Question

August 14, 2011 DO 4.4 VS 2010 SP1 VB.NET

The Visual Basic implementation of the Console sample application that comes with DataObjects.Net 4.4 includes the following code:

      Using session = myDomain.OpenSession()
      Using transactionScope = session.OpenTransaction()
          If session.Query.All(Of MyEntity)().Count() <> 1
              Throw New InvalidOperationException()
          End If
          If session.Query.All(Of MyEntity)().First().Text <> "Hello World!"
              Throw New InvalidOperationException()
          End If
          For Each myEntity In session.Query.All(Of MyEntity)()
              System.Console.WriteLine(myEntity.Text)
          Next
          transactionScope.Complete()
      End Using
  End Using

Even though the code runs as advertised, the following lines Throw an InvalidOperationException

          If session.Query.All(Of MyEntity)().First().Text <> "Hello World!"
              Throw New InvalidOperationException()
          End If

Actually I'm not sure this exception is actually thrown. For example it isn't trapped by a Try Catch block, but when single stepping through the code in the debugger the line

Throw New InvalidOperationException()

is reached in response to the test for an Entity with the "Hello World!" text, but NOT in the prior test for Count <> 1?

Does anyone know why?

Cheers, Mark

Accepted Answer

Hi Dmitri, I'm just using the default memory database configured for the sample in app.config:

  <domain name="Default" upgradeMode="Recreate" connectionUrl="memory://localhost/DO40-             Tests" >
    <types>
      <add assembly="Project1" />
    </types>
  </domain>

Not sure how to inspect the Memory database.

Here is the output in the Immediate Window when stepping into this line:

Step into: Stepping over non-user code 'Xtensive.Orm.Session.Query.get' Step into: Stepping over non-user code 'Project1.Model.MyEntity.~Xtensive.Aspects.FactoryMethod' Step into: Stepping over non-user code 'Project1.Model.MyEntity.MyEntity' Step into: Stepping over non-user code 'Project1.Model.MyEntity.~Xtensive.Aspects.FactoryMethod' Step into: Stepping over non-user code 'Xtensive.Orm.Internals.Activator.CreateEntity' Step into: Stepping over non-user code 'Xtensive.Orm.EntityState.Entity.get' Step into: Stepping over non-user code 'Xtensive.Orm.Linq.Materialization.ItemMaterializationContext.Materialize' Step into: Stepping over non-user code 'Xtensive.Core.DelegateBindExtensions.Bind<object[],xtensive.tuples.tuple,xtensive.orm.linq.materialization.itemmaterializationcontext,project1.model.myentity>.AnonymousMethod9' Step into: Stepping over non-user code 'Xtensive.Orm.Linq.Materialization.MaterializationHelper.Materialize<project1.model.myentity>.AnonymousMethod3' Step into: Stepping over non-user code 'System.Linq.Enumerable.WhereSelectEnumerableIterator<xtensive.tuples.tuple,project1.model.myentity>.MoveNext' Step into: Stepping over non-user code 'Xtensive.Core.EnumerableExtensions.Batch<project1.model.myentity>.MoveNext' Step into: Stepping over non-user code 'Xtensive.Core.EnumerableExtensions.ApplyBeforeAndAfter<project1.model.myentity>.MoveNext' Step into: Stepping over non-user code 'System.Linq.Enumerable.SelectManyIterator<system.collections.generic.ienumerable<project1.model.myentity>,Project1.Model.MyEntity>.MoveNext' Step into: Stepping over non-user code 'System.Linq.Enumerable.First<project1.model.myentity>' Step into: Stepping over non-user code 'Xtensive.Core.DelegateBindExtensions.Bind<object[],system.collections.generic.ienumerable<xtensive.tuples.tuple>,Xtensive.Orm.Session,System.Collections.Generic.Dictionary<xtensive.parameters.parameter<xtensive.tuplstep into:="" stepping="" over="" non-user="" code="" 'xtensive.orm.linq.translatedquery<project1.model.myentity="">.Execute' Step into: Stepping over non-user code 'Xtensive.Orm.Linq.QueryProvider.Execute<project1.model.myentity>'

Since the program displays "Hello World!" correctly in the console after querying this memory database, and myEntity has a "Synchronized" persistence state, it appears that indeed an Entity was created and persisted. Also even though the debugger single steps into the "Throw New InvalidOperationException" line, control flow is not interrupted. Rather it merely steps back out and continues to the For Each enumeration, which correctly outputs the text.

So I'm guessing now that something is interferring with the normal function of the debugger and that an exception is not actually thrown.

Mark

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