The connection was not closed. The connection's current state is connecting.

悬赏园豆：20 [已解决问题] 解决于 2018-07-16 15:23

ef core dbcontext在service中使用构造函数注入

    public class ReportService : IReportService {
        public ReportService(ApplicationDbContext context) {
            _context = context;

        }
        private ApplicationDbContext _context;
    }

调用时候偶尔会出现错误,肯定不是偶然~肯定有那里出错了

An unhandled exception occurred while processing the request.

InvalidOperationException: The connection was not closed. The connection's current state is connecting.
System.Data.ProviderBase.DbConnectionClosedConnecting.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource<DbConnectionInternal> retry, DbConnectionOptions userOptions)

Stack Query Cookies Headers
InvalidOperationException: The connection was not closed. The connection's current state is connecting.
System.Data.ProviderBase.DbConnectionClosedConnecting.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource<DbConnectionInternal> retry, DbConnectionOptions userOptions)
System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource<DbConnectionInternal> retry)
System.Data.SqlClient.SqlConnection.Open()
Microsoft.EntityFrameworkCore.Storage.RelationalConnection.Open(bool errorsExpected)
Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable+Enumerator.BufferlessMoveNext(bool buffer)
Microsoft.EntityFrameworkCore.Storage.Internal.SqlServerExecutionStrategy.Execute<TState, TResult>(TState state, Func<DbContext, TState, TResult> operation, Func<DbContext, TState, ExecutionResult<TResult>> verifySucceeded)
Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable+Enumerator.MoveNext()
Microsoft.EntityFrameworkCore.Query.QueryMethodProvider.GetResult<TResult>(IEnumerable<ValueBuffer> valueBuffers, bool throwOnNullResult)
lambda_method(Closure , QueryContext )
Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler+<>c__DisplayClass17_1.<CompileQueryCore>b__0(QueryContext qc)
System.Linq.Queryable.Any<TSource>(IQueryable<TSource> source)
Silver.CreditReport.Controllers.HomeController+<Index>d__4.MoveNext() in HomeController.cs

连接未关闭,这什么鬼?构造函数注入不会自动释放?

An unhandled exception occurred while processing the request.

SqlException: 服务器无法继续执行该事务。说明: 3400000006。
System.Data.SqlClient.SqlConnection.OnError(SqlException exception, bool breakConnection, Action<Action> wrapCloseInAction)

Stack Query Cookies Headers
SqlException: 服务器无法继续执行该事务。说明: 3400000006。
System.Data.SqlClient.SqlConnection.OnError(SqlException exception, bool breakConnection, Action<Action> wrapCloseInAction)
System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, bool breakConnection, Action<Action> wrapCloseInAction)
System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, bool callerHasConnectionLock, bool asyncClose)
System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, out bool dataReady)
System.Data.SqlClient.SqlDataReader.TryConsumeMetaData()
System.Data.SqlClient.SqlDataReader.get_MetaData()
System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, string resetOptionsString)
System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, bool returnStream, bool async, int timeout, out Task task, bool asyncWrite, SqlDataReader ds)
System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, bool returnStream, TaskCompletionSource<object> completion, int timeout, out Task task, bool asyncWrite, string method)
System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior)
System.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
System.Data.Common.DbCommand.ExecuteReader()
Microsoft.EntityFrameworkCore.Storage.Internal.RelationalCommand.Execute(IRelationalConnection connection, DbCommandMethod executeMethod, IReadOnlyDictionary<string, object> parameterValues)
Microsoft.EntityFrameworkCore.Storage.Internal.RelationalCommand.ExecuteReader(IRelationalConnection connection, IReadOnlyDictionary<string, object> parameterValues)
Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable+Enumerator.BufferlessMoveNext(bool buffer)
Microsoft.EntityFrameworkCore.Storage.Internal.SqlServerExecutionStrategy.Execute<TState, TResult>(TState state, Func<DbContext, TState, TResult> operation, Func<DbContext, TState, ExecutionResult<TResult>> verifySucceeded)
Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable+Enumerator.MoveNext()
Microsoft.EntityFrameworkCore.Query.Internal.LinqOperatorProvider+ExceptionInterceptor+EnumeratorExceptionInterceptor.MoveNext()
AspNetCore._Views_Home_Index_cshtml+<ExecuteAsync>d__28.MoveNext() in Index.cshtml

远扬 | 初学一级 | 园豆：30
提问于：2018-07-03 16:13

< >

最佳答案

Startup 中是如何注册 ApplicationDbContext 的？

收获园豆：20

dudu | 高人七级 |园豆：30757 | 2018-07-03 19:56

            services.AddDbContext<ApplicationDbContext>(options =>
                options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

asp.net core 2.0 默认就是ServiceLifetime.Scoped

这应该没问题吧?

