In this article I will explain with an example, how to set Default Selected value (Default Empty value) for Html.DropDownList from Model in ASP.Net MVC Razor.
The DropDownList with Default Selected value will be populated from database using Entity Framework and Html.DropDownList helper function in ASP.Net MVC Razor.
 
 
Database
I have made use of the following table Customers with the schema as follows. CustomerId is an Auto-Increment (Identity) column.
Set Default Selected (Empty) value for Html.DropDownList from Model in ASP.Net MVC
 
I have already inserted few records in the table.
Set Default Selected (Empty) value for Html.DropDownList from Model in ASP.Net MVC
 
Note: You can download the database table SQL by clicking the download link below.
          Download SQL file
 
 
Entity Framework Model
Once the Entity Framework is configured and connected to the database table, the Model will look as shown below.
Note: For beginners in ASP.Net MVC and Entity Framework, please refer my article ASP.Net MVC: Simple Entity Framework Tutorial with example. It covers all the information needed for connecting and configuring Entity Framework.
 
Set Default Selected (Empty) value for Html.DropDownList from Model in ASP.Net MVC
 
 
Controller
The Controller consists of the following two methods.
Action method for handling GET operation
Inside this Action method, the GetCustomers method is called.
Inside the GetCustomers method, the records are fetched from the Customers table using Entity Framework and are copied into Generic list of SelectListItem class.
Note: The SelectListItem class which is an in-built ASP.Net MVC class. It has all the properties needed for populating a DropDownList.
 
A Blank item is inserted at first position (0th index) in the Generic list of SelectListItem class and it will be used to show the Default item in DropDownList.
 
Action method for handling POST operation
This Action method handles the call made from the POST function from the View.
When the Form is submitted, the posted values are captured through the ddlCustomers parameter which is also set as the Name of the DropDownList.
Then the GetCustomers method is called and the selected Customer is fetched using Lambda expression.
Finally the Name and ID values of the selected Customer 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()
    {
        List<SelectListItem> customerList = GetCustomers();
        return View(customerList);
    }
 
    [HttpPost]
    public ActionResult Index(string ddlCustomers)
    {
        List<SelectListItem> customerList = GetCustomers();
        if (!string.IsNullOrEmpty(ddlCustomers))
        {
            SelectListItem selectedItem = customerList.Find(p => p.Value == ddlCustomers);
            ViewBag.Message = "Name: " + selectedItem.Text;
            ViewBag.Message += "\\nID: " + selectedItem.Value;
        }
        return View(customerList);
    }
 
    private static List<SelectListItem> GetCustomers()
    {
        CustomersEntities entities = new CustomersEntities();
        List<SelectListItem> customerList = (from p in entities.Customers.AsEnumerable()
                                            select new SelectListItem
                                            {
                                                Text = p.Name,
                                                Value = p.CustomerId.ToString()
                                            }).ToList();
 
 
        //Add Default Item at First Position.
        customerList.Insert(0, new SelectListItem { Text = "--Select Customer--", Value = "" });
        return customerList;
    }
}
 
 
View
Inside the View, in the very first line Generic list of SelectListItem 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 DropDownList and a Submit Button.
The DropDownList is generated using the Html.DropDownList Html Helper method.
The first parameter is the Name of the DropDownList, the same will also be used to fetch the selected value of the DropDownList inside Controller when the Form is submitted.
The second parameter is the Model class for populating the DropDownList i.e. its source of data.
When the Submit Button is clicked, the Form gets submitted and the Name and ID values of the selected Customer is sent to the Controller.
Finally the Name and ID values of the selected Customer are displayed using JavaScript Alert Message Box.
@model List<SelectListItem>
@{
    Layout = null;
}
 
<!DOCTYPE html>
 
<html>
<head>
    <meta name="viewport" content="width=device-width"/>
    <title>Index</title>
</head>
<body>
    @using (Html.BeginForm("Index", "Home", FormMethod.Post))
    {
        @Html.DropDownList("ddlCustomers", Model)
        <br/>
        <br/>
        <input type="submit" value="Submit"/>
    }
    @if (ViewBag.Message != null)
    {
        <script type="text/javascript">
            window.onload = function () {
                alert("@ViewBag.Message");
            };
        </script>
    }
</body>
</html>
 
 
Screenshot
Set Default Selected (Empty) value for Html.DropDownList from Model in ASP.Net MVC
 
 
Downloads
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