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Automatically Check TreeView Child Nodes When Parent Is Checked

    Question

  •  

    I have a XAML TreeView that has checkboxes defined for each TreeViewItem based on a HierarchicalDataTemplate. When a checkbox of a parent node is checked then I want all the child nodes to be automatically checked.
    Friday, April 04, 2008 8:33 PM

Answers

  • I think that you are using data binding to populate the tree items. You can refer to the following link to see how to do this. If you don't want to change your data source classes to add a new boolean property bound to CheckBox.IsChecked property, you can create a new class which contains the boolean property bound to CheckBox.IsChecked property to contain your data source classes.

     

    Code Snippet

    public partial class MainWindow : Window

    {

        public MainWindow()

        {

            this.Nodes = new ObservableCollection<Node>()

            {

                new Node(){Text="Node A"},

                new Node(){Text="Node B"},

            };

     

            this.Nodes[0].Children.Add(new Node() { Text = "Node C" });

            this.Nodes[0].Children.Add(new Node() { Text = "Node D" });

     

            this.Nodes[1].Children.Add(new Node() { Text = "Node E" });

            this.Nodes[1].Children.Add(new Node() { Text = "Node F" });

     

            InitializeComponent();

        }

     

        public ObservableCollection<Node> Nodes { get; private set; }

    }

     

    public class Node : INotifyPropertyChanged

    {

        ObservableCollection<Node> children = new ObservableCollection<Node>();

        string text;

        bool isChecked;

     

        public ObservableCollection<Node> Children

        {

            get { return this.children; }

        }

        public bool IsChecked

        {

            get { return this.isChecked; }

            set

            {

                this.isChecked = value;

                RaisePropertyChanged("IsChecked");

            }

        }

        public string Text

        {

            get { return this.text; }

            set

            {

                this.text = value;

                RaisePropertyChanged("Text");

            }

        }

     

        public event PropertyChangedEventHandler PropertyChanged;

        private void RaisePropertyChanged(string propertyName)

        {

            if (this.PropertyChanged != null)

                this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));

     

            if (propertyName == "IsChecked")

            {

                foreach (Node child in this.Children)

                    child.IsChecked = this.IsChecked;

            }

        }

    }

    <Window.Resources>

        <HierarchicalDataTemplate DataType="{x:Type local:Node}" ItemsSource="{Binding Children}">

            <StackPanel Orientation="Horizontal">

                <CheckBox IsChecked="{Binding IsChecked}"/>

                <TextBlock Text="{Binding Text}"/>

            </StackPanel>

        </HierarchicalDataTemplate>

    </Window.Resources>

    <TreeView ItemsSource="{Binding Nodes, ElementName=Window}"/>

     

    Container design:

    public class Container : INotifyPropertyChanged

    {

        bool isChecked;

        public bool IsChecked

        {

            get { return this.isChecked; }

            set

            {

                this.isChecked = value;

                RaisePropertyChanged("IsChecked");

            }

        }

     

        public Node Node { get; set; }

    }

     

     

    Best Regards,

    Wei Zhou

    Monday, April 07, 2008 4:35 AM
  • Ideally, you would want this to happen in the data layer.

     

    If you decide you absolutely need to do it in the UI layer, you can use one way binding and a RelativeSource of FindAncestor to bind the IsChecked property of the child CheckBox an attached property on the parent TreeViewItem and then bind the same attached property on the parent TreeViewItem to the IsChecked property the CheckBox in its template.

     

    If you want a sample, please supply a small repro of your scenario along with your hierarchical data templates.

     

    Friday, April 04, 2008 8:47 PM

All replies

  • Ideally, you would want this to happen in the data layer.

     

    If you decide you absolutely need to do it in the UI layer, you can use one way binding and a RelativeSource of FindAncestor to bind the IsChecked property of the child CheckBox an attached property on the parent TreeViewItem and then bind the same attached property on the parent TreeViewItem to the IsChecked property the CheckBox in its template.

