I want to converts objects to xml and reverse. I can serialize my objects without any problems to an xml document using this method:
public static void SaveObjectToXML(T _obj, string fileName)
{
XmlSerializer ser = new XmlSerializer(typeof(T));
FileStream str = new FileStream(fileName, FileMode.Create);
ser.Serialize(str, _obj);
str.Close();
}
But with the Deserializer I've got some problems... While the process I get no Errors or problems (same for calling methods of it) but when I try do acess any members the problem begins. All members are null (same for methods acessing any members). Heres the code:
public static T SaveXMLToObject(string fileName)
{
XmlSerializer ser = new XmlSerializer(typeof(T));
StreamReader sr = new StreamReader(fileName);
T dataSet = (T)ser.Deserialize(sr);
return dataSet;
}
Any Ideas?
edit:
OK I just added the using Statement, thanks for that :)
The complete classes are a bit to much, but they look like this:
public class User
{
private string _name;
public string Name
{
get { return _name; }
set { }
}
}
public class AllUser
{
private User[] _users;
public User[] Users
{
get { return _users; }
set { }
}
}
Assuming sample code is complete I am not surprised at all. You have empty setters (which is what serialization will use). Don't just satisfy serialization error by adding empty setter. It is required for populating your data.
Changes that to
set { _users = value; }
and it should work
I think you just need to mark the classes you are deserializing to as [Serializable]. For example:
[Serializable]
public class User
{
...
}
Related
I have an object Foo which I serialize to an XML stream.
public class Foo {
// The application version, NOT the file version!
public string Version {get;set;}
public string Name {get;set;}
}
Foo foo = new Foo { Version = "1.0", Name = "Bar" };
XmlSerializer xmlSerializer = new XmlSerializer(foo.GetType());
This works fast, easy and does everything currently required.
The problem I'm having is that I need to maintain a separate documentation file with some minor remarks. As in the above example, Name is obvious, but Version is the application version and not the data file version as one could expect in this case. And I have many more similar little things I want to clarify with a comment.
I know I can do this if I manually create my XML file using the WriteComment() function, but is there a possible attribute or alternative syntax I can implement so that I can keep using the serializer functionality?
This is possible using the default infrastructure by making use of properties that return an object of type XmlComment and marking those properties with [XmlAnyElement("SomeUniquePropertyName")].
I.e. if you add a property to Foo like this:
public class Foo
{
[XmlAnyElement("VersionComment")]
public XmlComment VersionComment { get { return new XmlDocument().CreateComment("The application version, NOT the file version!"); } set { } }
public string Version { get; set; }
public string Name { get; set; }
}
The following XML will be generated:
<Foo>
<!--The application version, NOT the file version!-->
<Version>1.0</Version>
<Name>Bar</Name>
</Foo>
However, the question is asking for more than this, namely some way to look up the comment in a documentation system. The following accomplishes this by using extension methods to look up the documentation based on the reflected comment property name:
public class Foo
{
[XmlAnyElement("VersionXmlComment")]
public XmlComment VersionXmlComment { get { return GetType().GetXmlComment(); } set { } }
[XmlComment("The application version, NOT the file version!")]
public string Version { get; set; }
[XmlAnyElement("NameXmlComment")]
public XmlComment NameXmlComment { get { return GetType().GetXmlComment(); } set { } }
[XmlComment("The application name, NOT the file name!")]
public string Name { get; set; }
}
[AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
public class XmlCommentAttribute : Attribute
{
public XmlCommentAttribute(string value)
{
this.Value = value;
}
public string Value { get; set; }
}
public static class XmlCommentExtensions
{
const string XmlCommentPropertyPostfix = "XmlComment";
static XmlCommentAttribute GetXmlCommentAttribute(this Type type, string memberName)
{
var member = type.GetProperty(memberName);
if (member == null)
return null;
var attr = member.GetCustomAttribute<XmlCommentAttribute>();
return attr;
}
public static XmlComment GetXmlComment(this Type type, [CallerMemberName] string memberName = "")
{
var attr = GetXmlCommentAttribute(type, memberName);
if (attr == null)
{
if (memberName.EndsWith(XmlCommentPropertyPostfix))
attr = GetXmlCommentAttribute(type, memberName.Substring(0, memberName.Length - XmlCommentPropertyPostfix.Length));
}
if (attr == null || string.IsNullOrEmpty(attr.Value))
return null;
return new XmlDocument().CreateComment(attr.Value);
}
}
For which the following XML is generated:
<Foo>
<!--The application version, NOT the file version!-->
<Version>1.0</Version>
<!--The application name, NOT the file name!-->
<Name>Bar</Name>
</Foo>
Notes:
The extension method XmlCommentExtensions.GetXmlCommentAttribute(this Type type, string memberName) assumes that the comment property will be named xxxXmlComment where xxx is the "real" property. If so, it can automatically determine the real property name by marking the incoming memberName attribute with CallerMemberNameAttribute. This can be overridden manually by passing in the real name.
