ExecuteReader要求命令具有一个事务
ExecuteReader要求命令具有一个事务
提问于 2016-06-28 17:00:59
当将事务传递给EF时，我们得到了一个奇怪的异常：
引发的异常：“System.InvalidOperationException”在System.Data.dll中 附加信息:当分配给命令的连接位于挂起的本地事务中时，ExecuteReader要求命令具有事务。命令的事务属性尚未初始化。
this.DbContext = this.DbContextFactory.CreateContext<TContext>(connection);
this.DbContext.Database.UseTransaction(transaction);EF会捕获此异常，因为只有在“抛出时中断”时才会显示该异常。它是预期的行为，还是我们做了什么潜在的错误？
下面是调用堆栈的样子：
System.Data.dll!System.Data.SqlClient.SqlCommand.ValidateCommand(string method, bool async)
System.Data.dll!System.Data.SqlClient.SqlCommand.RunExecuteReader(System.Data.CommandBehavior cmdBehavior, System.Data.SqlClient.RunBehavior runBehavior, bool returnStream, string method, System.Threading.Tasks.TaskCompletionSource<object> completion, int timeout, out System.Threading.Tasks.Task task, bool asyncWrite)
System.Data.dll!System.Data.SqlClient.SqlCommand.RunExecuteReader(System.Data.CommandBehavior cmdBehavior, System.Data.SqlClient.RunBehavior runBehavior, bool returnStream, string method)
System.Data.dll!System.Data.SqlClient.SqlCommand.ExecuteReader(System.Data.CommandBehavior behavior, string method)
EntityFramework.dll!System.Data.Entity.Infrastructure.Interception.InternalDispatcher<System.Data.Entity.Infrastructure.Interception.IDbCommandInterceptor>.Dispatch<System.Data.Common.DbCommand, System.Data.Entity.Infrastructure.Interception.DbCommandInterceptionContext<System.Data.Common.DbDataReader>, System.Data.Common.DbDataReader>(System.Data.Common.DbCommand target, System.Func<System.Data.Common.DbCommand, System.Data.Entity.Infrastructure.Interception.DbCommandInterceptionContext<System.Data.Common.DbDataReader>, System.Data.Common.DbDataReader> operation, System.Data.Entity.Infrastructure.Interception.DbCommandInterceptionContext<System.Data.Common.DbDataReader> interceptionContext, System.Action<System.Data.Entity.Infrastructure.Interception.IDbCommandInterceptor, System.Data.Common.DbCommand, System.Data.Entity.Infrastructure.Interception.DbCommandInterceptionContext<System.Data.Common.DbDataReader>> executing, System.Action<System.Data.Entity.Infrastructure.Interception.IDbCommandInterceptor, System.Data.Common.DbCommand, System.Data.Entity.Infrastructure.Interception.DbCommandInterceptionContext<System.Data.Common.DbDataReader>> executed)
EntityFramework.dll!System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.Reader(System.Data.Common.DbCommand command, System.Data.Entity.Infrastructure.Interception.DbCommandInterceptionContext interceptionContext)
EntityFramework.SqlServer.dll!System.Data.Entity.SqlServer.SqlVersionUtils.GetServerType(System.Data.Common.DbConnection connection)
EntityFramework.SqlServer.dll!System.Data.Entity.SqlServer.SqlProviderServices.QueryForManifestToken(System.Data.Common.DbConnection conn)
EntityFramework.SqlServer.dll!System.Data.Entity.SqlServer.SqlProviderServices.GetDbProviderManifestToken.AnonymousMethod__9(System.Data.Common.DbConnection conn)
EntityFramework.SqlServer.dll!System.Data.Entity.SqlServer.SqlProviderServices.UsingConnection.AnonymousMethod__32()
EntityFramework.SqlServer.dll!System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute.AnonymousMethod__0()
EntityFramework.SqlServer.dll!System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute<object>(System.Func<object> operation)
EntityFramework.SqlServer.dll!System.Data.Entity.SqlServer.SqlProviderServices.GetDbProviderManifestToken(System.Data.Common.DbConnection connection)
EntityFramework.dll!System.Data.Entity.Core.Common.DbProviderServices.GetProviderManifestToken(System.Data.Common.DbConnection connection)
EntityFramework.dll!System.Data.Entity.Utilities.DbProviderServicesExtensions.GetProviderManifestTokenChecked(System.Data.Entity.Core.Common.DbProviderServices providerServices, System.Data.Common.DbConnection connection)
mscorlib.dll!System.Collections.Concurrent.ConcurrentDictionary<System.Tuple<System.Type, string, string>, string>.GetOrAdd(System.Tuple<System.Type, string, string> key, System.Func<System.Tuple<System.Type, string, string>, string> valueFactory)
