System.InvalidOperationException:访问DbContext时

Question

我在运行我的 .Net Core 应用程序时遇到错误。我开始访问 DbContext 并弹出

System.InvalidOperationException: 'No database provider has been configured for this DbContext. A provider can be configured by overriding the DbContext.OnConfiguring method or by using AddDbContext on the application service provider. If AddDbContext is used, then also ensure that your DbContext type accepts a DbContextOptions object in its constructor and passes it to the base constructor for DbContext.'

我已经尝试修复它，但它仍然出现。

DbContext.cs

public class PartsDbContext : DbContext
{
    public DbSet<Tower> Towers { get; set; }
    public DbSet<Motherboard> Motherboards { get; set; }

    public PartsDbContext(DbContextOptions<PartsDbContext> options)
        : base(options)
    {
    }
}

Controller.cs

public class AdminController : Controller
{
    private readonly PartsDbContext _context;

    public AdminController(PartsDbContext context)
    {
        _context = context;
    }
    public IActionResult Index()
    {
        if (User.Identity.Name == null)
        {
            return RedirectToAction("Register", "Account");
        }
        return View();
    }

    public IActionResult Towers()
    {
        var model = _context.Towers.ToList();
        return View(model);
    }

    public IActionResult Motherboards()
    {
        var model = _context.Motherboards.ToList();
        return View(model);
    }
}

错误出现在 Towers() 的这一行

var model = _context.Towers.ToList();

Startup.cs

public void ConfigureServices(IServiceCollection services)
{
    // Add framework services.
    services.AddDbContext<ApplicationDbContext>(options =>
      options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

    services.AddIdentity<ApplicationUser, IdentityRole>()
        .AddEntityFrameworkStores<ApplicationDbContext>()
        .AddDefaultTokenProviders();

    services.AddEntityFramework()
        .AddDbContext<PartsDbContext>();

    services.AddMvc();

    // Add application services.
    services.AddTransient<IEmailSender, AuthMessageSender>();
    services.AddTransient<ISmsSender, AuthMessageSender>();
}

任何帮助都会很好。我确定我做错了什么，但我相信我已经完成了错误提示的所有事情。

谢谢。

Answer 1

您当前的 Startup.cs 文件已为一个数据库 (ApplicationDBContext) 配置了数据库提供程序，但不是您正在使用的数据库 (PartsDbContext)。

因此，添加以下行：

services.AddDbContext<PartsDbContext>(options =>  
    options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection"));
)

更多信息：https://docs.microsoft.com/en-us/ef/core/miscellaneous/configuring-dbcontext#using-dbcontext-with-dependency-injection

System.InvalidOperationException:访问DbContext时

System.InvalidOperationException: when accessing DbContext

c#

entity-framework

dbcontext

asp.net-core-1.1