Simple Vb Linq question

[Chris]

Hi,
I'm trying to figure out how to use LINQ with OA.  I'm not sure I'm on the right course, especially with regard to the .Extent extension.

Two questions:
1.  Do I need to use the .Extent extensions?  If not how do I do anything without it.
2.  I have a few simple lines of code:
        Dim scope As Telerik.OpenAccess.IObjectScope
        scope = OaMsTest1.ObjectScopeProvider1.GetNewObjectScope
        scope.Transaction.Begin()
        Dim ext As IQueryable(Of Category)
        ext = scope.Extent(Of Category)()
        Dim result = From c In ext _
                     Where Not c.CategoryName Is "something" _
                     Select c
        For Each c In result
            Console.WriteLine(c.CategoryName)
        Next

Now, each Category has a CategoryName field.  Intellisense recognizes it, but I get the following:

Identifier 'CategoryName' is not a parameter, variable or field of 'OaMsTest1.Category'. If 'CategoryName' is a property please add the FieldAlias attribute to it.

If I uncomment the following  FieldAlias:

 Private _catName As String
    '<Telerik.OpenAccess.FieldAlias("CategoryName")> _
    Public Property CategoryName() As String
        Get
            Return _catName
        End Get
        Set(ByVal value As String)
            _catName = value
        End Set
    End Property

Then I get:

Error    2    OpenAccess Error: The property 'CategoryName' of type 'Category' is declared to be an alias for field 'CategoryName', but such a field does not exist or is transient and not present in the database. [class=OaMsTest1.Category] [field=CategoryName]    C:\Development\OaMsTest1\OaMsTest1\Category.vb    2    


Anybody have any pointers?

THanks a million,
Chris

[Chris]

Some progress:
I now understand that the FieldAlias attribute should contain the internal field for the property's value, not an externally visiable name.  Correct?

The following seems to work:
 Dim scope As Telerik.OpenAccess.IObjectScope
        scope = OaMsTest1.ObjectScopeProvider1.GetNewObjectScope
        scope.Transaction.Begin()
        Dim ext As IQueryable(Of Category)
        ext = scope.Extent(Of Category)()

        Dim txt As String = "something"
        Dim result = From c In ext _
                     Where Not c.CategoryName = txt _
                     Select c

        For Each c In result
            Console.WriteLine(c.CategoryName)
        Next

[PetarP]

Hello Chris,
You are progressing quite fast which is really a good thing. And yes, what you have stated is correct. If you encounter any problems do not hesitate to contact us.

Best wishes,
PetarP
the Telerik team

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[Ryan]

Hey,

I'm getting the same error "Identifier 'PersonnelNo' is not a parameter, variable or field of 'LMS_Classes.RegistrationStatu'. If 'PersonnelNo' is a property please add the FieldAlias attribute to it.

However, I believe it is for a different reason. Here is my LINQ query:

Dim currentActiveRegistrationStatus As LMS_Classes.RegistrationStatu
      Try
         pScope.Transaction.Begin()
         Dim result As IQueryable(Of LMS_Classes.RegistrationStatu)
         result = From RS In pScope.Extent(Of LMS_Classes.RegistrationStatu)() _
                  Where RS.Registration.PersonnelNo = pPersNo
                  Select RS
         currentActiveRegistrationStatus = result.OfType(Of LMS_Classes.RegistrationStatu)().ToList.Item(0)
      Catch ex As Exception
         MsgBox("Error: " & ex.Message)
         currentActiveRegistrationStatus = Nothing
      End Try

Here is my 'RegistrationStatu' class (that contains my Registration object, which contains my personnelNo property)

Imports System.Collections.Generic


'Generated by Telerik OpenAccess
'NOTE: Field declarations and 'Object ID' class implementation are added to the 'designer' file.
'      Changes made to the 'designer' file will be overwritten by the wizard.
Partial Public Class RegistrationStatu

    'The 'no-args' constructor required by OpenAccess.
    Public Sub New()
    End Sub

    <Telerik.OpenAccess.FieldAlias("_registrationStatusID")> _
    Public Property RegistrationStatusID() As Integer
        Get
            Return _registrationStatusID
        End Get
        Set( ByVal Value As Integer )
            Me._registrationStatusID = Value
        End Set
    End Property