Once the type and member name are known, the extension method looks up the relevant comment by searching for an [XmlComment] attribute applied to the property. This could be replaced with a cached lookup into a separate documentation file.
While it is still necessary to add the xxxXmlComment properties for each property that might be commented, this is likely to be less burdensome than implementing IXmlSerializable directly which is quite tricky, can lead to bugs in deserialization, and can require nested serialization of complex child properties.
To ensure that each comment precedes its associated element, see Controlling order of serialization in C#.
For XmlSerializer to serialize a property it must have both a getter and setter. Thus I gave the comment properties setters that do nothing.
Working .Net fiddle.
Isn't possible using default infrastructure. You need to implement IXmlSerializable for your purposes.
Very simple implementation:
public class Foo : IXmlSerializable
{
[XmlComment(Value = "The application version, NOT the file version!")]
public string Version { get; set; }
public string Name { get; set; }
public void WriteXml(XmlWriter writer)
{
var properties = GetType().GetProperties();
foreach (var propertyInfo in properties)
{
if (propertyInfo.IsDefined(typeof(XmlCommentAttribute), false))
{
writer.WriteComment(
propertyInfo.GetCustomAttributes(typeof(XmlCommentAttribute), false)
.Cast<XmlCommentAttribute>().Single().Value);
}
writer.WriteElementString(propertyInfo.Name, propertyInfo.GetValue(this, null).ToString());
}
}
public XmlSchema GetSchema()
{
throw new NotImplementedException();
}
public void ReadXml(XmlReader reader)
{
throw new NotImplementedException();
}
}
[AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
public class XmlCommentAttribute : Attribute
{
public string Value { get; set; }
}
Output:
<?xml version="1.0" encoding="utf-16"?>
<Foo>
<!--The application version, NOT the file version!-->
<Version>1.2</Version>
<Name>A</Name>
</Foo>
Another way, maybe preferable: serialize with default serializer, then perform post-processing, i.e. update XML, e.g. using XDocument or XmlDocument.
Add comment at the end of xml after serialization (magic is to flush xmlWriter).
byte[] buffer;
XmlSerializer serializer = new XmlSerializer(result.GetType());
var settings = new XmlWriterSettings() { Encoding = Encoding.UTF8 };
using (MemoryStream memoryStream = new MemoryStream())
{
using (XmlWriter xmlWriter = XmlWriter.Create(memoryStream, settings))
{
serializer.Serialize(xmlWriter, result);
xmlWriter.WriteComment("test");
xmlWriter.Flush();
buffer = memoryStream.ToArray();
}
}
Probably late to the party but I had problems when I was trying to deserialize using Kirill Polishchuk solution. Finally I decided to edit the XML after serializing it and the solution looks like:
public static void WriteXml(object objectToSerialize, string path)
{
try
{
using (var w = new XmlTextWriter(path, null))
{
w.Formatting = Formatting.Indented;
var serializer = new XmlSerializer(objectToSerialize.GetType());
serializer.Serialize(w, objectToSerialize);
}
WriteComments(objectToSerialize, path);
}
catch (Exception e)
{
throw new Exception($"Could not save xml to path {path}. Details: {e}");
}
}
public static T ReadXml<T>(string path) where T:class, new()
{
if (!File.Exists(path))
return null;
try
{
using (TextReader r = new StreamReader(path))
{
var deserializer = new XmlSerializer(typeof(T));
var structure = (T)deserializer.Deserialize(r);
return structure;
}
}
catch (Exception e)
{
throw new Exception($"Could not open and read file from path {path}. Details: {e}");
}
}
private static void WriteComments(object objectToSerialize, string path)
{
try
{
var propertyComments = GetPropertiesAndComments(objectToSerialize);
if (!propertyComments.Any()) return;
var doc = new XmlDocument();
doc.Load(path);
var parent = doc.SelectSingleNode(objectToSerialize.GetType().Name);
if (parent == null) return;
var childNodes = parent.ChildNodes.Cast<XmlNode>().Where(n => propertyComments.ContainsKey(n.Name));
foreach (var child in childNodes)
{
parent.InsertBefore(doc.CreateComment(propertyComments[child.Name]), child);
}
doc.Save(path);
}
catch (Exception)
{
// ignored
}
}
private static Dictionary<string, string> GetPropertiesAndComments(object objectToSerialize)
{
var propertyComments = objectToSerialize.GetType().GetProperties()
.Where(p => p.GetCustomAttributes(typeof(XmlCommentAttribute), false).Any())
.Select(v => new
{
v.Name,
((XmlCommentAttribute) v.GetCustomAttributes(typeof(XmlCommentAttribute), false)[0]).Value
})
.ToDictionary(t => t.Name, t => t.Value);
return propertyComments;
}
[AttributeUsage(AttributeTargets.Property)]
public class XmlCommentAttribute : Attribute
{
public string Value { get; set; }
}
Proposed solution by user dbc looks fine, however it seems to need more manual work to create such comments than using an XmlWriter that knows how to insert comments based on XmlComment attributes.
