Getting Started with Blazor Dropdown List in Blazor Server App

1 Sep 202610 minutes to read

This section explains how to include the Blazor Dropdown List component in a Blazor Server App using Visual Studio, Visual Studio Code, and the .NET CLI.

Create a new Blazor Server App

Create a Blazor Server App by using the Blazor Web App template in Visual Studio via Microsoft Templates or the Syncfusion® Blazor Extension.

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

dotnet new blazor -o BlazorApp --interactivity Server
cd BlazorApp

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

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

dotnet new blazor -o BlazorApp --interactivity Server
cd BlazorApp

Configure the appropriate Interactive render mode and Interactivity location while creating a Blazor Server App. For detailed information, refer to the interactive render mode documentation.

Install the required Blazor packages

Install the 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.

  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 35.1.37
Install-Package Syncfusion.Blazor.Themes -Version 35.1.37

Open the terminal and run the following commands.

dotnet add package Syncfusion.Blazor.DropDowns -v 35.1.37
dotnet add package Syncfusion.Blazor.Themes -v 35.1.37

Open the command prompt and run the following commands.

dotnet add package Syncfusion.Blazor.DropDowns -v 35.1.37
dotnet add package Syncfusion.Blazor.Themes -v 35.1.37

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 the Blazor service

Open the Program.cs file in Blazor Server App and register the Blazor service and include the required namespace reference using Syncfusion.Blazor; at the top.

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 at the end of the <head> section in the App.razor file.

<link href="_content/Syncfusion.Blazor.Themes/fluent2.css" rel="stylesheet" />

Include the required script references at the end of the <body> section in the App.razor file to enable Dropdown List functionality.

<script src="_content/Syncfusion.Blazor.Core/scripts/syncfusion-blazor.min.js" type="text/javascript"></script>

Add Blazor Dropdown List component

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

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

@rendermode InteractiveServer
@using Syncfusion.Blazor.DropDowns

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

Run the application

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

Open the terminal and run the following command.

dotnet run

Open the command prompt and run the following command.

dotnet run
Blazor Dropdown List Component

Binding data source

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

@using Syncfusion.Blazor.DropDowns

<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"},
  };
}
Data Binding in Blazor Dropdown List

Configure the popup list

By default, the popup list width adjusts to match the DropDownList input width, and the popup list height is 350px. Customize the popup height and width using the PopupHeight and PopupWidth properties.

@using Syncfusion.Blazor.DropDowns

<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"},
  };
}
Changing Popup List Height in Blazor Dropdown List

Get selected value

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

@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 for the selected item in the ValueChange event using the ChangeEventArgs.ItemData property.

@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($"Selected - ID: {args.ItemData.ID}, Game: {args.ItemData.Text}");
    }
}

View the sample in GitHub.

See also

  1. Getting Started with Blazor Web App
  2. Getting Started with Blazor WebAssembly App
  3. Getting Started with Blazor Dropdown List Data Binding