Programming Microsoft Visual Basic .NET/Programming Microsoft Visual Basic .NET (Microsoft Press)(X08-78517)(2002).bin/11 object serialization/xmlserializationdemo/module1.vb

Text File | 2002-03-20 | 17.3 KB | 385 lines

Imports System.IO
Imports System.Xml.Serialization

Module MainModule

    Sub Main()
        ' Run one of the Textxxxx procedures below by uncommenting only one statement

        'TestXmlSerializer()
        'TestXmlSerializer2()
        'TestXmlSerializer3()
        'TestXmlSerializer4()
        'TestDeserializationEvents()
        'TestSerializationOverriding()
        'TestSerializationOverriding2()

        ' These statements are usuful when running inside Visual Studio.NET
        Console.WriteLine("")
        Console.WriteLine(">>> Press Enter to terminate the program <<<")
        Console.ReadLine()

    End Sub

    ' this procedure tests the XmlSerializer

    Sub TestXmlSerializer()
        ' Create an XMLSerializer object for the Customer class.
        Dim ser As New XmlSerializer(GetType(Customer))
        ' Create a Publisher object.
        Dim cust As New Customer(1, "Joe Doe", Nothing, "New York")

        ' Open the destination file.
        Dim fs As New FileStream("c:\customer.xml", FileMode.Create)
        ' Serialize the object to the stream and close it
        ser.Serialize(fs, cust)
        fs.Close()

        ' Reopen the stream.
        Dim fs2 As New FileStream("c:\customer.xml", FileMode.Open)
        ' Deserialize the file into another Customer object, and close the stream.
        Dim cust2 As Customer = CType(ser.Deserialize(fs2), Customer)
        fs2.Close()
        ' check object properties
        Console.WriteLine(cust2.Name & ", " & cust2.City)   ' => Joe Doe, New York
    End Sub

    ' this procedure tests the Publisher2 class, which contains attributes

    Sub TestXmlSerializer2()
        ' Create an XMLSerializer object for the Customer class.
        Dim ser As New XmlSerializer(GetType(Customer2))
        ' Create a Publisher object.
        Dim cust As New Customer2(1, "Joe Doe", Nothing, "New York")

        ' Open the destination file.
        Dim fs As New FileStream("c:\customer.xml", FileMode.Create)
        ' Serialize the object to the stream and close it
        ser.Serialize(fs, cust)
        fs.Close()

        ' Reopen the stream.
        Dim fs2 As New FileStream("c:\customer.xml", FileMode.Open)
        ' Deserialize the file into another Customer object, and close the stream.
        Dim cust2 As Customer2 = CType(ser.Deserialize(fs2), Customer2)
        fs2.Close()
        ' check object properties
        Console.WriteLine(cust2.Name & ", " & cust2.City)   ' => Joe Doe, New York
    End Sub

    ' this procedure tests the serialization of nested objects.

    Sub TestXmlSerializer3()
        ' Create an XMLSerializer object for the Customer class.
        Dim ser As New XmlSerializer(GetType(Customer4))
        ' Create a Publisher object.
        Dim cust As New Customer4(1, "Joe Doe", Nothing, "New York")
        ' add some orders
        cust.Orders(0) = New Order(1, #1/2/2001#, 123.5)
        cust.Orders(1) = New Order(2, #4/8/2001#, 450.8)

        ' Open the destination file.
        Dim fs As New FileStream("c:\customer.xml", FileMode.Create)
        ' Serialize the object to the stream and close it
        ser.Serialize(fs, cust)
        fs.Close()

        ' Reopen the stream.
        Dim fs2 As New FileStream("c:\customer.xml", FileMode.Open)
        ' Deserialize the file into another Customer object, and close the stream.
        Dim cust2 As Customer4 = CType(ser.Deserialize(fs2), Customer4)
        fs2.Close()

        ' check object properties
        Console.WriteLine(cust2.Name & ", " & cust2.City)   ' => Joe Doe, New York
        Console.WriteLine(cust2.Orders(0).Date)             ' => 1/2/2001 12:00:00 AM
    End Sub

    ' this procedure tests serialization of nested objects with namespaces

    Sub TestXmlSerializer4()
        ' Create an XMLSerializer object for the Customer class.
        Dim ser As New XmlSerializer(GetType(Customer4))
        ' Create a Publisher object.
        Dim cust As New Customer4(1, "Joe Doe", Nothing, "New York")
        ' add some orders
        cust.Orders(0) = New Order(1, #1/2/2001#, 123.5)
        cust.Orders(1) = New Order(2, #4/8/2001#, 450.8)

