Getting Started with Blazor TreeGrid in Blazor Web App

27 Apr 202623 minutes to read

This guide explains how to integrate the Syncfusion^® Blazor TreeGrid component in your Blazor Web App using Visual Studio, Visual Studio Code, and the .NET CLI.

• Visual Studio
• Visual Studio Code
• .NET CLI

Prerequisites

• System requirements for Blazor components

Create a new Blazor Web App in Visual Studio

Create a Blazor Web App using Visual Studio via Microsoft Templates or the Syncfusion^® Blazor Extension. For detailed instructions, refer to the Blazor Web App Getting Started documentation.

Prerequisites

• System requirements for Blazor components

Create a new Blazor Web App in Visual Studio Code

Create a Blazor Web App using Visual Studio Code via Microsoft Templates or the Syncfusion^® Blazor Extension. For detailed instructions, refer to the Blazor Web App Getting Started documentation.

For example, in a Blazor Web App with the Auto interactive render mode, use the following commands in the integrated terminal (Ctrl+`):

Blazor Web App

dotnet new blazor -o BlazorWebApp -int Auto
cd BlazorWebApp
cd BlazorWebApp.Client

Prerequisites

Install the latest version of .NET SDK. If you previously installed the SDK, determine the installed version by executing the following command in a command prompt (Windows) or terminal (macOS) or command shell (Linux).

.NET CLI

dotnet --version

Create a Blazor Web App using .NET CLI

Run the following command to create a new Blazor Web App in a command prompt (Windows) or terminal (macOS) or command shell (Linux). For detailed instructions, refer to the Blazor Web App Getting Started documentation.

For example, in a Blazor Web App with the Auto interactive render mode, use the following commands:

Blazor Web App

dotnet new blazor -o BlazorWebApp -int Auto
cd BlazorWebApp
cd BlazorWebApp.Client

NOTE

Configure the appropriate Interactive render mode and Interactivity location while creating a Blazor Web App. For detailed information, refer to the interactive render mode documentation.

Install Syncfusion^® Blazor packages

Install Syncfusion.Blazor.TreeGrid and Syncfusion.Blazor.Themes NuGet packages in your project using the NuGet Package Manager in Visual Studio (Tools → NuGet Package Manager → Manage NuGet Packages for Solution), or the integrated terminal in Visual Studio Code (dotnet add package), or the .NET CLI.

Alternatively, run the following commands in the Package Manager Console to achieve the same.

Package Manager

Install-Package Syncfusion.Blazor.TreeGrid -Version 33.2.3
Install-Package Syncfusion.Blazor.Themes -Version 33.2.3

If using the WebAssembly or Auto render modes in the Blazor Web App, install these packages in the client project.

NOTE

All Syncfusion Blazor packages are available on nuget.org. See the NuGet packages topic for details.

Add import namespaces

After the packages are installed, open the ~/_Imports.razor file in the client project and import the Syncfusion.Blazor and Syncfusion.Blazor.TreeGrid namespaces.

~/_Imports.razor

@using Syncfusion.Blazor
@using Syncfusion.Blazor.TreeGrid

Register Syncfusion^® Blazor service

Register the Syncfusion Blazor service in the Program.cs file of your Blazor Web App.

Program.cs

....
using Syncfusion.Blazor;
....
builder.Services.AddSyncfusionBlazor();
....

NOTE

If the Interactive Render Mode is set to WebAssembly or Auto, register the Syncfusion^® Blazor service in Program.cs files of both the server and client projects in your Blazor Web App.

Add stylesheet and script resources

The theme stylesheet and script can be accessed from NuGet through Static Web Assets. Include the stylesheet and script references in the ~/Components/App.razor file.

