Using an ItemsSource to populate a WPF ListBox is a good idea?

Question

I am a (relatively) experienced Cocoa / Objective-C encoder, and I myself teach C # and the WPF framework.

In Cocoa, when populated, NSTableViewit is relatively easy to assign a view to the delegate and data source. These delegate / data source methods are then used to populate the table and determine its behavior.

I am building a simple application that has a list of objects, allows you to call them Dogobjects, each of which has public string name. This is the return value Dog.ToString().

Objects will be displayed in ListBox, and I would like to populate this view using a similar Cocoa template NSTableViewDataSource. It currently works using:

public partial class MainWindow : Window, IEnumerable<Dog>
    {
        public Pound pound = new Pound();

        public MainWindow()
        {
            InitializeComponent();

            Dog fido = new Dog();
            fido.name = "Fido";
            pound.AddDog(fido);

            listBox1.ItemsSource = this;

            Dog spot = new Dog();
            spot.name = "Spot";
            pound.AddDog(spot);
        }

        public IEnumerator<Dog> GetEnumerator()
        {
            return currentContext.subjects.GetEnumerator();
        }

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return GetEnumerator();
        }
    }

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• (spot), , ListBox, , ?
• , Pound ?
• ListBox ? ( ?)

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Answer 1

, , ListBox. WPF MVVM, , , .

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, , MVVM, MVVM. , , , , INotifyPropertyChanged ObservableCollection; WPF.

MainWindow, DataContext :

public class MainWindow : Window
{
     // ...
     public MainWindow()
     {
         // Assigning to the DataContext is important
         // as all of the UIElement bindings inside the UI
         // will be a part of this hierarchy
         this.DataContext = new PoundViewModel();

         this.InitializeComponent();
     }
}

PoundViewModel DogViewModel:

public class PoundViewModel
{
    // No WPF application is complete without at least 1 ObservableCollection
    public ObservableCollection<DogViewModel> Dogs
    {
        get;
        private set;
    }

    // Commands play a large role in WPF as a means of 
    // transmitting "actions" from UI elements
    public ICommand AddDogCommand
    {
        get;
        private set;
    }

    public PoundViewModel()
    {
        this.Dogs = new ObservableCollection<DogViewModel>();

        // The Command takes a string parameter which will be provided
        // by the UI. The first method is what happens when the command
        // is executed. The second method is what is queried to find out
        // if the command should be executed
        this.AddDogCommand = new DelegateCommand<string>(
            name => this.Dogs.Add(new DogViewModel { Name = name }),
            name => !String.IsNullOrWhitespace(name)
        );
    }
}

XAML ( xmlns:local, XAML ):

<!-- <Window ...
             xmlns:local="clr-namespace:YourNameSpace" -->
<!-- Binding the ItemsSource to Dogs, will use the Dogs property
  -- On your DataContext, which is currently a PoundViewModel
  -->
<ListBox x:Name="listBox1"
         ItemsSource="{Binding Dogs}">
    <ListBox.Resources>
        <DataTemplate DataType="{x:Type local:DogViewModel}">
            <Border BorderBrush="Black" BorderThickness="1" CornerRadius="5">
                <TextBox Text="{Binding Name}" />
            </Border>
        </DataTemplate>
    </ListBox.Resources>
</ListBox>
<GroupBox Header="New Dog">
    <StackPanel>
        <Label>Name:</Label>
        <TextBox x:Name="NewDog" />

        <!-- Commands are another big part of WPF -->
        <Button Content="Add"
                Command="{Binding AddDogCommand}"
                CommandParameter="{Binding Text, ElementName=NewDog}" />
    </StackPanel>
</GroupBox>

, DogViewModel:

public class DogViewModel : INotifyPropertyChanged
{
    private string name;
    public string Name
    {
        get { return this.name; }
        set
        {
            this.name = value;

            // Needed to alert WPF to a change in the data
            // which will then update the UI
            this.RaisePropertyChanged("Name");
        }
    }

    public event PropertyChangedHandler PropertyChanged;

    private void RaisePropertyChanged(string propertyName)
    {
        var handler = this.PropertyChanged;
        if (handler != null)
            handler(this, new PropertyChangedEventArgs(propertyName));
    }
}

, DelegateCommand<T>:

public class DelegateCommand<T> : ICommand
{
    private readonly Action<T> execute;
    private readonly Func<T, bool> canExecute;
    public event EventHandler CanExecuteChanged;

    public DelegateCommand(Action<T> execute, Func<T, bool> canExecute)
    {
        if (execute == null) throw new ArgumentNullException("execute");
        this.execute = execute;
        this.canExecute = canExecute;
    }

    public bool CanExecute(T parameter)
    {
        return this.canExecute != null && this.canExecute(parameter); 
    }

    bool ICommand.CanExecute(object parameter)
    {
        return this.CanExecute((T)parameter);
    }

    public void Execute(T parameter)
    {
        this.execute(parameter);
    }

    bool ICommand.Execute(object parameter)
    {
        return this.Execute((T)parameter);
    }
}

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Answer 2

• WPF ItemsSource .

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• ListBox.Items.Refresh() , .

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