Category Archives: Entity Framework 4.0

.NET Entity Layer The member with identity ‘Result’ does not exist in the metadata collection

21st September 2011 andre Leave a comment

“The member with identity ‘Result’ does not exist in the metadata collection.
Parameter name: identity”

If you have stumbled across this error when trying to perform a transaction against your DB or any other action via your entity layer. If it is indeed a Microsoft SQL Database or any other database I would highly recommend you disable triggers on the affected tables and re run your test.

This error is the entity layer running home to its default error when either the error cannot be translated or the what ever is being returned from the transaction cannot be understood.

So if you stumble across this error, its because the entity layer is performing an operation that is causing a secondary separate operation which is where the underlying error is kicking back from, either because an error was raised or because the return is in an unexpected format.

.NET, ASP, Entity Framework 4.0, Linq, VB

VAT Information Exchange System (VIES)

7th December 2010 andre Leave a comment

What is the VIES ?
It is an electronic means of transmitting information relating to VAT-registration (= validity of VAT-numbers) of companies registered in EU. Furthermore, information relating to (tax exempt) intra-Community supplies between Member States’ administrations is also transmitted via VIES

The Taxation and Custom Union has provided us developers a nice little webservice to use for validating VAT numbers realtime.

This is their public facing page for one off manual validation
http://ec.europa.eu/taxation_customs/vies/
The service to be used by your application can be found here
http://ec.europa.eu/taxation_customs/vies/checkVatService.wsdl

The FAQ is here http://ec.europa.eu/taxation_customs/vies/faqvies.do

Ok so now i will demonstrate how to use this in your Visual Studio based application

If you have Visual Studio 2010, and your building a web app, in solution explorer right click the web app root node and you should see “Add Web Reference”, this will present you with the “Add Web Reference” dialog box
Paste the above web reference link into the “URL” and hit the “GO” green arrow

VIESVSWebReference — VIES Visual Studio Web Reference

Now Hit “Add Reference” and Visual Studio creates the Web Server Proxy and Wrapper Class.
Ok so now your project has the reference lets see how to use it

On your page that you wish to validate a vat number you should do the following
1. Collect a valid 2 character country code from the User
2. Collect a valid vat number from the User
3. Perform the needed filter on both of these values prior to envoking the webservice
4. Verify the return from the service and take action

First off you will need to import the reference into your page. For ease I use asp.net vb, C# will be similar and there are plenty of converters out there to see the code in c#

Imports eu.europa.ec

1	Imports eu.europa.ec

now your ready to use the reference
For this example we will be supplying country code and VAT number only. There are various other methods available but this suited me so its the only demo you will be getting.
The rules
1.The country code must be valid
2. The VAT number must contain no spaces and only be numerical numbers
3. We pass the validation boolean as a byref, if you also wanted to see what the company name and address the EU have on file for the company the webservice verified, you can pass two strings “Name” and “address” byref and view the content upon return.

This is how i do it

    ''' <summary>
    ''' Calls the Taxation Customs Union web service to validate the vat number
    ''' This works in most cases and is the best way to validate
    ''' VAT Information Exchange System (VIES)
    ''' </summary>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Function CheckVATEUNumber() As Boolean
        Dim IsValid As Boolean = False
        'get the country code of this User (they are logged in so we can find it)
        Dim Code As String = (From I In DLadoEntity.Items _
                             Join C In DLadoEntity.Countries On C.UID Equals I.CompanyCountryUID _
                             Join OC In DLadoEntity.OC_Locations On OC.UID Equals C.OCLocationUID _
                             Where I.UID = SC.intUserCompanyUID _
                             Select OC.ISO3166A2CountryCodes).FirstOrDefault

        'Prepare and clean up the VAT number supplied on the form
        Dim str As String = txtVatNumber.Text.Trim
        Dim vatnumber As String = ""
        For Each c As Char In str
            If IsNumeric(c) Then
                vatnumber = vatnumber & c
            End If
        Next

        'default to UK if we cant find a code
        If String.IsNullOrEmpty(Code) Then Code = "GB"

        'prepare our address and company name vars for return (we dont use them at the moment)
        Dim Add As String = "", Name As String = ""
        'encapsulate the webservice all in a try catch (if it fails in our case we dont worry very much)
        Try
            Dim ViesVATCheck As New eu.europa.ec.checkVatService
            ViesVATCheck.checkVat(Code, vatnumber, IsValid, Name, Add)
        Catch ex As Exception
            'if there is a problem validating the VAT number then we dont really care too much
            'we wont be buying anythingfrom them, they purchase from us so let let them through
            IsValid = True
        End Try

        Return IsValid
    End Function

''' <summary>

''' Calls the Taxation Customs Union web service to validate the vat number

''' This works in most cases and is the best way to validate

''' VAT Information Exchange System (VIES)

''' </summary>

''' <returns></returns>

''' <remarks></remarks>

Function CheckVATEUNumber() As Boolean

Dim IsValid As Boolean = False

'get the country code of this User (they are logged in so we can find it)

Dim Code As String = (From I In DLadoEntity.Items _

Join C In DLadoEntity.Countries On C.UID Equals I.CompanyCountryUID _

Join OC In DLadoEntity.OC_Locations On OC.UID Equals C.OCLocationUID _

Where I.UID = SC.intUserCompanyUID _

Select OC.ISO3166A2CountryCodes).FirstOrDefault

'Prepare and clean up the VAT number supplied on the form

Dim str As String = txtVatNumber.Text.Trim

Dim vatnumber As String = ""

