I am using VS 2019, SQL Server 2016, I try to use ADO.NET to update a registry, but I am getting an error:

The ConnectionString property has not been initialized

The controller:

If I use this one:

con = new SqlConnection(ConfigurationManager.ConnectionStrings["DevConnection"].ConnectionString);

I get the error:

Object reference not set to an instance of an object.'

If I use:

con = new SqlConnection(appSettings.Value.DbConnection);  

I get:

The ConnectionString property has not been initialized.

The rest of the code:

 cmd.CommandType = CommandType.StoredProcedure;
                cmd.Parameters.AddWithValue("@UserId", Convert.ToInt32(user.UserId));
                cmd.Parameters.AddWithValue("@DateOfBirth", user.DateOfBirth);
                cmd.Parameters.AddWithValue("@UserNames", user.UserNames);
                cmd.Parameters.AddWithValue("@UserLastNames", user.UserLastNames);
                cmd.Parameters.AddWithValue("@UserPlatformName", user.UserPlatformName);
                cmd.Parameters.AddWithValue("@UserPassword", user.UserPassword);
                cmd.Parameters.AddWithValue("@UserGender", user.UserGender);
                cmd.Parameters.AddWithValue("@UserDocumentNumber", Convert.ToInt32(user.UserDocumentNumber));
                 con.Open();
                result = cmd.ExecuteScalar().ToString();
                message.Data = result.ToString();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);            
                message.Data = e.Message;
            }
            finally
            {
                con.Close();
            }

Class to get the connection:

public class MySettings
{
    public string DbConnection { get; set; }
}

On Startup:

services.Configure<MySettings>(Configuration.GetSection("ConnectionStrings"));

The procedure:

ALTER PROCEDURE [dbo].[SPUpdateUser]
    (@UserId INTEGER,
     @DateOfBirth DATE,
     @UserNames NVARCHAR(30),
     @UserLastNames NVARCHAR(30), 
     @UserPlatformName VARCHAR(30),
     @UserPassword NVARCHAR(15),
     @UserGender NVARCHAR(9),
     @UserDocumentNumber INTEGER)
AS
BEGIN
    SET NOCOUNT ON;

    UPDATE Users
    SET DateOfBirth = @DateOfBirth,
        UserNames = @UserNames,
        UserLastNames = @UserLastNames,
        UserPlatformName = @UserPlatformName,
        UserPassword = @UserPassword,
        UserGender = @UserGender,
        UserDocumentNumber = @UserDocumentNumber
    WHERE  
        UserId = @UserId                
END

In Postman, I am sending:

{
            "userId": 1,
            "dateOfBirth": "1980-1-1",
            "userNames": "James",
            "userLastNames": "Rodriguez",
            "userPlatformName": "1",
            "userPassword": "1234",
            "userGender": "Masculino",
            "userDocumentNumber": 1,
            "relatives": []
        }

The two integers have their casts, so... why do I get this error?

And how can I fix this?

The project compiles, I see no errors in VS

The appsettings.json

 "ConnectionStrings": {
    "DevConnection": "Data Source=DESKTOP-ARVMMP2\\SQLEXPRESS;Initial Catalog=PraxedesDb;Integrated Security=True;Connect Timeout=30;Encrypt=False;TrustServerCertificate=False;ApplicationIntent=ReadWrite;MultiSubnetFailover=False"
  },

CodePudding user response：

ConfigurationManager does not work with appsettings.json in ASP.NET Core, you can use IConfiguration instead of ConfigurationManager ike below:

public class HomeController : Controller
{
    private readonly IConfiguration Configuration;

    public HomeController(IConfiguration Configuration)
    {
        this.Configuration = Configuration;
    }
    public async Task<IActionResult> Index()
    {
        var con = new SqlConnection(Configuration.GetConnectionString("DevConnection"));
        
        return View();           
    }
}