        Dim ns As New XmlSerializerNamespaces()
        ns.Add("Customer4", "http://www.vb2themax.com")
        ns.Add("Order", "http://www.wintellect.com")

        ' Open the destination file.
        Dim fs As New FileStream("c:\customer.xml", FileMode.Create)
        ' Serialize the object to the stream, enforcing the specified namespaces.
        ser.Serialize(fs, cust, ns)
        fs.Close()

        ' Reopen the stream, using the same XmlSerializer.
        Dim fs2 As New FileStream("c:\customer.xml", FileMode.Open)
        ' Deserialize the file into another Customer object, and close the stream.
        Dim cust2 As Customer4 = CType(ser.Deserialize(fs2), Customer4)
        fs2.Close()

        ' check object properties
        Console.WriteLine(cust2.Name & ", " & cust2.City)   ' => Joe Doe, New York
        Console.WriteLine(cust2.Orders(0).Date)             ' => 1/2/2001 12:00:00 AM
    End Sub

    ' this procedure tests deserialization events.

    Sub TestDeserializationEvents()
        ' Create an XMLSerializer object for the Publisher class.
        Dim ser As New XmlSerializer(GetType(Customer))
        ' dynamically create the event handler
        AddHandler ser.UnknownElement, AddressOf Deserialization_UnknownElement

        ' Reopen the stream.

        Dim fs2 As New FileStream("c:\customer2.xml", FileMode.Open)
        ' Deserialize the file into another Customer object, and close the stream.
        Dim cust2 As Customer = CType(ser.Deserialize(fs2), Customer)
        fs2.Close()

        ' check object properties
        Console.WriteLine(cust2.Name & ", " & cust2.City)   ' => Joe Doe, New York
    End Sub

    ' this event is raised when the XMLSerializer founds an unknown XML element

    Sub Deserialization_UnknownElement(ByVal sender As Object, ByVal e As XmlElementEventArgs)
        ' cast the element to a Customer object
        Dim cust As Customer = CType(e.ObjectBeingDeserialized, Customer)
        ' there are two cases: we've found a FirstName or LastName XML element
        If e.Element.Name = "FirstName" Then
            ' if it is a FirstName, prefix the current Name property.
            cust.Name = e.Element.InnerXml
        ElseIf e.Element.Name = "LastName" Then
            ' if it is a Lastname element, append to current Name property.
            cust.Name += " " & e.Element.InnerXml
        End If
    End Sub

    ' this procedure tests XML serialization overriding

    Sub TestSerializationOverriding()
        ' step 1: create an XmlAttributeOverrides object
        Dim xmlAttrOver As New XmlAttributeOverrides()

        ' (A) add the XmlRootAttribute("EmployeeList") attribute

        ' step A2: create the XmlAttributes object.
        Dim xmlAttrs As New XmlAttributes()
        ' step A3: create and initialize the XmlRootAttribute
        Dim attr1 As New XmlRootAttribute("EmployeeList")
        ' step A4: assign it to the correct property of the XmlAttributes object
        xmlAttrs.XmlRoot = attr1
        ' step A5: pass the XmlAttributes object to the Add method of XmlAttributeOverrides
        ' When you add an XmlRootAttribute you specify only 2 arguments:
        ' the 1st argument is the class that contains the overridden member
        ' the 2nd argument is the XmlAttributes object that defines how the member is overridden.
        xmlAttrOver.Add(GetType(AddressBook), xmlAttrs)

        ' (B) add the XmlArray("Employees") and XmlArrayItem("Employee") attributes.

        ' step B2: create a new XmlAttributes object.
        xmlAttrs = New XmlAttributes()

        ' step B3: create and initialize the XmlArrayAttribute object.
        Dim attr2 As New XmlArrayAttribute("Employees")
        ' step B4: assign it to the correct property of the XmlAttributes object
        xmlAttrs.XmlArray = attr2
        ' again step B3/B4, this time for the XmlArrayItemAttribute object.
        ' (Note that you can do both creation and assignment in one step.)
        xmlAttrs.XmlArrayItems.Add(New XmlArrayItemAttribute("Employee"))
        ' step B5: pass the XmlAttributes object to the Add method of XmlAttributeOverrides
        ' the 1st argument is the class that contains the overridden member
        ' the 2nd argument is the member being overridden
        ' the 3rd argument is the XmlAttributes object that defines how the member is overridden.
        xmlAttrOver.Add(GetType(AddressBook), "Contacts", xmlAttrs)

