Question

这个错误让我感到非常难过

让我解释一下情景

我在解决方案中有以下项目

一个Web服务项目 - 清空MVC
具有表（单表）定义的普通POCO类
具有从DBContext

我正在尝试使用EF 6.0在Azure上的数据库上创建/更新表。

注意：

解决方案正在编译确定

我已将EF 6安装到3以上

我在Web服务项目的web.config文件和该类的app.config文件中添加了一个连接字符串（如下）   派生自DBcontext

  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(D
   bProviderManifest providerManifest, String name)
   at 
 System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.Primiti
 vePropertyConfiguration.ConfigureColumn(EdmProperty column, EntityType table, 
 DbProviderManifest providerManifest)
   at 
 System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.Primiti
 vePropertyConfiguration.Configure(EdmProperty column, EntityType table, 
 DbProviderManifest providerManifest, Boolean allowOverride, Boolean 
 fillFromExistingConfiguration)
    at 
 System.Data.Entity.ModelConfiguration.Configuration.Properties.Primitive.Primiti
 vePropertyConfiguration.<>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.Primiti
 vePropertyConfiguration.Configure(IEnumerable`1 propertyMappings, 
 DbProviderManifest providerManifest, Boolean allowOverride, Boolean 
 fillFromExistingConfiguration)
    at 
 System.Data.Entity.ModelConfiguration.Configuration.Types.StructuralTypeConfigur
 ation.ConfigurePropertyMappings(IList`1 propertyMappings, DbProviderManifest 
 providerManifest, Boolean allowOverride)
    at 
 System.Data.Entity.ModelConfiguration.Configuration.Types.EntityTypeConfiguratio
 n.ConfigurePropertyMappings(DbDatabaseMapping databaseMapping, EntityType 
 entityType, DbProviderManifest providerManifest, Boolean allowOverride)
    at 
 System.Data.Entity.ModelConfiguration.Configuration.Types.EntityTypeConfiguratio
 n.Configure(EntityType entityType, DbDatabaseMapping databaseMapping, 
 DbProviderManifest providerManifest)
    at 
 System.Data.Entity.ModelConfiguration.Configuration.ModelConfiguration.Configure
 EntityTypes(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.LazyInternalContext.get_ModelBeingInitialized()
   at System.Data.Entity.Infrastructure.EdmxWriter.WriteEdmx(DbContext context, XmlWriter writer)
   at System.Data.Entity.Utilities.DbContextExtensions.<>c__DisplayClass1.<GetModel>b__0(XmlWriter w)
   at System.Data.Entity.Utilities.DbContextExtensions.GetModel(Action`1 writeXml)
   at System.Data.Entity.Utilities.DbContextExtensions.GetModel(DbContext context)
   at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration, DbContext usersContext, DatabaseExistenceState existenceState, Boolean calledByCreateDatabase)
   at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration)
   at System.Data.Entity.Migrations.Design.MigrationScaffolder..ctor(DbMigrationsConfiguration migrationsConfiguration)
   at System.Data.Entity.Migrations.Design.ToolingFacade.ScaffoldRunner.Run()
   at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
   at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
   at System.Data.Entity.Migrations.Design.ToolingFacade.Run(BaseRunner runner)
   at System.Data.Entity.Migrations.Design.ToolingFacade.Scaffold(String migrationName, String language, String rootNamespace, Boolean ignoreChanges)
   at System.Data.Entity.Migrations.AddMigrationCommand.Execute(String name, Boolean force, Boolean ignoreChanges)
   at System.Data.Entity.Migrations.AddMigrationCommand.<>c__DisplayClass2.<.ctor>b__0()
   at System.Data.Entity.Migrations.MigrationsDomainCommand.Execute(Action command)
Sequence contains no matching element

我已经在软件包管理器控制台启用了迁移 - 没有问题
当我开始添加迁移时，我收到以下运行时错误

PM＆GT;添加迁移IntitalTableCreation

t = text(position1, position2, txt);

我知道当你使用first（）而不是firstordefault（）之类的东西时，这是一个错误。

可能出现什么问题？

任何帮助都将不胜感激。

欢迎任何疑问

连接字符串中的提供者名称是否有问题??

Answer 1

唉！我不知道自己是怎么犯这么愚蠢的错误的！

在我的poco课程中，我试图将一个字节映射到一点！

AS如下！

[Column(TypeName = "BIT")]
public virtual System.Byte Status { get; set; }

一旦我纠正了这个错误，问题就解决了

首先使用EF代码连接到Azure时出现运行时错误

1 个答案: