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How to: Serialize and Deserialize Objects To and From Binary Stream

Entity types generated by the Entity Data Model (EDM) generator tool (EdmGen.exe) and the Entity Data Model Wizard support binary serialization. When you serialize an object to a binary stream, all related objects currently loaded into the object context will also be serialized. For more information, see Serializing Objects.

The example in this topic is based on the Adventure Works Sales Model. To run the code in this example, you must have already added the AdventureWorks Sales Model to your project and configured your project to use the Entity Framework. To do this, complete the procedures in How to: Manually Configure an Entity Framework Project and How to: Manually Define the Model and Mapping Files. You must also add using statements (Imports in Visual Basic) for the following namespaces:

Example

In this example, a SerializeToBinaryStream method queries for the Contact object for the specified last name value, and returns a binary MemoryStream. The MemoryStream contains an object graph of the Contact object and its related SalesOrderHeader and SalesOrderDetail objects.

Public Shared Sub ReadFromBinaryStream()
    Dim formatter As New BinaryFormatter()
    Using context As New AdventureWorksEntities()
        Try
            ' Get the object graph for the selected customer 
            ' as a binary stream. 
            Dim stream As MemoryStream = SerializeToBinaryStream("Adams")

            ' Read from the begining of the stream. 
            stream.Seek(0, SeekOrigin.Begin)

            ' Deserialize the customer graph from the binary stream 
            ' and attach to an ObjectContext. 
            Dim contact As Contact = DirectCast(formatter.Deserialize(stream), Contact)
            context.Attach(contact)

            ' Display information for each item 
            ' in the orders that belong to the first contact. 
            For Each order As SalesOrderHeader In contact.SalesOrderHeaders
                Console.WriteLine(String.Format("PO Number: {0}", order.PurchaseOrderNumber))
                Console.WriteLine(String.Format("Order Date: {0}", order.OrderDate.ToString()))
                Console.WriteLine("Order items:")
                For Each item As SalesOrderDetail In order.SalesOrderDetails
                    Console.WriteLine(String.Format("Product: {0}, Quantity: {1}", _
                                                      item.ProductID.ToString(), item.OrderQty.ToString()))
                Next
            Next
        Catch ex As SerializationException
            Console.WriteLine("The object graph could not be deserialized from " & _
                              "the binary stream because of the following error:")
            Console.WriteLine(ex.ToString())
        End Try
    End Using
End Sub
Private Shared Function SerializeToBinaryStream(ByVal lastName As String) As MemoryStream
    Dim formatter As New BinaryFormatter()
    Dim stream As New MemoryStream()

    Using context As New AdventureWorksEntities()
        ' Specify a timeout for queries in this context, in seconds. 
        context.CommandTimeout = 120

        ' Define a customer contact. 
        Dim customer As Contact

        ' Create a Contact query with a path that returns 
        ' orders and items for a contact. 
        Dim query As ObjectQuery(Of Contact) = context.Contacts.Include("SalesOrderHeaders.SalesOrderDetails")

        Try
            ' Return the first contact with the specified last name 
            ' along with its related orders and items. 
            customer = query.Where("it.LastName = @lastname", New ObjectParameter("lastname", lastName)).First()

            ' Serialize the customer object graph. 
            formatter.Serialize(stream, customer)
        Catch ex As EntitySqlException
            Throw New InvalidOperationException("The object query failed", ex)
        Catch ex As EntityCommandExecutionException
            Throw New InvalidOperationException("The object query failed", ex)
        Catch ex As SerializationException
            Throw New InvalidOperationException("The object graph could not be serialized", ex)
        End Try

        ' Return the streamed object graph. 
        Return stream
    End Using
End Function

See Also

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