How Can I Check/UnCheck All Checkboxes in Listbox in C# WPF?

Question

I have a ListBox contains checkboxes in DataTemplate and I have two buttons "Select All" and "UnSelect All".I want to make that checkboxes to check all and uncheck all with clicking select and unselect buttons and I want to implement INotifyPropertyChanged to class. How Can I do that things?

Thanks for your answers in advance..

XAML CODE

  <StackPanel>
        <ListBox Name="lstUserDefination" 
 ScrollViewer.VerticalScrollBarVisibility="Auto" SelectionMode="Multiple">
            <ListBox.ItemTemplate>
                <DataTemplate>
                    <ListBoxItem>
                    <CheckBox Name="chkUser" Content="{Binding AuthorityName}"/>
                    </ListBoxItem>
                </DataTemplate>
            </ListBox.ItemTemplate>
        </ListBox>
    </StackPanel>

C# CODE

   public partial class UserDefinationEdit : Window
{
    public ObservableCollection<Authority> authorityList { get; set; }

    public UserDefinationEdit()
    {
        InitializeComponent();
        CreateCheckBoxList();
        lstUserDefination.ItemsSource = authorityList;
    }


    private void Window_MouseDown(object sender, MouseButtonEventArgs e)
    {
        if (e.LeftButton == MouseButtonState.Pressed)
        {
            DragMove();
        }
    }

    public void CreateCheckBoxList()
    {
        authorityList = new ObservableCollection<Authority>();

        authorityList.Add(new Authority() {AuthorityValue = 0, AuthorityName = "0 - " });
        authorityList.Add(new Authority() { AuthorityValue = 1, AuthorityName = "1 - " });
        authorityList.Add(new Authority() { AuthorityValue = 2, AuthorityName = "2 - " });
        authorityList.Add(new Authority() { AuthorityValue = 3, AuthorityName = "3 - " });
        authorityList.Add(new Authority() { AuthorityValue = 4, AuthorityName = "4 - " });
        authorityList.Add(new Authority() { AuthorityValue = 5, AuthorityName = "5 - " });
        authorityList.Add(new Authority() { AuthorityValue = 6, AuthorityName = "6 - " });


        this.DataContext = this;
    }

    private void btnUnselectall_Click(object sender, RoutedEventArgs e)
    {
        lstUserDefination.UnselectAll();
    }

    private void btnSelectAll_Click(object sender, RoutedEventArgs e)
    {
        lstUserDefination.SelectAll();
    }

}
public class Authority
{
    public string AuthorityName { get; set; }
    public int AuthorityValue { get; set; }
    public bool IsChecked { get; set; }
}
}

Answer 1

Add binding for IsChecked property in ListBoxItem template

<CheckBox Name="chkUser" Content="{Binding AuthorityName}" IsChecked="{Binding IsChecked}"/>

And change your button handlers to

private void btnUnselectall_Click(object sender, RoutedEventArgs e)
{
    foreach (var a in authorityList)
    {
        a.IsChecked = false;
    }
}

private void btnSelectAll_Click(object sender, RoutedEventArgs e)
{
    foreach (var a in authorityList)
    {
        a.IsChecked = true;
    }
}

Note that your Authority class should implement INotifyPropertyChanged to make this work.

public class Authority : INotifyPropertyChanged
{
    private string authorityName;
    private int authorityValue;
    private bool isChecked;

    public string AuthorityName
    {
        get { return authorityName; }
        set
        {
            authorityName = value;
            NotifyPropertyChanged();
        }
    }

    public int AuthorityValue
    {
        get { return authorityValue; }
        set
        {
            authorityValue = value;
            NotifyPropertyChanged();
        }
    }

    public bool IsChecked
    {
        get { return isChecked; }
        set
        {
            isChecked = value;
            NotifyPropertyChanged();
        }
    }


    public event PropertyChangedEventHandler PropertyChanged;

    private void NotifyPropertyChanged(string propertyName = "")
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

Answer 2

Implement INotifyPropertyChanged:

public class Authority : INotifyPropertyChanged
{
    private string _authorityName;
    public string AuthorityName
    {
        get { return _authorityName; }
        set { _authorityName = value; NotifyPropertyChanged(); }
    }

    private string _authorityValue;
    public string AuthorityValue
    {
        get { return _authorityValue; }
        set { _authorityValue = value; NotifyPropertyChanged(); }
    }

    private bool  _isChecked;
    public bool IsChecked
    {
        get { return _isChecked; }
        set { _isChecked = value; NotifyPropertyChanged(); }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    private void NotifyPropertyChanged([CallerMemberName] String propertyName = "")
    {
        if (PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }
}

Set the IsChecked property of all Authority objects:

private void btnUnselectall_Click(object sender, RoutedEventArgs e)
{
    Select(false);
}

private void btnSelectAll_Click(object sender, RoutedEventArgs e)
{
    Select(true);
}

private void Select(bool select)
{
    foreach (Authority authority in authorityList)
        authority.IsChecked = select;
}

Bind the IsChecked property in your XAML:

<CheckBox Name="chkUser" IsChecked="{Binding IsChecked}" Content="{Binding AuthorityName}"/>