EntityFramework.dll!System.Data.Entity.Utilities.DbConnectionExtensions.GetProviderInfo(System.Data.Common.DbConnection connection, out System.Data.Entity.Core.Common.DbProviderManifest providerManifest)
EntityFramework.dll!System.Data.Entity.DbModelBuilder.Build(System.Data.Common.DbConnection providerConnection)
EntityFramework.dll!System.Data.Entity.Internal.LazyInternalContext.CreateModel(System.Data.Entity.Internal.LazyInternalContext internalContext)
EntityFramework.dll!System.Data.Entity.Internal.RetryLazy<System.Data.Entity.Internal.LazyInternalContext, System.Data.Entity.Infrastructure.DbCompiledModel>.GetValue(System.Data.Entity.Internal.LazyInternalContext input)
EntityFramework.dll!System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
EntityFramework.dll!System.Data.Entity.Internal.LazyInternalContext.GetObjectContextWithoutDatabaseInitialization()
EntityFramework.dll!System.Data.Entity.Database.UseTransaction(System.Data.Common.DbTransaction transaction)事务在会话的Open方法中创建：
public virtual void Open(IsolationLevel isolation, string user)
{
ValidateState(false);
this.m_user = user;
this.m_connection = this.m_database.CreateConnection();
this.m_connection.Open();
if (IsolationLevel.Unspecified != isolation)
{
this.m_transaction = this.m_connection.BeginTransaction(isolation);
}
}然后，该方法在支持EF的类中被过度使用：
public override void Open(System.Data.IsolationLevel isolation, string user)
{
if (isolation == System.Data.IsolationLevel.Unspecified)
{
throw new InvalidOperationException("Isolation level 'Unspecified' is not supported");
}
base.Open(isolation, user);
this.DbContext = this.DbContextFactory.CreateContext<TContext>(this.Connection);
this.DbContext.Database.UseTransaction(this.Transaction);
}回答 2
Stack Overflow用户
发布于 2021-04-05 00:13:53
在初始化期间，DdContext将确定Server的版本。此过程将尝试连接到底层服务器，并使用提供的连接查询select cast (serverproperty ('EngineEdition') as int)，或者在没有连接的情况下，从配置的连接字符串创建一个新的连接。
这将只发生一次，在第一次初始化之后。
因此，如果您在应用程序生命周期中第一次使用DbContext来自一个事务，这将导致DbContext尝试使用此连接并导致观察到的错误。
如果您确保首次对DbContext (用于查询的DbContext构造和使用)进行非事务性调用，则将避免此行为。
private static object _syncRoot = new object();
private static bool _Initialized = false;
private MyDbContext(string connectionString) : base(connectionString)
{
Database.SetInitializer<MyDbContext>(null);
}
private MyDbContext(DbTransaction dbTransaction) : base(dbTransaction.Connection, false)
{
Database.SetInitializer<MyDbContext>(null);
Database.UseTransaction(dbTransaction);
}
public static MyDbContext Factory()
{
return new MyDbContext(Tools.GetDefaultConnectionString());
}
public static MyDbContext Factory(DbTransaction dbTransaction)
{
if(_Initialized==false)
{
lock(_syncRoot)
{
if(_Initialized==false)
{
using (MyDbContext tempDbContext = new MyDbContext(dbTransaction.Connection.ConnectionString))
using (System.Data.Common.DbTransaction temptransaction = tempDbContext.BeginTransaction())
{
var mySampleData = tempDbContext.OneRowTable.AsNoTracking().ToList();
temptransaction.Commit();
_Initialized = true;
}
}
}
}
MyDbContext finalContext = new MyDbContext(dbTransaction);
return finalContext;
}这是一个解决方案，在一个场景中，您不能或不希望在软件中使用TransactionScope。
Stack Overflow用户
发布于 2021-03-26 00:32:21
这个问题出现在第一次访问底层ObjectContext时(试图设置事务访问底层上下文)。使用TransactionScope很好；当使用已经与其关联的本地事务的连接时，就会出现此问题。
虽然有点难看，像下面这样的方法确实可以解决这个问题。具体的实现细节，如确定notCreateYet，留作练习。
if (notCreatedYet)
{
// Create a second session/connection to not touch the incoming connection.
// Using a TransactionScope works and proper enlistment is done.
// Attempts to open a manual transaction prior to creation will fail.
using (new TransactionScope(TransactionScopeOption.RequiresNew))
using (var initConn = new SqlConnection(connection.ConnectionString))
{
initConn.Open();
var tempContext = this.DbContextFactory.CreateContext<TContext>(connection);
// Touch the object context.
if (tempContext is IObjectContextAdapter contextAdapter)
{
_ = contextAdapter.ObjectContext;
}
}
}
// Then later on this is fine.
this.DbContext = this.DbContextFactory.CreateContext<TContext>(connection);
this.DbContext.Database.UseTransaction(transaction);页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/38082180
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