Ok Here's the relevant documentation and the exceptions thrown. Note that we should also consider the LoadOptions property (and the DataLoadOption class<http://msdn.microsoft.com/en-us/library/system.data.linq.dataloadoptions.aspx> )
What shoud be the working plan? *bool ObjectTrackingEnabled* Instructs the framework to track the original value and object identity for this DataContext. Setting this property to false improves performance at retrieval time, because there are fewer items to track. An exception is thrown: - If the property is set to false after a query has been executed. [1] For more information, see the Valid Modes section in DataContext<http://msdn.microsoft.com/en-us/library/system.data.linq.datacontext.aspx> - If the property is set to false and SubmitChanges<http://msdn.microsoft.com/en-us/library/system.data.linq.datacontext.submitchanges.aspx>is called. [2] *bool **DeferredLoadingEnabled * Specifies whether to delay-load one-to-many or one-to-one relationships. When false and the code accesses one of these relationships, null is returned if the relationship is one-to-one, and an empty collection is returned if it is one-to-many. The relationships can still be filled by setting the LoadOptions<http://msdn.microsoft.com/en-us/library/system.data.linq.datacontext.loadoptions.aspx>property. Deferred loading requires object tracking. Only the following three modes are valid: - ObjectTrackingEnabled<http://msdn.microsoft.com/en-us/library/system.data.linq.datacontext.objecttrackingenabled.aspx>= false. DeferredLoadingEnabled is ignored and inferred to be false. This behavior corresponds to a read-only DataContext<http://msdn.microsoft.com/en-us/library/system.data.linq.datacontext.aspx> . - ObjectTrackingEnabled<http://msdn.microsoft.com/en-us/library/system.data.linq.datacontext.objecttrackingenabled.aspx>= true. DeferredLoadingEnabled = false. This situation corresponds to a DataContext<http://msdn.microsoft.com/en-us/library/system.data.linq.datacontext.aspx>that allows users to load an object graph by using LoadWith<http://msdn.microsoft.com/en-us/library/system.data.linq.dataloadoptions.loadwith.aspx>directives, but it does not enable deferred loading. - Both are set to true. This is the default. The flags may not be changed after a query has been executed. Any change after the execution of the first query that uses that DataContext<http://msdn.microsoft.com/en-us/library/system.data.linq.datacontext.aspx>throws an exception. [3] *Exceptions thrown*: [1] System.InvalidOperationException was unhandled Message="Data context options cannot be modified after results have been returned from a query." Source="System.Data.Linq" StackTrace: at System.Data.Linq.DataContext.set_ObjectTrackingEnabled(Boolean value) at DbLinq.Mssql.Example.Program.Main(String[] args) in C:\Projects\Labs\Linq\DbLinq\examples\DbLinq.Tests\Program.cs:line 109 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException: _____________ [2] System.InvalidOperationException was unhandled Message="Object tracking is not enabled for the current data context instance." Source="System.Data.Linq" StackTrace: at System.Data.Linq.DataContext.VerifyTrackingEnabled() at System.Data.Linq.DataContext.SubmitChanges(ConflictMode failureMode) at System.Data.Linq.DataContext.SubmitChanges() at DbLinq.Mssql.Example.Program.Main(String[] args) in C:\Projects\Labs\Linq\DbLinq\examples\DbLinq.Tests\Program.cs:line 109 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException: _____________ [3] System.InvalidOperationException was unhandled Message="Data context options cannot be modified after results have been returned from a query." Source="System.Data.Linq" StackTrace: at System.Data.Linq.DataContext.set_DeferredLoadingEnabled(Boolean value) at DbLinq.Mssql.Example.Program.Main(String[] args) in C:\Projects\Labs\Linq\DbLinq\examples\DbLinq.Tests\Program.cs:line 109 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException: _____________ On Tue, Mar 31, 2009 at 10:42 AM, Pascal Craponne <[email protected]> wrote: > Well, I suggest that you list all effects of such parameter (exceptions > thrown when specific methods are called), and then we'll see how to > implement them. > > Pascal. > > jabber/gtalk: [email protected] > msn: [email protected] > > > > > On Tue, Mar 31, 2009 at 10:37, Giacomo Tesio <[email protected]> wrote: > >> Hello everybody! >> I've figured now that we could need a readonly DataContext for security >> reasons. >> In >> http://msdn.microsoft.com/en-us/library/system.data.linq.datacontext.deferredloadingenabled.aspxit >> is said that that would be possible, by setting >> DataContext.ObjectTrackingEnabled = false. >> >> Actually those two proprerty required to get such a behaviour throws >> NotImplementedException. >> >> I could try to implement them, at least to get the readonly behaviour >> (which even if not trivial, should be possible in a reasonable time). >> >> Can someone get me an overview of the required modifications and point me >> to the place to start? >> >> >> Giacomo >> >> >> >> >> > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "DbLinq" group. 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