Checkbox in Xamarin TreeView (SfTreeView)

SfTreeView provides support for loading CheckBox in each node, and allows users to check/uncheck the corresponding node. So, you should add checkbox in the ItemTemplate of the SfTreeView and bind the IsChecked property of the TreeViewNode.

Working with Checkbox in BoundMode

When you are populating treeview nodes from ItemsSource, then you can get or set the checked items by using CheckedItems property.

SfTreeView supports to check multiple items through binding the CheckedItems property from view model with ObservableCollection<object> type.

NOTE

Set ItemTemplateContextType as Node to bind the TreeViewNode.IsChecked property to CheckBox in ItemTemplate. To know more about ItemTemplateContextType click here.

NOTE

TreeView process and sets TreeViewNode.IsChecked based on CheckedItems only when you are binding ItemsSource.

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:BoundMode_CheckBox"
             x:Class="BoundMode_CheckBox.MainPage"
             xmlns:TreeView="clr-namespace:Syncfusion.XForms.TreeView;assembly=Syncfusion.SfTreeView.XForms"
             xmlns:SfButtons="clr-namespace:Syncfusion.XForms.Buttons;assembly=Syncfusion.Buttons.XForms"
             xmlns:TreeViewEngine="clr-namespace:Syncfusion.TreeView.Engine;assembly=Syncfusion.SfTreeView.XForms">

    <ContentPage.BindingContext>
        <local:FileManagerViewModel />
    </ContentPage.BindingContext>

    <TreeView:SfTreeView x:Name="SfTreeView"
                         ItemsSource="{Binding Folders}"
                         AutoExpandMode="RootNodesExpanded"
                         ItemTemplateContextType="Node"
                         CheckBoxMode="Recursive"
                         CheckedItems="{Binding CheckedItems}">
        
        <TreeView:SfTreeView.HierarchyPropertyDescriptors>
            <TreeViewEngine:HierarchyPropertyDescriptor TargetType="{x:Type local:Folder}" ChildPropertyName="Files"/>
            <TreeViewEngine:HierarchyPropertyDescriptor TargetType="{x:Type local:File}" ChildPropertyName="SubFiles"/>
        </TreeView:SfTreeView.HierarchyPropertyDescriptors>
        
        <TreeView:SfTreeView.ItemTemplate>
            <DataTemplate>
                <ViewCell>
                    <ViewCell.View>
                        <Grid Padding="5">
                            <SfButtons:SfCheckBox 
                            x:Name="CheckBox"
                            Text="{Binding Content.FileName}"
                            IsChecked="{Binding IsChecked, Mode=TwoWay}"/>
                        </Grid>
                    </ViewCell.View>
                </ViewCell>
            </DataTemplate>
        </TreeView:SfTreeView.ItemTemplate>
    </TreeView:SfTreeView>
</ContentPage>
public class FileManagerViewModel
{
    private ObservableCollection<object> checkedItems;

    public ObservableCollection<object> CheckedItems
    {
        get { return checkedItems; }
        set { this.checkedItems = value; }
    }

    public ObservableCollection<Folder> Folders { get; set; }

    public FileManagerViewModel()
    {
        this.Folders = GetFiles();
    }

    private ObservableCollection<Folder> GetFiles()
    {
        var nodeImageInfo = new ObservableCollection<Folder>();
        Assembly assembly = typeof(MainPage).GetTypeInfo().Assembly;

        var doc = new Folder() { FileName = "Documents"};
        var download = new Folder() { FileName = "Downloads",};
        var mp3 = new Folder() { FileName = "Music"};
        var pictures = new Folder() { FileName = "Pictures"};
        var video = new Folder() { FileName = "Videos"};

        var pollution = new File() { FileName = "Environmental Pollution.docx"};
        var globalWarming = new File() { FileName = "Global Warming.ppt"};

        var games = new File() { FileName = "Game.exe"};
        var tutorials = new File() { FileName = "Tutorials.zip"};
        var TypeScript = new File() { FileName = "TypeScript.7z"};
        var uiGuide = new File() { FileName = "UI-Guide.pdf"};

        var song = new File() { FileName = "Gouts"};

        var camera = new File() { FileName = "Camera Roll"};
        var stone = new File() { FileName = "Stone.jpg"};
        var wind = new File() { FileName = "Wind.jpg"};

        var img0 = new SubFile() { FileName = "WIN_20160726_094117.JPG"};
        var img1 = new SubFile() { FileName = "WIN_20160726_094118.JPG"};

        var video1 = new File() { FileName = "Naturals.mp4"};
        var video2 = new File() { FileName = "Wild.mpg"};

        doc.Files = new ObservableCollection<File>
            {
                pollution,
                globalWarming
            };

        download.Files = new ObservableCollection<File>
            {
                games,
                tutorials,
                TypeScript,
                uiGuide
            };

        mp3.Files = new ObservableCollection<File>
            {
                song
            };

        pictures.Files = new ObservableCollection<File>
            {
                camera,
                stone,
                wind
            };
        camera.SubFiles = new ObservableCollection<SubFile>
            {
                img0,
                img1
            };

