Getting Started with .NET MAUI TreeView (SfTreeView)
20 Sep 202324 minutes to read
This section provides a quick overview for getting started with the TreeView with the .NET Maui TreeView (SfTreeView) for Maui. Walk through the entire process of creating real world of this control.
Creating an application using the .NET MAUI TreeView
- Create a new .NET MAUI application in Visual Studio.
- The Syncfusion .NET MAUI components are available on nuget.org. To add SfTreeView to your project, open the NuGet package manager in Visual Studio, search for
Syncfusion.Maui.TreeViewand then install it. - Import the control namespace
Syncfusion.Maui.TreeViewin XAML or C# code. - Initialize the SfTreeView control.
<ContentPage
. . .
xmlns:syncfusion="clr-namespace:Syncfusion.Maui.TreeView;assembly=Syncfusion.Maui.TreeView">
<syncfusion:SfTreeView />
</ContentPage>using Syncfusion.Maui.TreeView;
. . .
public partial class MainPage : ContentPage
{
public MainPage()
{
InitializeComponent();
SfTreeView treeView = new SfTreeView();
this.Content = treeView;
}
}Register the handler
The Syncfusion.Maui.Core NuGet is a dependent package for all the Syncfusion controls of .NET MAUI. In the MauiProgram.cs file, register the handler for Syncfusion core.
using Microsoft.Maui.Controls.Hosting;
using Microsoft.Maui.Controls.Xaml;
using Microsoft.Maui.Hosting;
using Syncfusion.Maui.Core.Hosting;
namespace GettingStarted
{
public class MauiProgram
{
public static MauiApp CreateMauiApp()
{
var builder = MauiApp.CreateBuilder();
builder
.UseMauiApp<App>()
.ConfigureFonts(fonts =>
{
fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");
});
builder.ConfigureSyncfusionCore();
return builder.Build();
}
}
}Populating Nodes without data source - Unbound Mode
You can create and manage the TreeViewNode objects by yourself to display the data in a hierarchical view. To create a tree view, you can use a TreeView control and a hierarchy of TreeViewNode objects. You can create the node hierarchy by adding one or more root nodes to the TreeView control’s Nodes collection. Each TreeViewNode can then have more nodes added to its Children collection. You can nest the tree view nodes to any depth you need.
IMPORTANT
ItemsSourceis an alternative mechanism toNodesfor adding content into the TreeView control. You cannot set bothItemsSourceandNodesat the same time. When you useItemsSource, nodes are created internally, but you cannot access them from theNodesproperty.
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:syncfusion="clr-namespace:Syncfusion.Maui.TreeView;assembly=Syncfusion.Maui.TreeView"
xmlns:treeviewengine="clr-namespace:Syncfusion.TreeView.Engine;assembly=Syncfusion.Maui.TreeView"
x:Class="GettingStarted.MainPage">
<ContentPage.Content>
<syncfusion:SfTreeView x:Name="treeView">
<syncfusion:SfTreeView.Nodes>
<treeviewengine:TreeViewNode Content="Australia">
<treeviewengine:TreeViewNode.ChildNodes>
<treeviewengine:TreeViewNode Content="New South Wales">
<treeviewengine:TreeViewNode.ChildNodes>
<treeviewengine:TreeViewNode Content="Sydney"/>
</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 Content="California">
<treeviewengine:TreeViewNode.ChildNodes>
<treeviewengine:TreeViewNode Content="San Francisco"/>
</treeviewengine:TreeViewNode.ChildNodes>
</treeviewengine:TreeViewNode>
</treeviewengine:TreeViewNode.ChildNodes>
</treeviewengine:TreeViewNode>
</syncfusion:SfTreeView.Nodes>
</syncfusion:SfTreeView>
</ContentPage.Content>
</ContentPage>using Microsoft.Maui.Controls;
using Syncfusion.Maui.TreeView;
using Syncfusion.TreeView.Engine;
using System;
namespace GettingStarted
{
public class MainPage : ContentPage
{
SfTreeView treeView;
public MainPage()
{
InitializeComponent();
treeView = new SfTreeView();
var australia = new TreeViewNode() { Content = "Australia" };
var nsw = new TreeViewNode() { Content = "New South Wales" };
var sydney = new TreeViewNode() { Content = "Sydney" };
australia.ChildNodes.Add(nsw);
nsw.ChildNodes.Add(sydney);
var usa = new TreeViewNode() { Content = "United States of America" };
var newYork = new TreeViewNode() { Content = "New York," };
var california = new TreeViewNode() { Content = "California" };
var sanFrancisco = new TreeViewNode() { Content = "San Francisco" };
usa.ChildNodes.Add(newYork);
usa.ChildNodes.Add(california);
California.ChildNodes.Add(sanFrancisco);
treeView.Nodes.Add(australia);
treeView.Nodes.Add(usa);
this.Content = treeView;
}
}
}Download the entire source code from GitHub here.
