In this article I will explain with an example, how to update data into database using Dapper library in ASP.Net Core.
Note: For beginners in ASP.Net Core (.Net Core 7), please refer my article ASP.Net Core 7: Hello World Tutorial with Sample Program example.
 
 

Installing Dapper package using Nuget

In order to install Dapper library using Nuget, please refer my article Install Dapper from Nuget in Visual Studio.
 
 

Database

I have made use of the following table Customers with the schema as follows.
Update using Dapper in ASP.Net Core
 
I have already inserted few records in the table.
Update using Dapper in ASP.Net Core
 
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.
public class CustomerModel
{
    public int CustomerId { get; set; }
    public string Name { get; set; }
    public string Country { get; set; }
}
 
 

Namespaces

You will need to import the following namespaces.
using Dapper;
using System.Data.SqlClient;
 
 

Controller

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 POST operation

This method accepts CustomerModel class object as a parameter.
Inside this Action method, first the connection is read from the ConnectionStrings section of the AppSettings.json file.
The CustomerModel class object is created and CustomerId, Name and County values are set.
Then, using Execute method of Dapper library, the record is updated into the SQL Server database.
Note: For more details on Execute method, please refer my article Understanding Dapper Execute in C# and VB.Net.
 
Finally, based on whether the record is updated or not an appropriate message is set into ViewBag object and the View is returned.
public class HomeController : Controller
{
    public IConfiguration Configuration { get; set; }
 
    public HomeController(IConfiguration _configuration)
    {
        this.Configuration = _configuration;
    }
 
    public IActionResult Index()
    {
        return View();
    }
 
    [HttpPost]
    public IActionResult Index(CustomerModel customer)
    {
        string constr = this.Configuration.GetSection("ConnectionStrings")["MyConn"];
        string sql = "UPDATE Customers SET Name=@Name, Country=@Country WHERE CustomerId=@CustomerId";
        using (SqlConnection con = new SqlConnection(constr))
        {
            customer = new CustomerModel
            {
                CustomerId = customer.CustomerId,
                Name = customer.Name,
                Country = customer.Country,
            };
            int i = con.Execute(sql, customer);
            if (i > 0)
            {
                ViewBag.Message = "Customer record updated.";
            }
            else
            {
                ViewBag.Message = "Customer not found.";
            }
        }
        return View();
    }
}
 
 

View

Inside the View, in the very first line the CustomerModel class is declared as Model for the View.
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
The View also consists of an HTML Table, which consists of three HTML INPUT TextBoxes and a Submit Button.
 

Submitting the Form

When the Update Button is clicked, the ViewBag object is checked for NULL and if it is not NULL then, the value of the ViewBag object is displayed using JavaScript Alert Message Box.
@model Dapper_Update_Core_MVC.Models.CustomerModel
@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-controller="Home" asp-action="Index">
        <table cellpadding="1" cellspacing="1">
            <tr>
                <td>
                    Id<br />
                   <input type="text" asp-for="CustomerId" style="width: 60px;" />
                </td>
                <td>
                    Name<br />
                   <input type="text" asp-for="Name" style="width: 150px;" />
                </td>
                <td>
                    Country:<br />
                   <input type="text" asp-for="Country" style="width: 150px;" />
                </td>
                <td>
                   <br />
                   <input type="submit" value="Update" />
                </td>
            </tr>
         </table>
    </form>
    @if (ViewBag.Message != null)
    {
        <script type="text/javascript">
            window.onload = function () {
                alert("@ViewBag.Message");
            };
        </script>
    }
</body>
</html>
 
 

Screenshot

Update using Dapper in ASP.Net Core
 
 

Downloads

Download Code