Microsoft Community Toolkit is an open-source project that provides a set of controls, services, and helpers for building Windows applications. One of the key features of the toolkit is its support for the Model-View-ViewModel (MVVM) pattern. In this blog post, we'll explore how to use Microsoft Community Toolkit for MVVM and how it can help simplify the development of Windows applications.
Step 1: Install the Microsoft Community Toolkit
The first step to using the Microsoft Community Toolkit for MVVM is to install it. You can install the toolkit through NuGet, the .NET package manager. You can do this by right-clicking on your project in the Solution Explorer, selecting "Manage NuGet Packages," and searching for "Microsoft.Toolkit.Mvvm." Click "Install" to add the package to your project.
Step 2: Set up the MVVM Structure
Once you have installed the Microsoft Community Toolkit, you can start setting up the MVVM structure. The MVVM pattern separates the user interface from the application logic, making it easier to maintain and test code. To set up the MVVM structure, you'll need to create three folders: Models, Views, and ViewModels. These folders will hold the classes that represent the data, user interface, and application logic.
Step 3: Create the Model
The Model contains the data and business logic of your application. In the Models folder, create a new class that represents the data you want to display in your application.
I want to create a simple application that displays a list of contacts.
So i will create a new class called "Contact" that represents a single contact. This class should contain properties for the contact's name, phone number, and email address. Here's an example of what the Contact class might look like:
public class Contact
{
public string Name { get; set; }
public string PhoneNumber { get; set; }
public string EmailAddress { get; set; }
}
Step 4: Create the ViewModel
The ViewModel acts as a bridge between the Model and the View. In the ViewModels folder, create a new class that inherits from the Microsoft.Toolkit.Mvvm.ComponentModel.ObservableObject class. This class will contain the properties and commands that your View will bind to.
I will create a new class called "ContactsViewModel" that inherits from the Microsoft.Toolkit.Mvvm.ComponentModel.ObservableObject class. This class will contain the properties and commands that your View will bind to.
Add a property of type ObservableCollection<Contact> called "Contacts" to the ContactsViewModel class. This property will hold the list of contacts that you want to display in your application.
Add a method called "LoadContacts" to the ContactsViewModel class. This method should populate the Contacts property with a list of contacts. Here's an example of what the ContactsViewModel class might look like:
public class ContactsViewModel : ObservableObject
{
private ObservableCollection<Contact> _contacts;
public ObservableCollection<Contact> Contacts
{
get => _contacts;
set => SetProperty(ref _contacts, value);
}
public ContactsViewModel()
{
LoadContacts();
}
private void LoadContacts()
{
// Populate the Contacts property with a list of contacts
Contacts = new ObservableCollection<Contact>
{
new Contact { Name = "John", PhoneNumber = "000-1234", EmailAddress = "john@example.com" },
new Contact { Name = "Smith", PhoneNumber = "000-5678", EmailAddress = "smith@example.com" },
new Contact { Name = "Johnson", PhoneNumber = "000-9876", EmailAddress = "johnson@example.com" }
};
}
}
Step 5: Create the View
The View is the user interface of your application. In the Views folder, create a new XAML file that represents the layout of your user interface. You can bind the controls in the View to the properties and commands in the ViewModel using the Binding syntax.
I will create a new XAML file called "ContactsView" that represents the layout of your user interface. This file should contain a ListView control that is bound to the Contacts property in the ViewModel.
Here's an example of what the ContactsView might look like:
<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:viewModels="clr-namespace:YourProject.ViewModels"
x:Class="YourProject.Views.ContactsView"
DataContext="{Binding ContactsViewModel, Source={StaticResource Locator}}">
<ListBox ItemsSource="{Binding Contacts}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding Name}" />
<TextBlock Text="{Binding PhoneNumber}" />
<TextBlock Text="{Binding EmailAddress}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Page>
Locator
In the context of the Microsoft Community Toolkit for MVVM, the "Locator" refers to a class that serves as a centralized location for creating and managing instances of view models in an MVVM (Model-View-ViewModel) architecture.
The Locator is typically implemented as a static class with static properties that expose instances of view model classes. These properties are then bound to the DataContext of Views in XAML, using the Binding markup extension syntax.
The purpose of using a Locator is to decouple the creation of view models from the Views that consume them, and to enable dependency injection and testability in an MVVM architecture. By using a Locator, Views can bind to view models without having to explicitly create or manage them, and the application can swap out different view model implementations at runtime without affecting the Views that consume them.
Step 6: Add the ViewModel to the View
Once you have created the Model, ViewModel, and View, you can add the ViewModel to the View. In the View's code-behind file, set the DataContext property to an instance of the ViewModel. This will allow the View to access the properties and commands in the ViewModel.
In the View's code-behind file, set the DataContext property to an instance of the ContactsViewModel. This will allow the View to access the Contacts property of the ViewModel.
public partial class ContactsView : Window
{
public ContactsView()
{
InitializeComponent();
DataContext = new ContactsViewModel();
}
}
Conclusion:
Microsoft Community Toolkit for MVVM provides a set of tools and services to simplify the development of Windows applications using the MVVM pattern. By following these six steps, you can create a simple Windows application that separates the user interface from the application logic. This will make your code easier to maintain and test, and provide a better experience for your users.
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