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Getting started with Blazor ComboBox component

This section briefly explains how to include a ComboBox Component in your Blazor client-side application. You can refer to the Getting Started with Syncfusion Blazor for Client-side in Visual Studio 2019 page for introduction and configure the common specifications.

To get start quickly with Blazor ComboBox component, you can check on this video.

Importing Syncfusion Blazor component in the application

  • Install Syncfusion.Blazor NuGet package to the application by using the NuGet Package Manager.

Please ensure to check the Include prerelease option for our Beta release.

  • You can add the client-side resources through CDN or from NuGet package in the HEAD element of the ~/Pages/_Host.cshtml page.
   <head>
           <link href="_content/Syncfusion.Blazor/styles/bootstrap4.css" rel="stylesheet" />
           @*<link href="https://cdn.syncfusion.com/blazor/{{version}}/styles/{{theme}}.css" rel="stylesheet" />*@
   </head>

For Internet Explorer 11 kindly refer the polyfills. Refer the documentation for more information.

   <head>
       <link href="_content/Syncfusion.Blazor/styles/bootstrap4.css" rel="stylesheet" />
       <script src="https://github.com/Daddoon/Blazor.Polyfill/releases/download/3.0.1/blazor.polyfill.min.js"></script>
   </head>

Adding component package to the application

Open ~/_Imports.razor file and import the Syncfusion.Blazor.DropDowns package.

@using Syncfusion.Blazor.DropDowns

Add SyncfusionBlazor service in Startup.cs

Open the Startup.cs file and add services required by Syncfusion components using services.AddSyncfusionBlazor() method. Add this method in the ConfigureServices function as follows.

using Syncfusion.Blazor;

namespace BlazorApplication
{
    public class Startup
    {
        ....
        ....
        public void ConfigureServices(IServiceCollection services)
        {
            ....
            ....
            services.AddSyncfusionBlazor();
        }
    }
}

To enable custom client side resource loading from CRG or CDN. You need to disable resource loading by AddSyncfusionBlazor(true) and load the scripts in the HEAD element of the ~/Pages/_Host.cshtml page.

   <head>
           <script src="https://cdn.syncfusion.com/blazor/18.2.59/syncfusion-blazor.min.js"></script>
   </head>

Adding ComboBox component to the application

To initialize the ComboBox component add the below code to your Index.razor view page which is present under ~/Pages folder.

<SfComboBox TValue="string" Placeholder="Select a game"></SfComboBox>

Run the application

After successful compilation of your application, press F5 to run the application.

The output will be as follows.

ComboBox

Binding data source

After initializing, populate the ComboBox with data using the DataSource property. Here, an array of string values is passed to the ComboBox component.

The following example illustrates the output in your browser.

<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"},
  };
}

The output will be as follows.

ComboBox

Custom values

The ComboBox allows the users to give input as custom value, which is not required to present in predefined set of values. By default, this support is enabled by AllowCustom property. In this case, both text field and value field is considered as same. The custom value will be sent to post back handler when a form is about to be submitted.

<SfComboBox TValue="string"  TItem="Games" AllowCustom=true 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"},
  };
}

The output will be as follows.

ComboBox

Configure the popup list

By default, the width of the popup list automatically adjusts according to the ComboBox 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.

In the following sample, popup list’s width and height are configured.

<SfComboBox TValue="string" TItem="Games"PopupHeight="350px" PopupWidth="350px" 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"},
  };
}

The output will be as follows.

ComboBox

See Also