Check a checkBox in a listView .net maui

Question

In my project maui i want a helper to check checkBox when I select an item from the listView with multiple selection. My listView in xaml:

<ListView x:Name="listViewComande"                  
           ItemSelected="listViewArticle_ItemSelected">
     <ListView.Header >        
     </ListView.Header>
     <ListView.ItemTemplate  >
         <DataTemplate >
             <ViewCell   >
                 <Grid RowDefinitions="Auto" 
                       ColumnDefinitions="5*,20*,45*,10*,10*,10*" 
                       Padding="3,10,3,10"  ColumnSpacing="8">
                       <CheckBox Grid.Row="1" Grid.Column="0" 
                       Color="LightGray"                     
                       x:Name="chekBoxListView" />                  
                     <Label Grid.Row="1" Grid.Column="2"  Text="{Binding DesignationComande}"      FontSize="13" VerticalTextAlignment="Center"
                          HorizontalTextAlignment="Start" MaxLines="1"  FontAttributes="None"/>                  
                 </Grid>
             </ViewCell>
         </DataTemplate>
     </ListView.ItemTemplate>
 </ListView>

public class ComandeTable
 {
    [PrimaryKey, AutoIncrement]
     public int ID { get; set; }
     public string ReferenceComande { get; set; }   
     public string DesignationComande { get; set; } 
 }

private void listViewArticle_ItemSelected(object sender, SelectedItemChangedEventArgs e)
{   
    if (e.SelectedItem != null)
    {       
    }
}

I used a bool variable but it doesn't work

Answer 1

Your xaml demonstrates an intent to display the DesignationComande property and respond when the check box changes (either programmatically or though user interaction). This will require a model for the items in your ListView bound to those properties.

For example:

---

Finish the bindings in xaml

Bind the IsChecked property in your DataTemplate

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="checked_list_view.MainPage">
    <Grid
        RowDefinitions="*,*" >
        <ListView
            Grid.Row="0"
            x:Name="listViewComande"                  
            BackgroundColor="Azure">
            <ListView.ItemTemplate >
                <DataTemplate>
                    <ViewCell>
                        <Grid 
                            RowDefinitions="Auto" 
                            ColumnDefinitions="Auto,20*,45*,10*,10*,10*" 
                            Padding="3,10,3,10" 
                            ColumnSpacing="8">
                            <CheckBox 
                                IsChecked="{Binding IsChecked}"
                                Grid.Row="1" 
                                Grid.Column="0" 
                                Color="CornflowerBlue" />
                            <Label 
                                Grid.Row="1" 
                                Grid.Column="2"  
                                BackgroundColor="LightGreen"
                                Text="{Binding DesignationComande}"      
                                FontSize="13" VerticalTextAlignment="Center"                            
                                HorizontalTextAlignment="Start" MaxLines="1"  
                                HorizontalOptions="Fill"
                                FontAttributes="None"
                                Padding="10,0"/>
                        </Grid>
                    </ViewCell>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
        <Editor 
            Grid.Row="1"
            Text="{Binding EditorText}"/>
    </Grid>
</ContentPage>

---

Make a Model for items in the ListView

This functionality requires a bindable property for IsChecked that fires a PropertyChanged event for the check boxes.

class CheckableCommand : INotifyPropertyChanged
{
    public string DesignationComande { get; set; }
    public override string ToString() => DesignationComande;

    public bool IsChecked
    {
        get => _isChecked;
        set
        {
            if (!Equals(_isChecked, value))
            {
                _isChecked = value;
                OnPropertyChanged();
            }
        }
    }
    bool _isChecked = false;
    private void OnPropertyChanged([CallerMemberName]string caller = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(caller));
    }
    public event PropertyChangedEventHandler PropertyChanged;
}

---

Glue it all together

In this sample, the code-behind for the MainPage sets the ItemsSource of the ListView (you could also do this in xaml) to an observable collection of CheckableCommand and subscribes to the PropertyChanged notification of the items.

public partial class MainPage : ContentPage
{
    public MainPage()
    {
        BindingContext = this;
        InitializeComponent();
        listViewComande.ItemsSource = new ObservableCollection<CheckableCommand>
        {
            new CheckableCommand{ DesignationComande = "Command 1" },
            new CheckableCommand{ DesignationComande = "Command 2" },
            new CheckableCommand{ DesignationComande = "Command 3" },
        };
        foreach (CheckableCommand command in listViewComande.ItemsSource)
        {
            command.PropertyChanged += (sender, e) =>
            {
                switch (e.PropertyName) 
                {
                    case nameof(CheckableCommand.IsChecked):
                        var checkedCommands = 
                            listViewComande
                            .ItemsSource
                            .OfType<CheckableCommand>()
                            .Where (_ => _.IsChecked)
                            .ToList();
                        if(checkedCommands.Any())
                        {
                            EditorText = string.Join(Environment.NewLine, checkedCommands);
                        }
                        else
                        {
                            EditorText = "No checked commands at this time.";
                        }
                        break;
                }
            };            
            listViewComande.ItemSelected += (sender, e) =>
            {
                // Option to check the checkbox when item is selected.
                if (e.SelectedItem is CheckableCommand cmd) cmd.IsChecked = true;
            };
        }
        EditorText = "Hello, I'll be keeping track of your checked commands.";
    }
    public string EditorText
    {
        get => _editorText;
        set
        {
            if (!Equals(_editorText, value))
            {
                _editorText = value;
                OnPropertyChanged();
            }
        }
    }
    string _editorText = string.Empty;
}