ConvMVVM3 (Convergence MVVM3) is a modern, cross-platform MVVM framework that combines the best features from Prism and Community Toolkit while adding unique innovations.

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📌 XAML Namespace Mapping

ConvMVVM3 exposes a single XAML XML namespace for a clean, consistent XAML experience:

<Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:convMVVM3="https://github.com/gellston/ConvMVVM3"
    convMVVM3:ViewModelLocator.AutoWireViewModel="True">
</Window>

• xmlns:convMVVM3="https://github.com/gellston/ConvMVVM3" → ConvMVVM3 XAML features (Regions, ViewModelLocator, Behaviors/Interactivity, etc.)
• convMVVM3:ViewModelLocator.AutoWireViewModel="True" → ViewModel auto-wiring (Prism-like)

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✨ Key Differentiators from Prism & Community Toolkit

🚀 UIDispatcher (UNIQUE - Cross-Platform)

Microsoft-compatible UI thread dispatcher for multiple platforms:

// Setup - Available for WPF, MAUI, Avalonia, WinUI
services.AddWPFUIDispatcher();      // WPF

// Usage - Cross-platform compatible
await dispatcher.InvokeAsync(() => Title = "Updated");

🔌 Smart Dependency Injection (UNIQUE - Built-in)

Lightweight service container with addon system - No external DI required:

// Built-in container - Zero external dependencies
services.AddSingleton<IMyService, MyService>();

📡 WeakReference Messenger (Memory-Safe, Cross-Platform)

Thread-safe messaging with automatic cleanup:

// Automatic weak references - Platform-agnostic
WeakReferenceMessenger.Default.Send<Message>(this, newData);

🎯 Region System (Prism-inspired, Cross-Platform)

Built-in region management for multiple frameworks:

<!-- Works on WPF, MAUI, Avalonia, WinUI -->
<ContentControl convMVVM3:RegionPlugin.RegionName="MainContent" />

⚡ Source Generator (Community Toolkit-inspired)

Automatic property and command generation with enhanced features:

[ObservableProperty] private string title;       // Generates Title property
[RelayCommand] private void Save();              // Generates SaveCommand
[AsyncRelayCommand] private async Task Load();   // Generates LoadCommand

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🏗️ Architecture Overview

Core MVVM Components (Platform-Agnostic)

ConvMVVM3.Core/
├── ObservableObject              # Base class with INotifyPropertyChanged
├── ObservableRecipient           # Message recipient base class
├── UIDispatcher                  # Cross-platform dispatcher interface
├── WeakReferenceMessenger        # Memory-safe messaging system
├── Commands/
│   ├── RelayCommand              # Synchronous command implementation
│   └── AsyncRelayCommand         # Async command with cancellation
└── DependencyInjection/          # Built-in DI container

WPF Implementation (One of Many Platforms)

ConvMVVM3.WPF/                    # WPF-specific implementation
├── Regions/                      # Region system (Prism-inspired)
├── WPFUIDispatcher               # WPF-specific dispatcher
├── Interactivity/                # Behaviors / triggers / actions
└── WeakEventManager              # Memory-efficient event handling

Source Generation (Cross-Platform)

ConvMVVM3.SourceGenerator/
├── ObservableProperty generation # Auto property implementation
├── RelayCommand generation       # Auto command creation
├── Dependency tracking           # Smart property notification
└── Compile-time validation       # Early error detection

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📁 Project Structure

ConvMVVM3.Core/                   # Platform-agnostic MVVM library
ConvMVVM3.SourceGenerator/        # Cross-platform source generator
ConvMVVM3.WPF/                    # WPF-specific interactivity + regions
ConvMVVM3.Host/                   # DI host implementation
ConvMVVM3.WPF.Tests/              # WPF unit tests
ConvMVVM3.Tests/                  # Core unit tests

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🛠️ Installation

dotnet add package ConvMVVM3

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🚀 Quick Start

1) Basic ViewModel with Cross-Platform Generation

// Works on ALL supported platforms
public partial class MainViewModel : ObservableObject
{
    [ObservableProperty]
    private string title = "Hello ConvMVVM3!";

