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

C#

    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

C#

    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