure 1: RadSyntaxEditor with breakpoints

See Also

• Margins
• Taggers