异常信息:
“System.Runtime.Serialization.SerializationException”类型的未经处理的异常在 System.Runtime.Serialization.dll 中发生
其他信息: 不应为数据协定名称为“Teacher:http://schemas.datacontract.org/2004/07/ConsoleApplication3”的类型“ConsoleApplication3.Teacher”。请考虑使用 DataContractResolver，或将任何未知类型以静态方式添加到已知类型的列表。例如，可以使用 KnownTypeAttribute 特性，或者将未知类型添加到传递给 DataContractSerializer 的已知类型列表。
想要序列化的对象：
1 public class Student : People
2 {
3 public Int32 Age { get; set; }
4 }
1 public abstract class People
2 {
3 public string Name { get; set; }
4 public string Address { get; set; }
5 }
序列化的方法：
1 public static string WriteJson<T>(T t)
2 {
3 using (MemoryStream ms = new MemoryStream())
4 {
5 DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));
6 serializer.WriteObject(ms, t);
7 return Encoding.UTF8.GetString(ms.ToArray());
8 }
9 }
方法调用:
1 People p = new Student()
2 {
3 Name = "小明",
4 Address = "章丘路110号",
5 Age = 14
6 };
7
8 string jsonString = WriteJson<People>(p);
9 Console.WriteLine(jsonString);
然后就有了上面的异常
根据异常可以知道，虽然Student继承了People类，但是序列化的时候是People类型，也就是说序列化的时候并不知道 想要序列化的对象（Student类型），故产生了异常；根据异常提示，有两种解决方案：考虑使用 DataContractResolver，或将任何未知类型以静态方式添加到已知类型的列表。
经过了MSDN一番查询后，得到了两种可以序列化继承关系的对象的方法，
方式一，继承DataContractResolver类来实现：
1 public abstract class Animal
2 {
3 public string Name { get; set; }
4 }
5
6 public class Bird : Animal
7 {
8 public string Color { get; set; }
9 public Feather BDeather { get; set; }
10 }
11
12 public class Feather
13 {
14 public string Color { get; set; }
15 }
1 public static string WriteJson<T>(T t)
2 {
3 using (MemoryStream ms = new MemoryStream())
4 {
5 Assembly assembly = Assembly.Load(new AssemblyName("ConsoleApplication3"));
6 DataContractSerializer serializer = new DataContractSerializer(typeof(T), null, Int32.MaxValue, false, true, null, new MyDataContractResolver(assembly));
7 serializer.WriteObject(ms, t);
8 return Encoding.UTF8.GetString(ms.ToArray());
9 }
10 }
1 Animal animal = new Bird()
2 {
3 Name = "鸭子",
4 Color = "白色",
5 BDeather = new Feather() { Color="纯白色"}
6 };
7 string jsonString = WriteJson<Animal>(animal);
8 Console.WriteLine(jsonString);
1 public class MyDataContractResolver : DataContractResolver
2 {
3
4 private XmlDictionary dictionary = new XmlDictionary();
5 Assembly assembly;
6 public MyDataContractResolver(Assembly assembly)
7 {
8 this.assembly = assembly;
9 }
10 public override Type ResolveName(string typeName, string typeNamespace, Type declaredType, DataContractResolver knownTypeResolver)
11 {
12 Type type = knownTypeResolver.ResolveName(typeName, typeNamespace, declaredType, knownTypeResolver);
13 if (type == null)
14 {
15 type = Type.GetType(typeName + ", " + typeNamespace);
16 }
17 return type;
18 }
19
20 public override bool TryResolveType(Type type, Type declaredType, DataContractResolver knownTypeResolver, out XmlDictionaryString typeName, out XmlDictionaryString typeNamespace)
21 {
22 knownTypeResolver.TryResolveType(type, declaredType, knownTypeResolver, out typeName, out typeNamespace);
23 if (typeName == null || typeNamespace == null)
24 {
25 XmlDictionary dictionary = new XmlDictionary();
26 typeName = dictionary.Add(type.FullName);
27 typeNamespace = dictionary.Add(type.Assembly.FullName);
28 }
29 return true;
30 }
31 }
输出结果：
方式二，通过KnownTypeAttribute添加识别类型：
1 [KnownType(typeof(Student))]
2 [KnownType(typeof(Teacher))]
3 [KnownType(typeof(Pupil))]
4 [DataContract]
5 public abstract class People
6 {
7 [DataMember]
8 public string Name { get; set; }
9 [DataMember]
10 public string Address { get; set; }
11 }
1 public class Student : People
2 {
3
4 public Int32 Age { get; set; }
5 }
6
7 public class Pupil : Student
8 {
9
10 }
1 public class Teacher : People
2 {
3 public Course T_course { get; set; }
4 }
5
6 public class Course
7 {
8 public string Name { get; set; }
9 public int Times { get; set; }
10 }
输出结果：
关于更详细的描述，请参考以下MSDN的内容：
http://msdn.microsoft.com/zh-cn/library/system.runtime.serialization.knowntypeattribute.aspx
http://msdn.microsoft.com/zh-cn/library/system.runtime.serialization.datacontractserializer%28v=vs.110%29.aspx