Templates in Combo Box Control

19 Feb 20248 minutes to read

The ComboBox has been provided with several options to customize each list item, group title, selected value, header, and footer elements. It uses the Essential JS 2 Template engine to compile and render the elements properly.

Item template

The content of each list item within the ComboBox can be customized with the help of itemTemplate property.

In the following sample, each list item is split into two columns to display relevant data.

@Html.EJS().ComboBox("customers").Placeholder("Select a customer").PopupHeight("200px").DataSource(obj => obj.Url("https://services.odata.org/V4/Northwind/Northwind.svc/").Adaptor("ODataV4Adaptor").CrossDomain(true)).ItemTemplate("<span><span class='name'>${FirstName}</span><span class ='city'>${City}</span></span>").Fields(new Syncfusion.EJ2.DropDowns.ComboBoxFieldSettings
            {
                Value = "FirstName"
            }).Query("new ej.data.Query().from('Employees').select(['FirstName', 'City', 'EmployeeID']).take(6)").Render()
<style>
    .city {
        right: 15px;
        position: absolute;
    }
</style>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using WebApplication1.Models;

namespace WebApplication1.Controllers
{
    public class ComboBoxController : Controller
    {
        public ActionResult Itemtemplate()
        {
            return View();
        }       
    }
}

Group template

The group header title under which appropriate sub-items are categorized can also be customized with the help of groupTemplate property. This template is common for both inline and floating group header template.

@Html.EJS().ComboBox("customers").Placeholder("Select a customer").PopupHeight("200px").DataSource(dataManger =>
            dataManger.Url("https://services.odata.org/V4/Northwind/Northwind.svc/").Adaptor("ODataV4Adaptor").CrossDomain(true)).GroupTemplate("<strong>${City}</strong>").Fields(new Syncfusion.EJ2.DropDowns.ComboBoxFieldSettings
            {
                Value = "FirstName",
                GroupBy = "City"
            }).Query("new ej.data.Query().from('Employees').select(['FirstName', 'City', 'EmployeeID']).take(6).where(new ej.data.Predicate('City', 'equal','london').or('City','equal','seattle'))").Render()
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using WebApplication1.Models;

namespace WebApplication1.Controllers
{
    public class ComboBoxController : Controller
    {
        public ActionResult grouptemplate()
        {
            return View();
        }       
    }
}

Header template

The header element is shown statically at the top of the popup list items within the ComboBox, and any custom element can be placed as a header element using the headerTemplate property.

@Html.EJS().ComboBox("customers").Placeholder("Select a customer").PopupHeight("200px").DataSource(dataManger =>
            dataManger.Url("https://services.odata.org/V4/Northwind/Northwind.svc/").Adaptor("ODataV4Adaptor").CrossDomain(true)).ItemTemplate("<span class='item' ><span class='name'>${FirstName}</span><span class='city'>${City}</span></span>").HeaderTemplate("<span class='head'><span class='name'>Name</span><span class='city'>City</span></span>").Fields(new Syncfusion.EJ2.DropDowns.ComboBoxFieldSettings
            {
                Value = "FirstName",
            }).Query("new ej.data.Query().from('Employees').select(['FirstName', 'City', 'EmployeeID']).take(6)").Render()
<style>
    .head, .item {
        display: table;
        width: 100%;
        margin: auto;
    }

    .head {
        height: 40px;
        font-size: 15px;
        font-weight: 600;
    }

    .name, .city {
        display: table-cell;
        vertical-align: middle;
        width: 50%;
    }

    .head .name {
        text-indent: 16px;
    }

    .head .city {
        text-indent: 10px;
    }
</style>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using WebApplication1.Models;

namespace WebApplication1.Controllers
{
    public class ComboBoxController : Controller
    {
        public ActionResult headertemplate()
        {
            return View();
        }       
    }
}

The ComboBox has options to show a footer element at the bottom of the list items in the popup list. Here, you can place any custom element as a footer element using the footerTemplate property.

@Html.EJS().ComboBox("games").DataSource((IEnumerable<object>)ViewBag.data).Placeholder("Select a game").PopupHeight("270px").FooterTemplate("<span class='foot'> Total list items: " + 5 + "</span>").Render()
<style>
    .foot {
        text-indent: 1.2em;
        display: block;
        font-size: 15px;
        line-height: 40px;
        border-top: 1px solid #e0e0e0;
    }
</style>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using WebApplication1.Models;

namespace WebApplication1.Controllers
{
    public class ComboBoxController : Controller
    {
        public IActionResult footertemplate()
        {
            ViewBag.data = new string[] { "Badminton", "Basketball", "Cricket", "Football", "Golf", "Gymnastics", "Hockey", "Tennis" };
            return View();
        }
    }
}

No records template

The ComboBox is provided with support to custom design the popup list content when no data is found and no matches are found on search with the help of noRecordsTemplate property.

@Html.EJS().ComboBox("games").Placeholder("Select a game").PopupHeight("200px").DataSource((IEnumerable<object>)ViewBag.data).NoRecordsTemplate("<span class='norecord'> NO DATA AVAILABLE</span>").Render()
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using WebApplication1.Models;

namespace WebApplication1.Controllers
{
    public class ComboBoxController : Controller
    {
        public ActionResult norecords()
        {
            ViewBag.data = new string[] { };
            return View();
        }
    }
}

Action failure template

There is also an option to custom design the popup list content when the data fetch request fails at the remote server. This can be achieved using the actionFailureTemplate property.

@Html.EJS().ComboBox("customers").Placeholder("Select a customer").PopupHeight("200px").DataSource(dataManger =>
            dataManger.Url("https://services.odata.org/V4/Northwind/Northwind.svcs/").Adaptor("ODataV4Adaptor").CrossDomain(true)).ActionFailureTemplate("<span class='action-failure'> Data fetch get fails</span>").Fields(new Syncfusion.EJ2.DropDowns.ComboBoxFieldSettings
            {
                Value = "FirstName"
            }).Query("new ej.data.Query().from('Employees').select(['FirstName']).take(6)").Render()
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using WebApplication1.Models;

namespace WebApplication1.Controllers
{
    public class ComboBoxController : Controller
    {
        public ActionResult actionfailure()
        {
            return View();
        }
    }
}

NOTE

View Sample in GitHub.

See also