See https://archive.codeplex.com/?p=xmlcomment - it seems you can pass such a writer to XmlSerializer and thus not have to implement your own serialization which could be tricky.
I did myself end up using dbc's solution though, nice and clean with no extra code. See https://dotnetfiddle.net/Bvbi0N. Make sure you provide a "set" accessor for the comment element (the XmlAnyElement). It doesn't need to have a name btw.
Update: better pass a unique name always, aka use [XmlAnyElement("someCommentElement")] instead of [XmlAnyElement]. Was using the same class with WCF and it was choking upon those XmlAnyElements that didn't have a name provided, even though I had [XmlIgnore, SoapIgnore, IgnoreDataMember] at all of them.
for nested xml, I changed the method this way(for me i was having simple property as string(its possible to make it more complex in the logic)
public void WriteXml(XmlWriter writer)
{
var properties = GetType().GetProperties();
foreach (var propertyInfo in properties)
{
if (propertyInfo.IsDefined(typeof(XmlCommentAttribute), false))
{
writer.WriteComment(
propertyInfo.GetCustomAttributes(typeof(XmlCommentAttribute), false)
.Cast<XmlCommentAttribute>().Single().Value);
}
if (propertyInfo.GetValue(this, null).GetType().ToString() != "System.String")
{
XmlSerializer xmlSerializer = new XmlSerializer(propertyInfo.GetValue(this, null).GetType());
xmlSerializer.Serialize(writer, propertyInfo.GetValue(this, null));
}
else
{
writer.WriteElementString(propertyInfo.Name, propertyInfo.GetValue(this, null).ToString());
}
}
}
Can I make XmlSerializer ignore the namespace (xmlns attribute) on deserialization so that it doesn't matter if the attribute is added or not or even if the attribute is bogus? I know that the source will always be trusted so I don't care about the xmlns attribute.
Yes, you can tell the XmlSerializer to ignore namespaces during de-serialization.
Define an XmlTextReader that ignores namespaces. Like so:
// helper class to ignore namespaces when de-serializing
public class NamespaceIgnorantXmlTextReader : XmlTextReader
{
public NamespaceIgnorantXmlTextReader(System.IO.TextReader reader): base(reader) { }
public override string NamespaceURI
{
get { return ""; }
}
}
// helper class to omit XML decl at start of document when serializing
public class XTWFND : XmlTextWriter {
public XTWFND (System.IO.TextWriter w) : base(w) { Formatting= System.Xml.Formatting.Indented;}
public override void WriteStartDocument () { }
}
Here's an example of how you would de-serialize using that TextReader:
public class MyType1
{
public string Label
{
set { _Label= value; }
get { return _Label; }
}
private int _Epoch;
public int Epoch
{
set { _Epoch= value; }
get { return _Epoch; }
}
}
String RawXml_WithNamespaces = #"
<MyType1 xmlns='urn:booboo-dee-doo'>
<Label>This document has namespaces on its elements</Label>
<Epoch xmlns='urn:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'>0</Epoch>
</MyType1>";
System.IO.StringReader sr;
sr= new System.IO.StringReader(RawXml_WithNamespaces);
var s1 = new XmlSerializer(typeof(MyType1));
var o1= (MyType1) s1.Deserialize(new NamespaceIgnorantXmlTextReader(sr));
System.Console.WriteLine("\n\nDe-serialized, then serialized again:\n");
XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
ns.Add("urn", "booboo-dee-doo");
s1.Serialize(new XTWFND(System.Console.Out), o1, ns);
Console.WriteLine("\n\n");
The result is like so:
<MyType1>
<Label>This document has namespaces on its elements</Label>
<Epoch>0</Epoch>
</MyType1>
If you expect no namespace, but the input has namespaces, then you can set
Namespaces = false
on your XmlTextReader.