Creating data model for the tree view
Create a data model to bind it to the control.
Create a simple data source as shown in the following code example in a new class file, and save it as FileManager.cs file:
public class FileManager : INotifyPropertyChanged
{
private string itemName;
private ImageSource imageIcon;
private ObservableCollection<FileManager> subFiles;
public ObservableCollection<FileManager> SubFiles
{
get { return subFiles; }
set
{
subFiles = value;
RaisedOnPropertyChanged("SubFiles");
}
}
public string ItemName
{
get { return itemName; }
set
{
itemName = value;
RaisedOnPropertyChanged("ItemName");
}
}
public ImageSource ImageIcon
{
get { return imageIcon; }
set
{
imageIcon = value;
RaisedOnPropertyChanged("ImageIcon");
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void RaisedOnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}NOTE
If you want your data model to respond to property changes, then implement INotifyPropertyChanged interface in your model class.
Create a model repository class with ImageNodeInfo collection property initialized with required number of data objects in a new class file as shown in the following code example, and save it as FileManagerViewModel.cs file:
public class FileManagerViewModel
{
private ObservableCollection<FileManager> imageNodeInfo;
public FileManagerViewModel()
{
GenerateSource();
}
public ObservableCollection<FileManager> ImageNodeInfo
{
get { return imageNodeInfo; }
set { this.imageNodeInfo = value; }
}
private void GenerateSource()
{
var nodeImageInfo = new ObservableCollection<FileManager>();
var doc = new FileManager() { ItemName = "Documents", ImageIcon = "folder.png" };
var download = new FileManager() { ItemName = "Downloads", ImageIcon = "folder.png" };
var mp3 = new FileManager() { ItemName = "Music", ImageIcon ="folder.png" };
var pictures = new FileManager() { ItemName = "Pictures", ImageIcon = "folder.png" };
var video = new FileManager() { ItemName = "Videos", ImageIcon ="folder.png" };
var pollution = new FileManager() { ItemName = "Environmental Pollution.docx", ImageIcon = "word.png" };
var globalWarming = new FileManager() { ItemName = "Global Warming.ppt", ImageIcon = "ppt.png" };
var sanitation = new FileManager() { ItemName = "Sanitation.docx", ImageIcon = "word.png"};
var socialNetwork = new FileManager() { ItemName = "Social Network.pdf", ImageIcon ="pdfimage.png" };
var youthEmpower = new FileManager() { ItemName = "Youth Empowerment.pdf", ImageIcon = "pdfimage.png" };
var tutorials = new FileManager() { ItemName = "Tutorials.zip", ImageIcon = "zip.png" };
var typeScript = new FileManager() { ItemName = "TypeScript.7z", ImageIcon ="zip.png" };
var uiGuide = new FileManager() { ItemName = "UI-Guide.pdf", ImageIcon = "pdfimage.png"};
var song = new FileManager() { ItemName = "Gouttes", ImageIcon = "audio.png" };
var camera = new FileManager() { ItemName = "Camera Roll", ImageIcon = "folder.png" };
var stone = new FileManager() { ItemName = "Stone.jpg", ImageIcon = "image.png" };
var wind = new FileManager() { ItemName = "Wind.jpg", ImageIcon = "image.png"};
var img0 = new FileManager() { ItemName = "WIN_20160726_094117.JPG", ImageIcon = "people_circle23.png" };
var img1 = new FileManager() { ItemName = "WIN_20160726_094118.JPG", ImageIcon = "people_circle2.png" };
var video1 = new FileManager() { ItemName = "Naturals.mp4", ImageIcon = "video.png" };
var video2 = new FileManager() { ItemName = "Wild.mpeg", ImageIcon = "video.png" };
doc.SubFiles = new ObservableCollection<FileManager>
{
pollution,
globalWarming,
sanitation,
socialNetwork,
youthEmpower
};
download.SubFiles = new ObservableCollection<FileManager>
{
tutorials,
TypeScript,
uiGuide
};
mp3.SubFiles = new ObservableCollection<FileManager>
{
song
};
pictures.SubFiles = new ObservableCollection<FileManager>
{
camera,
stone,
wind
};
camera.SubFiles = new ObservableCollection<FileManager>
{
img0,
img1
};
video.SubFiles = new ObservableCollection<FileManager>
{
video1,
video2
};
nodeImageInfo.Add(doc);
nodeImageInfo.Add(download);
nodeImageInfo.Add(mp3);
nodeImageInfo.Add(pictures);
nodeImageInfo.Add(video);
imageNodeInfo = nodeImageInfo;
}
}Bind to a hierarchical data source - Bound Mode
You can create a tree view by binding the ItemsSource to a hierarchical data source. To create a tree view using data binding, set a hierarchical collection to the ItemsSource property. Then in the ItemTemplate and ExpanderTemplate, set the child items collection to the ItemsSource property.
