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我正在使用带有 Sql server 2008 的 ASP.Net MVC 3（实体框架）。连接字符串在 web.config 中很好。但有时我从我的应用程序中得到以下异常：

    System.Data.SqlClient.SqlException: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)

Generated: Wed, 02 May 2012 05:05:21 GMT

System.Data.EntityException: The underlying provider failed on Open. ---> System.Data.SqlClient.SqlException: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)
   at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
   at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning()
   at System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity)
   at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, SqlConnection owningObject)
   at System.Data.SqlClient.SqlInternalConnectionTds.LoginWithFailover(Boolean useFailoverHost, ServerInfo primaryServerInfo, String failoverHost, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, TimeoutTimer timeout)
   at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, TimeoutTimer timeout, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance)
   at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance)
   at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection)
   at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options)
   at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject)
   at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject)
   at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject)
   at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)
   at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
   at System.Data.SqlClient.SqlConnection.Open()
   at System.Data.EntityClient.EntityConnection.OpenStoreConnectionIf(Boolean openCondition, DbConnection storeConnectionToOpen, DbConnection originalConnection, String exceptionCode, String attemptedOperation, Boolean& closeStoreConnectionOnFailure)
   --- End of inner exception stack trace ---
   at System.Data.EntityClient.EntityConnection.OpenStoreConnectionIf(Boolean openCondition, DbConnection storeConnectionToOpen, DbConnection originalConnection, String exceptionCode, String attemptedOperation, Boolean& closeStoreConnectionOnFailure)
   at System.Data.EntityClient.EntityConnection.Open()
   at System.Data.Objects.ObjectContext.EnsureConnection()
   at System.Data.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
   at System.Data.Objects.ObjectQuery`1.System.Collections.Generic.IEnumerable<T>.GetEnumerator()
   at System.Linq.Enumerable.SingleOrDefault[TSource](IEnumerable`1 source)
   at System.Data.Objects.ELinq.ObjectQueryProvider.<GetElementFunction>b__2[TResult](IEnumerable`1 sequence)
   at System.Data.Objects.ELinq.ObjectQueryProvider.ExecuteSingle[TResult](IEnumerable`1 query, Expression queryRoot)
   at System.Data.Objects.ELinq.ObjectQueryProvider.System.Linq.IQueryProvider.Execute[S](Expression expression)
   at System.Linq.Queryable.SingleOrDefault[TSource](IQueryable`1 source)
   at MyApp.Data.UserRepository.GetUserDetails(String username)
   at MyApp.Core.Services.SiteService.GetUserDetails(String username, Int64 userId)
   at MyApp.PublicSite.Web.Controllers.BaseController.Initialize(RequestContext requestContext)
   at System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext)
   at MyApp.PublicSite.Web.Controllers.BaseController.Execute(RequestContext requestContext)
   at System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext)
   at System.Web.Mvc.MvcHandler.<>c__DisplayClass6.<>c__DisplayClassb.<BeginProcessRequest>b__5()
   at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass1.<MakeVoidDelegate>b__0()
   at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass8`1.<BeginSynchronous>b__7(IAsyncResult _)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.End()
   at System.Web.Mvc.MvcHandler.<>c__DisplayClasse.<EndProcessRequest>b__d()
   at System.Web.Mvc.SecurityUtil.<GetCallInAppTrustThunk>b__0(Action f)
   at System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Action action)
   at System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult)
   at System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

连接字符串是：

    <connectionStrings>
    <add name="MyAppDBContainer" connectionString="metadata=res://*/MyAppDB.csdl|res://*/MyAppDB.ssdl|res://*/MyAppDB.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=SERVERNAME;initial catalog=MyAppDB;persist security info=True;user id=USERID;Password=PASSWORD;multipleactiveresultsets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
  </connectionStrings>

此异常是随机发生的，并且每次都无法获取/重现它。我可能在这里缺少任何可能的设置？请建议。

4

4 回答 4

2

鉴于它有时/大部分都有效（如您所说）：

  • 连接字符串没问题
  • SQL 配置正确（即允许远程连接等）

这可能是您的服务器（您的代码）和 SQL Server 之间的网络中断，或者 SQL Server 由于某种原因而关闭的唯一原因。

于 2012-05-02T05:59:16.983 回答
0

为了允许远程连接，我们需要在 sql server 配置管理器中将 tcp/IP 的属性设置为 true

于 2012-07-02T07:38:28.030 回答
0

我们必须为此检查以下内容

1.检查 sqlserver 配置管理器设置中的 Tcp/IP 设置。如果禁用，请确保我们必须启用 TCP/IP 的状态

2.在火灾设置中添加端口到防火墙异常。sql端口的详细信息：

名称：SQL

端口号：1433

协议：选择 TCP

于 2012-10-18T12:09:36.813 回答
-1

试试这个....

<add name="MyAppDBContainer" connectionString="metadata=res://*;provider=System.Data.SqlClient;provider connection string='data source=SERVERNAME;initial catalog=MyAppDB;persist security info=True;user id=USERID;Password=PASSWORD;multipleactiveresultsets=True;'" providerName="System.Data.EntityClient" />

我已经编辑了我的答案......

于 2012-05-02T08:34:00.577 回答