<link href="_content/Syncfusion.Blazor.Themes/fluent2.css" rel="stylesheet" />
....
<script src="_content/Syncfusion.Blazor.Core/scripts/syncfusion-blazor.min.js" type="text/javascript"></script>

NOTE

Check out the Blazor Themes topic to discover various methods (Static Web Assets, CDN, and CRG) for referencing themes in your Blazor application. Also, check out the Adding Script Reference topic to learn different approaches for adding script references in your Blazor application.

Add Syncfusion^® Blazor TreeGrid component

Add the Syncfusion Blazor TreeGrid component in the ~/Components/Pages/*.razor file. If the interactivity location is set to Per page/component in the Web App, define a render mode at the top of the ~/Pages/*.razor file. (For example, InteractiveServer, InteractiveWebAssembly or InteractiveAuto).

NOTE

If the Interactivity Location is set to Global with Auto or WebAssembly, the render mode is automatically configured in the App.razor file by default.

RAZOR

@* desired render mode define here *@
@rendermode InteractiveAuto

Home.razor

@using Syncfusion.Blazor.TreeGrid

<SfTreeGrid DataSource="@TreeData" IdMapping="TaskId" ParentIdMapping="ParentId" TreeColumnIndex="1">
    <TreeGridColumns>
        <TreeGridColumn Field="TaskId" HeaderText="Task ID" Width="5" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Center"></TreeGridColumn>
        <TreeGridColumn Field="TaskName" HeaderText="Task Name" Width="30" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Center"></TreeGridColumn>
    </TreeGridColumns>
</SfTreeGrid>

@code
{
    public class BusinessObject
    {
        public int TaskId { get; set; }
        public string TaskName { get; set; }
        public int? ParentId { get; set; }
    }

    public List<BusinessObject> TreeData = new List<BusinessObject>();

    protected override void OnInitialized()
    {
        TreeData.Add(new BusinessObject() { TaskId = 1, TaskName = "Parent Task 1", ParentId = null });
        TreeData.Add(new BusinessObject() { TaskId = 2, TaskName = "Child task 1", ParentId = 1 });
        TreeData.Add(new BusinessObject() { TaskId = 3, TaskName = "Child Task 2", ParentId = 1, });
        TreeData.Add(new BusinessObject() { TaskId = 4, TaskName = "Parent Task 2", ParentId = null });
        TreeData.Add(new BusinessObject() { TaskId = 5, TaskName = "Child Task 5", ParentId = 4 });
        TreeData.Add(new BusinessObject() { TaskId = 6, TaskName = "Child Task 6", ParentId = 5 });
    }
}

• Press Ctrl+F5 (Windows) or ⌘+F5 (macOS) to launch the application. This will render the Syncfusion^® Blazor TreeGrid component in the default web browser.

NOTE

View Sample in GitHub.

Defining columns

The Tree Grid has an option to define columns using the TreeGridColumns directive. In the TreeGridColumn directive there are properties to customize columns.

Let’s check the properties used here:

• Field to map with a property name in datasource has been added.
• HeaderText to change the title of columns has been added.
• TextAlign to change the alignment of columns is used. By default, columns will be left aligned. To change columns to right align, define TextAlign as Right.

Home.razor

@using Syncfusion.Blazor.TreeGrid

<SfTreeGrid DataSource="@TreeData" IdMapping="TaskId" ParentIdMapping="ParentId" TreeColumnIndex="1">
    <TreeGridColumns>
        <TreeGridColumn Field="TaskId" HeaderText="Task ID" Width="80" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="TaskName" HeaderText="Task Name" Width="160"></TreeGridColumn>
        <TreeGridColumn Field="Duration" HeaderText="Duration" Width="100" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="Progress" HeaderText="Progress" Width="100" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="Priority" HeaderText="Priority" Width="80"></TreeGridColumn>
    </TreeGridColumns>
</SfTreeGrid>

