我从一个网络应用程序中得到一个令人沮丧的错误。我已经追了两天了。在某些情况下，数据访问尝试期间会出现以下错误。发生错误时，它是对单击应用程序页面上的链接的响应。奇怪的是，在运行跟踪时，您会看到 SQL Server 正在使用适当的参数调用适当的存储过程。在其他情况下，数据访问执行得很好。
我发现好奇的一件事是应用程序事件日志警告的线程信息（如下）。Is impersonating:设置为 false，即使启用了 ASP.Net 模拟。当然，这可能只是我不知道我在说什么。
非常感谢您能提供的任何帮助或指导。
环境：Windows Server 2008 Standard、IIS7、.net 2.x、SQL Server 2005
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= Yellow Screen =
=======================
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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: 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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
Source Error:
Line 3892:
Line 3893: Sub getRenewalInformation(ByVal EntityID As Integer)
Line 3894: BLLParticipant.GetParticipantRenewalInformation(EntityID)
Line 3895: BLLParticipant.GetAdditionalInfo(EntityID)
Line 3896: End Sub
Source File: M:\VirtualWebs\Intranet\SafeAtHome\Participants.aspx.vb Line: 3894
Stack Trace:
[SqlException (0x80131904): 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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)]
System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +6256377
System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) +245
System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, SqlConnection owningObject) +6270399
System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject) +181
System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart) +6271242
System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance) +6271208
System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance) +354
System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection) +703
System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options) +54
System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject) +6272472
System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject) +81
System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject) +1657
System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection) +88
System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory) +6275911
System.Data.SqlClient.SqlConnection.Open() +258
SafeAtHome.DAL.Participant.GetParticipantRenewalInformation(Int32 EntityID) in C:\code\web\SafeAtHome2011\SafeAtHome.DAL\Participant.vb:42
SafeAtHome.BLL.Participant.GetParticipantRenewalInformation(Int32 EntityID) in C:\code\web\SafeAtHome2011\SafeAtHome.BLL\Participant.vb:38
Participant.getRenewalInformation(Int32 EntityID) in M:\VirtualWebs\Intranet\SafeAtHome\Participants.aspx.vb:3894
Participant.BindCombinedParticipants(DataSet dst) in M:\VirtualWebs\Intranet\SafeAtHome\Participants.aspx.vb:3962
Participant.grdParticipantSearchActive_Select(Object sender, DataGridCommandEventArgs e) in M:\VirtualWebs\Intranet\SafeAtHome\Participants.aspx.vb:959
System.Web.UI.WebControls.DataGrid.OnBubbleEvent(Object source, EventArgs e) +88
System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +70
System.Web.UI.WebControls.DataGridItem.OnBubbleEvent(Object source, EventArgs e) +110
System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +70
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +29
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2981
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Version Information: Microsoft .NET Framework Version:2.0.50727.5420; ASP.NET Version:2.0.50727.5420
=======================================
= Application Event Log Warning =
=======================================
Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 12/6/2012 8:53:00 AM
Event time (UTC): 12/6/2012 2:53:00 PM
Event ID: 52ff4f11e1d64e59b020623619f93fe9
Event sequence: 6
Event occurrence: 1
Event detail code: 0
Application information:
Application domain: /LM/W3SVC/1/ROOT/SafeAtHome-1-129992790193691690
Trust level: Full
Application Virtual Path: /SafeAtHome
Application Path: M:\VirtualWebs\Intranet\SafeAtHome\
Machine name: SOSDEVINTRA
Process information:
Process ID: 5068
Process name: w3wp.exe
Account name: IIS APPPOOL\ASP.NET 2.0
Exception information:
Exception type: SqlException
Exception message: 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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
Request information:
Request URL: .../safeathome/Participants.aspx
Request path: /safeathome/Participants.aspx
User host address: ::1
User: test
Is authenticated: True
Authentication Type: Forms
Thread account name: IIS APPPOOL\ASP.NET 2.0
Thread information:
Thread ID: 3
Thread account name: IIS APPPOOL\ASP.NET 2.0
Is impersonating: False
Stack trace: at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
at System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, SqlConnection owningObject)
at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject)
at System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart)
at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, 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 SafeAtHome.DAL.Participant.GetParticipantRenewalInformation(Int32 EntityID) in C:\code\web\SafeAtHome2011\SafeAtHome.DAL\Participant.vb:line 42
at SafeAtHome.BLL.Participant.GetParticipantRenewalInformation(Int32 EntityID) in C:\code\web\SafeAtHome2011\SafeAtHome.BLL\Participant.vb:line 38
at Participant.getRenewalInformation(Int32 EntityID) in M:\VirtualWebs\Intranet\SafeAtHome\Participants.aspx.vb:line 3894
at Participant.BindCombinedParticipants(DataSet dst) in M:\VirtualWebs\Intranet\SafeAtHome\Participants.aspx.vb:line 3962
at Participant.grdParticipantSearchActive_Select(Object sender, DataGridCommandEventArgs e) in M:\VirtualWebs\Intranet\SafeAtHome\Participants.aspx.vb:line 959
at System.Web.UI.WebControls.DataGrid.OnBubbleEvent(Object source, EventArgs e)
at System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args)
at System.Web.UI.WebControls.DataGridItem.OnBubbleEvent(Object source, EventArgs e)
at System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args)
at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)