我有以下方法来保存一个对象到一个文件:
// Save an object out to the disk
public static void SerializeObject<T>(this T toSerialize, String filename)
{
XmlSerializer xmlSerializer = new XmlSerializer(toSerialize.GetType());
TextWriter textWriter = new StreamWriter(filename);
xmlSerializer.Serialize(textWriter, toSerialize);
textWriter.Close();
}
我承认这不是我写的(我只是把它转换成一个接受类型参数的扩展方法)。
现在我需要它把xml作为字符串返回给我(而不是保存到文件中)。我正在调查这件事，但我还没有弄清楚。
我想对于熟悉这些物体的人来说，这可能很简单。如果没有，我最终会弄清楚的。
当前回答
使用StringWriter而不是StreamWriter:
public static string SerializeObject<T>(this T toSerialize)
{
XmlSerializer xmlSerializer = new XmlSerializer(toSerialize.GetType());
using(StringWriter textWriter = new StringWriter())
{
xmlSerializer.Serialize(textWriter, toSerialize);
return textWriter.ToString();
}
}
Note, it is important to use toSerialize.GetType() instead of typeof(T) in XmlSerializer constructor: if you use the first one the code covers all possible subclasses of T (which are valid for the method), while using the latter one will fail when passing a type derived from T. Here is a link with some example code that motivate this statement, with XmlSerializer throwing an Exception when typeof(T) is used, because you pass an instance of a derived type to a method that calls SerializeObject that is defined in the derived type's base class: http://ideone.com/1Z5J1.
此外，Ideone使用Mono来执行代码;使用Microsoft . net运行时得到的实际异常与Ideone上显示的异常有不同的消息，但它同样失败。
其他回答
我觉得我需要分享这个被操纵的代码到公认的答案-因为我没有声誉，我无法评论。
using System;
using System.Xml.Serialization;
using System.IO;
namespace ObjectSerialization
{
public static class ObjectSerialization
{
// THIS: (C): https://stackoverflow.com/questions/2434534/serialize-an-object-to-string
/// <summary>
/// A helper to serialize an object to a string containing XML data of the object.
/// </summary>
/// <typeparam name="T">An object to serialize to a XML data string.</typeparam>
/// <param name="toSerialize">A helper method for any type of object to be serialized to a XML data string.</param>
/// <returns>A string containing XML data of the object.</returns>
public static string SerializeObject<T>(this T toSerialize)
{
// create an instance of a XmlSerializer class with the typeof(T)..
XmlSerializer xmlSerializer = new XmlSerializer(toSerialize.GetType());
// using is necessary with classes which implement the IDisposable interface..
using (StringWriter stringWriter = new StringWriter())
{
// serialize a class to a StringWriter class instance..
xmlSerializer.Serialize(stringWriter, toSerialize); // a base class of the StringWriter instance is TextWriter..
return stringWriter.ToString(); // return the value..
}
}
// THIS: (C): VPKSoft, 2018, https://www.vpksoft.net
/// <summary>
/// Deserializes an object which is saved to an XML data string. If the object has no instance a new object will be constructed if possible.
/// <note type="note">An exception will occur if a null reference is called an no valid constructor of the class is available.</note>
/// </summary>
/// <typeparam name="T">An object to deserialize from a XML data string.</typeparam>
/// <param name="toDeserialize">An object of which XML data to deserialize. If the object is null a a default constructor is called.</param>
/// <param name="xmlData">A string containing a serialized XML data do deserialize.</param>
/// <returns>An object which is deserialized from the XML data string.</returns>
public static T DeserializeObject<T>(this T toDeserialize, string xmlData)
{
// if a null instance of an object called this try to create a "default" instance for it with typeof(T),
// this will throw an exception no useful constructor is found..
object voidInstance = toDeserialize == null ? Activator.CreateInstance(typeof(T)) : toDeserialize;
// create an instance of a XmlSerializer class with the typeof(T)..
XmlSerializer xmlSerializer = new XmlSerializer(voidInstance.GetType());
// construct a StringReader class instance of the given xmlData parameter to be deserialized by the XmlSerializer class instance..
using (StringReader stringReader = new StringReader(xmlData))
{
// return the "new" object deserialized via the XmlSerializer class instance..
return (T)xmlSerializer.Deserialize(stringReader);
}
}
// THIS: (C): VPKSoft, 2018, https://www.vpksoft.net
/// <summary>
/// Deserializes an object which is saved to an XML data string.
/// </summary>
/// <param name="toDeserialize">A type of an object of which XML data to deserialize.</param>
/// <param name="xmlData">A string containing a serialized XML data do deserialize.</param>
/// <returns>An object which is deserialized from the XML data string.</returns>
public static object DeserializeObject(Type toDeserialize, string xmlData)
{
// create an instance of a XmlSerializer class with the given type toDeserialize..