@code{

    public class BusinessObject
    {
        public int TaskId { get; set; }
        public string TaskName { get; set; }
        public int Duration { get; set; }
        public int Progress { get; set; }
        public string Priority { get; set; }
        public int? ParentId { get; set; }
    }

    public List<BusinessObject> TreeData = new List<BusinessObject>();

    protected override void OnInitialized()
    {
        TreeData.Add(new BusinessObject() { TaskId = 1, TaskName = "Parent Task 1", Duration = 10, Progress = 70, ParentId = null, Priority = "High" });
        TreeData.Add(new BusinessObject() { TaskId = 2, TaskName = "Child task 1", Duration = 4, Progress = 80, ParentId = 1, Priority = "Normal" });
        TreeData.Add(new BusinessObject() { TaskId = 3, TaskName = "Child Task 2", Duration = 5, Progress = 65, ParentId = 1, Priority = "Critical" });
        TreeData.Add(new BusinessObject() { TaskId = 4, TaskName = "Parent Task 2", Duration = 6, Progress = 77, ParentId = null, Priority = "Low" });
        TreeData.Add(new BusinessObject() { TaskId = 5, TaskName = "Child Task 5", Duration = 9, Progress = 25, ParentId = 4, Priority = "Normal" });
        TreeData.Add(new BusinessObject() { TaskId = 6, TaskName = "Child Task 6", Duration = 9, Progress = 7, ParentId = 5, Priority = "Normal" });
        TreeData.Add(new BusinessObject() { TaskId = 7, TaskName = "Parent Task 3", Duration = 4, Progress = 45, ParentId = null, Priority = "High" });
        TreeData.Add(new BusinessObject() { TaskId = 8, TaskName = "Child Task 7", Duration = 3, Progress = 38, ParentId = 7, Priority = "Critical" });
        TreeData.Add(new BusinessObject() { TaskId = 9, TaskName = "Child Task 8", Duration = 7, Progress = 70, ParentId = 7, Priority = "Low" });
    }
}

In the above code example, the Self-Referential data binding is represented in which the IdMapping and ParentIdMapping properties denotes the hierarchy relationship; whereas in Hierarchical data binding ChildMapping denotes the hierarchy relationship.

Enable paging

The paging feature enables users to view the tree grid record in a paged view. It can be enabled by setting the AllowPaging property to true. The pager can be customized using the PageSettings property.

In root-level paging mode, paging is based on the root-level rows only, i.e., it ignores the child row count and it can be enabled by using the PageSettings.PageSizeMode property.

Home.razor

@using Syncfusion.Blazor.TreeGrid

<SfTreeGrid DataSource="@TreeData" IdMapping="TaskId" ParentIdMapping="ParentId" TreeColumnIndex="1" AllowPaging="true">
    <TreeGridPageSettings PageSizeMode="PageSizeMode.Root" PageSize="2"></TreeGridPageSettings>
    <TreeGridColumns>
        <TreeGridColumn Field="TaskId" HeaderText="Task ID" Width="80" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="TaskName" HeaderText="Task Name" Width="160"></TreeGridColumn>
        <TreeGridColumn Field="Duration" HeaderText="Duration" Width="100" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="Progress" HeaderText="Progress" Width="100" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="Priority" HeaderText="Priority" Width="80"></TreeGridColumn>
    </TreeGridColumns>
</SfTreeGrid>

@code{

    public class BusinessObject
    {
        public int TaskId { get; set; }
        public string TaskName { get; set; }
        public int Duration { get; set; }
        public int Progress { get; set; }
        public string Priority { get; set; }
        public int? ParentId { get; set; }
    }

    public List<BusinessObject> TreeData = new List<BusinessObject>();

