Getting Started with Dropdown Tree

3 Mar 20255 minutes to read

This section briefly explains about how to include Blazor Dropdown Tree component in your Blazor WebAssembly App using Visual Studio and Visual Studio Code.

To get started quickly with Blazor Dropdown Tree, check on the following video:

Prerequisites

Create a new Blazor App in Visual Studio

You can create a Blazor WebAssembly App using Visual Studio via Microsoft Templates or the Syncfusion® Blazor Extension.

Install Syncfusion® Blazor Navigations and Themes NuGet in the App

To add Blazor Dropdown Tree component in the app, open the NuGet package manager in Visual Studio (Tools → NuGet Package Manager → Manage NuGet Packages for Solution), search and install Syncfusion.Blazor.Navigations and Syncfusion.Blazor.Themes. Alternatively, you can utilize the following package manager command to achieve the same.

Install-Package Syncfusion.Blazor.Navigations -Version 28.2.3
Install-Package Syncfusion.Blazor.Themes -Version 28.2.3

NOTE

Syncfusion® Blazor components are available in nuget.org. Refer to NuGet packages topic for available NuGet packages list with component details.

Prerequisites

Create a new Blazor App in Visual Studio Code

You can create a Blazor WebAssembly App using Visual Studio Code via Microsoft Templates or the Syncfusion® Blazor Extension.

Alternatively, you can create a WebAssembly application using the following command in the terminal(Ctrl+`).

dotnet new blazorwasm -o BlazorApp
cd BlazorApp

Install Syncfusion® Blazor Navigations and Themes NuGet in the App

  • Press Ctrl+` to open the integrated terminal in Visual Studio Code.
  • Ensure you’re in the project root directory where your .csproj file is located.
  • Run the following command to install a Syncfusion.Blazor.Navigations and Syncfusion.Blazor.Themes NuGet package and ensure all dependencies are installed.
dotnet add package Syncfusion.Blazor.Navigations -v 28.2.3
dotnet add package Syncfusion.Blazor.Themes -v 28.2.3
dotnet restore

NOTE

Syncfusion® Blazor components are available in nuget.org. Refer to NuGet packages topic for available NuGet packages list with component details.

Register Syncfusion® Blazor Service

Open ~/_Imports.razor file and import the Syncfusion.Blazor and Syncfusion.Blazor.Navigations namespace.

@using Syncfusion.Blazor
@using Syncfusion.Blazor.Navigations

Now, register the Syncfusion® Blazor Service in the ~/Program.cs file of your Blazor WebAssembly App.

using Microsoft.AspNetCore.Components.Web;
using Microsoft.AspNetCore.Components.WebAssembly.Hosting;
using Syncfusion.Blazor;

var builder = WebAssemblyHostBuilder.CreateDefault(args);
builder.RootComponents.Add<App>("#app");
builder.RootComponents.Add<HeadOutlet>("head::after");

builder.Services.AddScoped(sp => new HttpClient { BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) });

builder.Services.AddSyncfusionBlazor();
await builder.Build().RunAsync();
....

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 <head> section of the ~/index.html file.

<head>
    ....
    <link href="_content/Syncfusion.Blazor.Themes/bootstrap5.css" rel="stylesheet" />
    <script src="_content/Syncfusion.Blazor.Core/scripts/syncfusion-blazor.min.js" type="text/javascript"></script>
</head>

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 Blazor Dropdown Tree component

Add the Syncfusion® Blazor Dropdown Tree component in the ~/Pages/Index.razor file. The TValue parameter specifies the type of the Value property, while TItem specifies the model class for the DataSource property.

@using Syncfusion.Blazor.Navigations

<SfDropDownTree TItem="EmployeeData" TValue="string" Placeholder="Select an employee" Width="500px"> 
    <DropDownTreeField TItem="EmployeeData" DataSource="Data" Id="Id" Text="Name" HasChildren="HasChild" ParentID="PId"></DropDownTreeField>
</SfDropDownTree>

@code {
    List<EmployeeData> Data = new List<EmployeeData>
    {
        new EmployeeData() {Id="1", Name = "Steven Buchanan", HasChild=true, Expanded=true},
        new EmployeeData() {Id="2", PId="1", Name = "Laura Callahan", HasChild=true},
        new EmployeeData() {Id="3", PId="2", Name = "Andrew Fuller", HasChild=true },
        new EmployeeData() {Id="4", PId="3", Name = "Anne Dodsworth" },
        new EmployeeData() {Id="5", PId="3", Name = "Lilly" }
    };
    public class EmployeeData
    {
        public string? Id { get; set; }
        public string? Name { get; set; }
        public bool HasChild { get; set; }
        public bool Expanded { get; set; }
        public string? PId { get; set; }
    }
}
Blazor Dropdown Tree Component

NOTE

View Sample in GitHub.