    [RelayCommand]
    private void ShowMessage() => MessageBox.Show(Title);

    [AsyncRelayCommand]
    private async Task LoadDataAsync()
    {
        Title = "Loading...";
        await Task.Delay(1000);
        Title = "Data Loaded!";
    }
}

2) ViewModelLocator (AutoWireViewModel)

<Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:convMVVM3="https://github.com/gellston/ConvMVVM3"
    convMVVM3:ViewModelLocator.AutoWireViewModel="True">
    <!-- View content -->
</Window>

3) Cross-Platform UIDispatcher Integration

// Setup varies by platform
services.AddWPFUIDispatcher();       // WPF

// Usage is identical across platforms
public partial class MyViewModel : ObservableObject
{
    private readonly IUIDispatcher _dispatcher;

    public MyViewModel(IUIDispatcher dispatcher)
    {
        _dispatcher = dispatcher;
    }

    [AsyncRelayCommand]
    private async Task UpdateFromBackgroundAsync()
    {
        var data = await Task.Run(() => GetHeavyData());

        // Thread-safe UI update (cross-platform)
        await _dispatcher.InvokeAsync(() => Title = data);
    }
}

4) Cross-Platform Region Management

<!-- Works on WPF, MAUI, Avalonia, WinUI -->
<Grid>
    <ContentControl convMVVM3:RegionPlugin.RegionName="MainContent" />
</Grid>

// Platform-agnostic navigation
_regionManager.RequestNavigate("MainContent", typeof(HomeViewModel));

5) Memory-Safe Cross-Platform Messaging

// Sender (all platforms)
WeakReferenceMessenger.Default.Send<DataUpdatedMessage>(this, newData);

// Receiver (auto-cleanup, all platforms)
public partial class MyViewModel : ObservableObject, IRecipient<DataUpdatedMessage>
{
    public void Receive(DataUpdatedMessage message)
    {
        Title = message.Data;
    }
}

6) WPF Interactivity / Behaviors

<Button Content="Click Me">
    <convMVVM3:Interaction.Triggers>
        <convMVVM3:EventTrigger EventName="Click">
            <convMVVM3:InvokeCommandAction Command="{Binding SaveCommand}" />
        </convMVVM3:EventTrigger>
    </convMVVM3:Interaction.Triggers>
</Button>

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🧰 Helpful Utilities

This section includes a few practical helpers used frequently in Prism-style MVVM apps:

• ConvMVVM3.Core.Mvvm.Threading
• ConvMVVM3.Core.Mvvm.Collections
• ConvMVVM3.Host.DependencyInjection

A) BusyScope — ConvMVVM3.Core.Mvvm.Threading

Use a scope to ensure IsBusy is always restored (even if an exception occurs).
Recommended for simple “single operation” flows.

using ConvMVVM3.Core.Mvvm.Threading;

// In your ViewModel
private bool _isBusy;
public bool IsBusy
{
    get => _isBusy;
    set { _isBusy = value; /* RaisePropertyChanged */ }
}

public async Task RefreshAsync()
{
    using (BusyScope.Enter(v => IsBusy = v))
    {
        await LoadAsync();
    }
}

B) BusyCounterScope (Recommended) — ConvMVVM3.Core.Mvvm.Threading

Recommended when operations can overlap (nested calls, multiple async commands).

using ConvMVVM3.Core.Mvvm.Threading;

private int _busyCount;
private bool _isBusy;
public bool IsBusy
{
    get => _isBusy;
    set { _isBusy = value; /* RaisePropertyChanged */ }
}

public async Task RefreshAsync()
{
    using (BusyCounterScope.Enter(
        getCount: () => _busyCount,
        setCount: v => _busyCount = v,
        setBusy:  v => IsBusy = v))
    {
        await LoadAsync();
    }
}

C) OperationGuard — ConvMVVM3.Core.Mvvm.Threading

Prevents re-entrancy (double-click save, multiple async executions).
Combine it with BusyScope/BusyCounterScope for a great UX.

