feat: basic NavigationService && left panel

PCL2.Neo/App.axaml.cs

@@ -1,14 +1,16 @@
-using System;
 using System.Linq;
 using Avalonia;
 using Avalonia.Controls.ApplicationLifetimes;
-using Avalonia.Data.Core;
 using Avalonia.Data.Core.Plugins;
 using Avalonia.Markup.Xaml;
-using PCL2.Neo.Helpers;
-using PCL2.Neo.Utils;
+using CommunityToolkit.Mvvm.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection;
+using PCL2.Neo.Services;
 using PCL2.Neo.ViewModels;
+using PCL2.Neo.ViewModels.Download;
+using PCL2.Neo.ViewModels.Home;
 using PCL2.Neo.Views;
+using System;
 
 namespace PCL2.Neo
 {
@@ -19,14 +21,33 @@
             AvaloniaXamlLoader.Load(this);
         }
 
+        private static IServiceProvider ConfigureServices() => new ServiceCollection()
+            .AddTransient<MainWindowViewModel>()
+
+            .AddTransient<HomeViewModel>()
+            .AddTransient<HomeSubViewModel>()
+
+            .AddTransient<DownloadViewModel>()
+            .AddTransient<DownloadGameViewModel>()
+            .AddTransient<DownloadModViewModel>()
+
+            .AddSingleton<NavigationService>(s => new NavigationService(s))
+            .BuildServiceProvider();
+
         public override void OnFrameworkInitializationCompleted()
         {
+            Ioc.Default.ConfigureServices(ConfigureServices());
+
+            var vm = Ioc.Default.GetRequiredService<MainWindowViewModel>();
             if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
             {
                 // Avoid duplicate validations from both Avalonia and the CommunityToolkit.
                 // More info: https://docs.avaloniaui.net/docs/guides/development-guides/data-validation#manage-validationplugins
                 DisableAvaloniaDataAnnotationValidation();
-                desktop.MainWindow = new MainWindow();
+                desktop.MainWindow = new MainWindow
+                {
+                    DataContext = vm
+                };
             }
 
             base.OnFrameworkInitializationCompleted();
@@ -36,12 +57,12 @@
         {
             // Get an array of plugins to remove
             var dataValidationPluginsToRemove =
                 BindingPlugins.DataValidators.OfType<DataAnnotationsValidationPlugin>().ToArray();
 
             // remove each entry found
             foreach (var plugin in dataValidationPluginsToRemove)
             {
                 BindingPlugins.DataValidators.Remove(plugin);
             }
         }
     }

PCL2.Neo/Attributes.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace PCL2.Neo;
+
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct)]
+public class SubViewModelOfAttribute(Type parentViewModel) : Attribute
+{
+    public Type ParentViewModel { get; } = parentViewModel;
+}
+
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Struct)]
+public class DefaultSubViewModelAttribute(Type subViewModel) : Attribute
+{
+    public Type SubViewModel { get; } = subViewModel;
+}

PCL2.Neo/PCL2.Neo.csproj

@@ -35,8 +35,9 @@
       <PrivateAssets Condition="'$(Configuration)' != 'Debug'">All</PrivateAssets>
     </PackageReference>
     <PackageReference Include="Avalonia.Xaml.Behaviors" Version="11.2.7.1" />
-    <PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.0" />
     <PackageReference Include="DotNet.Bundle" Version="0.9.13" />
+    <PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.0" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="9.0.4" />
   </ItemGroup>
 
   <ItemGroup>
@@ -46,4 +47,22 @@
   <ItemGroup>
     <UpToDateCheckInput Remove="Controls\Style\ListBoxStyle.axaml" />
   </ItemGroup>
+
+  <ItemGroup>
+    <Compile Update="Views\HomeView.axaml.cs">
+      <DependentUpon>HomeLeftView.axaml</DependentUpon>
+    </Compile>
+    <Compile Update="Views\Home\HomeSubView.axaml.cs">
+      <DependentUpon>HomeRightView.axaml</DependentUpon>
+      <SubType>Code</SubType>
+    </Compile>
+    <Compile Update="Views\Download\DownloadGameView.axaml.cs">
+      <DependentUpon>DownloadRightView.axaml</DependentUpon>
+      <SubType>Code</SubType>
+    </Compile>
+    <Compile Update="Views\Download\DownloadModView.axaml.cs">
+      <DependentUpon>DownloadModView.axaml</DependentUpon>
+      <SubType>Code</SubType>
+    </Compile>
+  </ItemGroup>
 </Project>

