In this article I will explain with an example, how to bind (populate) Multiple Select (Multi-Select) DropDownList with CheckBoxes from database using jQuery in ASP.Net MVC Razor.
The Multiple Select (Multi-Select) DropDownList with CheckBoxes will be implemented using jQuery Bootstrap Multi-Select plugin.
Note: For beginners in using ADO.Net with ASP.Net MVC, please refer my article ASP.Net MVC: ADO.Net Tutorial with example.
 
 

Download Bootstrap and jQuery Bootstrap Multi-Select Plugin

The download locations are as follows.

Bootstrap

https://getbootstrap.com/
 

jQuery BoosStrap Multi-Select Plugin

You will need to download the plugin files from the following location.
https://github.com/davidstutz/bootstrap-multiselect/
The complete documentation can be read on the following page.
https://davidstutz.github.io/bootstrap-multiselect/
 
 

Database

I have made use of the following table Fruits with the schema as follows.
Multiple Select (Multi-Select) DropDownList with CheckBoxes in ASP.Net MVC Razor
 
I have already inserted few records in the table.
Multiple Select (Multi-Select) DropDownList with CheckBoxes in ASP.Net MVC Razor
 
Note: You can download the database table SQL by clicking the download link below.
           Download SQL file
 
 

Model

The Model class consists of following properties.
The Fruits property is a Generic list of SelectListItem class which is an in-built ASP.Net MVC class. It has all the properties needed for populating a ListBox.
public class FruitModel
{
    public List<SelectListItem> Fruits { get; set; }
    public int[] FruitIds { get; set; }
}
 
 

Namespaces

You will need to import the following namespaces.
using System.Configuration;
using System.Data.SqlClient;
using System.Collections.Generic;
 
 

Controller

The Controller consists of following Action methods.

Action method for handling GET operation

Inside this Action method, the PopulateFruits method is called.
Inside the PopulateFruits method, the records from the Fruits table are fetched using DataReader and generic list of SelectListItem class is populated.
The FruitName is stored in the Text property while the FruitId is stored in the Value property.
Finally, the FruitModel class object is returned to the View.
 

Action method for handling POST operation

This Action method handles the call made from the POST function from the View.
Note: This example uses Model class object for capturing Form field values, for more details please refer my article ASP.Net MVC: Form Submit (Post) example.
 
When the Form is submitted, the posted values are captured through the FruitModel class object.
Then the PopulateFruits method is called and the selected Fruit is fetched using Lambda expression.
Finally, the multiple selected Fruit names are set into a ViewBag object which will be later displayed in View using JavaScript Alert Message Box.
Note: For more details on displaying message using JavaScript Alert MessageBox, please refer my article ASP.Net MVC: Display Message from Controller in View using JavaScript Alert MessageBox.
 
public class HomeController : Controller
{
    // GET: Home
    public ActionResult Index()
    {
        FruitModel fruit = new FruitModel();
        fruit.Fruits = PopulateFruits();
        return View(fruit);
    }
 
    [HttpPost]
    public ActionResult Index(FruitModel fruit)
    {
        fruit.Fruits = PopulateFruits();
        if (fruit.FruitIds != null)
        {
            List<SelectListItem> selectedItems = fruit.Fruits.Where(p => fruit.FruitIds.Contains(int.Parse(p.Value))).ToList();
 
            ViewBag.Message = "Selected Fruits:";
            foreach (var selectedItem in selectedItems)
            {
                 selectedItem.Selected = true;
                 ViewBag.Message += "\\n" + selectedItem.Text;
            }
        }
 
        return View(fruit);
    }
 
    private static List<SelectListItem>PopulateFruits()
    {
        List<SelectListItem> items = new List<SelectListItem>();
        string constr = ConfigurationManager.ConnectionStrings["Constring"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constr))
        {
            string query = " SELECT FruitName, FruitId FROM Fruits";
            using (SqlCommand cmd = new SqlCommand(query))
            {
                cmd.Connection = con;
                con.Open();
                using (SqlDataReader sdr = cmd.ExecuteReader())
                {
                    while (sdr.Read())
                    {
                        items.Add(new SelectListItem
                        {
                            Text = sdr["FruitName"].ToString(),
                            Value = sdr["FruitId"].ToString()
                        });
                    }
                }
                con.Close();
            }
        }
 
        return items;
    }
}
 
 
View

HTML Markup

Inside the View, in the very first line the FruitModel class is declared as Model for the View.
The View consists of an HTML Form which has been created using the Html.BeginForm method with the following parameters.
ActionName – Name of the Action. In this case the name is Index.
ControllerName – Name of the Controller. In this case the name is Home.
FormMethod – It specifies the Form Method i.e. GET or POST. In this case it will be set to POST.
The Form consists of a ListBox, and a Submit Button.
The ListBox is generated using the Html.ListBoxFor Html Helper method.
The first parameter is the Lambda expression for specifying the property that will hold the selected values of the ListBox when the Form is submitted.
The second parameter is the Model class property for populating the ListBox i.e. its source of data.
 

Bootstrap Multiselect jQuery Plugin implementation

First, the jQuery and the JS and CSS files of the Bootstrap plugin and the jQuery Bootstrap Multi-Select plugin are inherited.
Inside the jQuery document ready event handler, the jQuery Bootstrap Multi-Select Plugin is applied to the ListBox element.
 

Form Submission

When the Submit Button is clicked, the Form gets submitted and the values of the selected Fruits are sent to the Controller.
Finally, the multiple selected Fruit names are displayed using JavaScript Alert Message Box.
@model CheckBox_DropDownList_MVC.Models.FruitModel
 
@{
     Layout = null;
}
 
<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
</head>
<body>
    @using (Html.BeginForm("Index", "Home", FormMethod.Post))
    {
        @Html.Label("Fruits:")
        <br />
        <br />
        @Html.ListBoxFor(m => m.FruitIds, Model.Fruits, new { @class = "listbox" })
        <br />
        <br />
        <input type="submit" value="Submit" />
    }
 
    <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
    <link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.0.3/css/bootstrap.min.css" />
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.0.3/js/bootstrap.min.js"></script>
    <link href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.13/css/bootstrap-multiselect.css" rel="stylesheet" type="text/css" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.13/js/bootstrap-multiselect.js" type="text/javascript"></script>
    <script type="text/javascript">
        $(function () {
            $('.listbox').multiselect({
                 includeSelectAllOption: true
            });
        });
    </script>
    @if (ViewBag.Message != null)
    {
        <script type="text/javascript">
            window.onload = function () {
                alert("@ViewBag.Message");
            };
        </script>
    }
</body>
</html>
 
 

Screenshot

Multiple Select (Multi-Select) DropDownList with CheckBoxes in ASP.Net MVC Razor
 
 

Downloads

Download Code