        video.Files = new ObservableCollection<File>
            {
                video1,
                video2
            };

        nodeImageInfo.Add(doc);
        nodeImageInfo.Add(download);
        nodeImageInfo.Add(mp3);
        nodeImageInfo.Add(pictures);
        nodeImageInfo.Add(video);

        checkedItems = new ObservableCollection<object>();
        checkedItems.Add(doc);
        checkedItems.Add(TypeScript);
        checkedItems.Add(uiGuide);
        checkedItems.Add(stone);
        checkedItems.Add(wind);
        checkedItems.Add(song);

        return nodeImageInfo;
    }
}

Xamarin Forms BoundMode TreeView with CheckBox

You can download the entire source of this demo from here

Working with Checkbox in UnboundMode

You can directly set the checkbox state by setting the TreeViewNode.IsChecked property value while creating nodes.

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:UnboundMode_Checkbox"
             x:Class="UnboundMode_Checkbox.MainPage"
             xmlns:treeviewengine="clr-namespace:Syncfusion.TreeView.Engine;assembly=Syncfusion.SfTreeView.XForms"
             xmlns:SfCheckBox="clr-namespace:Syncfusion.XForms.Buttons;assembly=Syncfusion.Buttons.XForms"
             xmlns:syncfusion="clr-namespace:Syncfusion.XForms.TreeView;assembly=Syncfusion.SfTreeView.XForms">

    <ContentPage.Content>
        <syncfusion:SfTreeView CheckBoxMode="Recursive">
            <syncfusion:SfTreeView.Nodes>
                <treeviewengine:TreeViewNode Content="Australia" IsChecked="True" IsExpanded="True">
                    <treeviewengine:TreeViewNode.ChildNodes>
                        <treeviewengine:TreeViewNode x:Name="newSouthWales" Content="New South Wales">
                            <treeviewengine:TreeViewNode.ChildNodes>
                                <treeviewengine:TreeViewNode Content="Sydney"/>
                                <treeviewengine:TreeViewNode Content="New York">
                                    <treeviewengine:TreeViewNode.ChildNodes>
                                        <treeviewengine:TreeViewNode Content="San Francisco"/>
                                    </treeviewengine:TreeViewNode.ChildNodes>
                                </treeviewengine:TreeViewNode>
                            </treeviewengine:TreeViewNode.ChildNodes>
                        </treeviewengine:TreeViewNode>
                        <treeviewengine:TreeViewNode Content="United States of America">
                            <treeviewengine:TreeViewNode.ChildNodes>
                                <treeviewengine:TreeViewNode Content="New York">
                                    <treeviewengine:TreeViewNode.ChildNodes>
                                        <treeviewengine:TreeViewNode Content="San Francisco"/>
                                    </treeviewengine:TreeViewNode.ChildNodes>
                                </treeviewengine:TreeViewNode>
                                <treeviewengine:TreeViewNode Content="California">
                                    <treeviewengine:TreeViewNode.ChildNodes>
                                        <treeviewengine:TreeViewNode Content="San Francisco"/>
                                    </treeviewengine:TreeViewNode.ChildNodes>
                                </treeviewengine:TreeViewNode>
                            </treeviewengine:TreeViewNode.ChildNodes>
                        </treeviewengine:TreeViewNode>
                        <treeviewengine:TreeViewNode Content="New South Wales" IsChecked="True">
                            <treeviewengine:TreeViewNode.ChildNodes>
                                <treeviewengine:TreeViewNode Content="Sydney"/>
                                <treeviewengine:TreeViewNode Content="New York">
                                    <treeviewengine:TreeViewNode.ChildNodes>
                                        <treeviewengine:TreeViewNode Content="San Francisco"/>
                                    </treeviewengine:TreeViewNode.ChildNodes>
                                </treeviewengine:TreeViewNode>