Exdended Wolfgang Grinfeld answer (w/o exception handling):
public static Message Convert(XmlDocument doc)
{
Message obj;
using (TextReader textReader = new StringReader(doc.OuterXml))
{
using (XmlTextReader reader = new XmlTextReader(textReader))
{
reader.Namespaces = false;
XmlSerializer serializer = new XmlSerializer(typeof(Message));
obj = (Message)serializer.Deserialize(reader);
}
}
return obj;
}
Solved this by using XmlSerializer Deserialize to read from xml instead from stream. This way before xml is Deserialized, using Regex to remove xsi:type from the xml. Was doing this is Portable Class Library for Cross Platform, so did not had many other options :(. After this the deserialization seems to work fine.
Following code can help,
public static TClass Deserialize<TClass>(string xml) where TClass : class, new()
{
var tClass = new TClass();
xml = RemoveTypeTagFromXml(xml);
var xmlSerializer = new XmlSerializer(typeof(TClass));
using (TextReader textReader = new StringReader(xml))
{
tClass = (TClass)xmlSerializer.Deserialize(textReader);
}
return tClass;
}
public static string RemoveTypeTagFromXml(string xml)
{
if (!string.IsNullOrEmpty(xml) && xml.Contains("xsi:type"))
{
xml = Regex.Replace(xml, #"\s+xsi:type=""\w+""", "");
}
return xml;
}
Why try to make the XmlSerializer forget how XML works? It's a fact of XML that two elements with the same name but different namespaces are different elements.
If you want to process XML that has no namespaces, then you should pre-process it to remove the namespaces, and then pass it to the serializer.
I have a very complex csla object. This object has been serialized to Database in binary. One of the child objects changes and I cannot deserialize the object anymore. (When I try to deserialize it, the properties contain junk or are not initialized because the deserialization did'nt work in the new class.) I'll post a simplified example here.
[serializable]
public class Head : BusinessBase<Head>
{
private static PropertyInfo<int> _eyesCountProperty = RegisterProperty<int>(new PropertyInfo<int>("EyesCount"));
public int EyesCount
{
get { return GetProperty(_eyesCountProperty ); }
set { SetProperty(_eyesCountProperty , value); }
}
}
[serializable]
public class Person : BusinessBase<Person>
{
private static PropertyInfo<string> _firstNameProperty = RegisterProperty<string>(new PropertyInfo<string>("FirstName"));
public string FirstName
{
get { return GetProperty(_firstNameProperty ); }
set { SetProperty(_firstNameProperty , value); }
}
}
public Head MyHead { get; set; }
}
So let's say I have an instance of "Person" class and I serialize it to the database.
Here's our serializing and deserializing methods.
public static byte[] ConvertToByteArray(object theObject)
{
byte[] result = null;
BinaryFormatter bf = new BinaryFormatter();
using(MemoryStream ms = new MemoryStream())
{
bf.Serialize(ms, theObject);
result = ms.ToArray();
}
return result;
}
public static object ConvertFromByteArray(byte[] serializedObject)
{
object result = null;
using(MemoryStream ms = new MemoryStream(serializedObject))
{
BinaryFormatter bf = new BinaryFormatter();
result = bf.Deserialize(ms);
}
return result;
}
Now let's say that the Head class changes and I now have the noseCount and mouthCount in it. So I try to rename it as "HeadV1" and create a "HeadV2" class with the new properties in it. (I would need to do a "PersonV1" class with the "HeadV1" property and a "PersonV2" class with the "HeadV2".)
In the PersonV2 class, I would like to have an "OnDeserializing" method that would let me know if the item I'm trying to deserialize is of type "PersonV1" or "PersonV2" in order to deserialize it the right way.
