Question

当我尝试创建多对多关系模型时，Asp.Net出现问题，尝试注册帐户时出现此错误：

序列不包含匹配元素

当我＆＃34;禁用＆＃34;我的更改，我可以正常在网站上注册，所以我的模型中有关于列结构的一些错误，我想但我自己无法修复它们。我想在我的Bookmark和Tag表之间创建多对多的连接，并且许多表应具有以下结构：Id，BookmarkID，{{1} }。

以下是我的模特：

TagID

以下是错误堆栈跟踪：

[InvalidOperationException：Sequence不包含匹配元素]
  System.Linq.Enumerable.Single（IEnumerable public class Bookmark { [Key] public int BookmarkID { get; set; } public string Url { get; set; } public ApplicationUser UserId { get; set; } public virtual ICollection<BookmarkTag> BookmarkTags { get; set; } } public class Tag { [Key] public int TagID { get; set; } [Column(TypeName="varchar(60)")] public string TagName { get; set; } public virtual ICollection<BookmarkTag> BookmarkTags { get; set; } } public class BookmarkTag { [Key, Column(Order = 0)] public int BookmarkTagID { get; set; } [Key, Column(Order = 1)] public int BookmarkID { get; set; } [Key, Column(Order = 2)] public int TagID { get; set; } public virtual Bookmark Bookmark { get; set; } public virtual Tag Tag { get; set;} } 2谓词）   +2603017 System.Data.Entity.Utilities.DbProviderManifestExtensions.GetStoreTypeFromName（DbProviderManifest）   providerManifest，String name）+81
  System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.ConfigureColumn（EdmProperty   column，EntityType table，DbProviderManifest providerManifest）+87
  System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.Configure（EdmProperty   column，EntityType表，DbProviderManifest providerManifest，Boolean   allowOverride，Boolean fillFromExistingConfiguration）+138
  System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive＆LT;＆GT; c__DisplayClass4.b__3（元组1 source, Func 1   行动2 pm) +38 System.Data.Entity.Utilities.IEnumerableExtensions.Each(IEnumerable 1   propertyMappings，DbProviderManifest providerManifest，Boolean   allowOverride，Boolean fillFromExistingConfiguration）+94
  System.Data.Entity.ModelConfiguration.Configuration.Types.StructuralTypeConfiguration.ConfigurePropertyMappings（IList 1 action) +130 System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.Configure(IEnumerable 1 entitySets，DbProviderManifest   providerManifest）+423
  System.Data.Entity.ModelConfiguration.Configuration.ModelConfiguration.Configure（DbDatabaseMapping   databaseMapping，DbProviderManifest providerManifest）+376
  System.Data.Entity.DbModelBuilder.Build（DbProviderManifest   providerManifest，DbProviderInfo providerInfo）+444
  System.Data.Entity.DbModelBuilder.Build（的DbConnection   providerConnection）+55
  System.Data.Entity.Internal.LazyInternalContext.CreateModel（LazyInternalContext   internalContext）+61
  System.Data.Entity.Internal.RetryLazy 1 propertyMappings, DbProviderManifest providerManifest, Boolean allowOverride) +154 System.Data.Entity.ModelConfiguration.Configuration.Types.EntityTypeConfiguration.ConfigurePropertyMappings(DbDatabaseMapping databaseMapping, EntityType entityType, DbProviderManifest providerManifest, Boolean allowOverride) +585 System.Data.Entity.ModelConfiguration.Configuration.Types.EntityTypeConfiguration.Configure(EntityType entityType, DbDatabaseMapping databaseMapping, DbProviderManifest providerManifest) +177 System.Data.Entity.ModelConfiguration.Configuration.ModelConfiguration.ConfigureEntityTypes(DbDatabaseMapping databaseMapping, ICollection 1.Initialize（）+53
  System.Data.Entity.Internal.Linq.InternalSet 2.GetValue(TInput input) +123 System.Data.Entity.Internal.LazyInternalContext.InitializeContext() +616 System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType) +18 System.Data.Entity.Internal.Linq.InternalSet 1.System.Linq.IQueryable.get_Provider（）   +39 System.Data.Entity.QueryableExtensions.FirstOrDefaultAsync（IQueryable 1.get_InternalContext() +16 System.Data.Entity.Infrastructure.DbQuery 1个谓词，CancellationToken cancellationToken）   +154 System.Data.Entity.QueryableExtensions.FirstOrDefaultAsync（IQueryable 1 source, Expression 1谓词）+163
  Microsoft.AspNet.Identity.EntityFramework.d__6c.MoveNext（）   +472 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务   任务）+99
  System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务   任务）+58 Microsoft.AspNet.Identity.CultureAwaiter 1 source, Expression 1.GetResult（）   +28 BookIT.Controllers.d__15.MoveNext（）在D：\ Projekti \ CS \ BookIT \ BookIT \ Controllers \ AccountController.cs：155
  System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess（任务   任务）+99
  System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification（任务   任务）+58
  System.Web.Mvc.Async.TaskAsyncActionDescriptor.EndExecute（IAsyncResult的   asyncResult）+97
  System.Web.Mvc.Async＆LT;＆GT; c__DisplayClass37.b__36（IAsyncResult的   asyncResult）+17
  System.Web.Mvc.Async.WrappedAsyncResult 1.GetResult() +59 Microsoft.AspNet.Identity.<ValidateUserName>d__4.MoveNext() +594 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 Microsoft.AspNet.Identity.<ValidateAsync>d__0.MoveNext() +266 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 Microsoft.AspNet.Identity.<CreateAsync>d__0.MoveNext() +568 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 Microsoft.AspNet.Identity.<CreateAsync>d__d.MoveNext() +483 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58 System.Runtime.CompilerServices.TaskAwaiter 1.End（）+49
  System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod（IAsyncResult的   asyncResult）+32
  System.Web.Mvc.Async.AsyncInvocationWithFilters.b__3d（）   +50 System.Web.Mvc.Async。＆lt;＆gt; c__DisplayClass46.b__3f（）   +225 System.Web.Mvc.Async。＆lt;＆gt; c__DisplayClass33.b__32（IAsyncResult asyncResult）+10
  System.Web.Mvc.Async.WrappedAsyncResult 1.CallEndDelegate(IAsyncResult asyncResult) +10 System.Web.Mvc.Async.WrappedAsyncResultBase 1.End（）+49
  System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters（IAsyncResult的   asyncResult）+34
  System.Web.Mvc.Async＆LT;＆GT; c__DisplayClass2b.b__1c（）   +26 System.Web.Mvc.Async。＆lt;＆gt; c__DisplayClass21.b__1e（IAsyncResult）   asyncResult）+100
  System.Web.Mvc.Async.WrappedAsyncResult 1.CallEndDelegate(IAsyncResult asyncResult) +10 System.Web.Mvc.Async.WrappedAsyncResultBase 1.End（）+49
  System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction（IAsyncResult的   asyncResult）+27
  System.Web.Mvc.Controller.b__1d（IAsyncResult的   asyncResult，ExecuteCoreState innerState）+13
  System.Web.Mvc.Async.WrappedAsyncVoid 1.CallEndDelegate(IAsyncResult asyncResult) +10 System.Web.Mvc.Async.WrappedAsyncResultBase 1.End（）+49
  System.Web.Mvc.Controller.EndExecuteCore（IAsyncResult asyncResult）+36   System.Web.Mvc.Controller.b__15（IAsyncResult的   asyncResult，控制器控制器）+12
  System.Web.Mvc.Async.WrappedAsyncVoid 1.CallEndDelegate(IAsyncResult asyncResult) +29 System.Web.Mvc.Async.WrappedAsyncResultBase 1.End（）+49
  System.Web.Mvc.Controller.EndExecute（IAsyncResult asyncResult）+26
  System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute（IAsyncResult的   asyncResult）+10
  System.Web.Mvc.MvcHandler.b__5（IAsyncResult的   asyncResult，ProcessRequestState innerState）+21
  System.Web.Mvc.Async.WrappedAsyncVoid 1.CallEndDelegate(IAsyncResult asyncResult) +22 System.Web.Mvc.Async.WrappedAsyncResultBase 1.End（）+49
  System.Web.Mvc.MvcHandler.EndProcessRequest（IAsyncResult asyncResult）   +28 System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest（IAsyncResult）   结果）+9
  System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute（）   +9711525 System.Web.HttpApplication.ExecuteStep（IExecutionStep step，Boolean＆amp; completedSynchronously）+155