                            </treeviewengine:TreeViewNode.ChildNodes>
                        </treeviewengine:TreeViewNode>
                        <treeviewengine:TreeViewNode Content="United States of America" IsChecked="True">
                            <treeviewengine:TreeViewNode.ChildNodes>
                                <treeviewengine:TreeViewNode Content="New York">
                                    <treeviewengine:TreeViewNode.ChildNodes>
                                        <treeviewengine:TreeViewNode Content="San Francisco"/>
                                    </treeviewengine:TreeViewNode.ChildNodes>
                                </treeviewengine:TreeViewNode>
                                <treeviewengine:TreeViewNode Content="California">
                                    <treeviewengine:TreeViewNode.ChildNodes>
                                        <treeviewengine:TreeViewNode Content="San Francisco"/>
                                    </treeviewengine:TreeViewNode.ChildNodes>
                                </treeviewengine:TreeViewNode>
                            </treeviewengine:TreeViewNode.ChildNodes>
                        </treeviewengine:TreeViewNode>
                    </treeviewengine:TreeViewNode.ChildNodes>
                </treeviewengine:TreeViewNode>
                <treeviewengine:TreeViewNode x:Name="America" Content="United States of America">
                    <treeviewengine:TreeViewNode.ChildNodes>
                        <treeviewengine:TreeViewNode Content="New York"/>
                        <treeviewengine:TreeViewNode Content="California">
                            <treeviewengine:TreeViewNode.ChildNodes>
                                <treeviewengine:TreeViewNode Content="San Francisco"/>
                            </treeviewengine:TreeViewNode.ChildNodes>
                        </treeviewengine:TreeViewNode>
                    </treeviewengine:TreeViewNode.ChildNodes>
                </treeviewengine:TreeViewNode>
                <treeviewengine:TreeViewNode x:Name="India" Content="India">
                    <treeviewengine:TreeViewNode.ChildNodes>
                        <treeviewengine:TreeViewNode Content="TamilNadu">
                            <treeviewengine:TreeViewNode.ChildNodes>
                                <treeviewengine:TreeViewNode Content="Chennai"/>
                            </treeviewengine:TreeViewNode.ChildNodes>
                        </treeviewengine:TreeViewNode>
                    </treeviewengine:TreeViewNode.ChildNodes>
                </treeviewengine:TreeViewNode>
                <treeviewengine:TreeViewNode Content="United Arab Emirates">
                    <treeviewengine:TreeViewNode.ChildNodes>
                        <treeviewengine:TreeViewNode Content="Abu Dhabi"/>
                        <treeviewengine:TreeViewNode Content="Dubai">
                            <treeviewengine:TreeViewNode.ChildNodes>
                                <treeviewengine:TreeViewNode Content="Burj Khalifa"/>
                            </treeviewengine:TreeViewNode.ChildNodes>
                        </treeviewengine:TreeViewNode>
                    </treeviewengine:TreeViewNode.ChildNodes>
                </treeviewengine:TreeViewNode>
            </syncfusion:SfTreeView.Nodes>

            <syncfusion:SfTreeView.ItemTemplate>
                <DataTemplate>
                    <ViewCell>
                        <ViewCell.View>
                            <Grid Padding="5">
                                <SfCheckBox:SfCheckBox 
                                    Text="{Binding Content}"
                                    IsChecked="{Binding IsChecked, Mode=TwoWay}" />
                            </Grid>
                        </ViewCell.View>
                    </ViewCell>
                </DataTemplate>
            </syncfusion:SfTreeView.ItemTemplate>
        </syncfusion:SfTreeView>
    </ContentPage.Content>
</ContentPage>

Xamarin Forms UnboundMode TreeView with CheckBox

You can download the entire source of this demo here

CheckBox State

SfTreeView process IsChecked property (checkbox state) of TreeViewNode based on CheckBoxMode property. CheckBoxMode defines how parent and child node’s checkbox state updates when user check or un-check the node. By default, its value is None. Checkbox contains the following three states:

  • None: Check and uncheck are updates only in the view, but it will not affect the CheckedItems collection.
  • Individual: Checkbox state affect individual node only, and it does not affect the parent node or child nodes checkbox state or IsChecked property value.
  • Recursive: Check and uncheck the node value affects the parent and child nodes checkbox state. For example, If parent nodes checkbox state is check/uncheck then the all of its child nodes checkbox state is check/uncheck. If all the child nodes are check/uncheck within the parent node, then parent node will be check/uncheck. If any of the child node is check, then the parent node will be in intermediate state.
<syncfusion:SfTreeView x:Name="TreeView" CheckBoxMode="Recursive"/>
TreeView.CheckBoxMode = CheckBoxMode.Recursive;

NOTE

In recursive mode, the parent nodes checkbox state or IsChecked property value is updated only in UI interaction.

Get or Set Checked Items

Get or Set Checked Items in Bound Mode

You can get or set list of items to be checked or un-checked by using CheckedItems property.

When the CheckBoxMode is other than None, the individual TreeViewNode or collection of TreeViewNode can be checked from the code by setting the CheckedItems, or adding items to the CheckedItems property based on the CheckBoxMode.

NOTE

Programmatically adding or removing the node value not affects their parent and child nodes checkbox state.

treeView.CheckedItems.Add(viewModel.Folders[2]);
treeView.CheckedItems.Add(viewModel.Folders[3]);

Get or Set Checked Nodes in Unbound Mode

You can get the list of checked nodes by using GetCheckedNodes method. You can set checkbox state by setting TreeViewNode.IsChecked property.

treeView.GetCheckedNodes();

Events

NodeChecked event

The NodeChecked event raised when checking and unchecking the checkbox at run time. The NodeCheckedEventArgs has the following members, which provide information for the NodeChecked event.

  • Node: Gets the TreeViewNode and data associated with the checked item as its arguments.
treeView.NodeChecked += TreeView_NodeChecked;

private void TreeView_NodeChecked(object sender, Syncfusion.XForms.TreeView.NodeCheckedEventArgs e)
{
     
}

NOTE

NodeChecked event occurs only in UI interactions.