数据库集<;T>;.Add(T实体)引发System.InvalidOperationException:序列不
本文关键字:InvalidOperationException System 引发 lt gt Add 实体 数据库 | 更新日期: 2023-09-27 18:25:34
我有一个EF6 Code First模型,它的实体看起来像这样:
[Table("Updates")]
public class Update
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Key]
public Guid Id { get; set; }
[Required]
public string CreatedBy { get; set; }
[Column(TypeName="varchar(max)")]
public string Comments { get; set; }
[Required]
public DateTime CreatedTimestampUtc { get; set; }
}
我的数据库上下文类如下:
public class MyContext : DbContext, IUnitOfWork
{
private static readonly string ConnectionString = ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;
public GlobalizationContext() : base(ConnectionString)
{
}
public DbSet<Update> UpdatesDbSet { get; set; }
public IQueryable<Update> Updates //IUnitOfWork implementation
{
get { return UpdatesDbSet; }
}
public async Task AddUpdateTokenAsync(Update updateToken)
{
var entity = UpdatesDbSet.Add(updateToken);
var result = await SaveChangesAsync();
}
}
当我点击var entity = UpdatesDbSet.Add(updateToken);
行时,我生成以下异常:
SetUpdateTokenAsync(Update) System.InvalidOperationException: Sequence contains no matching element
at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source, Func`2 predicate)
at System.Data.Entity.Utilities.DbProviderManifestExtensions.GetStoreTypeFromName(DbProviderManifest providerManifest, String name)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.ConfigureColumn(EdmProperty column, EntityType table, DbProviderManifest providerManifest)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.Configure(EdmProperty column, EntityType table, DbProviderManifest providerManifest, Boolean allowOverride, Boolean fillFromExistingConfiguration)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.<>c__DisplayClass4.<Configure>b__3(Tuple`2 pm)
at System.Data.Entity.Utilities.IEnumerableExtensions.Each[T](IEnumerable`1 ts, Action`1 action)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.PrimitivePropertyConfiguration.Configure(IEnumerable`1 propertyMappings, DbProviderManifest providerManifest, Boolean allowOverride, Boolean fillFromExistingConfiguration)
at System.Data.Entity.ModelConfiguration.Configuration.Types.StructuralTypeConfiguration.ConfigurePropertyMappings(IList`1 propertyMappings, DbProviderManifest providerManifest, Boolean allowOverride)
at System.Data.Entity.ModelConfiguration.Configuration.Types.EntityTypeConfiguration.ConfigurePropertyMappings(DbDatabaseMapping databaseMapping, EntityType entityType, DbProviderManifest providerManifest, Boolean allowOverride)
at System.Data.Entity.ModelConfiguration.Configuration.Types.EntityTypeConfiguration.Configure(EntityType entityType, DbDatabaseMapping databaseMapping, DbProviderManifest providerManifest)
at System.Data.Entity.ModelConfiguration.Configuration.ModelConfiguration.ConfigureEntityTypes(DbDatabaseMapping databaseMapping, ICollection`1 entitySets, DbProviderManifest providerManifest)
at System.Data.Entity.ModelConfiguration.Configuration.ModelConfiguration.Configure(DbDatabaseMapping databaseMapping, DbProviderManifest providerManifest)
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.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)
看看DbSet
对象和Update
对象,它们似乎都被实例化了,我不明白为什么.Add()
需要找到匹配的元素。有人能向我解释一下这里的问题是什么吗?我应该怎么做才能纠正它?
更新
根据请求,以下是我的web.config文件中的EF配置:
<configSections>
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
</configSections>
. . .
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
<parameters>
<parameter value="mssqllocaldb" />
</parameters>
</defaultConnectionFactory>
<providers>
<provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
</providers>
</entityFramework>
我意识到这是错误的,并将其更改为:
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
<providers>
<provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
</providers>
</entityFramework>
这并没有改变症状。我还尝试了如下建议的装饰器更改:
[Column("Comments", TypeName="varchar")]
public string Comments { get; set; }
同样,在行为上没有差异。
更新2
所以我想我应该早点提到这一点,我不知道它是否重要(但根据建议的方向,它看起来可能是),但我指的是一个预先存在的数据库。有问题的表是这样创建的:
CREATE TABLE [dbo].[Updates](
[Id] [uniqueidentifier] NOT NULL,
[CreatedTimestampUtc] [datetime] NOT NULL,
[Comments] [varchar](MAX) NULL,
[CreatedBy] [nvarchar](260) NOT NULL,
CONSTRAINT [PK_Updates] PRIMARY KEY CLUSTERED
(
[Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
SET ANSI_PADDING ON
GO
ALTER TABLE [dbo].[Updates] ADD CONSTRAINT [DF_Updates_Id] DEFAULT (newid()) FOR [Id]
GO
ALTER TABLE [dbo].[Updates] ADD CONSTRAINT [DF_Updates_CreatedTimestampUtc] DEFAULT (getutcdate()) FOR [CreatedTimestampUtc]
GO
ALTER TABLE [dbo].[Updates] ADD CONSTRAINT [DF_Updates_CreatedBy] DEFAULT (suser_sname()) FOR [CreatedBy]
GO
所以这是两件事的结合。
- 我的迁徙处于一种奇怪的状态;自从我的主(启动)该项目与我的数据访问项目不同不同的连接字符串,EF绝对拒绝正确地生成迁移代码,即使在Package manager控制台中明确告知要从哪个项目中工作,也同样荒谬错误我偶然发现了这个,我很生气与问题相比,消息的神秘性
- 我想多了
MAX
的值;结果EF6默认为除非明确说明,否则所有字符串列的NVARCHAR(MAX)
否则(我个人认为这是一个非常糟糕的主意)——或者我想是通过惯例。只需指定VARCHAR
,然后调整迁移代码,我可以得到VARCHAR(MAX)
。。。为所有人字符串属性,其中NVARCHAR(MAX)
不合适,我不得不放入StringLength
装饰器
所以最后,我现在有了新的神秘错误。。。但这是另一个问题。感谢大家的帮助。
尝试更改
[Column(TypeName="varchar(max)")]
public string Comments { get; set; }
至
[Column(TypeName="[varchar](MAX) NULL")]
public string Comments { get; set; }