Serialize an object to string
C#StringSerializationXml SerializationC# Problem Overview
I have the following method to save an Object to a file:
// 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();
}
I confess I did not write it (I only converted it to a extension method that took a type parameter).
Now I need it to give the xml back to me as a string (rather than save it to a file). I am looking into it, but I have not figured it out yet.
I thought this might be really easy for someone familiar with these objects. If not I will figure it out eventually.
C# Solutions
Solution 1 - C#
Use a StringWriter instead of a 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.
Also, Ideone uses Mono to execute code; the actual Exception you would get using the Microsoft .NET runtime has a different Message than the one shown on Ideone, but it fails just the same.
Solution 2 - C#
Serialize and Deserialize 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);
}
}
}
Solution 3 - C#
I know this is not really an answer to the question, but based on the number of votes for the question and the accepted answer, I suspect the people are actually using the code to serialize an object to a string.
Using XML serialization adds unnecessary extra text rubbish to the output.
For the following class
public class UserData
{
public int UserId { get; set; }
}
it generates
<?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>
Better solution is to use JSON serialization (one of the best is Json.NET). To serialize an object:
var userData = new UserData {UserId = 0};
var userDataString = JsonConvert.SerializeObject(userData);
To deserialize an object:
var userData = JsonConvert.DeserializeObject<UserData>(userDataString);
The serialized JSON string would look like:
{"UserId":0}
Solution 4 - C#
Code Safety Note
Regarding the accepted answer, 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 scenarios, while using the latter one fails sometimes.
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<T>() that is defined in the derived type's base class: http://ideone.com/1Z5J1. Note that Ideone uses Mono to execute code: the actual Exception you would get using the Microsoft .NET runtime has a different Message than the one shown on Ideone, but it fails just the same.
For the sake of completeness I post the full code sample here for future reference, just in case Ideone (where I posted the code) becomes unavailable in the future:
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();
}
}
Solution 5 - C#
My 2p...
string Serialise<T>(T serialisableObject)
{
var xmlSerializer = new XmlSerializer(serialisableObject.GetType());
using (var ms = new MemoryStream())
{
using (var xw = XmlWriter.Create(ms,
new XmlWriterSettings()
{
Encoding = new UTF8Encoding(false),
Indent = true,
NewLineOnAttributes = true,
}))
{
xmlSerializer.Serialize(xw,serialisableObject);
return Encoding.UTF8.GetString(ms.ToArray());
}
}
}
Solution 6 - C#
public static string SerializeObject<T>(T objectToSerialize)
{
System.Runtime.Serialization.Formatters.Binary.BinaryFormatter bf = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
MemoryStream memStr = new MemoryStream();
try
{
bf.Serialize(memStr, objectToSerialize);
memStr.Position = 0;
return Convert.ToBase64String(memStr.ToArray());
}
finally
{
memStr.Close();
}
}
public static T DerializeObject<T>(string objectToDerialize)
{
System.Runtime.Serialization.Formatters.Binary.BinaryFormatter bf = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
byte[] byteArray = Convert.FromBase64String(objectToDerialize);
MemoryStream memStr = new MemoryStream(byteArray);
try
{
return (T)bf.Deserialize(memStr);
}
finally
{
memStr.Close();
}
}
Solution 7 - C#
I felt a like I needed to share this manipulated code to the accepted answer - as I have no reputation, I'm unable to comment..
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);
}
}
}
}
Solution 8 - C#
I was unable to use the JSONConvert method suggested by xhafan
In .Net 4.5 even after adding the "System.Web.Extensions" assembly reference I was still unable to access the JSONConvert.
However, once you add the reference you can get the same string print out using:
JavaScriptSerializer js = new JavaScriptSerializer();
string jsonstring = js.Serialize(yourClassObject);
Solution 9 - C#
In some rare cases you might want to implement your own String serialization.
But that probably is a bad idea unless you know what you are doing. (e.g. serializing for I/O with a batch file)
Something like that would do the trick (and it would be easy to edit by hand/batch), but be careful that some more checks should be done, like that name doesn't contain a newline.
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;
}
Solution 10 - C#
[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;
}