IMPORTANT
ItemsSource is an alternative mechanism to Nodes for adding content into the TreeView control. You cannot set both ItemsSource and Nodes at the same time. When you use ItemsSource, nodes are created internally, but you cannot access them from the Nodes property.
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:syncfusion="clr-namespace:Syncfusion.Maui.TreeView;assembly=Syncfusion.Maui.TreeView"
xmlns:local="clr-namespace:GettingStarted;assembly=GettingStarted"
x:Class="GettingStarted.MainPage">
<ContentPage.BindingContext>
<local:FileManagerViewModel x:Name="viewModel" />
</ContentPage.BindingContext>
<syncfusion:SfTreeView x:Name="treeView"
ItemsSource="{Binding ImageNodeInfo}"
ChildPropertyName="SubFiles"/>
</ContentPage>using Syncfusion.Maui.TreeView;
namespace GettingStarted;
public partial class MainPage : ContentPage
{
public MainPage()
{
InitializeComponent();
SfTreeView treeView = new SfTreeView();
FileManagerViewModel viewModel = new FileManagerViewModel();
treeView.ItemsSource = viewModel.ImageNodeInfo;
treeView.ChildPropertyName = "SubFiles";
this.Content = treeView;
}
}Creating hierarchical Data Model for tree view
Create an hierarchical data model to bind it to the control.
Create a simple hierarchical data source as shown in the following code example in a new class file, and save it as FileManager.cs file.
public class Folder : INotifyPropertyChanged
{
private string itemName;
private ImageSource imageIcon;
private ObservableCollection<File> files;
public Folder()
{
}
public ObservableCollection<File> Files
{
get { return files; }
set
{
files = value;
RaisedOnPropertyChanged("Files");
}
}
public string ItemName
{
get { return itemName; }
set
{
itemName = value;
RaisedOnPropertyChanged("ItemName");
}
}
public ImageSource ImageIcon
{
get { return imageIcon; }
set
{
imageIcon = value;
RaisedOnPropertyChanged("ImageIcon");
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void RaisedOnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
public class File : INotifyPropertyChanged
{
private string itemName;
private ImageSource imageIcon;
private ObservableCollection<SubFile> subFiles;
public File()
{
}
public ObservableCollection<SubFile> SubFiles
{
get { return subFiles; }
set
{
subFiles = value;
RaisedOnPropertyChanged("SubFiles");
}
}
public string ItemName
{
get { return itemName; }
set
{
itemName = value;
RaisedOnPropertyChanged("ItemName");
}
}
public ImageSource ImageIcon
{
get { return imageIcon; }
set
{
imageIcon = value;
RaisedOnPropertyChanged("ImageIcon");
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void RaisedOnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
public class SubFile : INotifyPropertyChanged
{
private string itemName;
private ImageSource imageIcon;
public SubFile()
{
}
public string ItemName
{
get { return itemName; }
set
{
itemName = value;
RaisedOnPropertyChanged("ItemName");
}
}
public ImageSource ImageIcon
{
get { return imageIcon; }
set
{
imageIcon = value;
RaisedOnPropertyChanged("ImageIcon");
}
}
public event PropertyChangedEventHandler PropertyChanged;
public void RaisedOnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}NOTE
If you need your hierarchical data model to respond to the property changes, then implement the
INotifyPropertyChangedinterface in your model class.
Create a model repository class with the Folders collection property initialized with the required number of data objects in a new class file as shown in the following code example, and save it as FileManagerViewModel.cs file:
public class FileManagerViewModel
{
public ObservableCollection<Folder> Folders { get; set; }
public FileManagerViewModel()
{
this.Folders = GetFiles();
}
private ObservableCollection<Folder> GetFiles()
{
var nodeImageInfo = new ObservableCollection<Folder>();
var doc = new Folder() { ItemName = "Documents", ImageIcon = "folder.png" };
var download = new Folder() { ItemName = "Downloads", ImageIcon = "folder.png" };
var mp3 = new Folder() { ItemName = "Music", ImageIcon ="folder.png" };
var pictures = new Folder() { ItemName = "Pictures", ImageIcon = "folder.png" };
var video = new Folder() { ItemName = "Videos", ImageIcon ="folder.png" };
var pollution = new File() { ItemName = "Environmental Pollution.docx", ImageIcon = "word.png" };
var globalWarming = new File() { ItemName = "Global Warming.ppt", ImageIcon = "ppt.png" };
var sanitation = new File() { ItemName = "Sanitation.docx", ImageIcon = "word.png"};
var socialNetwork = new File() { ItemName = "Social Network.pdf", ImageIcon ="pdfimage.png" };
var youthEmpower = new File() { ItemName = "Youth Empowerment.pdf", ImageIcon = "pdfimage.png" };
var tutorials = new File() { ItemName = "Tutorials.zip", ImageIcon = "zip.png" };
var typeScript = new File() { ItemName = "TypeScript.7z", ImageIcon ="zip.png" };
var uiGuide = new File() { ItemName = "UI-Guide.pdf", ImageIcon = "pdfimage.png"};
var song = new File() { ItemName = "Gouttes", ImageIcon = "audio.png" };
var camera = new File() { ItemName = "Camera Roll", ImageIcon = "folder.png" };
var stone = new File() { ItemName = "Stone.jpg", ImageIcon = "image.png" };
var wind = new File() { ItemName = "Wind.jpg", ImageIcon = "image.png"};
var img0 = new SubFile() { ItemName = "WIN_20160726_094117.JPG", ImageIcon = "people_circle23.png" };
var img1 = new SubFile() { ItemName = "WIN_20160726_094118.JPG", ImageIcon = "people_circle2.png" };
var video1 = new File() { ItemName = "Naturals.mp4", ImageIcon = "video.png" };
var video2 = new File() { ItemName = "Wild.mpeg", ImageIcon = "video.png" };
doc.Files = new ObservableCollection<File>
{
pollution,
globalWarming,
sanitation,
socialNetwork,
youthEmpower
};
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);
return nodeImageInfo;
}
}Bind to a Hierarchy Property Descriptors data source - Bound mode
You can create a tree view by binding the ItemsSource to the hierarchy property descriptors data source. To create a tree view using hierarchical data binding, set a hierarchical collection to the ItemsSource property, and then set the TargetType and ChildPropertyName property values in HirearchyPropertyDescriptors .
IMPORTANT
ItemsSourceis an alternative mechanism to Nodes for adding content into the TreeView control. You cannot set bothItemsSourceandNodesat the same time. When you useItemsSource, nodes are created internally, but you cannot access them from theNodesproperty.
