Serialization issue

Question

I get the following error after
adding the IsReference = true property on a datacontract attribute

'CCWin.Shared.CCVTypes.ContractItemType.LineNumber' has the IsRequired setting of 'True. However, 'CCWin.Shared.CCVTypes.ContractItemType' has the IsReference setting of 'True', because either it is set explicitly, or it is derived from a base class. Set IsRequired on 'CCWin.Shared.CCVTypes.ContractItemType.LineNumber' to false, or disable IsReference on 'CCWin.Shared.CCVTypes.ContractItemType'.

does any one know what cuases this or how to solve it?

Answer 1

when you make your datacontract referable using [DC(IsReference=true)] )] the framework is not going to allow the use of [DM(IsRequired=true)] on members of that DC.
The runtime exception which you are receiving is by-design, since this prevents the serialization stack to artificially emit dummy values for those members for schema validation purposes.

It should work if you remove the IsRequired property from your datamember

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Amit Sharma

Answer 2

Does that mean there is an error with the sample shown on the msdn website http://msdn.microsoft.com/en-us/library/system.runtime.serialization.datacontractattribute.isreference(VS.95).aspx

Below is the sample i am talking about. Is this just a mistake with the documentation or is there a way to have isreference = true and isrequired=true
    ' Define the data contract.
    <DataContract(Name := "Customer", Namespace := "http://www.contoso.com", IsReference := True)> _
    Public Class User
        Private privateName As String
        <DataMember(Name := "Last", EmitDefaultValue := True, IsRequired := True, Order := 2)> _
        Public Property Name() As String
            Get
                Return privateName
            End Get
            Set(ByVal value As String)
                privateName = value
            End Set
        End Property

        Private privateAge As Integer
        <DataMember(Order := 1)> _
        Public Property Age() As Integer
            Get
                Return privateAge
            End Get
            Set(ByVal value As Integer)
                privateAge = value
            End Set
        End Property

        Public Sub New()
        End Sub

        Public Sub New(ByVal newName As String, ByVal newAge As Integer)
            Name = newName
            Age = newAge
        End Sub
    End Class

Answer 3

That is correct.  Unfortunately, the doc has the incorrect example.  I have notified the appropriate group to get this example fixed.  Thanks

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Amit Sharma