Getting Started with Blazor MultiSelect DropDown Component

30 Apr 20258 minutes to read

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

To get started quickly with Blazor MultiSelect DropDown component in the Blazor WebAssembly App, you can check the video below or GitHub.

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 DropDowns and Themes NuGet in the App

To add Blazor MultiSelect DropDown 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.DropDowns and Syncfusion.Blazor.Themes. Alternatively, you can utilize the following package manager command to achieve the same.

Install-Package Syncfusion.Blazor.DropDowns -Version 30.2.4
Install-Package Syncfusion.Blazor.Themes -Version 30.2.4

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 DropDowns 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.DropDowns and Syncfusion.Blazor.Themes NuGet package and ensure all dependencies are installed.
dotnet add package Syncfusion.Blazor.DropDowns -v 30.2.4
dotnet add package Syncfusion.Blazor.Themes -v 30.2.4
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.DropDowns namespace.

@using Syncfusion.Blazor
@using Syncfusion.Blazor.DropDowns

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 MultiSelect component

Add the Syncfusion® Blazor MultiSelect DropDown component in the ~/Pages/Index.razor file.

<SfMultiSelect TValue="string[]" TItem="string" Placeholder='First Name'></SfMultiSelect>
  • Press Ctrl+F5 (Windows) or ⌘+F5 (macOS) to launch the application. This will render the Syncfusion® Blazor MultiSelect DropDown component in your default web browser.
Blazor MultiSelect DropDown Component

Binding data source

After initialization, populate the MultiSelect with data using the DataSource property. Here, an array of string values is passed to the MultiSelect component. TItem specifies the type of the Datasource in MultiSelect.

<SfMultiSelect TValue="string[]" TItem="Games" Placeholder="Favorite Sports" DataSource="@LocalData">
    <MultiSelectFieldSettings Text="Text" Value="ID"></MultiSelectFieldSettings>
</SfMultiSelect>

@code {

    public class Games
    {
        public string ID { get; set; }
        public string Text { get; set; }
    }
    List<Games> LocalData = new List<Games> {
    new Games() { ID= "Game1", Text= "American Football" },
    new Games() { ID= "Game2", Text= "Badminton" },
    new Games() { ID= "Game3", Text= "Basketball" },
    new Games() { ID= "Game4", Text= "Cricket" },
    new Games() { ID= "Game5", Text= "Football" },
    new Games() { ID= "Game6", Text= "Golf" },
    new Games() { ID= "Game7", Text= "Hockey" },
    new Games() { ID= "Game8", Text= "Rugby"},
    new Games() { ID= "Game9", Text= "Snooker" },
    new Games() { ID= "Game10", Text= "Tennis"},
    };
}
Data Binding in Blazor MultiSelect DropDown

Configure the popup list

By default, the width of the popup list automatically adjusts according to the MultiSelect input element’s width, and the height auto adjust’s according to the height of the popup list items.

The height and width of the popup list can also be customized using the PopupHeight and PopupWidth properties respectively.

<SfMultiSelect TValue="string[]" TItem="Games" Placeholder="Favorite Sports" PopupHeight="350px" PopupWidth="350px" DataSource="@LocalData">
    <MultiSelectFieldSettings Text="Text" Value="ID"></MultiSelectFieldSettings>
</SfMultiSelect>
Configuring Popup List in Blazor MultiSelect DropDown

Get selected value

Get the selected value of the MultiSelect component in the ValueChange event using ChangeEventArgs.Value property.

  • CSHTML
    • @using Syncfusion.Blazor.DropDowns

<SfMultiSelect TValue="string[]" TItem="Games" Placeholder="Select a game" DataSource="@LocalData">
    <MultiSelectFieldSettings Value="Text" Text="Text"></MultiSelectFieldSettings>
    <MultiSelectEvents TValue="string[]" TItem="Games" ValueChange="OnValueChange"></MultiSelectEvents>
</SfMultiSelect>

@code {
    public class Games
    {  
        public string ID { get; set; }
        public string Text { get; set; }
    }
    List<Games> LocalData = new List<Games> {
        new Games() { ID= "Game1", Text= "American Football" },
        new Games() { ID= "Game2", Text= "Badminton" },
        new Games() { ID= "Game3", Text= "Basketball" },
        new Games() { ID= "Game4", Text= "Cricket" },
        new Games() { ID= "Game5", Text= "Football" },
        new Games() { ID= "Game6", Text= "Golf" },
        new Games() { ID= "Game7", Text= "Hockey" },
        new Games() { ID= "Game8", Text= "Rugby"},
        new Games() { ID= "Game9", Text= "Snooker" },
        new Games() { ID= "Game10", Text= "Tennis"},
    };
    public void OnValueChange(MultiSelectChangeEventArgs<string[]> args)
    {
        Console.WriteLine("The MultiSelect Value is: ", args.Value);
    }
}

    See also