XmlSerializer xmlSerializer = new XmlSerializer(toDeserialize);
// construct a StringReader class instance of the given xmlData parameter to be deserialized by the XmlSerializer class instance..
using (StringReader stringReader = new StringReader(xmlData))
{
// return the "new" object deserialized via the XmlSerializer class instance..
return xmlSerializer.Deserialize(stringReader);
}
}
}
}
使用StringWriter而不是StreamWriter:
public static string SerializeObject<T>(this T toSerialize)
{
XmlSerializer xmlSerializer = new XmlSerializer(toSerialize.GetType());
using(StringWriter textWriter = new StringWriter())
{
xmlSerializer.Serialize(textWriter, toSerialize);
return textWriter.ToString();
}
}
Note, it is important to use toSerialize.GetType() instead of typeof(T) in XmlSerializer constructor: if you use the first one the code covers all possible subclasses of T (which are valid for the method), while using the latter one will fail when passing a type derived from T. Here is a link with some example code that motivate this statement, with XmlSerializer throwing an Exception when typeof(T) is used, because you pass an instance of a derived type to a method that calls SerializeObject that is defined in the derived type's base class: http://ideone.com/1Z5J1.
此外，Ideone使用Mono来执行代码;使用Microsoft . net运行时得到的实际异常与Ideone上显示的异常有不同的消息，但它同样失败。
代码安全说明
关于接受的答案，在XmlSerializer构造函数中使用toSerialize.GetType()而不是typeof(T)是很重要的:如果使用第一种方法，代码将覆盖所有可能的场景，而使用后一种方法有时会失败。
下面是一些示例代码的链接，其中XmlSerializer在使用typeof(T)时抛出异常，因为您将派生类型的实例传递给调用SerializeObject<T>()的方法，该方法是在派生类型的基类中定义的:http://ideone.com/1Z5J1。注意，Ideone使用Mono来执行代码:使用Microsoft . net运行时获得的实际异常有一个与Ideone上显示的不同的消息，但它同样失败。
为了完整起见，我在这里发布了完整的代码示例，以供将来参考，以防Ideone(我发布代码的地方)将来不可用:
using System;
using System.Xml.Serialization;
using System.IO;
public class Test
{
public static void Main()
{
Sub subInstance = new Sub();
Console.WriteLine(subInstance.TestMethod());
}
public class Super
{
public string TestMethod() {
return this.SerializeObject();
}
}
public class Sub : Super
{
}
}
public static class TestExt {
public static string SerializeObject<T>(this T toSerialize)
{
Console.WriteLine(typeof(T).Name); // PRINTS: "Super", the base/superclass -- Expected output is "Sub" instead
Console.WriteLine(toSerialize.GetType().Name); // PRINTS: "Sub", the derived/subclass
XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));
StringWriter textWriter = new StringWriter();
// And now...this will throw and Exception!
// Changing new XmlSerializer(typeof(T)) to new XmlSerializer(subInstance.GetType());
// solves the problem
xmlSerializer.Serialize(textWriter, toSerialize);
return textWriter.ToString();
}
}
在极少数情况下，您可能希望实现自己的String序列化。
但这可能是个坏主意，除非你知道自己在做什么。(例如用批处理文件序列化I/O)
类似这样的方法就可以达到目的(而且手动/批处理编辑也很容易)，但是要注意应该做更多的检查，比如名称不包含换行符。
public string name {get;set;}
public int age {get;set;}
Person(string serializedPerson)
{
string[] tmpArray = serializedPerson.Split('\n');
if(tmpArray.Length>2 && tmpArray[0].Equals("#")){
this.name=tmpArray[1];
this.age=int.TryParse(tmpArray[2]);
}else{
throw new ArgumentException("Not a valid serialization of a person");
}
}
public string SerializeToString()
{
return "#\n" +
name + "\n" +
age;
}
[VB]
Public Function XmlSerializeObject(ByVal obj As Object) As String
Dim xmlStr As String = String.Empty
Dim settings As New XmlWriterSettings()
settings.Indent = False
settings.OmitXmlDeclaration = True
settings.NewLineChars = String.Empty
settings.NewLineHandling = NewLineHandling.None
Using stringWriter As New StringWriter()
Using xmlWriter__1 As XmlWriter = XmlWriter.Create(stringWriter, settings)
Dim serializer As New XmlSerializer(obj.[GetType]())
serializer.Serialize(xmlWriter__1, obj)
xmlStr = stringWriter.ToString()
xmlWriter__1.Close()
End Using
stringWriter.Close()
End Using
Return xmlStr.ToString
End Function
Public Function XmlDeserializeObject(ByVal data As [String], ByVal objType As Type) As Object
Dim xmlSer As New System.Xml.Serialization.XmlSerializer(objType)
Dim reader As TextReader = New StringReader(data)
Dim obj As New Object
obj = DirectCast(xmlSer.Deserialize(reader), Object)
Return obj
End Function
[C#]
public string XmlSerializeObject(object obj)
{
string xmlStr = String.Empty;
XmlWriterSettings settings = new XmlWriterSettings();
settings.Indent = false;
settings.OmitXmlDeclaration = true;
settings.NewLineChars = String.Empty;
settings.NewLineHandling = NewLineHandling.None;
using (StringWriter stringWriter = new StringWriter())
{
using (XmlWriter xmlWriter = XmlWriter.Create(stringWriter, settings))
{
XmlSerializer serializer = new XmlSerializer( obj.GetType());
serializer.Serialize(xmlWriter, obj);
xmlStr = stringWriter.ToString();
xmlWriter.Close();
}
}
return xmlStr.ToString();
}
public object XmlDeserializeObject(string data, Type objType)
{
XmlSerializer xmlSer = new XmlSerializer(objType);
StringReader reader = new StringReader(data);
object obj = new object();
obj = (object)(xmlSer.Deserialize(reader));
return obj;
}
