“如何修复无法跟踪‘实体类型的实例’，因为已经跟踪了具有键值‘{TypeId: 1}’的另一个实例。

Question

无法跟踪实体类型 'WalletType' 的实例，因为已在跟踪具有键值“{TypeId: 1}”的另一个实例。附加现有实体时，确保只附加一个具有给定键值的实体实例。

//WalletType.cs public class 钱包类型

{
    public WalletType()
    {

    }
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.None)]
    public int TypeId { get; set; }


    [MaxLength(150)]
    public string TypeTitle { get; set; }



    public virtual ICollection<Wallet> Wallets { get; set; }
}

////////////////////////////// //SeedData.cs public class 种子数据 { public static void Initialize(IServiceProvider serviceProvider) { 使用 (var context = new ApplicationDbContext( serviceProvider.GetRequiredService>())) { // 寻找任何电影。如果 (context.WalletTypes.Any()) { return; // 数据库已经播种 }

            context.WalletTypes.AddRange(
                new WalletType
                {
                    TypeId = 1,
                    TypeTitle = "function1"

                },

                new WalletType
                {
                    TypeId = 1,
                    TypeTitle = "function2"
                }


            );
            context.SaveChanges();
        }
    }

}

//////////////////////////////////// //Program.cs public class 计划 {

    public static void Main(string[] args)
    {
        var host = CreateWebHostBuilder(args).Build();

        using (var scope = host.Services.CreateScope())
        {
            var services = scope.ServiceProvider;

            try
            {
                var context = services.
                    GetRequiredService<ApplicationDbContext>();
                context.Database.Migrate();
                SeedData.Initialize(services);
            }
            catch (Exception ex)
            {
                var logger = services.GetRequiredService<ILogger<Program>>();
                logger.LogError(ex, "An error occurred seeding the DB.");
            }
        }

        host.Run();
    }

    public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
            .UseStartup<Startup>();

}

Answer 1

那是因为你添加到 WalletType 时使用了 TypeId。您可以将标识设置为自动或手动提供唯一值。

 context.WalletTypes.AddRange(
                new WalletType
                {
                    TypeId = 1,
                    TypeTitle = "function1"

                },

                new WalletType
                {
                    TypeId = 2,
                    TypeTitle = "function2"
                }


            );

“如何修复无法跟踪‘实体类型的实例’，因为已经跟踪了具有键值‘{TypeId: 1}’的另一个实例。

“How to fix ‘The instance of entity type ' cannot be tracked because another instance with the key value '{TypeId: 1}' is already being tracked.

asp.net

asp.net-core-2.2