␡
- XmlSerializer
- Demonstrating Serialization
- Serialization Attributes
Like this article? We recommend
Like this article? We recommend
Like this article? We recommend
Like this article? We recommend
Demonstrating Serialization
The first process that I will illustrate involves exporting an instance of the Domain class to an XML document using the Serialize method of XmlSerializer. Serialize has a variety of method overloads to handle different I/O objects: Stream, TextWriter, and XmlWriter. The easiest way to deal with file I/O is to use the StreamWriter; it provides a TextWriter-compatible interface on top of the file system.
Before we can serialize, we have to create security object hierarchy that provides us with sufficient content for educational value by executing our CreateDomain method. After object creation, we pass the class type, a reference to our top-level Domain object, and the filename as parameters to the ExportDomain method in Listing 2. It relays the parameters to the Serialize method of the XmlSerializer creating the XML document in Listing 3.
Listing 2: Code for Export and Import of Domain Class via XML
using System;
using System.IO;
using System.Xml.Serialization;
namespace Serialize
{
class SerializeMain
{
static void Main(string[] args)
{
// call routine that constructs our
// tree of domain objects
Domain expdomain = CreateDomain();
ExportDomain(typeof(Domain),
expdomain,"C:\\Domain.xml");
// call routine that retrieves a
// tree of domain objects from disk
// and returns us an object reference
Domain impdomain = ImportDomain(typeof(Domain),
"C:\\Domain.xml");
DisplayDomain(impdomain);
}
static string GetNewGUIDString()
{
// create a GUID
return Guid.NewGuid().ToString();
}
static void ExportDomain(System.Type type, Object o,
string filename)
{
// create the serializer
XmlSerializer serializer = new XmlSerializer(type);
// set up the serialize to write its output to
// to a streamwriter that is pointing at a file
StreamWriter writer = new StreamWriter(filename);
// serialize the object to disk
serializer.Serialize(writer,o);
// close the writer to release the file resource
writer.Close();
}
static Domain ImportDomain(System.Type type,
string filename)
{
// create the serializer
XmlSerializer serializer = new XmlSerializer(type);
// create a streamreader that reads from the
// input file
StreamReader reader = new StreamReader(filename);
// instruct serializer to deserialize an object
// reference form the file and cast it to the
// appropriate reference type
Domain newdomain = (Domain)
serializer.Deserialize(reader);
// close the reader to release the file resource
reader.Close();
// return our newly minted object
return newdomain;
}
static Domain CreateDomain()
{
Domain domain = new Domain();
domain.ID = GetNewGUIDString();
domain.Name = "InformIT";
User[] users = new User[3];
users[0] = new User();
users[0].ID = GetNewGUIDString();
users[0].Name = "Dale Michalk";
users[0].Password = "password";
users[1] = new User();
users[1].ID = GetNewGUIDString();
users[1].Name = "Joe User";
users[1].Password = "password";
users[2] = new User();
users[2].ID = GetNewGUIDString();
users[2].Name = "Guest User";
users[2].Password = "password";
Group[] groups = new Group[3];
groups[0] = new Group();
groups[0].ID = GetNewGUIDString();
groups[0].Name = "Admins";
groups[0].Users = new UserRef[1];
groups[0].Users[0] = new UserRef();
groups[0].Users[0].ID = users[0].ID;
groups[1] = new Group();
groups[1].ID = GetNewGUIDString();
groups[1].Name = "Users";
