How to connect a database to an ASP.NET MVC web application in Visual Studio 2017?

U

Useyd112019-06-07 14:24:53

ASP.NET

Useyd11, 2019-06-07 14:24:53

I work with Entity Framework. There is a database placed in the App_Data folder - Database1.mdf. I create a model, context, controller.

namespace Test.Models
{
    public class Team
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Coach { get; set; }
    }
 public class Player
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public int Age { get; set; }
        public string Position { get; set; }

        public int? TeamId { get; set; }
        public Team Team { get; set; }
    }
public class Context : DbContext
    {
        public DbSet<Team> Teams { get; set; }
        public DbSet<Player> Players { get; set; }
    }

namespace Test.Controllers
{
    public class HomeController : Controller
    {
        Context c = new Context();
        public ActionResult Index()
        {
            var players = c.Players.Include(p => p.Team);
            return View(players.ToList());
        }
  }
}

The view looks similar to the example below. In the Web.config file, I write the connection string as follows

<connectionStrings>
    <add name="Context" connectionString="Data Source=(LocalDB)\v11.0;AttachDbFilename='|DataDirectory|\Database1.mdf';Integrated Security=True" providerName="System.Data.SqlClient"/>
  </connectionStrings>

When running the application, VS throws the following error, underlining the output line in the controller:

System.Data.SqlClient.SqlException: "Cannot create file 'c:\users\alex\source\repos\Test\Test\App_Data\Database1.mdf' because it already exists. Change the file path or the file name, and retry the operation.
CREATE DATABASE failed. Some file names listed could not be created. Check related errors."

Renaming or creating another database does not help. What could be wrong?
There is also a database on MS SQL Server 2012. I'm trying to connect it using the ADO.NET EDM model. VS creates the necessary models, but it is not clear how to work with them further. Creating a context class, as in the first case, does not help - the data from the database is not loaded onto the page.

namespace MusicShopWeb
{
    using System;
    using System.Collections.Generic;
    using System.Data.Entity;

    public partial class Buyers
    {
        public int Id { get; set; }
        public string fio { get; set; }
        public string address { get; set; }
        public string phone { get; set; }
    }
    public class BuyersContext : DbContext
    {
        public DbSet<Buyers> Buyers { get; set; }
    }
}
namespace MusicShopWeb.Controllers
{
    public class Buyersontroller : Controller
    {
        private BuyersContext db = new BuyersContext();

        public ActionResult Index()
        {
            return View(db.Buyers.ToList());
        }
}

@model IEnumerable<MusicShopWeb.Buyers>

@{
    Layout = null;
}

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
</head>
<body>
    <table class="table">
        <tr>
            <th>
                @Html.DisplayNameFor(model => model.fio)
            </th>
            <th>
                @Html.DisplayNameFor(model => model.address)
            </th>
            <th>
                @Html.DisplayNameFor(model => model.phone)
            </th>
            <th></th>
        </tr>
    @foreach (var item in Model) {
        <tr>
            <td>
                @Html.DisplayFor(modelItem => item.fio)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.address)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.phone)
            </td>
        </tr>
    }
    </table>
</body>
</html>

How to retrieve data from database?

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1 answer(s)

A

Amffore, 2019-06-07
@Amffore

How are you trying to work with EF? Judging by the code, this is the Code First approach. Try removing the database from App_Data. After all, the error itself indicates that the database already exists and cannot be created.