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Xcalibur.Extensions.MVVM.V2 1.0.5

Xcalibur.Extensions.MVVM.V2

👁 .NET Version
👁 NuGet

A comprehensive .NET MVVM extension library providing base models, commands, validation, and property subscription utilities for use in WPF, UWP, Xamarin, and MAUI applications.

Created by: Joshua Arzt | Company: Xcalibur Systems, LLC.

📋 Table of Contents

• Features
  • Base Models
  • Commands
  • Validation
  • Subscriptions
  • Extensions
• Installation
• Requirements
• Usage
  • ModelBase
  • ValidationModelBase
  • RelayCommand
  • RelayCommand<T>
  • RelayCommandAsync
  • RelayCommandAsync<T>
  • Property Subscriptions
  • Validation Helper
• API Overview
• Dependencies
• License

Features

Base Models

• ModelBase: Abstract base class implementing INotifyPropertyChanged with unique instance identity (Guid), active state tracking, and property change notification via NotifyOfChange
• ValidationModelBase: Extends ModelBase with full data annotation–based validation, validation exception tracking, and an ObservableCollection of validation errors

Commands

• RelayCommand: Synchronous ICommand implementation exposing an Action and optional CanExecute evaluator to the view, with RaiseCanExecuteChanged support
• RelayCommand<T>: Generic variant of RelayCommand accepting a typed parameter
• RelayCommandAsync: Asynchronous ICommand implementation wrapping a Func<Task>, with automatic execution-guard to prevent re-entrant invocations and RaiseCanExecuteChanged support
• RelayCommandAsync<T>: Generic variant of RelayCommandAsync accepting a typed parameter

Validation

• ValidationHelper: Static helper providing key-input validation (numeric-only, decimal support) and data annotation–based model validation utilities
• ValidationModelBase: Integrates ValidationHelper to expose structured ValidationExceptionItem collections directly on the model

Subscriptions

• SubscriptionItem / ISubscriptionItem: Represents a named property subscription, linking a callback action to a specific property's change event
• SubscriptionExtensions: Fluent extension methods (Subscribe, ClearSubscriptions) for registering and removing strongly-typed property subscriptions using lambda expressions

Extensions

• ModelBaseExtensions: Extension methods that augment ModelBase with additional convenience functionality
• SubscriptionExtensions: Strongly-typed, expression-based subscribe/unsubscribe extensions targeting any ISubscribe implementation

Installation

NuGet Package Manager

Install-Package Xcalibur.Extensions.MVVM.V2

.NET CLI

dotnet add package Xcalibur.Extensions.MVVM.V2

Package Reference

<PackageReference Include="Xcalibur.Extensions.MVVM.V2" Version="1.0.5" />

Requirements

• .NET 8 or .NET 10
• Xcalibur.Extensions.V2 (included as dependency)

Usage

ModelBase

Inherit from ModelBase to get INotifyPropertyChanged, a unique Guid identifier, IsActive tracking, and property subscription support out of the box.

using Xcalibur.Extensions.MVVM.V2.Models;

public class PersonViewModel : ModelBase
{
 private string _name;

 public string Name
 {
 get => _name;
 set => NotifyOfChange(value, ref _name);
 }
}

ValidationModelBase

Inherit from ValidationModelBase to add data annotation–based validation on top of ModelBase.

using System.ComponentModel.DataAnnotations;
using Xcalibur.Extensions.MVVM.V2.Models;

public class LoginViewModel : ValidationModelBase
{
 private string _username;

 [Required(ErrorMessage = "Username is required.")]
 public string Username
 {
 get => _username;
 set => NotifyOfChange(value, ref _username);
 }

 public bool TryLogin()
 {
 Validate();
 return IsValid;
 }
}

RelayCommand

using Xcalibur.Extensions.MVVM.V2.Commands;

public class MyViewModel : ModelBase
{
 public RelayCommand SaveCommand { get; }

 public MyViewModel()
 {
 SaveCommand = new RelayCommand(OnSave, CanSave);
 }

 private bool CanSave() => true;
 private void OnSave() { /* save logic */ }
}

RelayCommand<T>

using Xcalibur.Extensions.MVVM.V2.Commands;

public class MyViewModel : ModelBase
{
 public RelayCommand<string> GreetCommand { get; }

 public MyViewModel()
 {
 GreetCommand = new RelayCommand<string>(name => Console.WriteLine($"Hello, {name}!"));
 }
}

RelayCommandAsync

using Xcalibur.Extensions.MVVM.V2.Commands;

public class MyViewModel : ModelBase
{
 public RelayCommandAsync LoadCommand { get; }

 public MyViewModel()
 {
 LoadCommand = new RelayCommandAsync(OnLoadAsync);
 }

 private async Task OnLoadAsync()
 {
 await Task.Delay(500); // simulate async work
 }
}

RelayCommandAsync<T>

using Xcalibur.Extensions.MVVM.V2.Commands;

public class MyViewModel : ModelBase
{
 public RelayCommandAsync<int> FetchCommand { get; }

 public MyViewModel()
 {
 FetchCommand = new RelayCommandAsync<int>(async id =>
 {
 var result = await FetchDataAsync(id);
 });
 }
}

Property Subscriptions

Subscribe to a specific property's change event using a strongly-typed lambda expression. Subscriptions can be scoped to an owner Guid for easy cleanup.

using Xcalibur.Extensions.MVVM.V2.Extensions;

var vm = new PersonViewModel();

// Subscribe to Name changes
vm.Subscribe(x => x.Name, newValue =>
{
 Console.WriteLine($"Name changed to: {newValue}");
});

// Clear the Name subscription
vm.ClearSubscriptions(x => x.Name);

Validation Helper

using Xcalibur.Extensions.MVVM.V2.Helpers;

// Check if a keycode is numeric-only (e.g., in a PreviewKeyDown handler)
bool isNumeric = ValidationHelper.IsKeyNumericOnly(e.KeyValue);

// Allow decimals as well
bool isNumericWithDecimal = ValidationHelper.IsKeyNumericOnly(e.KeyValue, allowDecimals: true);

API Overview

Dependencies

License

Licensed under the .

Copyright © 2006 – 2026, Xcalibur Systems, LLC. All Rights Reserved.