我正在尝试序列化和反序列化 Node 对象树。我的抽象“节点”类以及从它派生的其他抽象类和具体类都在我的“Informa”项目中定义。此外,我在 Informa 中创建了一个用于序列化/反序列化的静态类。
首先,我将我的树解构为 Dictionary(guid,Node) 类型的平面列表,其中 guid 是节点的唯一 ID。
我能够毫无问题地序列化我的所有节点。但是当我尝试反序列化时,出现以下异常。
Error in line 1 position 227. Element 'http://schemas.microsoft.com/2003/10/Serialization/Arrays:Value' contains data of the 'Informa:Building' data contract. The deserializer has no knowlege of any type that maps to this contract. Add the type corresponding to 'Building' to the list of known types - for example, by usying the KnownTypeAttribute or by adding it to the list of known types passed to DataContract Serializer.
所有派生自 Node 的类,包括 Building,都应用了 [KnownType(typeof(type t))] 属性。
我的序列化和反序列化方法如下:
public static void SerializeProject(Project project, string filePath)
{
try
{
Dictionary<Guid, Node> nodeDic = DeconstructProject(project);
Stream stream = new FileStream(filePath, FileMode.Create, FileAccess.Write, FileShare.None);
//serialize
DataContractSerializer ser = new DataContractSerializer(typeof(Dictionary<Guid, Node>),"InformaProject","Informa");
ser.WriteObject(stream,nodeDic);
// Cleanup
stream.Close();
}
catch (Exception e)
{
MessageBox.Show("There was a problem serializing " + Path.GetFileName(filePath) + ". \n\nException:" + e.Message, "Doh!", MessageBoxButtons.OK, MessageBoxIcon.Error);
throw e;
}
}
public static Project DeSerializeProject(string filePath)
{
try
{
Project proj;
// Read the file back into a stream
Stream stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
DataContractSerializer ser = new DataContractSerializer(typeof(Dictionary<Guid, Node>), "InformaProject", "Informa");
Dictionary<Guid, Node> nodeDic = (Dictionary<Guid, Node>)ser.ReadObject(stream);
proj = ReconstructProject(nodeDic);
// Cleanup
stream.Close();
return proj;
}
catch (Exception e)
{
MessageBox.Show("There was a problem deserializing " + Path.GetFileName(filePath) + ". \n\nException:" + e.Message, "Doh!", MessageBoxButtons.OK, MessageBoxIcon.Error);
return null;
}
}
最佳答案
All classes that derive from Node, including Building, have the [KnownType(typeof(type t))] attribute applied to them.
KnownType
通常应用于 base 类型 - 即
[DataContract, KnownType(typeof(Building)), ...]
abstract class Node { ... }
(注意 - 您还可以在 DataContractSerializer
构造函数中指定已知类型,不需要属性)
编辑您的回复
如果框架类不知道所有派生类型,那么您需要在创建序列化程序时指定已知类型:
[DataContract] abstract class SomeBase { }
[DataContract] class Foo : SomeBase { }
[DataContract] class Bar : SomeBase { }
...
// here the knownTypes argument is important
new DataContractSerializer(typeof(SomeBase),
new Type[] { typeof(Foo), typeof(Bar) });
这可以与(例如)preserveObjectReferences
等结合使用,方法是替换上一个示例中的 null
。
结束编辑
但是,如果没有可重现的东西(即 Node
和 Building
),将很难提供太多帮助。
另一个奇怪的事情;树结构非常适合DataContractSerializer
之类的东西——通常不需要先将它们展平,因为树可以简单地用 xml 表示。你真的需要把它弄平吗?
例子:
using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.Serialization;
using System.Xml;
[DataContract, KnownType(typeof(Building))]
abstract class Node {
[DataMember]
public int Foo {get;set;}
}
[DataContract]
class Building : Node {
[DataMember]
public string Bar {get;set;}
}
static class Program
{
static void Main()
{
Dictionary<Guid, Node> data = new Dictionary<Guid, Node>();
Type type = typeof(Dictionary<Guid, Node>);
data.Add(Guid.NewGuid(), new Building { Foo = 1, Bar = "a" });
StringWriter sw = new StringWriter();
using (XmlWriter xw = XmlWriter.Create(sw))
{
DataContractSerializer dcs = new DataContractSerializer(type);
dcs.WriteObject(xw, data);
}
string xml = sw.ToString();
StringReader sr = new StringReader(xml);
using (XmlReader xr = XmlReader.Create(sr))
{
DataContractSerializer dcs = new DataContractSerializer(type);
Dictionary<Guid, Node> clone = (Dictionary<Guid, Node>)
dcs.ReadObject(xr);
foreach (KeyValuePair<Guid, Node> pair in clone)
{
Console.WriteLine(pair.Key + ": " + pair.Value.Foo + "/" +
((Building)pair.Value).Bar);
}
}
}
}
关于c# - 反序列化器不知道映射到该契约的任何类型,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/736900/