Exception if two person access the same page at the same time

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Exception if two person access the same page at the same time

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Trent Taylor	Trent Taylor posted 15 Years Ago Post Details Share Post
Group: StrataFrame Developers Posts: 6.6K, Visits: 6.9K	I will send you a link to a custom build to test this this afternoon. We are building this now.
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Trent Taylor	Trent Taylor posted 15 Years Ago Post Details Share Post
Group: StrataFrame Developers Posts: 6.6K, Visits: 6.9K	We will do another build tomorrow morning.
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ChanKK	ChanKK posted 15 Years Ago Post Details Share Post
Group: Forum Members Posts: 190, Visits: 1.3K	Hi, May I know when would it available for download? Thank you
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StrataFrame Team	S StrataFrame Team posted 15 Years Ago Post Details Share Post
S Group: StrataFrame Developers Posts: 3K, Visits: 2.5K	I've wrapped most of those that needed it in a SyncLock. Several of the places were already using Monitor.Enter() & Exit() to ensure threadsafe saving. I changed all of the ones that are used in a static context. We'll do another build and see if that helps. If it doesn't, then we'll need to figure out how to get this into a reproducible state because the NullReferenceException is being thrown by .NET, not from within our code.
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ChanKK	ChanKK posted 15 Years Ago Post Details Share Post
Group: Forum Members Posts: 190, Visits: 1.3K	Hi, I confident that SF Team would fix ALL the similar/potential static/share issue. Anyhow, I would like to share with you that, I have roughly search thru SF source code and found the following method that MIGHT NOT thread safe. BusinessLayer ResetIsSavedOnTransactionFlagOnBusinessObjects DbDataSourceItem TransactionBegin TransactionCommit TransactionRollback Currently, we could use Guid as transactionkey as workaround to ensure threadsafe. However, this is not mentioned in any documentation as I know, therefore other developers might hit the same problem again. DataLayer RowHasErrors typepropertycache SetPropertyValue
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ChanKK	ChanKK posted 15 Years Ago Post Details Share Post
Group: Forum Members Posts: 190, Visits: 1.3K	Hi, Thank you for update. Just would like to share with you, we found that, the problem can be consistently if we do IISRESET, delete temporary ASP,NET cache and then run the app. Once the problem occurred, try to refresh the screen and the chance to hit the problem would be reduced. Hope it helps. Thank you
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Trent Taylor	Trent Taylor posted 15 Years Ago Post Details Share Post
Group: StrataFrame Developers Posts: 6.6K, Visits: 6.9K	We are trying to reproduce this....as you could suspect...and we seem to have good luck with this towards you for some reason...we cannot reproduce. I am waiting for another developer looking at this and when we know something or need something I will let you know. Thanks.
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ChanKK	ChanKK posted 15 Years Ago Post Details Share Post
Group: Forum Members Posts: 190, Visits: 1.3K	Hi, Please update me if any status, whether SF team is checking on this, fixing it or still think that it is not SF problem. I need to know so that I can plan for next step. FYI, I am trying to scale down my project in order to reproduce it. It will take me some time. Meanwhile, I would like to get updated ASAP so that I will not waste my time anymore to do something that not helpful. Thank you
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ChanKK	ChanKK posted 15 Years Ago Post Details Share Post
Group: Forum Members Posts: 190, Visits: 1.3K	Hi, After whole day debugging and tracing by modify SF source code, I found that, we hit new error which is more "explainable" for me. As we can see the error "An item with the same key has already been added", and I found that, TypePropertyCache.GetPropertyInfo() is a static/shared method. Meanwhile, _Dictionary used by TypePropertyCache is also static/shared. However, I couldn't find any code that ensure thread-safe. Is it a mistake? Regarding why I hit Object reference is null ... I still unable to find out the cause. Server Error in '/FlexHR' Application. -------------------------------------------------------------------------------- An item with the same key has already been added. 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.ArgumentException: An item with the same key has already been added. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [ArgumentException: An item with the same key has already been added.] System.ThrowHelper.ThrowArgumentException(ExceptionResource resource) +48 System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add) +2668392 System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value) +11 MicroFour.StrataFrame.Business.TypePropertyCache.GetPropertyInfo(Type OwnerType, String PropertyName) +505 MicroFour.StrataFrame.Business.TypePropertyCache.GetPropertyInfo(Object Owner, String PropertyName) +45 MicroFour.StrataFrame.Business.BusinessLayer.BindDataToWebControl(IWebBusinessBindable ControlToBind, IWebBinding Binding) +251 MicroFour.StrataFrame.Business.BusinessLayer.BindDataToWebControlPrimary(IWebBusinessBindable ControlToBind) +55 MicroFour.StrataFrame.UI.Web.BasePage.BindControls() +166 [UIException: An error occurred while binding data to the web control 'deDateFrom'.] Vfs.Generic.UI.Web.Strataframe.Forms.BasePage.OnPreRender(EventArgs e) +322 System.Web.UI.Control.PreRenderRecursiveInternal() +86 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2041 Beside, I also hit this error, if not mistaken no other user is running beside myself. As I check _SharedTables is also static/shared and didn't see any code ensure threadsafe in ShareCurrentDataTable(). Server Error in '/FlexHR' Application. Object reference not set to an instance of an object. 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.NullReferenceException: Object reference not set to an instance of an object. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [NullReferenceException: Object reference not set to an instance of an object.] System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add) +455 System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value) +11 MicroFour.StrataFrame.Business.SharedDataTableCollection.AddBusinessObjectTable(BusinessLayer BusinessObject) +243 MicroFour.StrataFrame.Business.BusinessLayer.ShareCurrentDataTable(BusinessLayer BusinessObject) +162 MicroFour.StrataFrame.Business.BusinessBindingSource.CreateShareAndAddBusinessObject(Int32 index) +94 MicroFour.StrataFrame.Business.BusinessBindingSource.get_Item(Int32 index) +115 MicroFour.StrataFrame.Business.Enumerator.get_Current() +34 MicroFour.StrataFrame.UI.Web.Enumerator.get_Current() +9 DevExpress.Web.ASPxClasses.Internal.CommonUtils.ConvertEnumerableToList(IEnumerable source) +98 DevExpress.Web.Data.WebDataProxy.SetDataSource(Object dataSource) +48 DevExpress.Web.ASPxGridView.ASPxGridView.PerformDataBinding(String dataHelperName, IEnumerable data) +48 DevExpress.Web.ASPxClasses.Internal.DataHelper.PerformDataBinding(IEnumerable data) +26 DevExpress.Web.ASPxClasses.Internal.DataHelper.OnDataSourceViewSelectCallback(IEnumerable data) +75 System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) +29 MicroFour.StrataFrame.UI.Web.WebBusinessBindingSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) +8 DevExpress.Web.ASPxClasses.Internal.DataHelper.PerformSelect() +197 DevExpress.Web.ASPxGridView.GridViewDataHelper.PerformSelect() +116 DevExpress.Web.ASPxClasses.Internal.DataContainer.PerformSelect() +118 DevExpress.Web.ASPxClasses.ASPxDataWebControlBase.DataBindCore() +15 DevExpress.Web.ASPxClasses.ASPxDataWebControlBase.DataBind() +138 DevExpress.Web.ASPxGridView.ASPxGridView.DataBind() +157 DevExpress.Web.ASPxClasses.Internal.DataHelperBase.EnsureDataBound(Boolean ensureChildControls) +89 DevExpress.Web.ASPxClasses.Internal.DataContainer.EnsureDataBound() +128 DevExpress.Web.ASPxClasses.ASPxDataWebControlBase.OnPreRender(EventArgs e) +19 Vfs.Generic.UI.Web.DevEx.Controls.BaseGridView.OnPreRender(EventArgs e) +40 System.Web.UI.Control.PreRenderRecursiveInternal() +86 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Control.PreRenderRecursiveInternal() +170 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2041 Finally, FYI, I have recompile all SF dll from source code. Please advice. Thank you
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Trent Taylor	Trent Taylor posted 15 Years Ago Post Details Share Post
Group: StrataFrame Developers Posts: 6.6K, Visits: 6.9K	This is the first time that I have ever heard of anything like this. And we have a number of SF users with large web applications....so I really feel confident that this is either in the configuration of IIS, permissions, or something within your code. But without the ability to reproduce (small scale preferred) it is going to be impossible to give a straight answer. Also, I don't think that sending me your entire application is the answer here. This would require a lot of investigative work and trying to dissimenate your entire applicaiton which is not something that I am prepared to do at this point. If it happens large scale then you should be able to make it happen small scale as well. Also, if you can't reproduce until you get it into a production environment, that should be a clue as well.
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