本机测试,win7+vs2017+sql server 2014

远扬 | 园豆：30 (初学一级) | 2018-07-04 00:45

@远扬: 注册没问题，是否可以提供一下对应的 LINQ 部分的代码？

dudu | 园豆：30757 (高人七级) | 2018-07-04 12:14

@远扬: 这个问题不是 EF Core 本身的问题，EF Core 会在每次 LINQ 查询（比如 ToListAsync() ）时打开并关闭连接，怀疑可能在代码中的某个地方打开了 EF Core 所关联的数据库连接而没有及时关闭

dudu | 园豆：30757 (高人七级) | 2018-07-04 13:04

@dudu:

        public IQueryable<ReportListViewModel> GetList()
        {
            var data = (from c in _context.Report
                from d in _context.Investigation
                where d.Id == c.InvestigationId
                from e in _context.Order
                where e.Id == d.OrderId
                select new ReportListViewModel {
                    Id = c.Id,
                    CreateTime = c.CreateTime,
                    IsOverdue = c.IsOverdue,
                    Name = d.Name,
                    OverdueDate = c.CreateTime,
                    PhoneNumber = d.PhoneNumber,
                    ReportNo = e.OrderNo,
                    IdentityId = d.IdentityId
                }).OrderByDescending(c => c.CreateTime);
            return data;
        }

我直接返回IQueryable<model>到View

远扬 | 园豆：30 (初学一级) | 2018-07-04 14:28

@远扬: 在哪里进行了 ToList() 或 ToListAsync() 操作？建议提供一下相关代码

dudu | 园豆：30757 (高人七级) | 2018-07-04 15:09

@dudu:

        public async Task<IActionResult> Index() {
　　　　　　　　return View(_reportService.GetList());
        }

没有做ToList()或者ToListAsync()操作直接给视图

使用ToList()或者ToListAsync()也会出现这个错误~试过了

远扬 | 园豆：30 (初学一级) | 2018-07-04 22:56

@远扬: 注册 ReportService 时用的是哪种 ServiceLifetime ？

dudu | 园豆：30757 (高人七级) | 2018-07-05 14:36

@dudu: 使用autofac自动注册

    public class DefaultModule : Module {
        protected override void Load(ContainerBuilder builder)
        {
            var baseType = typeof(IDependency);
            var assemblys = AppDomain.CurrentDomain.GetAssemblies().ToList();
            builder.RegisterAssemblyTypes(assemblys.ToArray())
                .Where(t => baseType.IsAssignableFrom(t) && t != baseType)
                .AsImplementedInterfaces()
                .InstancePerLifetimeScope();
　　　　　　  base.Load(builder);
        }
    }

　　public IServiceProvider ConfigureServices(IServiceCollection services) {
            services.AddDbContext<ApplicationDbContext>(options =>
                options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

            services.AddRouting(opt => opt.LowercaseUrls = true);

            services.AddMvc();

            var builder = new ContainerBuilder();
            builder.RegisterModule<DefaultModule>();
            builder.Populate(services);
            ApplicationContainer = builder.Build();
            return new AutofacServiceProvider(ApplicationContainer);
        }

远扬 | 园豆：30 (初学一级) | 2018-07-05 15:18

@远扬: 知道了，问题应该出在你将 IQueryable 作为 ViewModel 传递给了视图，建议将 ReportService.GetList() 方法的返回值类型改为 IList 或 IEnumerable

dudu | 园豆：30757 (高人七级) | 2018-07-05 15:28

@dudu: 发现在action传递数据给视图做ToList()或者ToListAsync()操作返回给视图会出现

Exception: Unable to cast object of type 'System.Data.ProviderBase.DbConnectionClosedConnecting' to type 'System.Data.SqlClient.SqlInternalConnectionTds'.

远扬 | 园豆：30 (初学一级) | 2018-07-05 17:19

@远扬: 不要在视图中 ToList( )或者 ToListAsync()

dudu | 园豆：30757 (高人七级) | 2018-07-05 17:22

@dudu:

在MVC5+EF6这样使用不会出错的

远扬 | 园豆：30 (初学一级) | 2018-07-05 17:39

@dudu: 如果一个action同时返回ViewBag和ViewModel,都是涉及到数据库读取,是不是使用异步才不会出错.

远扬 | 园豆：30 (初学一级) | 2018-07-05 17:48

@远扬: 推荐一个参考材料，其他帮不上了：https://stackoverflow.com/q/41217906/5989202

dudu | 园豆：30757 (高人七级) | 2018-07-05 17:50

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The connection was not closed. The connection's current state is connecting.

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