c# – 实体框架验证错误没有定义密钥.定义此EntityType的键

这可能发生什么？

我怎样才能找出问题所在呢？

谢谢.

{System.Data.Entity.ModelConfiguration.ModelValidationException: One or more validation errors were detected during model generation:

tSystem.Data.Entity.Edm.EdmEntityType: : EntityType 'Exception' has no key defined. Define the key for this EntityType.
tSystem.Data.Entity.Edm.EdmEntityType: : EntityType 'AssemblyName' has no key defined. Define the key for this EntityType.
tSystem.Data.Entity.Edm.EdmEntityType: : EntityType 'CultureInfo' has no key defined. Define the key for this EntityType.
tSystem.Data.Entity.Edm.EdmEntityType: : EntityType 'DateTimeFormatInfo' has no key defined. Define the key for this EntityType.
tSystem.Data.Entity.Edm.EdmEntityType: : EntityType 'IdentityReference' has no key defined. Define the key for this EntityType.
tSystem.Data.Entity.Edm.EdmEntitySet: EntityType: EntitySet 'Exceptions' is based on type 'Exception' that has no keys defined.
tSystem.Data.Entity.Edm.EdmEntitySet: EntityType: EntitySet 'AssemblyNames' is based on type 'AssemblyName' that has no keys defined.
tSystem.Data.Entity.Edm.EdmEntitySet: EntityType: EntitySet 'CultureInfoes' is based on type 'CultureInfo' that has no keys defined.
tSystem.Data.Entity.Edm.EdmEntitySet: EntityType: EntitySet 'DateTimeFormatInfoes' is based on type 'DateTimeFormatInfo' that has no keys defined.
tSystem.Data.Entity.Edm.EdmEntitySet: EntityType: EntitySet 'IdentityReferences' is based on type 'IdentityReference' that has no keys defined.

   at System.Data.Entity.ModelConfiguration.Edm.EdmModelExtensions.ValidateAndSerializeCsdl(EdmModel model,XmlWriter writer)
   at System.Data.Entity.ModelConfiguration.Edm.EdmModelExtensions.ValidateCsdl(EdmModel model)
   at System.Data.Entity.DbModelBuilder.Build(DbProviderManifest providerManifest,DbProviderInfo providerInfo)
   at System.Data.Entity.DbModelBuilder.Build(DbConnection providerConnection)
   at System.Data.Entity.Internal.LazyInternalContext.CreateModel(LazyInternalContext internalContext)
   at System.Data.Entity.Internal.RetryLazy`2.GetValue(TInput input)
   at System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
   at System.Data.Entity.Internal.InternalContext.Initialize()
   at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)
   at System.Data.Entity.Internal.Linq.InternalSet`1.Initialize()
   at System.Data.Entity.Internal.Linq.InternalSet`1.get_InternalContext()
   at System.Data.Entity.Internal.Linq.InternalSet`1.ActOnSet(Action action,EntityState newState,Object entity,String methodName)
   at System.Data.Entity.Internal.Linq.InternalSet`1.Add(Object entity)
   at System.Data.Entity.DbSet`1.Add(TEntity entity)
   at MVCDaemon.Controllers.AwardBadgesController.FromUnprocessedEvents() in Hobby StuffHeheHehe.DaemonControllersAwardBadgesController.cs:line 58}

和我的其他东西：

DaemonDB.Tasks.Add(T);

和

public class DaemonDBContext : DbContext
    {
        public DaemonDBContext() : base("DefaultConnection") { }

        //Collections also in BaseDBContext:
        public DbSet<Badge> Badges { get; set; }
        public DbSet<BadgeGroup> BadgeGroups { get; set; }
        public DbSet<Event> Events { get; set; }

        //Collections only in DaemonDBContext
        public DbSet<EventCheckedForBadgeReward> EventCheckedForBadgeReward { get; set; }
        public DbSet<Task> Tasks { get; set; }
    }

和

public class Task
    {
        public int ID { get; set; }
        public string FriendlyTitle { get; set; }
        public DateTime TimeOfExecution { get; set; }
        public TimeSpan LengthOfExecution { get; set; }
        public Stopwatch StopWatch;
        public Exception ExceptionEncountered { get; set; }

        public Task() {
            TimeOfExecution = DateTime.Now;
        }

        public void StartStopwatch()
        {
            StopWatch = Stopwatch.StartNew();
            StopWatch.Start();
        }

        public void StopStopwatch()
        {
            StopWatch.Stop();
        }

        public string GetStatusAsFriendly()
        {
            return ExceptionEncountered == null ? "Success" : "Failed";
        }
    }