For Each c As Char In str

If IsNumeric(c) Then

vatnumber = vatnumber & c

End If

'default to UK if we cant find a code

If String.IsNullOrEmpty(Code) Then Code = "GB"

'prepare our address and company name vars for return (we dont use them at the moment)

Dim Add As String = "", Name As String = ""

'encapsulate the webservice all in a try catch (if it fails in our case we dont worry very much)

Try

Dim ViesVATCheck As New eu.europa.ec.checkVatService

ViesVATCheck.checkVat(Code, vatnumber, IsValid, Name, Add)

Catch ex As Exception

'if there is a problem validating the VAT number then we dont really care too much

'we wont be buying anythingfrom them, they purchase from us so let let them through

IsValid = True

End Try

Return IsValid

End Function

Most of the above code is preparation, there are very few ines tha perform the webservice method.
The actual call is made in the try catch

Dim ViesVATCheck As New eu.europa.ec.checkVatService
ViesVATCheck.checkVat(Code, vatnumber, IsValid, Name, Add)

1 2	Dim ViesVATCheck As New eu.europa.ec.checkVatService ViesVATCheck.checkVat(Code, vatnumber, IsValid, Name, Add)

My particular app verifies the value of IsValid in the calling function, how you validate the values is up to you, on asuccessful return the value will be true and the byref Name and Add will contain the registered company name and address.

For your reference there is also another way to reference the web service described here http://softwareobjects.net/technology/other/vies-vat-number-checker/

.NET, Entity Framework 4.0, Linq

LINQ to Entities does not recognize the method ‘System.String ToString()’ method

5th May 2010 andre Leave a comment

If you use the entity framework from microsoft, latest version at the date of this post is framework 4.0
You might run into this little angel when you try to envoke the string value of an object

LINQ to Entities does not recognize the method ‘System.String ToString()’ method

This happens when applying a filter to an integer field and you want to use the

.contians

.contians

method of a string. So my code looked ike this

 query = query.Where(Function(Results) (Results.UID.ToString.Contains(fltrtxtRef.Text)))

1	query = query.Where(Function(Results) (Results.UID.ToString.Contains(fltrtxtRef.Text)))

From the master query

  Dim query = From UE In DLadoEntity.UserEnquiries _
                  Join A In DLadoEntity.Accounts On A.UID Equals UE.ToAccountUID _
                  Where UE.IsFromProfileView = True _
                  Order By UE.Status Descending, UE.TimeStamp Descending _
                  Select UE.UID _
                        , UE.NonRegisteredAddress _
                        , UE.NonRegisteredCompanyName _
                        , UE.NonRegisteredCompanyPosition _
                        , UE.NonRegisteredCountryUID _
                        , UE.NonRegisteredEmailAddress _

Dim query = From UE In DLadoEntity.UserEnquiries _

Join A In DLadoEntity.Accounts On A.UID Equals UE.ToAccountUID _

Where UE.IsFromProfileView = True _

Order By UE.Status Descending, UE.TimeStamp Descending _

Select UE.UID _

, UE.NonRegisteredAddress _

, UE.NonRegisteredCompanyName _

, UE.NonRegisteredCompanyPosition _

, UE.NonRegisteredCountryUID _

, UE.NonRegisteredEmailAddress _

etc…

The only way i Could get round this was to onvert the UID field into a string in the master select query like so

  Dim query = From UE In DLadoEntity.UserEnquiries _
                  Join A In DLadoEntity.Accounts On A.UID Equals UE.ToAccountUID _
                  Where UE.IsFromProfileView = True _
                  Order By UE.Status Descending, UE.TimeStamp Descending _
                  Select [UID] = "" & UE.UID _
                        , UE.NonRegisteredAddress _
                        , UE.NonRegisteredCompanyName _
                        , UE.NonRegisteredCompanyPosition _
                        , UE.NonRegisteredCountryUID _
                        , UE.NonRegisteredEmailAddress _

Dim query = From UE In DLadoEntity.UserEnquiries _

Join A In DLadoEntity.Accounts On A.UID Equals UE.ToAccountUID _

Where UE.IsFromProfileView = True _

Order By UE.Status Descending, UE.TimeStamp Descending _

Select [UID] = "" & UE.UID _

, UE.NonRegisteredAddress _

, UE.NonRegisteredCompanyName _

, UE.NonRegisteredCompanyPosition _

, UE.NonRegisteredCountryUID _

, UE.NonRegisteredEmailAddress _

notice the cure was to force linq to convert the resulting field into a string, allowing the filter to look like this

 query = query.Where(Function(Results) (Results.UID.Contains(fltrtxtRef.Text)))

1	query = query.Where(Function(Results) (Results.UID.Contains(fltrtxtRef.Text)))

Microsoft have a list os supported methods here

Sometimes Interesting, Always Useful, Mostly Technical

Category Archives: Entity Framework 4.0

.NET Entity Layer The member with identity ‘Result’ does not exist in the metadata collection

VAT Information Exchange System (VIES)

LINQ to Entities does not recognize the method ‘System.String ToString()’ method

Information Technology, Life, Interesting Stumbles, Servers, Configuration, Topology, Security, Best Practices, Developing, Fire Fighting, Problem solving, Visual Studio 2005 – 2015 .NET 1.1 – 4.5, jQuery, JSON & much much more