Extension to detect when a string get hovered on the document

Question

I'm trying to create a Visual Studio 2022 extension to detect whenever a specific string on a .cpp or .h file get hovered, the project atm have only two files.

I have set a breakpoint on InitializeAsync of ImagePackage.cs, when i start debugging the extension it does hit and does print:

MEF components initialized successfully.

I also have set breakpoints on all functions of Image.cs but no one gets hit.

I'm missing something anywhere to make the hover detection to work?

ImagePackage.cs

using Microsoft.VisualStudio.ComponentModelHost;
using Microsoft;
using Microsoft.VisualStudio.Shell;
using System;
using System.Runtime.InteropServices;
using System.Threading;
using Task = System.Threading.Tasks.Task;
using Microsoft.VisualStudio.Text.Classification;
using Microsoft.VisualStudio.Text.Operations;
using Microsoft.VisualStudio.Shell.Interop;
namespace Image
{
    [PackageRegistration(UseManagedResourcesOnly = true, AllowsBackgroundLoading = true)]
    [Guid(ImagePackage.PackageGuidString)]
    [ProvideAutoLoad(UIContextGuids.NoSolution, PackageAutoLoadFlags.BackgroundLoad)] // Ensure it loads when VS starts
    public sealed class ImagePackage : AsyncPackage
    {
        public const string PackageGuidString = "908f5230-d345-4ee5-a854-d9397bfa6ede";
        #region Package Members
        protected override async Task InitializeAsync(CancellationToken cancellationToken, IProgress<ServiceProgressData> progress)
        {
            await this.JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
            // Get the IComponentModel service to initialize MEF components
            var componentModel = (IComponentModel)await GetServiceAsync(typeof(SComponentModel));
            Assumes.Present(componentModel);
            var navigatorService = componentModel.GetService<ITextStructureNavigatorSelectorService>();
            var formatMapService = componentModel.GetService<IEditorFormatMapService>();
            Assumes.Present(navigatorService);
            Assumes.Present(formatMapService);
            
            System.Diagnostics.Debug.WriteLine("MEF components initialized successfully.");
        }
        #endregion
    }
}

Image.cs

using System;
using System.ComponentModel.Composition;
using System.Windows;
using System.Windows.Input;
using System.Windows.Media;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Editor;
using Microsoft.VisualStudio.Text.Operations;
using Microsoft.VisualStudio.Utilities;
using Microsoft.VisualStudio.Text.Classification;
using Microsoft.VisualStudio.Text.Formatting;

namespace Image
{
    [Export(typeof(IMouseProcessorProvider))]
    [Name("WordHoverMouseProcessorProvider")]
    [ContentType("code")] //[ContentType("C/C++")]
    [TextViewRole(PredefinedTextViewRoles.Editable)]
    internal sealed class WordHoverMouseProcessorProvider : IMouseProcessorProvider
    {
        [Export(typeof(AdornmentLayerDefinition))]
        [Name("WordHoverAdornmentLayer")]
        [Order(After = PredefinedAdornmentLayers.Selection, Before = PredefinedAdornmentLayers.Text)]
        public AdornmentLayerDefinition WordHoverAdornmentLayerDefinition;

        [Import]
        internal ITextStructureNavigatorSelectorService NavigatorService { get; set; }

        [Import]
        internal IEditorFormatMapService FormatMapService { get; set; }

        public IMouseProcessor GetAssociatedProcessor(IWpfTextView wpfTextView)
        {
            return wpfTextView.Properties.GetOrCreateSingletonProperty(() => 
                new WordHoverMouseProcessor(wpfTextView, NavigatorService.GetTextStructureNavigator(wpfTextView.TextBuffer), FormatMapService.GetEditorFormatMap(wpfTextView)));
        }
    }

    internal class WordHoverMouseProcessor : MouseProcessorBase
    {
        private readonly IWpfTextView _textView;
        private readonly ITextStructureNavigator _navigator;
        private readonly IEditorFormatMap _formatMap;
        private readonly IAdornmentLayer _adornmentLayer;

        public WordHoverMouseProcessor(IWpfTextView textView, ITextStructureNavigator navigator, IEditorFormatMap formatMap)
        {
            _textView = textView;
            _navigator = navigator;
            _formatMap = formatMap;
            _adornmentLayer = textView.GetAdornmentLayer("WordHoverAdornmentLayer");
        }

        public override void PostprocessMouseMove(MouseEventArgs e)
        {
            SnapshotPoint? point = GetMousePosition(e);

            if (!point.HasValue)
                return;

            TextExtent extent = _navigator.GetExtentOfWord(point.Value);
            string wordUnderMouse = extent.Span.GetText();

            if (wordUnderMouse.Contains("test123"))
            {
                HighlightWord(extent.Span);
                MessageBox.Show("Word 'test123' detected!", "Word Hover Extension");
            }
            else
            {
                ClearHighlight();
            }
        }

        private SnapshotPoint? GetMousePosition(MouseEventArgs e)
        {
            Point position = e.GetPosition(_textView.VisualElement);
            return _textView.TextViewLines.GetTextViewLineContainingYCoordinate(position.Y)
                ?.GetBufferPositionFromXCoordinate(position.X);
        }

        private void HighlightWord(SnapshotSpan span)
        {
            var properties = _formatMap.GetProperties("Selected Text");
            var brush = properties["Background"] as SolidColorBrush;

            if (brush != null)
            {
                var geometry = _textView.TextViewLines.GetMarkerGeometry(span);
                
                if (geometry != null)
                {
                    var drawing = new GeometryDrawing(brush, new Pen(Brushes.Red, 0.5), geometry);
                    drawing.Freeze();

                    var drawingImage = new DrawingImage(drawing);
                    drawingImage.Freeze();

                    var image = new System.Windows.Controls.Image
                    {
                        Source = drawingImage,
                    };

                    _adornmentLayer.AddAdornment(AdornmentPositioningBehavior.TextRelative, span, null, image, null);
                }
            }
        }

        private void ClearHighlight()
        {
            _adornmentLayer.RemoveAllAdornments();
        }
    }
}

.

Answer 1

I tried your code and it worked as expected.

Have you added MefComponent to Assets in your VSIXManifest file?

Let's modify the constructor of the class so that you can see it being loaded.

namespace Image
{
    [Export(typeof(IMouseProcessorProvider))]
    [Name("WordHoverMouseProcessorProvider")]
    [ContentType("code")] //[ContentType("C/C++")]
    [TextViewRole(PredefinedTextViewRoles.Editable)]
    internal sealed class WordHoverMouseProcessorProvider : IMouseProcessorProvider
    {
        static WordHoverMouseProcessorProvider()
        {
            System.Diagnostics.Debug.WriteLine("Success MEF Load");
        }

        public WordHoverMouseProcessorProvider()
        {

        }