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Getting Started with Blazor ComboBox Component

16 Apr 20267 minutes to read

This section explains how to include the Syncfusion® Blazor ComboBox component in a Blazor WebAssembly App using Visual Studio, Visual Studio Code, and the .NET CLI.

Prerequisites

Create a new Blazor App in Visual Studio

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

Prerequisites

Create a new Blazor App in Visual Studio Code

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

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

dotnet new blazorwasm -o BlazorApp
cd BlazorApp

Prerequisites

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

dotnet --version

Create a Blazor WebAssembly App using .NET CLI

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

dotnet new blazorwasm -o BlazorApp
cd BlazorApp

Install Syncfusion® Blazor packages

Install Syncfusion.Blazor.DropDowns 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.

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

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 and import the Syncfusion.Blazor and Syncfusion.Blazor.DropDowns namespaces.

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

Register Syncfusion® Blazor service

Register the Syncfusion® Blazor service in the Program.cs file of your Blazor WebAssembly 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 ~/index.html 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 the Blazor application. Also, check out the Adding Script Reference topic to learn different approaches for adding script references in the Blazor application.

Add Syncfusion® Blazor ComboBox component

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

@using Syncfusion.Blazor.DropDowns

<SfComboBox TValue="string" TItem="string" Placeholder="Select a game"></SfComboBox>
  • Press Ctrl+F5 (Windows) or ⌘+F5 (macOS) to launch the application. This will render the Syncfusion® Blazor ComboBox component in the default web browser.
Blazor ComboBox Component

Binding data source

After initialization, populate the ComboBox with data using the DataSource property. In the following example, a list of objects (with ID and Text fields) is bound to the ComboBox.

@using Syncfusion.Blazor.DropDowns

<SfComboBox TValue="string" TItem="Games" Placeholder="Select a game" DataSource="@LocalData">
    <ComboBoxFieldSettings Value="ID" Text="Text"></ComboBoxFieldSettings>
</SfComboBox>

@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"},
  };
}
Blazor ComboBox with Data Binding

Custom values

The ComboBox supports custom values that are not present in the predefined list. This behavior is enabled by the AllowCustom property. In this mode, the typed text is treated as both the display text and the value, and the custom value is posted with the form on submit.

<SfComboBox TValue="string"  TItem="Games" AllowCustom=true Placeholder="Select a game" DataSource="@LocalData">
    <ComboBoxFieldSettings Value="ID" Text="Text"></ComboBoxFieldSettings>
</SfComboBox>
Blazor ComboBox with Custom Values

Configure the popup list

By default, the popup list width automatically adjusts to the ComboBox input width, and the popup height is 350px. The height and width of the popup list can be customized using the PopupHeight and PopupWidth properties.

<SfComboBox TValue="string" TItem="Games"PopupHeight="350px" PopupWidth="350px" Placeholder="Select a game" DataSource="@LocalData">
    <ComboBoxFieldSettings Value="ID" Text="Text"></ComboBoxFieldSettings>
</SfComboBox>
Customizing popup height and width in Blazor ComboBox

NOTE

View sample in GitHub.

See also