Getting Started with Blazor DropDown List in Web App

2 Sep 202514 minutes to read

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

Prerequisites

System requirements for Blazor components

Create a new Blazor Web App in Visual Studio

You can create a Blazor Web App using Visual Studio 2022 via Microsoft Templates or the Syncfusion^® Blazor Extension. For detailed instructions, refer to this Blazor Web App Getting Started documentation.

You need to configure the corresponding Interactive render mode and Interactivity location while creating a Blazor Web Application.

Install Syncfusion^® Blazor DropDowns and Themes NuGet in the Blazor Web App

To add Blazor DropDown List 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.

If you utilize WebAssembly or Auto render modes in the Blazor Web App need to be install Syncfusion^® Blazor components NuGet packages within the client project.

Alternatively, you can utilize the following package manager command to achieve the same.

Package Manager
Install-Package Syncfusion.Blazor.DropDowns -Version 31.1.17
Install-Package Syncfusion.Blazor.Themes -Version 31.1.17

NOTE

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

Prerequisites

System requirements for Blazor components

Create a new Blazor Web App in Visual Studio Code

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

You need to configure the corresponding Interactive render mode and Interactivity location while creating a Blazor Web Application.

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

For more information on creating a Blazor Web App with various interactive modes and locations, refer to this link.

Install Syncfusion^® Blazor DropDowns and Themes NuGet in the App

If you utilize WebAssembly or Auto render modes in the Blazor Web App need to be install Syncfusion^® Blazor components NuGet packages within the client project.

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.

Package Manager
dotnet add package Syncfusion.Blazor.DropDowns -v 31.1.17
dotnet add package Syncfusion.Blazor.Themes -v 31.1.17
dotnet restore

NOTE

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

Prerequisites

Latest version of the .NET Core SDK. If you previously installed the SDK, you can 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 project 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 a Blazor Web App with WebAssembly interactive render mode & Per page/component interactivity location, use the following commands

.NET CLI
dotnet new blazor -o BlazorApp -int WebAssembly
cd BlazorApp
cd BlazorApp.Client

For a Blazor Web App with Auto interactive render mode & Per page/component interactivity location, use the following commands

.NET CLI
dotnet new blazor -o BlazorApp -int Auto
cd BlazorApp
cd BlazorApp.Client

This command creates new Blazor Web app project and places it in a new directory called BlazorApp inside your current location. See Create Blazor app topic and dotnet new CLI command topics for more details.

Install Syncfusion^® Blazor DropDowns and Themes NuGet in the App

Here’s an example of how to add Blazor DropDown List component in the application using the following command in the command prompt (Windows) or terminal (Linux and macOS) to install a Syncfusion.Blazor.DropDowns and Syncfusion.Blazor.Themes NuGet package. See Install and manage packages using the dotnet CLI topics for more details.

If you utilize WebAssembly or Auto render modes in the Blazor Web App need to be install Syncfusion^® Blazor components NuGet packages within the client project.

.NET CLI
dotnet add package Syncfusion.Blazor.DropDowns --version 31.1.17
dotnet add package Syncfusion.Blazor.Themes --version 31.1.17
dotnet restore

NOTE

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

Add Import Namespaces

Open the ~/_Imports.razor file from the client project and import the Syncfusion.Blazor and Syncfusion.Blazor.DropDowns namespace.

~/_Imports.razor
@using Syncfusion.Blazor
@using Syncfusion.Blazor.DropDowns

Register Syncfusion^® Blazor Service

If the Interactive Render Mode is set to WebAssembly or Auto, you need to register the Syncfusion^® Blazor service in both ~/Program.cs files of your Blazor Web App.

