How to find and implement an event which gets called on Expand of nodes (project or folder) in Solution Explorer ??

Question

Hello Visual Studio Extension Experts,

1. I am struggling to get the event, which gets called when a user Expands any node (project or folder) in Solution Explorer in Visual Studio. (I want to implement a logic to get latest status of file from source repo on the expand click of a user.)
2. Also, I am trying to find the visibility of the files while opening any solution in visual studio. Some files may be already visible. And some files might be hidden due to folder/project is not expanded. (So status of only visible files can be fetched from the source repo.)

It would be really helpful for me if the above 2 things are resolved for me. It will help me in implementing source control manager extension.

Answer 1

I tried to use IVsHierarchy.AdviseHierarchyEvents with VSHPROPID_Expanded to IVsSolution , but the event is not fire.

So next, I tried registering event detect from tree control.

// PresentationCore
// PresentationFramework
// System.Xaml
// WindowsBase

using System;
using System.Runtime.InteropServices;
using System.Threading;
using Microsoft.VisualStudio.Shell;
using Microsoft.VisualStudio.Shell.Interop;
using System.Collections.Generic;
using System.Linq;
using static Microsoft.VisualStudio.ErrorHandler;

namespace Gekka.VisualStudio.SolutionExploreExpandHackPackage
{
    [PackageRegistration(UseManagedResourcesOnly = true, AllowsBackgroundLoading = true)]
    [ProvideAutoLoad(Microsoft.VisualStudio.Shell.Interop.UIContextGuids.NoSolution, PackageAutoLoadFlags.BackgroundLoad)]
    [ProvideAutoLoad(Microsoft.VisualStudio.Shell.Interop.UIContextGuids.EmptySolution, PackageAutoLoadFlags.BackgroundLoad)]
    [ProvideAutoLoad(Microsoft.VisualStudio.Shell.Interop.UIContextGuids.SolutionExists, PackageAutoLoadFlags.BackgroundLoad)]
    [ProvideAutoLoad(Microsoft.VisualStudio.Shell.Interop.UIContextGuids.SolutionHasSingleProject, PackageAutoLoadFlags.BackgroundLoad)]
    [ProvideAutoLoad(Microsoft.VisualStudio.Shell.Interop.UIContextGuids.SolutionHasMultipleProjects, PackageAutoLoadFlags.BackgroundLoad)]
    [Guid(SolutionExploreExpandHackPackage.PackageGuidString)]
    public sealed class SolutionExploreExpandHackPackage : AsyncPackage
    {
        public const string PackageGuidString = "026bc0c8-e89a-412e-aae1-66a5f34f7727";

        protected override async System.Threading.Tasks.Task InitializeAsync(CancellationToken cancellationToken, IProgress<ServiceProgressData> progress)
        {
            await this.JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);

            System.Windows.EventManager.RegisterClassHandler
                (typeof(Microsoft.Internal.VisualStudio.PlatformUI.PivotTreeView)
                , Microsoft.Internal.VisualStudio.PlatformUI.PivotTreeView.PreviewMouseDownEvent
                , new System.Windows.RoutedEventHandler((s, e) =>
                {
                    if (s.GetType().Name.Contains("SolutionPivotTreeView"))
                    {
                        var ptv = (Microsoft.Internal.VisualStudio.PlatformUI.PivotTreeView)s;
                        ptv.NodeExpanded -= treeView_NodeExpanded;
                        ptv.NodeExpanded += treeView_NodeExpanded;
                    }
                }), true);
        }

        private void treeView_NodeExpanded(object sender, Microsoft.Internal.VisualStudio.PlatformUI.TreeNodeEventArgs e)
        {
            if (e.Node != null)
            {
                 Dump(e.Node, 0);
            }           
        }

        private static void Dump(Microsoft.Internal.VisualStudio.PlatformUI.IVirtualizingTreeNode node, int lv)
        {
              ThreadHelper.ThrowIfNotOnUIThread();
            if (node.Item is Microsoft.VisualStudio.Shell.IAttachedCollectionSource cs)
            {
                if (cs.SourceItem is Microsoft.VisualStudio.Shell.IVsHierarchyItem hitem)
                {
                    IVsHierarchyItemIdentity hii = hitem.HierarchyIdentity;

                    Succeeded(hii.Hierarchy.GetProperty(hii.ItemID, (int)__VSHPROPID.VSHPROPID_Name, out var name));
                    Succeeded(hii.Hierarchy.GetProperty(hii.ItemID, (int)__VSHPROPID.VSHPROPID_Caption, out var caption));
                    Succeeded(hii.Hierarchy.GetProperty(hii.ItemID, (int)__VSHPROPID2.VSHPROPID_IsLinkFile, out var isLink));
                    
                    System.Diagnostics.Debug.WriteLine($"{new string(' ', lv)}└ {caption}\t{name}\t{isLink}");

                }
            }
            foreach (Microsoft.Internal.VisualStudio.PlatformUI.IVirtualizingTreeNode childNode in node.ChildNodes)
            {
                Dump(childNode, lv + 1);
            }
        }
    }

}

Solution Explore can be displayed in multiple views, this code can detect expand the nodes in each view.