Effort抛出InvalidOperationException：Sequence包含多个匹配元素

时间：2016-03-17 06:42:16

标签： c# entity-framework effort

我通过创建连接并将其传递给DB上下文以常规方式使用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();
    }
}

等等：

    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，除了抛出这个测试的那个：

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，除了这种情况外它都可以工作：

var query = db.MyEntities.Count(); // will throw the exception above ONLY FOR SOME DB CONTEXTS

事实上，像Add这样的上下文的任何操作都会抛出。

我在Effort网站上或通过Google搜索找不到任何人遇到同样的问题。也许这是一个错误？我使用的是最新版本的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内容，但没有找到任何内容。

1 个答案:

答案 0 :(得分：1)

我遇到了这个问题，发现每个上下文使用单独的连接（<form method="post" id="onlineorder" action="sendform.php"> <fieldset id="listproducts"> <legend>PRODUCTS</legend> <div id='forclone'> <select name="product" id="product"> <optgroup label="PRODUCT 1"> <option>PRODUCT 1 - BLUE</option> <option>PRODUCT 1 - RED</option> <option>PRODUCT 1 - YELLOW</option> </optgroup> <optgroup label="PRODUCT 2"> <option>PRODUCT 2 - WHITE</option> <option>PRODUCT 2 - BLACK</option> <option>PRODUCT 2 - GRAY</option> </optgroup> </select> &nbsp; <label for="quantity">Quantity:<span style="color:red">*</span> </label>&nbsp; <input type="number" name="quantity" id="quantity" placeholder="Qnt" min="0" max="9999" required/> </div> <div id="dynamicinput"></div> <input type="button" value="New Product" onclick="addInput('dynamicinput');" /> </fieldset> <p></p> <input type="submit" value="SUBMIT"> </form>）解决了这个问题。

在我的情况下，每个上下文都在完全不同的表上运行，所以在Effort / NMemory中不应该发生冲突 - 所以我认为错误报告是合理的 - 但是这个信息可能会在此期间解锁人。

权衡的是，这可能会警告你，你确实有两个在同一张桌子上运行的情境，这很糟糕 - 所以你也要注意这一点。

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