Discussion :

[clem_alain]

Bonjour,
Je suis en train de plus ou moins débuter en WPF et j'en suis au Data Binding. Je suis sur un exemple de https://wpf-tutorial.com/fr/38/data-...x-changements/
Cela fonctionne très bien, mais moi je voudrais rafraichir un TextBlock et un Label après que la source de données ait changé, mais cela ne fonctionne pas. Est-ce que quelqu'un pourrait me dire pourquoi, parce que je pédale un peu dans la semoule depuis un bon moment :-(
Voici la partie XAML :

Code :

Sélectionner tout - Visualiser dans une fenêtre à part

1
2
3
4
5
6
7
8
9
10
 
    <Grid Margin="10">
        <Button Name="btnAddUser" Click="btnAddUser_Click" Margin="650,0,0,371">Add user</Button>
        <Button Name="btnChangeUser" Click="btnChangeUser_Click" Margin="650,59,0,313">Change user</Button>
        <Button Name="btnDeleteUser" Click="btnDeleteUser_Click" Margin="650,116,0,255">Delete user</Button>
        <ListBox Name="lbUsers" DisplayMemberPath="Name" BorderBrush="Black" BorderThickness="1 1 1 1" Height="192" Width="300" Margin="10,15,470,207" ></ListBox>
        <TextBox x:Name="tbNom" HorizontalAlignment="Left" Margin="52,287,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="152" Height="25" FontSize="16"/>
        <TextBlock x:Name="tbCopie" VerticalAlignment="Top" Width="202" Height="25" FontSize="16" Margin="289,282,289,0" Text="{Binding Path=users[1].Name}" />
        <Label x:Name="lblCopie" BorderBrush="Black" BorderThickness="1 1 1 1"  Content="{Binding Path=users[1].Name}" HorizontalAlignment="Left" Margin="273,339,0,0" VerticalAlignment="Top" Height="37" Width="140"/>
    </Grid>

Et là la partie Code Behind :

Code :

Sélectionner tout - Visualiser dans une fenêtre à part

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
 
namespace WpfTuto
{
    /// <summary>
    /// Logique d'interaction pour WinUpdateSource.xaml
    /// </summary>
    public partial class WinUpdateSource : Window
    {
        public class User : INotifyPropertyChanged
        {
            private string name;
            public string Name
            {
                get { return this.name; }
                set
                {
                    if (this.name != value)
                    {
                        this.name = value;
                        this.NotifyPropertyChanged("Name");
                    }
                }
            }
 
            public event PropertyChangedEventHandler PropertyChanged;
 
            public void NotifyPropertyChanged(string propName)
            {
                if (this.PropertyChanged != null)
                    this.PropertyChanged(this, new PropertyChangedEventArgs(propName));
            }
        }
        // private List<User> users = new List<User>();
        private ObservableCollection<User> users = new ObservableCollection<User>();
        public WinUpdateSource()
        {
            InitializeComponent();
            users.Add(new User() { Name = "John Doe" });
            users.Add(new User() { Name = "Jane Doe" });
            tbCopie.Text = users[1].Name;
            lblCopie.Content = users[1].Name;
            lbUsers.ItemsSource = users;
        }
        private void btnAddUser_Click(object sender, RoutedEventArgs e)
        {
 
            users.Add(new User() { Name = tbNom.Text });
        }
 
        private void btnChangeUser_Click(object sender, RoutedEventArgs e)
        {
            if (lbUsers.SelectedItem != null)
                (lbUsers.SelectedItem as User).Name = "Random Name";
        }
 
        private void btnDeleteUser_Click(object sender, RoutedEventArgs e)
        {
            if (lbUsers.SelectedItem != null)
                users.Remove(lbUsers.SelectedItem as User);
        }
    }
}

Merci d'avance pour votre aide.

[Noxen]

En fait aucun de tes binding n'est correctement branché, tu en as juste l'impression parce-que dans le constructeur de la fenêtre tu affectes les propriétés de tes composants, mais sans passer par un binding.

[champy_30]

Bonjour,

Il date un peu mais tous les concepts WPF MVVM sont expliqués :

https://japf.developpez.com/tutoriel...-et-testables/

[clem_alain]

Bonjour,
Merci pour vos réponses je vais lire attentivement le support proposé.

[Noxen]

Ça fait un moment que je n'ai pas fait de WPF, mais j'ai tenté de préparer un exemple à peu près complet. À noter que j'ai importé le package CommunityToolkit.Mvvm (héritier de MvvmLight de Laurent Bugnion).

Le fichier de code avec la fenêtre et un view model :

Code :

Sélectionner tout - Visualiser dans une fenêtre à part

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
using CommunityToolkit.Mvvm.Input;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Windows;
using System.Windows.Input;
 
namespace D2174215
{
	/// <summary>
	/// Interaction logic for MainWindow.xaml
	/// </summary>
	public partial class MainWindow : Window
	{
		public MainWindow()
		{
			InitializeComponent();
		}
 
		private void MainViewModel_PropertyChanged(object sender, PropertyChangedEventArgs e)
		{
			if (sender is not MainViewModel mvm) return;
			if (e.PropertyName == nameof(MainViewModel.PlayerName) && mvm.PlayerName == string.Empty)
				PlayerName.Focus();
		}
	}
 
	public class MainViewModel : CommunityToolkit.Mvvm.ComponentModel.ObservableObject
	{
		public MainViewModel()
		{
			Players = new(_players);
 
			_addPlayerCommand = new RelayCommand(AddPlayer, CanAddPlayer);
			_removePlayerCommand = new RelayCommand<Player>(RemovePlayer);
		}
 
		public string? PlayerName
		{
			get => _playerName;
			set
			{
				if (SetProperty(ref _playerName, value))
					_addPlayerCommand.NotifyCanExecuteChanged();
			}
		}
		private string? _playerName;
 
		public ReadOnlyObservableCollection<Player> Players { get; }
		private readonly ObservableCollection<Player> _players = [];
 
		public ICommand AddPlayerCommand => _addPlayerCommand;
		private readonly RelayCommand _addPlayerCommand;
		public void AddPlayer()
		{
			if (string.IsNullOrWhiteSpace(PlayerName)) return;
			_players.Add(new Player { Name = PlayerName.Trim() });
			PlayerName = string.Empty;
		}
		public bool CanAddPlayer() => !string.IsNullOrWhiteSpace(PlayerName);
 
		public ICommand RemovePlayerCommand => _removePlayerCommand;
		private readonly RelayCommand<Player> _removePlayerCommand;
		public void RemovePlayer(Player? player)
		{
			if (player is not null)
				_players.Remove(player);
		}
 
		public ICommand IncreaseScoreCommand => _increaseScoreCommand;
		private readonly RelayCommand<Player> _increaseScoreCommand = new(IncreaseScore);
		private static void IncreaseScore(Player? player)
		{
			if (player is not null)
				player.Score++;
		}
 
		public ICommand DecreaseScoreCommand => _decreaseScoreCommand;
		private readonly RelayCommand<Player> _decreaseScoreCommand = new(DecreaseScore);
		private static void DecreaseScore(Player? player)
		{
			if (player is not null)
				player.Score--;
		}
	}
 
	public class Player : INotifyPropertyChanged
	{
		public string Name
		{
			get => _name;
			set
			{
				if (_name == value) return;
				_name = value ?? string.Empty;
				OnPropertyChanged();
			}
		}
		private string _name = string.Empty;
 
		public int Score
		{
			get => _score;
			set
			{
				if (_score == value) return;
				_score = value;
				OnPropertyChanged();
			}
		}
		private int _score;
 
		private void OnPropertyChanged([CallerMemberName] string? propertyName = null) =>
			PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
 
		public event PropertyChangedEventHandler? PropertyChanged;
	}
}

Le code xaml pour la fenêtre :

Code :