        ' (C) add the XmlAttributeAttribute("ID") attribute

        ' step C2: create a new XmlAttributes object.
        xmlAttrs = New XmlAttributes()
        ' step C3/C4: create and initialize the XmlArrayAttribute object
        ' and assign it to the
        xmlAttrs.XmlAttribute = New XmlAttributeAttribute("id")
        ' step C5: pass the XmlAttributes object to the Add method of XmlAttributeOverrides
        ' (arguments are as in step B5)
        xmlAttrOver.Add(GetType(Person), "ID", xmlAttrs)

        ' (D) add the XmlElement("Phone") attribute

        ' step D2: create a new XmlAttributes object.
        xmlAttrs = New XmlAttributes()
        ' step D3/D4: create and initialize the XmlElementAttribute object
        ' and add it to the XmlAttributes's XmlElements collection
        xmlAttrs.XmlElements.Add(New XmlElementAttribute("Phone"))
        ' step D5: pass the XmlAttributes object to the Add method of XmlAttributeOverrides
        ' (arguments are as in step B5)
        xmlAttrOver.Add(GetType(Person), "PhoneNumber", xmlAttrs)

        ' Step 6: create the XmlSerializer that eses the XmlAttributeOverrides.
        Dim ser As New XmlSerializer(GetType(AddressBook), xmlAttrOver)

        '----  create an object tree.
        Dim addrBook As New AddressBook()
        addrBook.Name = "My Employee Book"     ' Name of this address book
        ReDim addrBook.Contacts(1)          ' We expect two Persons.

        Dim p0 As New Person()              ' First Person
        p0.ID = 1
        p0.Name = "Joe Doe"
        p0.PhoneNumber = "234-456-6789"
        Dim p1 As New Person()              ' Second Person
        p1.ID = 2
        p1.Name = "Robert Smith"
        p1.PhoneNumber = "234-987-6543"
        addrBook.Contacts(0) = p0           ' Store into the Contacts array.
        addrBook.Contacts(1) = p1

        ' Open the destination file.
        Dim fs As New FileStream("c:\addrbook.xml", FileMode.Create)
        ' Serialize the object to the stream and close it
        ser.Serialize(fs, addrBook)
        fs.Close()

        ' Reopen the stream.
        Dim fs2 As New FileStream("c:\addrbook.xml", FileMode.Open)
        ' Deserialize the file into another Customer object, and close the stream.
        Dim addrBook2 As AddressBook = CType(ser.Deserialize(fs2), AddressBook)
        fs2.Close()

        ' check object properties
        Dim p As Person = CType(addrBook.Contacts(0), Person)
        Console.WriteLine(p.ID.ToString & " - " & p.Name & " " & p.PhoneNumber)
        p = CType(addrBook.Contacts(1), Person)
        Console.WriteLine(p.ID.ToString & " - " & p.Name & " " & p.PhoneNumber)

    End Sub

    ' this procedure tests xmlserializer overriding with inherited classes

    Sub TestSerializationOverriding2()
        ' step 1: create an XmlAttributeOverrides object
        Dim xmlAttrOver As New XmlAttributeOverrides()

        ' (A) add the XmlRootAttribute("EmployeeList") attribute

        ' step A2: create the XmlAttributes object.
        Dim xmlAttrs As New XmlAttributes()
        ' step A3: create and initialize the XmlRootAttribute
        Dim attr1 As New XmlRootAttribute("EmployeeList")
        ' step A4: assign it to the correct property of the XmlAttributes object
        xmlAttrs.XmlRoot = attr1
        ' step A5: pass the XmlAttributes object to the Add method of XmlAttributeOverrides
        ' When you add an XmlRootAttribute you specify only 2 arguments:
        ' the 1st argument is the class that contains the overridden member
        ' the 2nd argument is the XmlAttributes object that defines how the member is overridden.
        xmlAttrOver.Add(GetType(AddressBook), xmlAttrs)

        ' (B) add the XmlArray("Employees") and XmlArrayItem("Employee") attributes.

        ' step B2: create a new XmlAttributes object.
        xmlAttrs = New XmlAttributes()

        ' step B3/B4: create and initialize the XmlArrayAttribute object.
        '  and assign it to the correct property of the XmlAttributes object
        xmlAttrs.XmlArray = New XmlArrayAttribute("Employees")
        ' again step B3/B4, this time for the two XmlArrayItemAttribute objects.
        xmlAttrs.XmlArrayItems.Add(New XmlArrayItemAttribute("Employee", GetType(Employee)))
        xmlAttrs.XmlArrayItems.Add(New XmlArrayItemAttribute("CandidateEmployee", GetType(CandidateEmployee)))

