Implement IDisposable on Views and ViewModels

Directory.Build.props

@@ -1,6 +1,6 @@
 <Project>  
   <PropertyGroup>
-    <Version>0.2.9</Version>
+    <Version>0.3.0</Version>
 
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>

TrailBlazr/Components/ViewContainer.razor

@@ -1,8 +1,12 @@
-<DynamicComponent Type="@this.CurrentViewType" Parameters="@this.CurrentParameters" />
+<CascadingValue Value="this">
+    <DynamicComponent Type="@this.CurrentViewType" Parameters="@this.CurrentParameters" />
+</CascadingValue>
 
 @using Microsoft.Extensions.Logging
 @using TrailBlazr.Models
 @using TrailBlazr.Services
+@using TrailBlazr.Views
+@implements IDisposable
 @code {
     [Inject]
     public required IViewManager ViewManager { get; init; }
@@ -41,4 +45,12 @@
             this.Logger.LogError(ex, "Error changing view to {newView}", request.ViewType.Name);
         }
     }
+
+    public void Dispose()
+    {
+        if (this.ViewManager is not null)
+        {
+            this.ViewManager.ShowViewRequested -= this.UpdateCurrentView;
+        }
+    }
 }

TrailBlazr/ViewModels/ViewModelBase.cs

@@ -3,10 +3,12 @@ using TrailBlazr.Views;
 
 namespace TrailBlazr.ViewModels;
 
-public abstract class ViewModelBase<TViewModel, TView> : INotifyPropertyChanged
+public abstract class ViewModelBase<TViewModel, TView> : INotifyPropertyChanged, IDisposable
     where TViewModel : ViewModelBase<TViewModel, TView>
     where TView : ViewBase<TView, TViewModel>
 {
+    private bool disposed = false;
+
     public event PropertyChangedEventHandler? PropertyChanged;
 
     protected TView? View
@@ -42,4 +44,24 @@ public abstract class ViewModelBase<TViewModel, TView> : INotifyPropertyChanged
     public virtual ValueTask Initialize(CancellationToken cancellationToken) => ValueTask.CompletedTask;
 
     public virtual ValueTask ParametersSet(TView view, CancellationToken cancellationToken) => ValueTask.CompletedTask;
+
+    protected virtual void Dispose(bool disposing)
+    {
+        if (!this.disposed)
+        {
+            if (disposing)
+            {
+                this.View = null;
+                this.PropertyChanged = null;
+            }
+            
+            this.disposed = true;
+        }
+    }
+
+    public void Dispose()
+    {
+        this.Dispose(true);
+        GC.SuppressFinalize(this);
+    }
 }

TrailBlazr/Views/ViewBase.cs

@@ -1,18 +1,22 @@
 using Microsoft.AspNetCore.Components;
 using Microsoft.Extensions.Logging;
+using TrailBlazr.Components;
 using TrailBlazr.ViewModels;
 
 namespace TrailBlazr.Views;
-public abstract class ViewBase<TView, TViewModel> : ComponentBase
+public abstract class ViewBase<TView, TViewModel> : ComponentBase, IDisposable
     where TView : ViewBase<TView, TViewModel>
     where TViewModel : ViewModelBase<TViewModel, TView>
 {
     public readonly static TimeSpan InitializationTimeout = TimeSpan.FromSeconds(5);
+    private bool disposed = false;
 
     [Inject]
-    public TViewModel ViewModel { get; set; } = default!;
+    public required TViewModel ViewModel { get; set; }
     [Inject]
-    protected ILogger<TView> Logger { get; set; } = default!;
+    public required ILogger<TView> Logger { get; set; }
+    [CascadingParameter]
+    public required ViewContainer ViewContainer { get; set; }
 
     protected override async Task OnAfterRenderAsync(bool firstRender)
     {
@@ -27,6 +31,11 @@ public abstract class ViewBase<TView, TViewModel> : ComponentBase
             throw new InvalidOperationException($"View is not of type {typeof(TView).Name}. Actual type: {this.GetType().Name}");
         }
 
+        if (this.ViewContainer is null)
+        {
+            throw new InvalidOperationException("ViewContainer is not set. Ensure that this view is placed within a ViewContainer component");
+        }
+
         this.ViewModel.SetView(view);
         using var initializationCts = new CancellationTokenSource(InitializationTimeout);
         _ = this.ViewModel ?? throw new InvalidOperationException("Cannot initialize ViewModel. ViewModel is null");
@@ -61,5 +70,26 @@ public abstract class ViewBase<TView, TViewModel> : ComponentBase
     {
         await this.InvokeAsync(this.StateHasChanged);
     }
+
+    protected virtual void Dispose(bool disposing)
+    {
+        if (!this.disposed)
+        {
+            if (disposing)
+            {
+                this.ViewModel = null!;
+                this.Logger = null!;
+                this.ViewContainer = null!;
+            }
+
+            this.disposed = true;
+        }
+    }
+
+    public void Dispose()
+    {
+        this.Dispose(true);
+        GC.SuppressFinalize(this);
+    }
 }