Update workspace event registration

Author: davidwengier

src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Discovery/ProjectStateChangeDetector.TestAccessor.cs

@@ -39,7 +39,7 @@ public Task ListenForWorkspaceChangesAsync(params WorkspaceChangeKind[] kinds)
 
         public void WorkspaceChanged(WorkspaceChangeEventArgs e)
         {
-            instance.Workspace_WorkspaceChanged(instance, e);
+            instance.Workspace_WorkspaceChanged(e);
         }
     }
 }

src/Razor/src/Microsoft.VisualStudio.LanguageServices.Razor/Discovery/ProjectStateChangeDetector.cs

@@ -37,7 +37,7 @@ public override int GetHashCode()
     private readonly ProjectSnapshotManager _projectManager;
     private readonly LanguageServerFeatureOptions _options;
     private readonly CodeAnalysis.Workspace _workspace;
-
+    private readonly WorkspaceEventRegistration _changeRegistration;
     private readonly CancellationTokenSource _disposeTokenSource;
     private readonly AsyncBatchingWorkQueue<Work> _workQueue;
     private readonly HashSet<Work> _workerSet;
@@ -80,7 +80,7 @@ public ProjectStateChangeDetector(
         _projectManager.Changed += ProjectManager_Changed;
 
         _workspace = workspaceProvider.GetWorkspace();
-        _workspace.WorkspaceChanged += Workspace_WorkspaceChanged;
+        _changeRegistration = _workspace.RegisterWorkspaceChangedHandler(Workspace_WorkspaceChanged);
 
         // This will usually no-op, in the case that another project snapshot change trigger
         // immediately adds projects we want to be able to handle those projects.
@@ -95,7 +95,7 @@ public void Dispose()
         }
 
         _projectManager.Changed -= ProjectManager_Changed;
-        _workspace.WorkspaceChanged -= Workspace_WorkspaceChanged;
+        _changeRegistration.Dispose();
 
         _disposeTokenSource.Cancel();
         _disposeTokenSource.Dispose();
@@ -118,7 +118,7 @@ private ValueTask ProcessBatchAsync(ImmutableArray<Work> items, CancellationToke
         return default;
     }
 
-    private void Workspace_WorkspaceChanged(object? sender, WorkspaceChangeEventArgs e)
+    private void Workspace_WorkspaceChanged(WorkspaceChangeEventArgs e)
     {
         switch (e.Kind)
         {

src/Razor/src/Microsoft.VisualStudioCode.RazorExtension/RazorWorkspaceListenerBase.cs

@@ -4,7 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
-using System.Diagnostics;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
@@ -29,6 +28,7 @@ internal abstract class RazorWorkspaceListenerBase : IDisposable
 
     private Stream? _stream;
     private Workspace? _workspace;
+    private WorkspaceEventRegistration? _changeRegistration;
     private bool _disposed;
 
     internal record Work(ProjectId ProjectId);
@@ -45,10 +45,7 @@ protected RazorWorkspaceListenerBase(ILogger logger)
 
     public void Dispose()
     {
-        if (_workspace is not null)
-        {
-            _workspace.WorkspaceChanged -= Workspace_WorkspaceChanged;
-        }
+        _changeRegistration?.Dispose();
 
         if (_disposed)
         {
@@ -57,7 +54,7 @@ public void Dispose()
         }
 
         _disposed = true;
-        _logger.LogInformation("Tearing down named pipe for pid {pid}", Process.GetCurrentProcess().Id);
+        _logger.LogInformation("Tearing down named pipe for pid {pid}", Environment.ProcessId);
 
         _disposeTokenSource.Cancel();
         _disposeTokenSource.Dispose();
@@ -105,11 +102,11 @@ private protected void EnsureInitialized(Workspace workspace, Func<Stream> creat
         }
 
         _workspace = workspace;
-        _workspace.WorkspaceChanged += Workspace_WorkspaceChanged;
+        _changeRegistration = _workspace.RegisterWorkspaceChangedHandler(Workspace_WorkspaceChanged);
         _stream = createStream();
     }
 
-    private void Workspace_WorkspaceChanged(object? sender, WorkspaceChangeEventArgs e)
+    private void Workspace_WorkspaceChanged(WorkspaceChangeEventArgs e)
     {
         switch (e.Kind)
         {

src/Razor/test/Microsoft.AspNetCore.Razor.Test.Common.Tooling/Workspaces/WorkspaceTestBase.cs

@@ -126,7 +126,7 @@ protected Task<bool> UpdateWorkspaceAsync(Solution solution)
             {
                 var currentCount = 0;
 
-                Workspace.WorkspaceChanged += OnWorkspaceChanged;
+                using var _ = Workspace.RegisterWorkspaceChangedHandler(OnWorkspaceChanged);
 
                 if (!Workspace.TryApplyChanges(solution))
                 {
@@ -142,10 +142,9 @@ protected Task<bool> UpdateWorkspaceAsync(Solution solution)
                 }
                 while (lastCount != currentCount);
 
-                Workspace.WorkspaceChanged -= OnWorkspaceChanged;
                 return true;
 
-                void OnWorkspaceChanged(object? sender, WorkspaceChangeEventArgs e)
+                void OnWorkspaceChanged(WorkspaceChangeEventArgs e)
                 {
                     currentCount++;
                 }