    protected override void OnInitialized()
    {
        TreeData.Add(new BusinessObject() { TaskId = 1, TaskName = "Parent Task 1", Duration = 10, Progress = 70, ParentId = null, Priority = "High" });
        TreeData.Add(new BusinessObject() { TaskId = 2, TaskName = "Child task 1", Duration = 4, Progress = 80, ParentId = 1, Priority = "Normal" });
        TreeData.Add(new BusinessObject() { TaskId = 3, TaskName = "Child Task 2", Duration = 5, Progress = 65, ParentId = 1, Priority = "Critical" });
        TreeData.Add(new BusinessObject() { TaskId = 4, TaskName = "Parent Task 2", Duration = 6, Progress = 77, ParentId = null, Priority = "Low" });
        TreeData.Add(new BusinessObject() { TaskId = 5, TaskName = "Child Task 5", Duration = 9, Progress = 25, ParentId = 4, Priority = "Normal" });
        TreeData.Add(new BusinessObject() { TaskId = 6, TaskName = "Child Task 6", Duration = 9, Progress = 7, ParentId = 5, Priority = "Normal" });
        TreeData.Add(new BusinessObject() { TaskId = 7, TaskName = "Parent Task 3", Duration = 4, Progress = 45, ParentId = null, Priority = "High" });
        TreeData.Add(new BusinessObject() { TaskId = 8, TaskName = "Child Task 7", Duration = 3, Progress = 38, ParentId = 7, Priority = "Critical" });
        TreeData.Add(new BusinessObject() { TaskId = 9, TaskName = "Child Task 8", Duration = 7, Progress = 70, ParentId = 7, Priority = "Low" });
    }
}

Enable sorting

The sorting feature enables to order the records. It can be enabled by setting the AllowSorting property to true.

Home.razor

@using Syncfusion.Blazor.TreeGrid

<SfTreeGrid DataSource="@TreeData" IdMapping="TaskId" ParentIdMapping="ParentId" TreeColumnIndex="1" AllowPaging="true" AllowSorting="true">
    <TreeGridPageSettings PageSizeMode="PageSizeMode.Root" PageSize="2"></TreeGridPageSettings>
    <TreeGridColumns>
        <TreeGridColumn Field="TaskId" HeaderText="Task ID" Width="80" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="TaskName" HeaderText="Task Name" Width="160"></TreeGridColumn>
        <TreeGridColumn Field="Duration" HeaderText="Duration" Width="100" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="Progress" HeaderText="Progress" Width="100" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="Priority" HeaderText="Priority" Width="80"></TreeGridColumn>
    </TreeGridColumns>
</SfTreeGrid>

@code{

    public class BusinessObject
    {
        public int TaskId { get; set; }
        public string TaskName { get; set; }
        public int Duration { get; set; }
        public int Progress { get; set; }
        public string Priority { get; set; }
        public int? ParentId { get; set; }
    }

    public List<BusinessObject> TreeData = new List<BusinessObject>();

    protected override void OnInitialized()
    {
        TreeData.Add(new BusinessObject() { TaskId = 1, TaskName = "Parent Task 1", Duration = 10, Progress = 70, ParentId = null, Priority = "High" });
        TreeData.Add(new BusinessObject() { TaskId = 2, TaskName = "Child task 1", Duration = 4, Progress = 80, ParentId = 1, Priority = "Normal" });
        TreeData.Add(new BusinessObject() { TaskId = 3, TaskName = "Child Task 2", Duration = 5, Progress = 65, ParentId = 1, Priority = "Critical" });
        TreeData.Add(new BusinessObject() { TaskId = 4, TaskName = "Parent Task 2", Duration = 6, Progress = 77, ParentId = null, Priority = "Low" });
        TreeData.Add(new BusinessObject() { TaskId = 5, TaskName = "Child Task 5", Duration = 9, Progress = 25, ParentId = 4, Priority = "Normal" });
        TreeData.Add(new BusinessObject() { TaskId = 6, TaskName = "Child Task 6", Duration = 9, Progress = 7, ParentId = 5, Priority = "Normal" });
        TreeData.Add(new BusinessObject() { TaskId = 7, TaskName = "Parent Task 3", Duration = 4, Progress = 45, ParentId = null, Priority = "High" });
        TreeData.Add(new BusinessObject() { TaskId = 8, TaskName = "Child Task 7", Duration = 3, Progress = 38, ParentId = 7, Priority = "Critical" });
        TreeData.Add(new BusinessObject() { TaskId = 9, TaskName = "Child Task 8", Duration = 7, Progress = 70, ParentId = 7, Priority = "Low" });
    }
}