PCL2.Neo/Services/NavigationService.cs

@@ -0,0 +1,83 @@
+using Microsoft.Extensions.DependencyInjection;
+using PCL2.Neo.ViewModels;
+using System;
+using System.Reflection;
+
+namespace PCL2.Neo.Services;
+
+public class NavigationService
+{
+    public IServiceProvider ServiceProvider { get; init; }
+
+    public event Action<ViewModelBase?>? CurrentViewModelChanged;
+    public event Action<ViewModelBase?>? CurrentSubViewModelChanged;
+
+    private ViewModelBase? _currentViewModel;
+    public ViewModelBase? CurrentViewModel
+    {
+        get => _currentViewModel;
+        protected set
+        {
+            if (value == _currentViewModel)
+                return;
+            _currentViewModel = value;
+            CurrentViewModelChanged?.Invoke(value);
+        }
+    }
+
+    private ViewModelBase? _currentSubViewModel;
+    public ViewModelBase? CurrentSubViewModel
+    {
+        get => _currentSubViewModel;
+        protected set
+        {
+            if (value == _currentSubViewModel)
+                return;
+            _currentSubViewModel = value;
+            CurrentSubViewModelChanged?.Invoke(value);
+        }
+    }
+
+    public NavigationService(IServiceProvider serviceProvider)
+    {
+        ServiceProvider = serviceProvider;
+    }
+
+    public virtual T Goto<T>() where T : ViewModelBase
+    {
+        if (typeof(T).GetCustomAttribute<DefaultSubViewModelAttribute>() is { } dsvm)
+        {
+            var vm = CurrentViewModel as T;
+            if (vm?.GetType() != typeof(T))
+            {
+                vm = ServiceProvider.GetRequiredService<T>();
+                CurrentViewModel = vm;
+            }
+            if (CurrentSubViewModel?.GetType() != dsvm.SubViewModel)
+                CurrentSubViewModel = ServiceProvider.GetRequiredService(dsvm.SubViewModel) as ViewModelBase;
+            return vm;
+        }
+
+        if (typeof(T).GetCustomAttribute<SubViewModelOfAttribute>() is { } svmo)
+        {
+            var subVm = CurrentSubViewModel as T;
+            if (CurrentViewModel?.GetType() != svmo.ParentViewModel)
+                CurrentViewModel = ServiceProvider.GetRequiredService(svmo.ParentViewModel) as ViewModelBase;
+            if (subVm?.GetType() != typeof(T))
+            {
+                subVm = ServiceProvider.GetRequiredService<T>();
+                CurrentSubViewModel = subVm;
+            }
+            return subVm;
+        }
+
+        var targetVm = CurrentViewModel?.GetType() != typeof(T) || CurrentSubViewModel?.GetType() != typeof(T)
+            ? ServiceProvider.GetRequiredService<T>()
+            : (T)CurrentViewModel;
+        if (CurrentViewModel?.GetType() != typeof(T))
+            CurrentViewModel = targetVm;
+        if (CurrentSubViewModel?.GetType() != typeof(T))
+            CurrentSubViewModel = targetVm;
+        return targetVm;
+    }
+}

PCL2.Neo/ViewLocator.cs

@@ -3,28 +3,28 @@
 using Avalonia.Controls.Templates;
 using PCL2.Neo.ViewModels;
 
-namespace PCL2.Neo
+namespace PCL2.Neo;
+
+public class ViewLocator : IDataTemplate
 {
-    public class ViewLocator : IDataTemplate
+    public Control? Build(object? param)
     {
-        public Control? Build(object? param)
-        {
-            if (param is null)
-                return null;
+        if (param is null)
+            return null;
 
