In this article I will explain with an example, how to implement Bootstrap AutoComplete TextBox using jQuery TypeAhead plugin in ASP.Net Core (.Net Core 8) MVC.
The jQuery Bootstrap AutoComplete TextBox data will be populated from database using Entity Framework in ASP.Net Core (.Net Core 8) MVC.
This article makes use of Bootstrap version 5.
Note: For beginners in ASP.Net Core (.Net Core 8), please refer my article ASP.Net Core 8: Hello World Tutorial with Sample Program example.
 
 

Download TypeAhead Plugin

You will need to download the plugin files from the following location.
Download TypeAhead Plugin
 
 

Database

Here I am making use of Microsoft’s Northwind Database. You can download it from here.
Download and install Northwind Database
 
 

Model

The model class consists of following properties.
public class CustomerModel
{
    [Key]
    public string CustomerID { get; set; }
    public string ContactName { get; set; }
}
 
 

Database Context

Once the Entity Framework is configured and connected to the database table, the Database Context will look as shown below.
Note: For beginners in ASP.Net Core and Entity Framework, please refer my article ASP.Net Core 7: Simple Entity Framework Tutorial with example. It covers all the information needed for connecting and configuring Entity Framework with ASP.Net Core.
 
using Microsoft.EntityFrameworkCore;
 
namespace Bootstrap_5_AutoComplete_Core
{
    public class DBCtx : DbContext
    {
        public DBCtx(DbContextOptions<DBCtx> options) : base(options)
        {
        }
 
        public DbSet<CustomerModel> Customers { get; set; }
    }
}
 
 

Controller

Inside the Controller, first the private property of DbContext class is created.
Then, the DbContext class is injected into the Constructor (HomeController) using Dependency Injection method and the injected object is assigned to the private property of DbContext class.
The Controller consists of following Action methods.

Action method for handling GET operation

Inside this Action method, simply the View is returned.
 

Action method for handling the jQuery AutoComplete

This Action method accepts a parameter named prefix. When this method is accessed by the jQuery AutoComplete plugin, the records of the Customers Table of the Northwind database are fetched using the Entity Framework.
The fetched records are then filtered and returned back to the View as JSON.
 

Action method for handling POST operation

Inside this Action method, the CustomerName and CustomerId of the selected item in jQuery AutoComplete is set into a ViewBag object.
public class HomeController : Controller
{
    private DBCtx Context { get; set; }
    public HomeController(DBCtx _context)
    {
        this.Context = _context;
    }
 
    public IActionResult Index()
    {
        return View();
    }
 
    [HttpPost]
    public JsonResult AutoComplete(string prefix)
    {
        var customers = (from customer in this.Context.Customers
                         where customer.ContactName.StartsWith(prefix)
                         select new
                         {
                              label = customer.ContactName,
                              val = customer.CustomerID
                         }).ToList();
        return Json(customers);
    }
 
    [HttpPost]
    public IActionResult Index(string CustomerName, string CustomerId)
    {
        ViewBag.Message = "CustomerName: " + CustomerName + "<br /> CustomerId: " + CustomerId;
        return View();
    }
}
 
 

View

HTML Markup

Inside the View, the ASP.Net TagHelpers is inherited.
The View consists of an HTML Form which has been created using the following TagHelpers attributes.
asp-action – Name of the Action. In this case the name is Index.
asp-controller – Name of the Controller. In this case the name is Home.
method – It specifies the Form Method i.e. GET or POST. In this case it will be set to POST.
Inside the HTML Form, there is an HTML INPUT TextBox (implemented as AutoComplete), a Hidden Field (for saving the Value part of the Autocomplete Item) and a Submit Button.
 

Bootstrap TypeAhead AutoComplete plugin implementation

Inside the HTML, the following CSS file is inherited.
1. bootstrap.min.css
 
Then, the following script files are inherited.
1. jquery.min.js
2. bootstrap.bundle.min.js
3. bootstrap3-typeahead.min.js
 
The TextBox has been applied with the Bootstrap jQuery TypeAhead AutoComplete plugin.
The Bootstrap jQuery TypeAhead AutoComplete plugin has been set with the following porperties and event handlers:
 
Properties:
minLength – For setting minimum character length needed for suggestions to be rendered. Here it is set to 1.
 
Events:
source - Inside this event handler, a jQuery AJAX call is made to the Controller’s AutoComplete Action method and the list of customers returned acts as source of data to the Bootstrap jQuery TypeAhead AutoComplete.
The data received from the server is processed inside the jQuery AJAX call success event handler. A FOR EACH loop is executed for each received item in the list of items and then an object with text part in the name property and value part in the id property is returned.
updater - When an item is selected from the List of the Bootstrap jQuery TypeAhead AutoComplete, then the updater event handler is triggered which saves the ID of the selected item in the HiddenField element.
@addTagHelper*,Microsoft.AspNetCore.Mvc.TagHelpers
@{
     Layout = null;
}
 
<!DOCTYPE html>
 
<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
</head>
<body>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/5.3.2/css/bootstrap.min.css" media="screen" />
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/5.3.2/js/bootstrap.bundle.min.js"></script>
    <script type="text/javascript" src="https://cdn.rawgit.com/bassjobsen/Bootstrap-3-Typeahead/master/bootstrap3-typeahead.min.js"></script>
 
    <script type="text/javascript">
        $(function () {
            $("#txtCustomer").typeahead({
                 hint: true,
                 source: function (request, response) {
                    $.ajax({
                         type: "POST",
                         url: '/Home/AutoComplete/',
                         data: { prefix: request },
                         success: function (data) {
                           items = [];
                            map = {};
                            $.each(data, function (i, item) {
                                var id = item.val;
                                var name = item.label;
                                map[name] = { id: id, name: name };
                                items.push(name);
                            });
                            response(items);
                        },
                        error: function (response) {
                            alert(response.responseText);
                        },
                        failure: function (response) {
                            alert(response.responseText);
                        }
                    });
                },
                updater: function (item) {
                    $('#hfCustomer').val(map[item].id);
                    return item;
                }
            });
        });
    </script>
    <form method="post" asp-controller="Home" asp-action="Index">
        <input type="text" id="txtCustomer" name="CustomerName" class="form-control" autocomplete="off" style="width:300px" />
        <input type="hidden" id="hfCustomer" name="CustomerID" />
        <br />
        <input type="submit" id="btnSubmit" value="Submit" />
        <br />
        <br />
        @Html.Raw(ViewBag.Message)
    </form>
</body>
</html>
 
 

Screenshot

ASP.Net Core: Bootstrap 5 AutoComplete TextBox using jQuery TypeAhead plugin
 
 

Downloads

Download Code