Handling exceptions

Exception handling in Tree Grid identifies exceptions and notifies them through the OnActionFailure event. When configuring the Tree Grid or enabling specific features through its API, mistakes can occur. The OnActionFailure event can be used to manage these exceptions. This event triggers when such mistakes happen. The OnActionFailure event handles various scenarios, including:

• For CRUD operations, row drag and drop, and persisting the selection, ensure the IsPrimaryKey property is mapped to a unique data column. Failure to do so will cause an exception.
• Paging is not supported with Virtualization. Enabling Paging with Virtualization will result in an exception.
• To render the Tree Grid, map either the DataSource or Columns property. Failure to do so will result in an exception.
• Freeze columns by mapping either IsFrozen or FrozenColumns. Enabling both properties simultaneously will result in an exception.

• The DetailTemplate is not supported with Virtualization and Stacked Header. Enabling them with these features will result in an exception.

• The FrozenRows and FrozenColumns are not supported with RowTemplate, DetailTemplate, and Cell Editing. Enabling them with these features will result in an exception.

• In Stacked Header, the Freeze direction is incompatible with Column Reordering.
• Selection functionality is not supported when using RowTemplate. Enabling both properties simultaneously will result in an exception.
• Set the TreeColumnIndex value to display the tree structure. Make sure the value does not exceed the total column count, or it will result in an exception.
• For Virtualization, do not specify height and width in percentages. Using percentages will result in an error.
• When using the default filter (FilterBar) type, do not apply the other FilterType to columns within the same tree grid, as this will result in an exception.
• In Tree Grid, avoid enabling IdMapping and ChildMapping simultaneously. Enabling both properties at the same time will result in an exception.
• The ShowCheckbox column should only be defined in the tree column. Defining it elsewhere will result in an exception.
• The TextAlign right is not applicable for tree columns in the Tree Grid. Enabling right alignment for tree columns will result in an exception.

The following code example shows how to use the OnActionFailure event in the Tree Grid control to display an exception when IsPrimaryKeyare not configured properly in the Tree Grid.

Home.razor

@using Syncfusion.Blazor.TreeGrid;
@using Syncfusion.Blazor.Data;

 <span class="error">@ErrorDetails</span>
<SfTreeGrid DataSource="@TreeData" IdMapping="TaskId" ParentIdMapping="ParentId" TreeColumnIndex="1">
    <TreeGridEditSettings AllowEditing></TreeGridEditSettings>
    <TreeGridEvents TValue="BusinessObject" OnActionFailure="ActionFailure"></TreeGridEvents>
    <TreeGridColumns>
        <TreeGridColumn Field="TaskId" HeaderText="Task ID" Width="80" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="TaskName" HeaderText="Task Name" Width="160"></TreeGridColumn>
        <TreeGridColumn Field="StartDate" HeaderText="Start Date" Format="d" Type="Syncfusion.Blazor.Grids.ColumnType.DateOnly" Width="152" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="StartTime" HeaderText="Start Time" Type="Syncfusion.Blazor.Grids.ColumnType.TimeOnly" Width="100" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="Duration" HeaderText="Duration" Width="100" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
        <TreeGridColumn Field="Progress" HeaderText="Progress" Width="100" TextAlign="Syncfusion.Blazor.Grids.TextAlign.Right"></TreeGridColumn>
    </TreeGridColumns>
</SfTreeGrid>
<style>
    .error {
        color: red;
    }
</style>