     

    If you want a sample, please supply a small repro of your scenario along with your hierarchical data templates.

     

    Friday, April 04, 2008 8:47 PM
  • I think that you are using data binding to populate the tree items. You can refer to the following link to see how to do this. If you don't want to change your data source classes to add a new boolean property bound to CheckBox.IsChecked property, you can create a new class which contains the boolean property bound to CheckBox.IsChecked property to contain your data source classes.

     

    Code Snippet

    public partial class MainWindow : Window

    {

        public MainWindow()

        {

            this.Nodes = new ObservableCollection<Node>()

            {

                new Node(){Text="Node A"},

                new Node(){Text="Node B"},

            };

     

            this.Nodes[0].Children.Add(new Node() { Text = "Node C" });

            this.Nodes[0].Children.Add(new Node() { Text = "Node D" });

     

            this.Nodes[1].Children.Add(new Node() { Text = "Node E" });

            this.Nodes[1].Children.Add(new Node() { Text = "Node F" });

     

            InitializeComponent();

        }

     

        public ObservableCollection<Node> Nodes { get; private set; }

    }

     

    public class Node : INotifyPropertyChanged

    {

        ObservableCollection<Node> children = new ObservableCollection<Node>();

        string text;

        bool isChecked;

     

        public ObservableCollection<Node> Children

        {

            get { return this.children; }

        }

        public bool IsChecked

        {

            get { return this.isChecked; }

            set

            {

                this.isChecked = value;

                RaisePropertyChanged("IsChecked");

            }

        }

        public string Text

        {

            get { return this.text; }

            set

            {

                this.text = value;

                RaisePropertyChanged("Text");

            }

        }

     

        public event PropertyChangedEventHandler PropertyChanged;

        private void RaisePropertyChanged(string propertyName)

        {

            if (this.PropertyChanged != null)

                this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));

     

            if (propertyName == "IsChecked")

            {

                foreach (Node child in this.Children)

                    child.IsChecked = this.IsChecked;

            }

        }

    }

    <Window.Resources>

        <HierarchicalDataTemplate DataType="{x:Type local:Node}" ItemsSource="{Binding Children}">

            <StackPanel Orientation="Horizontal">

                <CheckBox IsChecked="{Binding IsChecked}"/>

                <TextBlock Text="{Binding Text}"/>

            </StackPanel>

        </HierarchicalDataTemplate>

    </Window.Resources>

    <TreeView ItemsSource="{Binding Nodes, ElementName=Window}"/>

     

    Container design:

    public class Container : INotifyPropertyChanged

    {

        bool isChecked;

        public bool IsChecked

        {

            get { return this.isChecked; }

            set

            {

                this.isChecked = value;

                RaisePropertyChanged("IsChecked");

            }

        }

     

        public Node Node { get; set; }

    }

     

     

    Best Regards,

    Wei Zhou

    Monday, April 07, 2008 4:35 AM
  •  Dr. WPF wrote:

    Ideally, you would want this to happen in the data layer.

     

    If you decide you absolutely need to do it in the UI layer, you can use one way binding and a RelativeSource of FindAncestor to bind the IsChecked property of the child CheckBox an attached property on the parent TreeViewItem and then bind the same attached property on the parent TreeViewItem to the IsChecked property the CheckBox in its template.

     

    If you want a sample, please supply a small repro of your scenario along with your hierarchical data templates.

     

     

    I was interested to know why you consider it ideal to do something like this in the model, rather than in the view/presenter/controller?

     

    I'm starting to look at an implementation of a "checkable" TreeView, and leaning towards the opposite conclusion -- that this is more a property of the Control itself rather than of the bound data, in the same manner that the "selected" or "expanded" state of a TreeViewItem isn't drawn from the data model. After all, I want to be able to bind any tree-shaped data to the control and still get "checkability", without having to have the model objects know anything about whether or not they are "checked".

    Thursday, April 24, 2008 3:14 PM