提前致谢

添加了：

1.CallEndDelegate(IAsyncResult
  asyncResult) +29

  System.Web.Mvc.Async.WrappedAsyncResultBase

Answer 1

您有太多Key属性，EF Framework无法解决您的模型。您可以使用流畅的api来准确配置您想要的内容。解决问题的最简单方法是使用EF功能约定优于配置。基本上，遵循惯例，EF框架将为您做繁重的工作。我在这里添加了一个关于配置方法的约定，它至少在我的visual studio中运行。我测试了这个，它运行成功。

public class Bookmark
{
   public int BookmarkID { get; set; }
   public string Url { get; set; }
   public ApplicationUser UserId { get; set; }
   public virtual ICollection<BookmarkTag> BookmarkTags { get; set; }
 }

 public class BookmarkTag
 {
    public int BookmarkTagID { get; set; }
    public virtual Bookmark Bookmark { get; set; }
    public virtual Tag Tag { get; set; }
 }

 public class Tag
 {
    public int TagID { get; set; }
    public string TagName { get; set; }
    public virtual ICollection<BookmarkTag> BookmarkTags { get; set; }
 }

Answer 2

最后我发现导致错误的原因...... 这就是这条线

 [Column(TypeName="varchar(60)")]
public string TagName { get; set; }

Whene我删除了Column（TypeName）部分代码进行编译没有任何问题......它现在有效但我不确定它为什么会这样做或为什么它会抛出该错误。任何人都可以解释为什么它以前不起作用？

尝试在asp.net

2 个答案: