我通过创建连接并将其传递给DB Context来定期使用Effort：
public class InMemoryContextInitializer
{
public void BeforeAllTests()
{
Effort.Provider.EffortProviderConfiguration.RegisterProvider();
}
public DbConnection BeforeEachTest()
{
return Effort.DbConnectionFactory.CreateTransient();
}
public void AfterEachTest(DbConnection prevUsedConnection)
{
prevUsedConnection.Dispose();
}
}
像这样：
private static InMemoryContextInitializer _testHarness;
private DbConnection _conn;
private MyDbContext _myContext;
[ClassInitialize]
public static void BeforeAllTests(TestContext testCtx)
{
_testHarness = new InMemoryContextInitializer();
_testHarness.BeforeAllTests(); // registers provider
}
[TestInitialize]
public void BeforeTest()
{
_conn = _testHarness.BeforeEachTest();
_myContext = new MyDbContext(_conn);
}
[TestCleanup]
public void AfterTest()
{
_testHarness.AfterEachTest(_conn);
}
我的所有努力测试都通过了，但其中一项抛出了以下问题：
System.Data.DataException: An exception occurred while initializing the database. See the InnerException for details. --->
System.Data.Entity.Infrastructure.DbUpdateException: An error occurred while updating the entries. See the inner exception for details. --->
System.Data.Entity.Core.UpdateException: An error occurred while updating the entries. See the inner exception for details. --->
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. --->
NMemory.Exceptions.NMemoryException: Error code: GenericError --->
System.InvalidOperationException: Sequence contains more than one matching element
at System.Linq.Enumerable.SingleOrDefault(IEnumerable`1 source, Func`2 predicate)
at NMemory.Tables.TableCollection.FindTable(Type entityType)
at NMemory.Utilities.TableCollectionExtensions.FindTable(TableCollection tableCollection)
at NMemory.Execution.CommandExecutor.ExecuteInsert(T entity, IExecutionContext context)
at NMemory.Tables.DefaultTable`2.InsertCore(TEntity entity, Transaction transaction)
at Effort.Internal.DbManagement.Engine.ExtendedTable`2.InsertCore(TEntity entity, Transaction transaction)
at NMemory.Tables.Table`2.Insert(TEntity entity, Transaction transaction)
--- End of inner exception stack trace ---
at NMemory.Tables.Table`2.Insert(TEntity entity, Transaction transaction)
at Effort.Internal.Common.DatabaseReflectionHelper.WrapperMethods.InsertEntity(ITable`1 table, TEntity entity, Transaction transaction)
--- End of inner exception stack trace ---
at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at Effort.Internal.Common.DatabaseReflectionHelper.InsertEntity(ITable table, Object entity, Transaction transaction)
at Effort.Internal.CommandActions.InsertCommandAction.CreateAndInsertEntity(ITable table, IList`1 memberBindings, Transaction transaction)
at Effort.Internal.CommandActions.InsertCommandAction.ExecuteNonQuery(ActionContext context)
at Effort.Provider.EffortEntityCommand.ExecuteNonQuery()
at System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.<NonQuery>b__0(DbCommand t, DbCommandInterceptionContext`1 c)
at System.Data.Entity.Infrastructure.Interception.InternalDispatcher`1.Dispatch(TTarget target, Func`3 operation, TInterceptionContext interceptionContext, Action`3 executing, Action`3 executed)
at System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.NonQuery(DbCommand command, DbCommandInterceptionContext interceptionContext)
at System.Data.Entity.Internal.InterceptableDbCommand.ExecuteNonQuery()
at System.Data.Entity.Core.Mapping.Update.Internal.DynamicUpdateCommand.Execute(Dictionary`2 identifierValues, List`1 generatedValues)
at System.Data.Entity.Core.Mapping.Update.Internal.UpdateTranslator.Update()
--- End of inner exception stack trace ---