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:syncfusion="clr-namespace:Syncfusion.Maui.TreeView;assembly=Syncfusion.Maui.TreeView"
xmlns:treeviewengine="clr-namespace:Syncfusion.TreeView.Engine;assembly=Syncfusion.Maui.TreeView"
xmlns:local="clr-namespace:GettingStarted;assembly=GettingStarted"
x:Class="GettingStarted.MainPage">
<ContentPage.BindingContext>
<local:FileManagerViewModel x:Name="viewModel" />
</ContentPage.BindingContext>
<syncfusion:SfTreeView x:Name="treeView"
ItemsSource="{Binding Folders}" >
<syncfusion:SfTreeView.HierarchyPropertyDescriptors>
<treeviewengine:HierarchyPropertyDescriptor TargetType="{x:Type local:Folder}" ChildPropertyName="Files"/>
<treeviewengine:HierarchyPropertyDescriptor TargetType="{x:Type local:File}" ChildPropertyName="SubFiles"/>
</syncfusion:SfTreeView.HierarchyPropertyDescriptors>
</syncfusion:SfTreeView>
</ContentPage>using Syncfusion.Maui.TreeView;
using Syncfusion.TreeView.Engine;
using System;
namespace GettingStarted
{
public partial class MainPage : ContentPage
{
InitializeComponent();
SfTreeView treeView = new SfTreeView();
FileManagerViewModel viewModel = new FileManagerViewModel();
treeView.ItemsSource = viewModel.Folders;
var propertyDescriptor = new HierarchyPropertyDescriptors();
propertyDescriptor.Add(new Syncfusion.TreeView.Engine.HierarchyPropertyDescriptor() { TargetType = typeof(Folder), ChildPropertyName = "Files" });
propertyDescriptor.Add(new Syncfusion.TreeView.Engine.HierarchyPropertyDescriptor() { TargetType = typeof(Files), ChildPropertyName = "SubFiles" });
treeView.HierarchyPropertyDescriptors = propertyDescriptor;
this.Content = treeView;
}
}Defining a template to expander and content view
By defining the ExpanderTemplate and ItemTemplate properties, a custom user interface (UI) can be created to display the data items for both expander and content view. It is applicable for both the Unbound and Bound mode data items.
NOTE
By default, the binding context for each tree view item will be the data model object for Bound Mode and TreeViewNode for Unbound Mode. However, you can change the binding context for tree view items in Bound Mode as
TreeViewNodeby defining the ItemTemplateContextType enumeration toNode, which is applicable for bothExpanderTemplateandItemTemplateproperties.
The following code example demonstrates how to customize your content view using the ItemTemplate and ExpanderTemplate property in both XAML and C#.
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:syncfusion="clr-namespace:Syncfusion.Maui.TreeView;assembly=Syncfusion.Maui.TreeView"
xmlns:local="clr-namespace:GettingStarted.ViewModel"
x:Class="GettingStarted.MainPage">
<ContentPage.BindingContext>
<local:FileManagerViewModel x:Name="viewModel"></local:FileManagerViewModel>
</ContentPage.BindingContext>
<ContentPage.Content>
<syncfusion:SfTreeView x:Name="treeView"
ItemsSource="{Binding ImageNodeInfo}"
ItemTemplateContextType="Node">
<syncfusion:SfTreeView.ItemTemplate>
<DataTemplate>
<Grid x:Name="grid" RowSpacing="0"
BackgroundColor="Transparent">
<Grid Padding="5,5,5,5">
<Image Source="{Binding Content.ImageIcon}"
VerticalOptions="Center"
HorizontalOptions="Center"
HeightRequest="35"
WidthRequest="35"/>
</Grid>
<Grid Grid.Column="1"
RowSpacing="1"
Padding="1,0,0,0"
VerticalOptions="Center">
<Label LineBreakMode="NoWrap"
Text="{Binding Content.ItemName}"
VerticalTextAlignment="Center"/>
</Grid>
</Grid>
</DataTemplate>
</syncfusion:SfTreeView.ItemTemplate>
<syncfusion:SfTreeView.ExpanderTemplate>
<DataTemplate>
<Image IsVisible="{Binding HasChildNodes,Converter={StaticResource IconVisibleConverter}}"
Source="{ Binding IsExpanded,Converter={StaticResource ExpanderIconConverter}}"
VerticalOptions="Center"
HorizontalOptions="Center"/>
</DataTemplate>
</syncfusion:SfTreeView.ExpanderTemplate>
</syncfusion:SfTreeView>
</ContentPage.Content>
</ContentPage>using Syncfusion.Maui.TreeView;
namespace GettingStarted
{
public partial class MainPage : ContentPage
{
InitializeComponent();
SfTreeView treeView = new SfTreeView();
FileManagerViewModel viewModel = new FileManagerViewModel();
treeView.ItemsSource = viewModel.ImageNodeInfo;
treeView.ChildPropertyName = "SubFiles";
treeView.ItemTemplateContextType = ItemTemplateContextType.Node;
treeView.ItemTemplate = new DataTemplate(() =>
{
HorizontalStackLayout stack = new HorizontalStackLayout();
var imageIcon = new Image { WidthRequest = 24, HeightRequest = 24 };
imageIcon.SetBinding(Image.SourceProperty, new Binding("Content.ImageIcon"));
var itemName = new Label { FontSize = 15, VerticalTextAlignment=TextAlignment.Center, Padding=5 };
itemName.SetBinding(Label.TextProperty, new Binding("Content.ItemName"));
stack.Children.Add(imageIcon);
stack.Children.Add(itemName);
return stack;
});
treeView.ExpanderTemplate = new DataTemplate(()=>
{
var grid = new Grid();
var expanderIcon = new Image();
expanderIcon.SetBinding(Image.SourceProperty, new Binding("IsExpanded"));
expanderIcon.SetBinding(Image.IsVisibleProperty, new Binding("HasChildNodes"));
grid.Children.Add(expanderIcon);
return grid;
});
this.Content = treeView;
}
}Download the entire source code from GitHub here.
Interacting with a tree view
The TreeView allows you to expand and collapse the nodes either by user interaction on the nodes or by programmatically. The expanding and collapsing interactions can be handled with the help of NodeCollapsing and NodeExpanding events.
You can define how the nodes to be expanded while loading the TreeView by using the AutoExpandMode property. Also, the TreeView allows you to set the restrictions whether expanding and collapsing of nodes can be performed only by tapping in expander view or in both expander view and content view by using the ExpandActionTarget property.
NOTE
the
AutoExpandModeproperty is only applicable for bound mode. For Unbound mode you need to setIsExpandedproperty totruewhile creating the nodes, to be in expanded state while loading the TreeView.
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:syncfusion="clr-namespace:Syncfusion.Maui.TreeView;assembly=Syncfusion.Maui.TreeView"
xmlns:local="clr-namespace:GettingStarted;assembly=GettingStarted"
x:Class="GettingStarted.MainPage">
<syncfusion:SfTreeView x:Name="treeView"
AutoExpandMode="AllNodesExpanded"
ExpandActionTarget="Node"/>
</ContentPage>using Syncfusion.Maui.TreeView;
using Syncfusion.TreeView.Engine;
namespace GettingStarted
{
public class MainPage : ContentPage
{
public MainPage()
{
InitializeComponent();
SfTreeView treeView = new SfTreeView();
treeView.AutoExpandMode = TreeViewAutoExpandMode.AllNodesExpanded;
treeView.ExpandActionTarget = TreeViewExpandActionTarget.Node;
this.Content = treeView;
}
}
}Selection
The TreeView allows selecting the item by setting the SelectionMode property. Set the SelectionMode property to single, single-deselect, multiple, extended and none based on the requirements. Informations about the selected item can be tracked using the SelectedItem, CurrentItem and SelectedItems properties. Also, TreeView provides key board navigation support in WinUI and MacCatalyst platform.
It also allows changing the selection highlight color by using the SelectionBackground property. Additionally, for unbound mode, you can change the selection foreground color of the text by using the SelectionForeground property.
The selection operations can be handled with the help of SelectionChanging and SelectionChanged events.
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:syncfusion="clr-namespace:Syncfusion.Maui.TreeView;assembly=Syncfusion.Maui.TreeView"
xmlns:local="clr-namespace:GettingStarted.ViewModel"
x:Class="GettingStarted.MainPage">
<syncfusion:SfTreeView x:Name="treeView"
SelectionMode="Single"
SelectionBackground="#EADDFF"
SelectionForeground="#1C1B1F"/>
</ContentPage>using Syncfusion.Maui.TreeView;
namespace GettingStarted
{
public class MainPage : ContentPage
{
SfTreeView treeView;
public MainPage()
{
treeView = new SfTreeView();
treeView.SelectionMode = TreeViewSelectionMode.Single;
treeView.SelectionBackground = Color.FromHex("#EADDFF");
treeView.SelectionForeground = Color.FromHex("#1C1B1F");
this.Content=treeView;
}
}
}Reset tree view items
You can reset the visible treeview items by using the ResetTreeViewItems method. If the parameter is null, all the visible treeview items will reset. If you are passing the data object as a parameter, a particular treeview item will reset.
treeView.ResetTreeViewItems();Refresh view
You can refresh the view by using the RefreshView method. It will be used to refresh the items in the treeview at runtime while updating the view.
treeView.RefreshView();