        ' step B5: pass the XmlAttributes object to the Add method of XmlAttributeOverrides
        ' the 1st argument is the class that contains the overridden member
        ' the 2nd argument is the member being overridden
        ' the 3rd argument is the XmlAttributes object that defines how the member is overridden.
        xmlAttrOver.Add(GetType(AddressBook), "Contacts", xmlAttrs)

        ' (C) add the XmlAttributeAttribute("ID") attribute

        ' step C2: create a new XmlAttributes object.
        xmlAttrs = New XmlAttributes()
        ' step C3/C4: create and initialize the XmlAttribute object
        ' and assign it to the correct property of XmlAttributes object
        xmlAttrs.XmlAttribute = New XmlAttributeAttribute("id")
        ' step C5: pass the XmlAttributes object to the Add method of XmlAttributeOverrides
        ' (arguments are as in step B5)
        xmlAttrOver.Add(GetType(Person), "ID", xmlAttrs)

        ' (D) add the XmlElement("Phone") attribute

        ' step D2: create a new XmlAttributes object.
        xmlAttrs = New XmlAttributes()
        ' step D3/D4: create and initialize the XmlElementAttribute object
        ' and add it to the XmlAttributes's XmlElements collection
        xmlAttrs.XmlElements.Add(New XmlElementAttribute("Phone"))
        ' step D5: pass the XmlAttributes object to the Add method of XmlAttributeOverrides
        ' (arguments are as in step B5)
        xmlAttrOver.Add(GetType(Person), "PhoneNumber", xmlAttrs)

        ' (E) add the XmlAttribute() attribute to the SSN element in Employee class

        ' step E2: create a new XmlAttributes object.
        xmlAttrs = New XmlAttributes()
        ' step E3/E4: create and initialize the XmlAttribute object
        ' and assign it to the correct property of XmlAttributes object
        xmlAttrs.XmlAttribute = New XmlAttributeAttribute("SSN")
        ' step E5: pass the XmlAttributes object to the Add method of XmlAttributeOverrides
        xmlAttrOver.Add(GetType(Employee), "SSN", xmlAttrs)

        ' (F) add the XmlIgnore() attribute to the HireDate element in Employee class

        ' step F2: create a new XmlAttributes object.
        xmlAttrs = New XmlAttributes()
        ' step F3/F4: note that you don't actually create an XmlIgnoreAttribute object;
        ' as for all those attribute whose presence is enough to affect the serialization behavior,
        ' in this case you just set the corresponding XmlIgnore property to True.
        xmlAttrs.XmlIgnore = True
        ' step F5: pass the XmlAttributes object to the Add method of XmlAttributeOverrides
        xmlAttrOver.Add(GetType(Employee), "HireDate", xmlAttrs)

        ' Step 6: create the XmlSerializer that eses the XmlAttributeOverrides.
        Dim ser As New XmlSerializer(GetType(AddressBook), xmlAttrOver)

        '----  create an object tree.
        Dim addrBook As New AddressBook()
        addrBook.Name = "My Address Book"     ' Name of this address book
        ReDim addrBook.Contacts(1)          ' We expect two Employee.

        Dim e0 As New Employee()                    ' First, an Employee
        e0.Name = "Joe Doe"
        e0.SSN = "111-222-3333"
        e0.PhoneNumber = "234-456-6789"
        Dim e1 As New CandidateEmployee()            ' Second, a CandidateEmployee
        e1.ID = 2
        e1.Name = "Robert Smith"
        e1.PhoneNumber = "234-987-6543"
        e1.InterviewDate = #2/8/2001#
        addrBook.Contacts(0) = e0           ' Store into the Contacts array.
        addrBook.Contacts(1) = e1

        ' Open the destination file.
        Dim fs As New FileStream("c:\addrbook.xml", FileMode.Create)
        ' Serialize the object to the stream and close it
        ser.Serialize(fs, addrBook)
        fs.Close()

        ' Reopen the stream.
        Dim fs2 As New FileStream("c:\addrbook.xml", FileMode.Open)
        ' Deserialize the file into another Customer object, and close the stream.
        Dim addrBook2 As AddressBook = CType(ser.Deserialize(fs2), AddressBook)
        fs2.Close()

        ' check object properties
        Dim e As Employee = CType(addrBook.Contacts(0), Employee)
        Console.WriteLine(e.Name & " " & e.PhoneNumber & " " & e.SSN)
        Dim ce As CandidateEmployee = CType(addrBook.Contacts(1), CandidateEmployee)
        Console.WriteLine(ce.Name & " " & ce.PhoneNumber & " " & ce.InterviewDate)

    End Sub

End Module