at System.Data.Entity.Core.Mapping.Update.Internal.UpdateTranslator.Update()
at System.Data.Entity.Core.EntityClient.Internal.EntityAdapter.<Update>b__2(UpdateTranslator ut)
at System.Data.Entity.Core.EntityClient.Internal.EntityAdapter.Update(T noChangesResult, Func`2 updateFunction)
at System.Data.Entity.Core.EntityClient.Internal.EntityAdapter.Update()
at System.Data.Entity.Core.Objects.ObjectContext.<SaveChangesToStore>b__35()
at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction(Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)
at System.Data.Entity.Core.Objects.ObjectContext.SaveChangesToStore(SaveOptions options, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction)
at System.Data.Entity.Core.Objects.ObjectContext.<>c__DisplayClass2a.<SaveChangesInternal>b__27()
at System.Data.Entity.Infrastructure.DefaultExecutionStrategy.Execute(Func`1 operation)
at System.Data.Entity.Core.Objects.ObjectContext.SaveChangesInternal(SaveOptions options, Boolean executeInExistingTransaction)
at System.Data.Entity.Core.Objects.ObjectContext.SaveChanges(SaveOptions options)
at System.Data.Entity.Internal.InternalContext.SaveChanges()
--- End of inner exception stack trace ---
at System.Data.Entity.Internal.InternalContext.SaveChanges()
at System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
at System.Data.Entity.DbContext.SaveChanges()
at System.Data.Entity.Migrations.History.HistoryRepository.BootstrapUsingEFProviderDdl(VersionedModel versionedModel)
at System.Data.Entity.Internal.InternalContext.<SaveMetadataToDatabase>b__7()
at System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action)
at System.Data.Entity.Internal.InternalContext.SaveMetadataToDatabase()
at System.Data.Entity.Internal.DatabaseCreator.CreateDatabase(InternalContext internalContext, Func`3 createMigrator, ObjectContext objectContext)
at System.Data.Entity.Internal.InternalContext.CreateDatabase(ObjectContext objectContext, DatabaseExistenceState existenceState)
at System.Data.Entity.Database.Create(DatabaseExistenceState existenceState)
at System.Data.Entity.CreateDatabaseIfNotExists`1.InitializeDatabase(TContext context)
at System.Data.Entity.Internal.InternalContext.<>c__DisplayClassf`1.<CreateInitializationAction>b__e()
at System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action)
--- End of inner exception stack trace ---
at System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action)
at System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization()
at System.Data.Entity.Internal.LazyInternalContext.<InitializeDatabase>b__4(InternalContext c)
at System.Data.Entity.Internal.RetryAction`1.PerformAction(TInput input)
at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action`1 action)
at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabase()
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.Infrastructure.DbQuery`1.System.Linq.IQueryable.get_Provider()
at System.Linq.Queryable.Count(IQueryable`1 source)
at Model.MyProj... my test method call stack here
我在这些测试中使用了多个数据库上下文，并且除了这种情况外，它们都可以工作：
var query = db.MyEntities.Count(); // will throw the exception above ONLY FOR SOME DB CONTEXTS
实际上，对此上下文进行的任何操作（例如
Add）都将引发。在Effort网站上或通过谷歌搜索找不到我遇到相同问题的人。也许是个错误？我正在使用最新版本的Effort-1.1.4和Entity Framework-6.1.3。
我检查了有关DbContext或实体类的任何特殊信息，但没有找到任何东西。
最佳答案
我遇到了这个问题，发现对每个上下文使用单独的连接（Effort.DbConnectionFactory.CreatePersistent）解决了该问题。
以我为例，每个上下文都在完全不同的表上运行，因此在Effort / NMemory中应该不会有冲突-因此我认为错误报告是正确的-但此信息可能会同时阻止人们。
权衡取舍的是，这可能会警告您实际上在同一表上确实有两个上下文在运行，这很不好-因此您也必须提防这一点。
关于c# - 努力引发InvalidOperationException:序列包含多个匹配元素，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/36053318/