Getting Started with Blazor MultiSelect Dropdown in Blazor Web App

1 Jul 20269 minutes to read

This section briefly explains about how to include Blazor MultiSelect Dropdown component in your Blazor Web App using Visual Studio, Visual Studio Code, and the .NET CLI.

Create a new Blazor Web App

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.

Run the following command to create a new Blazor Web App.

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

Alternatively, create a Blazor Web App using Visual Studio Code via Microsoft Templates, the Syncfusion® Blazor Extension, or the C# Dev Kit extension.

Run the following command to create a new Blazor Web App.

dotnet new blazor -o BlazorWebApp --interactivity 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 the required Blazor packages

Install Syncfusion.Blazor.DropDowns and Syncfusion.Blazor.Themes NuGet packages. All Syncfusion Blazor packages are available on nuget.org. See the NuGet packages topic for details. If using the WebAssembly or Auto render modes in the Blazor Web App, install these packages in the .Client project.

  1. Go to Tools → NuGet Package Manager → Manage NuGet Packages for Solution.
  2. Search the required NuGet packages (Syncfusion.Blazor.DropDowns and Syncfusion.Blazor.Themes) and install them.

Alternatively, you can install the same packages using the Package Manager Console with the following commands.

Install-Package Syncfusion.Blazor.DropDowns -Version 34.1.29
Install-Package Syncfusion.Blazor.Themes -Version 34.1.29

Open the terminal and run the following commands.

dotnet add package Syncfusion.Blazor.DropDowns -v 34.1.29
dotnet add package Syncfusion.Blazor.Themes -v 34.1.29

Open the command prompt and run the following commands.

dotnet add package Syncfusion.Blazor.DropDowns -v 34.1.29
dotnet add package Syncfusion.Blazor.Themes -v 34.1.29

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.DropDowns namespaces.

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

Register the Blazor service

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

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

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 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>

Add Blazor MultiSelect Dropdown component

Open a Razor file located in the ~/Pages/*.razor (for example, Home.razor) and add the Blazor MultiSelect Dropdown component inside the razor file.

NOTE

If the interactivity location is set to Per page/component in the Web App, define a render mode at the top of the razor file. (For example, InteractiveServer, InteractiveWebAssembly or InteractiveAuto). If the Interactivity is set to Global with Auto or WebAssembly, the render mode is automatically configured in the App.razor file by default.

@rendermode InteractiveAuto

@using Syncfusion.Blazor.DropDowns

<SfMultiSelect TValue="string[]" TItem="string" Placeholder='First Name'></SfMultiSelect>

Run the application

Press Ctrl+F5 (Windows) or +F5 (macOS) to launch the application. The Blazor MultiSelect Dropdown component will render in your default web browser.

Open the terminal and navigate to the main project folder (for example, BlazorWebApp) and run the following command.

cd ..
cd BlazorWebApp
dotnet run

Open the command prompt and navigate to the main project folder (for example, BlazorWebApp) and run the following command.

cd ..
cd BlazorWebApp
dotnet run
Blazor MultiSelect Dropdown Component

NOTE

View Sample in GitHub.

Binding data source

After initialization, populate the MultiSelect using the DataSource property. In the following example, a list of objects is bound to the component, and TItem specifies the data type. Display and value fields are mapped via MultiSelectFieldSettings.

@using Syncfusion.Blazor.DropDowns

<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.

@using Syncfusion.Blazor.DropDowns

<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

Handle the ValueChange event using ChangeEventArgs.Value property.

  • Home.razor
  • @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

    1. Getting Started with Blazor for Client-Side in .NET Core CLI
    2. Getting Started with Blazor for Server-side in Visual Studio
    3. Getting Started with Blazor for Server-Side in .NET Core CLI