I receive the following message

There is already an open DataReader associated with this Connection which must be closed first

but I am not sure what is causing it. It happens sporadically on the server. Any ideas on what may be causing this or possible solutions for preventing it?

Thanks

Do you have a stacktrace with that exception?

No I do not. It is occurring in production during runtime.

jeffkararo wrote:

No I do not. It is occurring in production during runtime.

When you get the exception as you describe, it always comes with a stacktrace. Or do you log the exception somewhere and not the stacktrace?

Here is the StackTrace

System.InvalidOperationException: The SqlCommand is currently busy Open, Fetching.

Server stack trace: at System.Data.SqlClient.SqlCommand.set_Connection(SqlConnection value) at System.Data.SqlClient.SqlCommand.System.Data.IDbCommand.set_Connection(IDbConnection value) at SD.LLBLGen.Pro.ORMSupportClasses.Query.set_Connection(IDbConnection value) at SD.LLBLGen.Pro.ORMSupportClasses.DataAccessAdapterBase.ExecuteSingleRowRetrievalQuery(IRetrievalQuery queryToExecute, IEntityFields2 fieldsToFill, IFieldPersistenceInfo[] fieldsPersistenceInfo) at SD.LLBLGen.Pro.ORMSupportClasses.DataAccessAdapterBase.FetchEntityUsingFilter(IEntityFields2 fieldsToFetch, IFieldPersistenceInfo[] persistenceInfos, IRelationPredicateBucket filter) at SD.LLBLGen.Pro.ORMSupportClasses.DataAccessAdapterBase.FetchEntity(IEntity2 entityToFetch, IPrefetchPath2 prefetchPath, Context contextToUse) at SD.LLBLGen.Pro.ORMSupportClasses.DataAccessAdapterBase.FetchEntity(IEntity2 entityToFetch, IPrefetchPath2 prefetchPath) at HRImaging.Biz.RemoteServer.Server.GetOrganization(Int32 id, Boolean retrieveRelated) at System.Runtime.Remoting.Messaging.StackBuilderSink.PrivateProcessMessage(MethodBase mb, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs) at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg, Int32 methodPtr, Boolean fExecuteInContext)

Exception rethrown at [0]: at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) at HRImaging.Biz.Interfaces.IRemoteServerBase.GetOrganization(Int32 id, Boolean retrieveRelated) at HRImaging.Win.Organization.OrganizationDetails.PopulateData() at HRImaging.Win.Organization.OrganizationDetails.PopulateForm() at HRImaging.Win.Organization.OrganizationDetails.OrganizationDetails_Load(Object sender, EventArgs e) at System.Windows.Forms.Form.OnLoad(EventArgs e) at HRImaging.Win.BaseForm.OnLoad(EventArgs e) at System.Windows.Forms.Form.OnCreateControl() at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible) at System.Windows.Forms.Control.CreateControl() at System.Windows.Forms.Control.WmShowWindow(Message& m) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ScrollableControl.WndProc(Message& m) at System.Windows.Forms.ContainerControl.WndProc(Message& m) at System.Windows.Forms.Form.WmShowWindow(Message& m) at System.Windows.Forms.Form.WndProc(Message& m) at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Are you sharing the DataAccessAdapter object among requests to your remoted service? (so subsequent calls use the same dataaccessadapter object) ?

Yes

jeffkararo wrote:

Yes

Then that's the cause.

Thread A starts a fetch, halfway through the resultset, the processor is passed to thread B. B then starts a fetch: boom.

Don't share a DataAccessAdapter among threads. If you have to, make sure just 1 thread can access the adapter object at any given moment.