Server(~/_Program.cs)
Client(~/_Program.cs)
...
...
using Syncfusion.Blazor;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddRazorComponents()
    .AddInteractiveServerComponents()
    .AddInteractiveWebAssemblyComponents();
builder.Services.AddSyncfusionBlazor();

var app = builder.Build();
....
...
using Syncfusion.Blazor;

var builder = WebAssemblyHostBuilder.CreateDefault(args);
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 reference in the <head> section and the script reference at the end of the <body> in the ~/Components/App.razor file as shown below:

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

    //Blazor DropDown List Component script reference.
    <!-- <script src="_content/Syncfusion.Blazor.DropDowns/scripts/sf-dropdownlist.min.js" type="text/javascript"></script> -->
</body>

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 the Syncfusion^® Blazor DropDown List component in .razor file inside the Pages folder. If an interactivity location as Per page/component in the web app, define a render mode at top of the component, as follows:

Interactivity location	RenderMode	Code
Per page/component	Auto	@rendermode InteractiveAuto
	WebAssembly	@rendermode InteractiveWebAssembly
	None	—

NOTE

If an Interactivity Location is set to Global and the Render Mode is set to Auto or WebAssembly, the render mode is configured in the App.razor file by default.

RAZOR

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

RAZOR
<SfDropDownList TValue="string" TItem="string" Placeholder="Select a game"></SfDropDownList>

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

Binding data source

After initialization, populate the DropDownList with data using the DataSource property.

RAZOR
<SfDropDownList TValue="string" TItem="Games" Placeholder="Select a game" DataSource="@LocalData">
  <DropDownListFieldSettings Value="ID" Text="Text"></DropDownListFieldSettings>
</SfDropDownList>

@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"},
  };
}

By default, the width of the popup list automatically adjusts according to the DropDownList input element’s width, and the height of the popup list has 350px. The height and width of the popup list can also be customized using the PopupHeight and PopupWidth properties respectively.

RAZOR
<SfDropDownList TValue="string" TItem="Games" PopupHeight="350px" PopupWidth="350px" Placeholder="Select a game" DataSource="@LocalData">
  <DropDownListFieldSettings Value="ID" Text="Text"></DropDownListFieldSettings>
</SfDropDownList>

@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"},
  };
}

Get selected value

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

CSHTML

@using Syncfusion.Blazor.DropDowns

<SfDropDownList TValue="string" TItem="Games" Placeholder="Select a game" DataSource="@LocalData">
  <DropDownListFieldSettings Value="Text" Text="Text"></DropDownListFieldSettings>
  <DropDownListEvents TValue="string" TItem="Games" ValueChange="OnValueChange"></DropDownListEvents>
</SfDropDownList>

@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(ChangeEventArgs<string, Games> args)
    {
        Console.WriteLine("The DropDownList Value is: ", args.Value);
    }
}

Get the complete object list of the selected value in the ValueChange event using the ChangeEventArgs.ItemData property.

CSHTML

@using Syncfusion.Blazor.DropDowns

<SfDropDownList TValue="string" TItem="Games" Placeholder="Select a game" DataSource="@LocalData">
  <DropDownListFieldSettings Value="ID" Text="Text"></DropDownListFieldSettings>
  <DropDownListEvents TValue="string" TItem="Games" ValueChange="OnValueChange"></DropDownListEvents>
</SfDropDownList>

@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(ChangeEventArgs<string, Games> args)
    {
        Console.WriteLine("The complete data of the selected value is: ", args.ItemData);
    }
}

NOTE

View Sample in GitHub.

Getting Started with Blazor DropDown List Component in Web App

Prerequisites

Create a new Blazor Web App in Visual Studio

Install Syncfusion® Blazor DropDowns and Themes NuGet in the Blazor Web App

Prerequisites

Create a new Blazor Web App in Visual Studio Code

Install Syncfusion® Blazor DropDowns and Themes NuGet in the App

Prerequisites

Create a Blazor Web project using .NET CLI

Install Syncfusion® Blazor DropDowns and Themes NuGet in the App

Add Import Namespaces

Register Syncfusion® Blazor Service

Add stylesheet and script resources

Add Syncfusion® Blazor DropDown List component

Binding data source

Configure the popup list

Get selected value

See also

Install Syncfusion^® Blazor DropDowns and Themes NuGet in the Blazor Web App

Install Syncfusion^® Blazor DropDowns and Themes NuGet in the App

Install Syncfusion^® Blazor DropDowns and Themes NuGet in the App

Register Syncfusion^® Blazor Service

Add Syncfusion^® Blazor DropDown List component