    <Telerik.OpenAccess.FieldAlias("_isActive")> _
    Public Property IsActive() As Boolean
        Get
            Return _isActive
        End Get
        Set( ByVal Value As Boolean )
            Me._isActive = Value
        End Set
    End Property

    <Telerik.OpenAccess.FieldAlias("_lastUpdatedBy")> _
    Public Property LastUpdatedBy() As Short
        Get
            Return _lastUpdatedBy
        End Get
        Set( ByVal Value As Short )
            Me._lastUpdatedBy = Value
        End Set
    End Property

    <Telerik.OpenAccess.FieldAlias("_statusDate")> _
    Public Property StatusDate() As Date
        Get
            Return _statusDate
        End Get
        Set( ByVal Value As Date )
            Me._statusDate = Value
        End Set
    End Property

    <Telerik.OpenAccess.FieldAlias("_registration")> _
    Public Property Registration() As Registration
        Get
            Return _registration
        End Get
        Set( ByVal Value As Registration )
            Me._registration = Value
        End Set
    End Property

End Class

Here is my 'Registration' class (that contains my personnelNo property)

Imports System.Collections.Generic


'Generated by Telerik OpenAccess
'NOTE: Field declarations and 'Object ID' class implementation are added to the 'designer' file.
'      Changes made to the 'designer' file will be overwritten by the wizard.
Partial Public Class Registration

    'The 'no-args' constructor required by OpenAccess.
    Public Sub New()
    End Sub

    <Telerik.OpenAccess.FieldAlias("_registrationID")> _
    Public Property RegistrationID() As Integer
        Get
            Return _registrationID
        End Get
        Set( ByVal Value As Integer )
            Me._registrationID = Value
        End Set
    End Property

   <Telerik.OpenAccess.FieldAlias("_checkInDate")> _
    Public Property CheckInDateTime() As Nullable(Of Date)
      Get
         Return _checkInDate
      End Get
      Set(ByVal Value As Nullable(Of Date))
         Me._checkInDate = Value
      End Set
   End Property

   <Telerik.OpenAccess.FieldAlias("_checkOutDate")> _
    Public Property CheckOutDateTime() As Nullable(Of Date)
      Get
         Return _checkOutDate
      End Get
      Set(ByVal Value As Nullable(Of Date))
         Me._checkOutDate = Value
      End Set
   End Property

    <Telerik.OpenAccess.FieldAlias("_personnelNo")> _
    Public Property PersonnelNo() As Short
        Get
            Return _personnelNo
        End Get
        Set( ByVal Value As Short )
            Me._personnelNo = Value
        End Set
    End Property

    <Telerik.OpenAccess.FieldAlias("_preferredRoomate")> _
    Public Property PreferredRoomate() As Short
        Get
            Return _preferredRoomate
        End Get
        Set( ByVal Value As Short )
            Me._preferredRoomate = Value
        End Set
    End Property

End Class

The intellisense works fine (which is how I made the LINQ). Which is why I don't understand why I'm getting the error.

Any point in the right direction would be appreciated!

Cheers,

Ryan

[PetarP]

Hi Ryan,
can you please provide us with some additional information. What version of our product are you using as we fail to see any record of previous downloads of yours.
Using reverse mapping should apply the proper field attributes to your properties so this should work out fine. If you are using some old version can you please download a free trial of the latest version from our site and check if everything with your project works fine.

Sincerely yours,
Petar
the Telerik team

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[Ryan]

Hey Petar,

I am using version 2009.2.701.5.

I agree it should work fine, but that does not seem to be the case. It seems to appear when I get deeper into each class. If I'm getting a direct property from a class, it's fine, but when I get a property from a class that is a property of a class, then it gives me that error.

ie. RegistrationStatu.IsActive works fine
     RegistrationStatu.Registration.PersonnelNo does not work.

Cheers,

Ryan

[PetarP]

Hello Ryan,

We were unable to reproduce this odd behavior using our latest internal build (2009.2.720.1). I have attached a sample project to the support ticket you opened with the suggestion to upgrade to our latest internal build. If you have any further questions, please do let us know.

Kind regards,
Petar
the Telerik team

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