@code{

    private string ErrorDetails = "";
    public class BusinessObject
    {
        public int TaskId { get; set; }
        public string TaskName { get; set; }
        public DateOnly? StartDate { get; set; }
        public TimeOnly? StartTime { get; set; }
        public int Duration { get; set; }
        public int Progress { get; set; }
        public string Priority { get; set; }
        public int? ParentId { get; set; }
    }

    public void ActionFailure(Syncfusion.Blazor.Grids.FailureEventArgs args)
    {
        this.ErrorDetails = args.Error.Message.ToString();
        StateHasChanged();
    }

    public List<BusinessObject> TreeData = new List<BusinessObject>();

    protected override void OnInitialized()
    {
        TreeData.Add(new BusinessObject() { TaskId = 1, TaskName = "Parent Task 1", StartDate = new DateOnly(2021, 03, 02), StartTime = new TimeOnly(10, 00, 00), Duration = 10, Progress = 70, ParentId = null, Priority = "High" });
        TreeData.Add(new BusinessObject() { TaskId = 2, TaskName = "Child task 1", StartDate = new DateOnly(2021, 03, 04), StartTime = new TimeOnly(11, 30, 00), Duration = 4, Progress = 80, ParentId = 1, Priority = "Normal" });
        TreeData.Add(new BusinessObject() { TaskId = 3, TaskName = "Child Task 2", StartDate = new DateOnly(2021, 03, 06), StartTime = new TimeOnly(12, 00, 00), Duration = 5, Progress = 65, ParentId = 1, Priority = "Critical" });
        TreeData.Add(new BusinessObject() { TaskId = 4, TaskName = "Parent Task 2", StartDate = new DateOnly(2021, 03, 08), StartTime = new TimeOnly(13, 30, 00), Duration = 6, Progress = 77, ParentId = null, Priority = "Low" });
        TreeData.Add(new BusinessObject() { TaskId = 5, TaskName = "Child Task 5", StartDate = new DateOnly(2021, 07, 10), StartTime = new TimeOnly(14, 00, 00), Duration = 9, Progress = 25, ParentId = 4, Priority = "Normal" });
        TreeData.Add(new BusinessObject() { TaskId = 6, TaskName = "Child Task 6", StartDate = new DateOnly(2021, 10, 12), StartTime = new TimeOnly(16, 00, 00), Duration = 9, Progress = 7, ParentId = 5, Priority = "Normal" });
        TreeData.Add(new BusinessObject() { TaskId = 7, TaskName = "Parent Task 3", StartDate = new DateOnly(2021, 10, 14), StartTime = new TimeOnly(17, 30, 00), Duration = 4, Progress = 45, ParentId = null, Priority = "High" });
        TreeData.Add(new BusinessObject() { TaskId = 8, TaskName = "Child Task 7", StartDate = new DateOnly(2021, 10, 16), StartTime = new TimeOnly(18, 00, 00), Duration = 3, Progress = 38, ParentId = 7, Priority = "Critical" });
        TreeData.Add(new BusinessObject() { TaskId = 9, TaskName = "Child Task 8", StartDate = new DateOnly(2021, 02, 18), StartTime = new TimeOnly(19, 30, 00), Duration = 7, Progress = 70, ParentId = 7, Priority = "Low" });
    }
}

See also

• Getting Started with Syncfusion^® Blazor for Server-Side in .NET Core CLI
• Getting Started with Syncfusion^® Blazor for Client-Side in Visual Studio
• Getting Started with Syncfusion^® Blazor for Client-Side in .NET Core CLI
• Getting Started with Syncfusion^® JavaScript documentation
• Getting Started with Syncfusion^® JavaScript (ES5) documentation
• Getting Started with Syncfusion^® Angular documentation
• Getting Started with Syncfusion^® React documentation
• Getting Started with Syncfusion^® Vue documentation
• Getting Started with Syncfusion^® ASP.NET Core documentation
• Getting Started with Syncfusion^® ASP.NET MVC documentation