groups[1].Users = new UserRef[2];
groups[1].Users[0] = new UserRef();
groups[1].Users[0].ID = users[0].ID;
groups[1].Users[1] = new UserRef();
groups[1].Users[1].ID = users[1].ID;
groups[2] = new Group();
groups[2].ID = GetNewGUIDString();
groups[2].Name = "Guests";
groups[2].Users = new UserRef[1];
groups[2].Users[0] = new UserRef();
groups[2].Users[0].ID = users[2].ID;
domain.Users = users;
domain.Groups = groups;
return domain;
}
static void DisplayDomain(Domain domain)
{
// Domain
Console.WriteLine("Domain: {0}",domain.Name);
Console.WriteLine("\tID:{0}",domain.ID);
// Users
Console.WriteLine("");
Console.WriteLine("Users");
foreach (User user in domain.Users)
{
Console.WriteLine("\tName:{0}",user.Name);
Console.WriteLine("\t\tID:{0}",user.ID);
Console.WriteLine("\t\tPassword:{0}",
user.Password);
}
// Groups
Console.WriteLine("");
Console.WriteLine("Groups");
foreach (Group group in domain.Groups)
{
Console.WriteLine("\tName:{0}",group.Name);
Console.WriteLine("\t\tID:{0}",group.ID);
Console.WriteLine("\t\tUsers:");
foreach (UserRef userref in group.Users)
{
Console.WriteLine("\t\t\t{0}",
,userref.ID);
}
Console.WriteLine("");
}
}
}
}
Listing 3: XML Document Result from ExportDomain
<?xml version="1.0" encoding="utf-8"?>
<Domain xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<ID>2ca519b2-a558-4b7b-b243-408588ba629a</ID>
<Name>InformIT</Name>
<Users>
<User>
<ID>03ae3f5a-e46d-4fcf-bc33-fdaeee22dcc0</ID>
<Name>Dale Michalk</Name>
<Password>password</Password>
</User>
<User>
<ID>2831d8af-55aa-4f7c-b212-c87e7fc1eea2</ID>
<Name>Joe User</Name>
<Password>password</Password>
</User>
<User>
<ID>0c5864a6-b37d-4424-b57e-3a2b86f0e183</ID>
<Name>Guest User</Name>
<Password>password</Password>
</User>
</Users>
<Groups>
<Group>
<ID>91d08bbd-8838-4413-8dcf-c63fb02848e0</ID>
<Name>Admins</Name>
<Users>
<UserRef>
<ID>03ae3f5a-e46d-4fcf-bc33-fdaeee22dcc0</ID>
</UserRef>
</Users>
</Group>
<Group>
<ID>b36c1cfb-7de1-4ac9-8f21-9de7ab3cf76d</ID>
<Name>Users</Name>
<Users>
<UserRef>
<ID>03ae3f5a-e46d-4fcf-bc33-fdaeee22dcc0</ID>
</UserRef>
<UserRef>
<ID>2831d8af-55aa-4f7c-b212-c87e7fc1eea2</ID>
</UserRef>
</Users>
</Group>
<Group>
<ID>db3efa55-f228-435c-9833-e62f7dca4078</ID>
<Name>Guests</Name>
<Users>
<UserRef>
<ID>0c5864a6-b37d-4424-b57e-3a2b86f0e183</ID>
</UserRef>
</Users>
</Group>
</Groups>
</Domain>
To rehydrate an object from an existing XML store, we use the DeSerialize method of the XmlSerializer. It is overloaded to take a variety of input sources: Stream, TextReader, or XmlReader. In the ImportDomain method, the example uses the StreamReader to pull the XML document from disk and provide a TextReader-compatible source. To verify the process, the code calls on the DisplayDomain method to spit out information to the console. The data in the document and object instance report in Listing 4 should be the same if the process is working properly.
Listing 4: DisplayDomain Console Output
Domain: InformIT
ID:830651e9-b7e7-4c81-9a99-34cc7f583264
Users
Name:Dale Michalk
ID:99a13f10-9317-41d2-9370-62581371a49f
Password:password
Name:Joe User
ID:3d3cc57d-5a19-491a-be4e-e2bee5e4bdd7
Password:password
Name:Guest User
ID:2d113809-d77f-427a-b5c9-17641b2a8467
Password:password
Groups
Name:Admins
ID:85317acc-8991-47e7-af0b-3d97bf45aab4
Users:
99a13f10-9317-41d2-9370-62581371a49f
Name:Users
ID:2bb3ccc7-d386-41cf-b480-c8c1e9860aa2
Users:
99a13f10-9317-41d2-9370-62581371a49f
3d3cc57d-5a19-491a-be4e-e2bee5e4bdd7
Name:Guests
ID:d119d679-f4fc-4ba2-b3d2-52f2146965c9
Users:
2d113809-d77f-427a-b5c9-17641b2a8467