-            var name = param.GetType().FullName!.Replace("ViewModel", "View", StringComparison.Ordinal);
-            var type = Type.GetType(name);
+        var name = param.GetType().FullName!.Replace("ViewModel", "View", StringComparison.Ordinal);
+        var type = Type.GetType(name);
 
-            if (type != null)
-            {
-                return (Control)Activator.CreateInstance(type)!;
-            }
-
-            return new TextBlock { Text = "Not Found: " + name };
-        }
-        public bool Match(object? data)
+        if (type != null)
         {
-            return data is ViewModelBase;
+            return (Control)Activator.CreateInstance(type)!;
         }
+
+        return new TextBlock { Text = "Not Found: " + name };
+    }
+
+    public bool Match(object? data)
+    {
+        return data is ViewModelBase;
     }
-}
+}

PCL2.Neo/ViewModels/Download/DownloadGameViewModel.cs

@@ -0,0 +1,7 @@
+namespace PCL2.Neo.ViewModels.Download;
+
+[SubViewModelOf(typeof(DownloadViewModel))]
+public class DownloadGameViewModel : ViewModelBase
+{
+
+}

PCL2.Neo/ViewModels/Download/DownloadModViewModel.cs

@@ -0,0 +1,7 @@
+namespace PCL2.Neo.ViewModels.Download;
+
+[SubViewModelOf(typeof(DownloadViewModel))]
+public class DownloadModViewModel : ViewModelBase
+{
+
+}

PCL2.Neo/ViewModels/DownloadViewModel.cs

@@ -0,0 +1,44 @@
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using PCL2.Neo.Services;
+using PCL2.Neo.ViewModels.Download;
+
+namespace PCL2.Neo.ViewModels;
+
+[DefaultSubViewModel(typeof(DownloadGameViewModel))]
+public partial class DownloadViewModel : ViewModelBase
+{
+    public NavigationService NavigationService { get; }
+
+    [ObservableProperty]
+    private string _message = "I am from DownloadViewModel";
+
+    public DownloadViewModel(NavigationService navigationService)
+    {
+        NavigationService = navigationService;
+    }
+
+    [RelayCommand]
+    private void NavigateToDownloadGame()
+    {
+        this.NavigationService.Goto<DownloadGameViewModel>();
+    }
+
+    [RelayCommand]
+    private void NavigateToDownloadMod()
+    {
+        this.NavigationService.Goto<DownloadModViewModel>();
+    }
+
+    [RelayCommand]
+    private void Btn_Test1()
+    {
+        Message = "I am from DownloadViewModel Test1";
+    }
+
+    [RelayCommand]
+    private void Btn_Test2()
+    {
+        Message = "I am from DownloadViewModel Test2";
+    }
+}

PCL2.Neo/ViewModels/Home/HomeSubViewModel.cs

@@ -0,0 +1,22 @@
+using CommunityToolkit.Mvvm.Input;
+using PCL2.Neo.Services;
+using PCL2.Neo.ViewModels.Download;
+
+namespace PCL2.Neo.ViewModels.Home;
+
+[SubViewModelOf(typeof(HomeViewModel))]
+public partial class HomeSubViewModel : ViewModelBase
+{
+    public NavigationService NavigationService { get; }
+
+    public HomeSubViewModel(NavigationService navigationService)
+    {
+        this.NavigationService = navigationService;
+    }
+
+    [RelayCommand]
+    private void NavigateToDownloadMod()
+    {
+        this.NavigationService.Goto<DownloadModViewModel>();
+    }
+}

PCL2.Neo/ViewModels/HomeViewModel.cs

@@ -0,0 +1,9 @@
+using PCL2.Neo.ViewModels.Home;
+
+namespace PCL2.Neo.ViewModels;
+
+[DefaultSubViewModel(typeof(HomeSubViewModel))]
+public class HomeViewModel : ViewModelBase
+{
+
+}