nhab / WPF-CommunityToolkit-HelloWorld

A Hello,World! sample app for WPF MVVM CommunityToolkit.

Setup

• To use CommunityToolkit.Mvvm in the project, its nuget package is added to the project
• The application Main window is set In the StartupUrl property of Application tag of App.xaml
• Set Datacontext of the mainWindow.xaml to the corresponding viewModel:

xmlns:viewmodels1="clr-namespace:ViewModels;assembly=Domains"
d:DataContext="{d:DesignInstance Type= viewmodels1:MainWindowViewModel}"

or set the datacontext in the code behind of the MainWindow xaml:

 public MainWindow()
 {
     DataContext = new MainWindow_ViewModel();
     InitializeComponent();
 }

Relay command

• The Button funcionality is set in the command property :

 <Button  Command="{Binding ClickCommand}"  ... />

• The real impelementation of the Click command is in Click() method > MainWindowViewModel class > MainWindowViewModel.cs :

[RelayCommand(CanExecute = nameof(CanClick))]
private async Task Click()

ObservableObject

• MainWindowViewModel inherits form ObservableObject
• It makes notification when a property changed
• For example you define

    [ObservableProperty]
    private DataView dataView1 = new DataView();

CommunityToolkit creates public DataView1 property which can be changed inside the code.for example inside the Click relay command:

 [RelayCommand(CanExecute = nameof(CanClick))]
 private async Task Click()
 {
     DataView1 = FolderService.Get(thePath).DefaultView;   
 }

This will be reflected to any element which is binded to DataView1 in the Xaml file(MainWindow.xaml) for Example:

<DataGrid
    x:Name="datagrid1"
    AutoGenerateColumns="True" 
    ItemsSource="{Binding Path=DataView1}"
 />