In this article I will explain with an example, how to update data into Database using Entity Framework in .Net Core.
Note: For more details on inserting data into Database in .Net Core using Entity Framework, please refer my article ASP.Net Core: Insert Data into Database using Entity Framework.
 
 
Database
I have made use of the following table Customers with the schema as follows. CustomerId is an Auto-Increment (Identity) column.
.Net Core: Update Data into Database using Entity Framework
 
I have already inserted few records in the table.
.Net Core: Update Data into Database using Entity Framework
 
Note: You can download the database table SQL by clicking the download link below.
          Download SQL file
 
 
Model
Following class is used as the Model class.
public class Customer
{
    public int CustomerId { get; set; }
    public string Name { get; set; }
    public string Country { 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: 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 EF_Update_MVC_Core
{
    public class DBCtx : DbContext
    {
        public DBCtx(DbContextOptions<DBCtx> options) : base(options)
        {
        }
 
        public DbSet<Customer> Customers { get; set; }
    }
}
 
 
Controller
The Controller consists of following two Action methods.
Action method for handling GET operation
Inside this Action method, simply the View is returned.
 
Action method for handling POST operation
Inside this Action method, the Customer object is received as parameter. The CustomerId value of the received Customer object is used to reference the Customer record using Entity Framework.
Once the record is referenced, the values of Name and Country are updated and the changes are updated into the Customers table.
Based on whether the reference of the Customer is found or not, an appropriate message is set in the ViewBag object.
public class HomeController : Controller
{
    private DBCtx Context { get; }
    public HomeController(DBCtx _context)
    {
        this.Context = _context;
    }
 
    public IActionResult Index()
    {
        return View();
    }
 
    [HttpPost]
    public IActionResult Index(Customer customer)
    {
        Customer updatedCustomer = (from c in this.Context.Customers
                                    where c.CustomerId == customer.CustomerId
                                    select c).FirstOrDefault();
 
        if (updatedCustomer != null)
        {
            updatedCustomer.Name = customer.Name;
            updatedCustomer.Country = customer.Country;
            this.Context.SaveChanges();
            ViewBag.Message = "Customer record updated.";
        }
        else
        {
            ViewBag.Message = "Customer not found.";
        }
 
        return View();
    }
}
 
 
View
Inside the View, in the very first line the Customer Model class is declared as Model for the View.
The View consists of an HTML Form which has been created using following Tag Helpers 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.
The HTML Form consists of three TextBoxes and a Submit Button.
When the Update button is clicked, the values of CustomerId, Name and Country are passed to the Controller’s Action method.
Finally, the value of the ViewBag object is displayed using JavaScript Alert Message Box.
@model EF_Update_MVC_Core.Models.Customer
@addTagHelper*, Microsoft.AspNetCore.Mvc.TagHelpers
@{
    Layout = null;
}
 
<!DOCTYPE html>
 
<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
</head>
<body>
    <form method="post" asp-action="Index" asp-controller="Home">
        <table border="0" cellpadding="0" cellspacing="0">
            <tr>
                <td style="width: 60px">
                    Id<br />
                    <input type="text" asp-for="CustomerId" style="width:50px" />
                </td>
                <td style="width: 150px">
                    Name<br />
                    <input type="text" asp-for="Name" style="width: 140px" />
                </td>
                <td style="width: 150px">
                    Country:<br />
                    <input type="text" asp-for="Country" style="width: 140px" />
                </td>
                <td style="width: 200px">
                    <br />
                    <input type="submit" id="btnUpdate" value="Update" />
                </td>
            </tr>
        </table>
    </form>
    @if (ViewBag.Message != null)
    {
        <script type="text/javascript">
            window.onload = function () {
                alert("@ViewBag.Message");
            };
        </script>
    }
</body>
</html>
 
 
Screenshot
.Net Core: Update Data into Database using Entity Framework
 
 
Downloads
Download Code