Getting Started with ASP.NET Core ComboBox Control

19 Dec 20224 minutes to read

This section briefly explains about how to include ASP.NET Core ComboBox control in your ASP.NET Core application using Visual Studio.

Prerequisites

System requirements for ASP.NET Core controls

Create ASP.NET Core web application with Razor pages

Install ASP.NET Core package in the application

Syncfusion ASP.NET Core controls are available in nuget.org.. Refer to NuGet packages topic to learn more about installing NuGet packages in various OS environments. To add ASP.NET Core controls in the application, open the NuGet package manager in Visual Studio (Tools → NuGet Package Manager → Manage NuGet Packages for Solution), search for Syncfusion.EJ2.AspNet.Core and then install it.

NOTE

The Syncfusion.EJ2.AspNet.Core NuGet package has dependencies, Newtonsoft.Json for JSON serialization and Syncfusion.Licensing for validating Syncfusion license key.

Add Syncfusion ASP.NET Core Tag Helper

Open ~/Views/_ViewImports.cshtml file and import the Syncfusion.EJ2 TagHelper.

~/_ViewImports.cshtml
@addTagHelper *, Syncfusion.EJ2

Add style sheet

Checkout the Themes topic to learn different ways (CDN, NPM package, and CRG) to refer styles in ASP.NET Core application, and to have the expected appearance for Syncfusion ASP.NET Core controls. Here, the theme is referred using CDN inside the <head> of ~/Pages/Shared/_Layout.cshtml file as follows,

~/_Layout.cshtml
<head>
    ...
    <!-- Syncfusion ASP.NET Core controls styles -->
    <link rel="stylesheet" href="https://cdn.syncfusion.com/ej2/20.4.48/fluent.css" />
</head>

Add script reference

In this getting started walk-through, the required scripts are referred using CDN inside the <head> of ~/Pages/Shared/_Layout.cshtml file as follows,

~/_Layout.cshtml
<head>
    ...
    <!-- Syncfusion ASP.NET Core controls scripts -->
    <script src="https://cdn.syncfusion.com/ej2/20.4.48/dist/ej2.min.js"></script>
</head>

Register Syncfusion Script Manager

Open ~/Pages/Shared/_Layout.cshtml page and register the script manager at the end of `<body>` in the ASP.NET Core application as follows.

~/_Layout.cshtml
<body>
...
    <!-- Syncfusion ASP.NET Core Script Manager -->
    <ejs-scripts></ejs-scripts>
</body>

Add ASP.NET Core ComboBox control

Now, add the Syncfusion ASP.NET Core ComboBox tag helper in ~/Pages/Index.cshtml page.

CSHTML
@{
    ...
    var data = new string[] { "Badminton", "Basketball", "Cricket", "Football", "Golf", "Gymnastics", "Hockey", "Tennis" };
}

<ejs-combobox id="games" dataSource="data" placeholder="Select a game">
</ejs-combobox>

Press Ctrl+F5 (Windows) or ⌘+F5 (macOS) to run the app. Then, the Syncfusion ASP.NET Core ComboBox control will be rendered in the default web browser.

ASP.NET Core ComboBox Control

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 control.

CSHTML
@{
    ...
    var data = new string[] { "Badminton", "Basketball", "Cricket", "Football", "Golf", "Gymnastics", "Hockey", "Tennis" };
}

<ejs-combobox id="games" dataSource="data" placeholder="Select a Country" popupHeight="220px">
</ejs-combobox>

Custom values

The ComboBox allows the user 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 are considered as same. The custom value will be sent to post back handler when a form is about to be submitted.

CSHTML
@{
    ...
    var data = new string[] { "Badminton", "Basketball", "Cricket", "Football", "Golf", "Gymnastics", "Hockey", "Tennis" };
}

<ejs-combobox id="games" allowCustom="true" dataSource="data" placeholder="Select a Country" popupHeight="220px">
</ejs-combobox>

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 ‘300px’.

The height and width of the popup list can also be customized using the popupHeight and popupWidth properties respectively.

CSHTML
@{
    ...
    var data = new string[] { "Badminton", "Basketball", "Cricket", "Football", "Golf", "Gymnastics", "Hockey", "Tennis" };
}

<ejs-combobox id="games" dataSource="data" popupWidth="300px" placeholder="Select a game" popupHeight="220px">
</ejs-combobox>

NOTE

View Sample in GitHub.