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Welcome to our newest blog post, where we explore the vibrant realm of MVVM
(Model-View-ViewModel) architecture using the cutting-edge MVVM Toolkit in
.NET MAUI. In this comprehensive guide, we will unravel the intricacies of
MVVM and demonstrate how the MVVM Toolkit in .NET MAUI empowers developers to
create robust, responsive, and easily maintainable cross-platform mobile
applications. Join us on this enlightening journey as we unravel the secrets
of mastering MVVM in the context of .NET MAUI.
Launch Visual Studio 2022, and in the start window click Create a new
project to create a new project.
In the Create a new project window, select MAUI in the All project types
drop-down, select the .NET MAUI App template, and click the Next button:
In the configure your new project window, name your project, choose a
suitable location for it, and click the Next button:
- In the Additional information window, click the Create button:
Once the project is created, we can able to see the Android, iOS, Windows
and other running options in the toolbar. Press the emulator or run button
to build and run the app
In this steps, we will see the steps to install “MVVM Toolkit” in .NET MAUI
Access NuGet Package Manager: In Visual Studio, right-click on your
.NET MAUI project in the Solution Explorer. From the context menu, select
“Manage NuGet Packages.”
Search for “CommunityToolkit.Mvvm”: In the NuGet Package Manager,
click on the “Browse” tab. In the search bar, type “CommunityToolkit.Mvvm”
and hit Enter. The package should appear in the search results.
Select and Install the Package: Once you find “CommunityToolkit.Mvvm”
in the search results, click on it to select it. Ensure you choose the
appropriate version compatible with your .NET MAUI project. Click on the
“Install” button to begin the installation process.
Accept License Agreement: During the installation, you may be
prompted to accept the license agreement. Review the terms and conditions
and click on the “Accept” button to proceed.
Wait for Installation to Complete: Visual Studio will download and
install the package along with its dependencies. This process may take a few
moments, depending on your internet connection speed.
Verify Installation: After the installation is complete, verify that
there are no error messages in the Output window. This indicates a
successful installation of the package.
In this step, we create a ViewModel that inherits from the ObservableObject
class. This inheritance is pivotal because ObservableObject implements the
INotifyPropertyChanged interface. By doing so, we gain the ability to
trigger the PropertyChanged event, a vital mechanism enabling the
notification of property value changes to subscribers, primarily the UI.
This synchronization is fundamental for effective data binding, ensuring
seamless coordination between the user interface and the underlying
public partial class ItemEntryPageModel : ObservableObject [ObservableProperty] private int _id; [ObservableProperty] private string _name; [ObservableProperty] private string _description; [ICommand] public async void Save() await Application.Current.MainPage.DisplayAlert("MAUI MVVM Sample", "Item Saved Successfully", "OK");
When we use the [ObservableProperty] attribute, properties can send
automatic alerts when they change. This is important for connecting data and
updating the user interface (UI) when properties change. When you apply the
[ObservableProperty] attribute to a property, it does a lot of necessary
coding work behind the scenes. It sets up the code needed to tell other
parts of the program when a property changes. This attribute saves time
because you don’t have to write all this code manually. For Example:
“_description” & “_name” produces “Description” & “Name”
The [ICommand] implementation is a way to connect methods or actions
in the app with what the user sees on the screen. For instance, it can
create a command called SaveCommand that’s linked to the Save method. This
linking is crucial for making sure that when a user does something, like
clicking a button, the right action happens in the app.
Finally, we will design the View, where we create the user interface using
XAML. Here, we connect the UI elements to the ViewModel properties using
data binding expressions.
This connection enables the View to show and modify task data in real-time,
ensuring a dynamic and responsive user experience.
<?xml version="1.0" encoding="utf-8" ?> <ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="MauiMVVM.Views.ItemEntryPage" Title="Item Entry"> <StackLayout Margin="20" Spacing="10"> <VerticalStackLayout> <Label Text="Name:" FontSize="16"/> <Entry Text="Binding Name" Placeholder="Item Name"/> </VerticalStackLayout> <VerticalStackLayout> <Label Text="Description:" FontSize="16"/> <Entry Text="Binding Description" Placeholder="Item Description"/> </VerticalStackLayout> <Button x:Name="btn_save" Text="Save" Command="Binding SaveCommand"/> </StackLayout> </ContentPage>
ViewModel and the View without manual intervention.
View. When the title changes, it instantly updates in the UI.
for handling events manually.
Wire-up View and View Model
The created view and view model should be added in MauiProgram.cs like below.
var builder = MauiApp.CreateBuilder(); builder .UseMauiApp<App>() .ConfigureFonts(fonts => fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular"); fonts.AddFont("OpenSans-Semibold.ttf", "OpenSansSemibold"); ); #if DEBUG builder.Logging.AddDebug(); #endif builder.Services.AddTransient<ItemEntryPage>(); builder.Services.AddTransient<ItemEntryPageModel>(); return builder.Build();
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