using ConvMVVM3.Core.Mvvm.Threading;

private readonly OperationGuard _saveGuard = new OperationGuard();
private int _busyCount;

public Task SaveAsync()
{
    return _saveGuard.RunAsync(async () =>
    {
        using (BusyCounterScope.Enter(
            () => _busyCount,
            v => _busyCount = v,
            v => IsBusy = v))
        {
            await SaveAsyncCore();
        }
    });
}

D) ObservableRangeCollection — ConvMVVM3.Core.Mvvm.Collections

Use AddRange/ReplaceRange to avoid thousands of per-item collection change notifications.

using ConvMVVM3.Core.Mvvm.Collections;

public ObservableRangeCollection<ItemViewModel> Items { get; } = new();

public async Task LoadItemsAsync()
{
    var items = await LoadFromServerAsync();

    // One reset notification instead of N adds
    Items.ReplaceRange(items);
}

E) ActivatorUtilities — ConvMVVM3.Host.DependencyInjection

ActivatorUtilities helps create objects by mixing:

• DI-resolved services from IServiceResolver
• runtime arguments you provide (e.g., IDs, parameters, view references)

using ConvMVVM3.Core.DependencyInjection.Abstractions;
using ConvMVVM3.Host.DependencyInjection;

// Example types
public sealed class UserDetailsViewModel
{
    public UserDetailsViewModel(IUserService service, int userId)
    {
        // service comes from DI, userId comes from runtime args
    }
}

public static class Example
{
    public static void CreateWithRuntimeArgs(IServiceResolver resolver)
    {
        // 1) CreateInstance: DI + runtime args
        var vm = (UserDetailsViewModel)ActivatorUtilities.CreateInstance(
            resolver,
            typeof(UserDetailsViewModel),
            123);

        // 2) GetServiceOrCreateInstance: prefer registered instance, otherwise create
        var shell = ActivatorUtilities.GetServiceOrCreateInstance<MainShellViewModel>(resolver);

        // 3) CreateFactory: preselect ctor + argument mapping for speed
        var factory = ActivatorUtilities.CreateFactory(
            typeof(UserDetailsViewModel),
            new[] { typeof(int) });

        var vmFast = (UserDetailsViewModel)factory(resolver, new object[] { 456 });
    }
}

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🧩 Bootstrapper

ConvMVVM3 supports a Prism-style Bootstrapper flow for registering modules, building the shell, and initializing regions/services.

public class AppBootStrapper : Bootstrapper
{
    protected override void ConfigureRegion(IRegionManager regionManager)
    {
    }

    protected override Window CreateShell(IServiceContainer provider)
    {
        return (Window)provider.GetService("MainWindowView");
    }

    protected override void OnInitialized(IServiceContainer provider)
    {
    }

    protected override void RegisterModules()
    {
        this.RegisterModule<AModule>();
        this.RegisterModule<BModule>();
        this.RegisterModule<CModule>();
        this.RegisterModule<MainModule>();
    }

    protected override void RegisterServices(IServiceRegistry container)
    {
    }
}

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🎯 Platform Support Matrix

Feature	WPF	MAUI	Avalonia	WinUI	UNO
Core MVVM	✅	✅	✅	✅	✅
UIDispatcher	✅	🔄	🔄	🔄	🔄
Source Generator	✅	✅	✅	✅	✅
Region System	✅	🔄	🔄	🔄	🔄
Built-in DI	✅	✅	✅	✅	✅
Weak Messenger	✅	✅	✅	✅	✅
WPF Interactivity	✅	❌	❌	❌	❌
Platform Interactivity	❌	🔄	🔄	🔄	🔄

✅ Available | 🔄 Planned | ❌ Not applicable

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📄 License

MIT License - see LICENSE file

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ConvMVVM3: Modern, cross-platform MVVM framework that bridges the gap between Prism's power and Community Toolkit's simplicity while adding unique cross-platform innovations.

Future Roadmap: MAUI, Avalonia, WinUI, and UNO Platform support coming soon!