Sélectionner tout - Visualiser dans une fenêtre à part

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
<Window x:Class="D2174215.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:system="clr-namespace:System;assembly=mscorlib"
        xmlns:local="clr-namespace:D2174215"
        mc:Ignorable="d"
        Title="Scoreboard" Height="450" Width="800">
    <Window.Resources>
        <ResourceDictionary>
            <system:String x:Key="Title">Scoreboard</system:String>
            <system:String x:Key="Player_name">Player name:</system:String>
            <system:String x:Key="Add_player">Add player</system:String>
            <system:String x:Key="Remove">Remove</system:String>
            <system:String x:Key="Number_of_players">Number of players:</system:String>
        </ResourceDictionary>
    </Window.Resources>
    <Window.DataContext>
        <local:MainViewModel PropertyChanged="MainViewModel_PropertyChanged" />
    </Window.DataContext>
    <DockPanel>
        <TextBlock DockPanel.Dock="Top" Text="{StaticResource ResourceKey=Title}" FontSize="16" FontWeight="Bold" Padding="5" TextAlignment="Center"/>
        <Grid DockPanel.Dock="Top" Margin="5">
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="100"/>
                <ColumnDefinition MinWidth="150"/>
                <ColumnDefinition Width="100"/>
                <ColumnDefinition Width="*"/>
            </Grid.ColumnDefinitions>
            <TextBlock Grid.Column="0" Text="{StaticResource ResourceKey=Player_name}" />
            <TextBox Grid.Column="1" Text="{Binding PlayerName, UpdateSourceTrigger=PropertyChanged}" x:Name="PlayerName">
                <TextBox.InputBindings>
                    <KeyBinding Key="Return" Command="{Binding AddPlayerCommand}" />
                </TextBox.InputBindings>
            </TextBox>
            <Button Grid.Column="2" Command="{Binding AddPlayerCommand}" Margin="5,0,5,0" Content="{StaticResource ResourceKey=Add_player}">
                <Button.InputBindings>
                    <KeyBinding Key="Return" Command="{Binding AddPlayerCommand}" />
                </Button.InputBindings>
            </Button>
        </Grid>
        <StackPanel DockPanel.Dock="Bottom" Margin="10,5,10,10" Orientation="Horizontal">
            <TextBlock Text="{StaticResource ResourceKey=Number_of_players}" Margin="0,0,10,0"/>
            <TextBlock Text="{Binding Players.Count}"/>
        </StackPanel>
        <ListView Margin="5" ItemsSource="{Binding Players}">
            <d:ListView.ItemsSource>
                <x:Array Type="local:Player">
                    <local:Player Name="Hector"/>
                    <local:Player Name="Deliah"/>
                </x:Array>
            </d:ListView.ItemsSource>
            <ListView.ItemTemplate>
                <DataTemplate>
                    <Grid>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition  Width="100" />
                            <ColumnDefinition Width="20" />
                            <ColumnDefinition  Width="20"/>
                            <ColumnDefinition Width="20" />
                            <ColumnDefinition MinWidth="100" />
                            <ColumnDefinition Width="100" />
                        </Grid.ColumnDefinitions>
                        <TextBlock Grid.Column="0" Text="{Binding Name}" />
                        <Button Grid.Column="1"
                                Content="-"
                                Command="{Binding DataContext.DecreaseScoreCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window}}"
                                CommandParameter="{Binding}" />
                        <TextBlock Grid.Column="2" Text="{Binding Score}" TextAlignment="Left" Padding="5" />
                        <Button Grid.Column="3"
                                Content="+"
                                Command="{Binding DataContext.IncreaseScoreCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window}}"
                                CommandParameter="{Binding}" />
                        <Border Grid.Column="4" />
                        <Button Grid.Column="5" Margin="10,0,0,0"
                                Content="{StaticResource ResourceKey=Remove}"
                                Command="{Binding DataContext.RemovePlayerCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window}}"
                                CommandParameter="{Binding}" />
                    </Grid>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
    </DockPanel>
</Window>

[popo]

C'est dommage d'utiliser CommunityToolkit.Mvvm et de coder manuellement les mécaniques qu'il propose.
https://learn.microsoft.com/en-us/do...ators/overview