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
[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;
}
其他回答
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。
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();
}
}
我知道这不是问题的真正答案，但根据问题的投票数和接受的答案，我怀疑人们实际上是在使用代码将对象序列化为字符串。
使用XML序列化会给输出增加不必要的额外文本垃圾。
对于下面的类
public class UserData
{
public int UserId { get; set; }
}
它生成
<?xml version="1.0" encoding="utf-16"?>
<UserData xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<UserId>0</UserId>
</UserData>
更好的解决方案是使用JSON序列化(最好的方法之一是Json.NET)。 序列化一个对象:
var userData = new UserData {UserId = 0};
var userDataString = JsonConvert.SerializeObject(userData);
反序列化一个对象:
var userData = JsonConvert.DeserializeObject<UserData>(userDataString);
序列化的JSON字符串看起来像这样:
{"UserId":0}
序列化和反序列化XML/JSON (SerializationHelper.cs):
using Newtonsoft.Json;
using System.IO;
using System.Xml.Serialization;
namespace MyProject.Helpers
{
public static class SerializationHelper
{
public static T DeserializeXml<T>(this string toDeserialize)
{
XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));
using (StringReader textReader = new StringReader(toDeserialize))
{
return (T)xmlSerializer.Deserialize(textReader);
}
}
public static string SerializeXml<T>(this T toSerialize)
{
XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));
using (StringWriter textWriter = new StringWriter())
{
xmlSerializer.Serialize(textWriter, toSerialize);
return textWriter.ToString();
}
}
public static T DeserializeJson<T>(this string toDeserialize)
{
return JsonConvert.DeserializeObject<T>(toDeserialize);
}
public static string SerializeJson<T>(this T toSerialize)
{
return JsonConvert.SerializeObject(toSerialize);
}
}
}
[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;
}