[OnDeserializing()]
internal void OnDeserializingMethod(StreamingContext context)
{
// Determine if data is of type "PersonV1" or "PersonV2"
}
But I'm stuck, I don't know how to do it and I can't seem to find how to do it. Is there any way to do so? I don't seem to have access to the data inside the "OnDeserializing" method?
I have an interface with exposes a property called Pages:
public interface INameSet
{
IQueryable<string> Names { get; }
}
I have this class which implements the interface and must also be parsed from a JSON object:
[DataContract(Name = "surveyPageSet")]
public class SurveyPage : INameSet
{
[DataMember(Name = "names")]
public List<string> SurveyNames { get; set; }
public IQueryable<string> Names
{
get
{
//Returns SurveyNames after some filtration logic
}
}
}
My problem is that when I pass in this object:
{
"names": ["testname"]
}
The JSON interpreter is trying to deserialize it to match the Names property instead of the SurveyNames property. I know this happens because when removing the implementation of the interface and changing SurveyNames to Names it populates the property fine. Is there any way to get it to serialize to the correct property or do I need to create a translator class that will generate the proper concretion of the INameSet interface?
EDIT: This is with the built-in serializer. If there is a solution with Newtonsoft/JSON.NET that would be fine with me.
JavaScriptSerializer doesn't allow for remapping of names out of the box, so don't use it.
Instead, use Json.NET or DataContractJsonSerializer. In fact, both should already work given the data contract attributes you have applied.
For instance, using Json.NET, if I do:
var page1 = JsonConvert.DeserializeObject<SurveyPage>(json);
Debug.Assert(page1.SurveyNames != null && page1.SurveyNames.SequenceEqual(new string [] { "testname" }));
Then there is no assert. Similarly there is no assert if I do:
var page2 = DataContractJsonSerializerHelper.GetObject<SurveyPage>(json);
Debug.Assert(page2.SurveyNames != null && page2.SurveyNames.SequenceEqual(new string[] { "testname" }));
using the helper class:
public static class DataContractJsonSerializerHelper
{
private static MemoryStream GenerateStreamFromString(string value)
{
return new MemoryStream(Encoding.Unicode.GetBytes(value ?? ""));
}
public static string GetJson<T>(T obj, DataContractJsonSerializer serializer)
{
using (var memory = new MemoryStream())
{
serializer.WriteObject(memory, obj);
memory.Seek(0, SeekOrigin.Begin);
using (var reader = new StreamReader(memory))
{
return reader.ReadToEnd();
}
}
}
public static string GetJson<T>(T obj) where T : class
{
DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));
return GetJson(obj, serializer);
}
public static T GetObject<T>(string json) where T : class
{
DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));
return GetObject<T>(json, serializer);
}
public static T GetObject<T>(string json, DataContractJsonSerializer serializer)
{
T obj = default(T);
using (var stream = GenerateStreamFromString(json))
{
obj = (T)serializer.ReadObject(stream);
}
return obj;
}
}
Update
If you really want to continue to use JavaScriptConverter, you can write your own JavaScriptConverter and deserialize each field manually. But it's a bother and I wouldn't recommend it.
i get an empty xmlfile after serializing an object. I'm using Monodevelop and Unity 4. I searched for such a long time mostly in this community, but i only found difficult problems with even more difficult answers :) I think mine is so simple, please help me. (I am new to c#)
The serialized object is this:
[System.Serializable]
public class information {
private string data1;
private string data2;
private string data3;
public void Data1(string text)
{
data1 = text;
}
public string GetData1 ()
{
return data1;
}
public void Data2(string text)
{
data2 = text;
}
public string GetData2 ()
{
return data2;
}
public void Data3(string text)
{
data3 = text;
}
}
the serializing class is this, here might be the problem:
public class SaveXml {
public void SaveData(object obj, string filename)
{
XmlSerializer sr = new XmlSerializer(obj.GetType());
TextWriter writer = new StreamWriter(filename);
sr.Serialize(writer, obj);
writer.Close();
}
public string Load()
{
if(File.Exists("accdata.xml"))
{
XmlSerializer xs = new XmlSerializer(typeof(information));
FileStream read = new FileStream("accdata.xml",FileMode.Open, FileAccess.Read, FileShare.Read);
information info = (information)xs.Deserialize(read);
return info.GetData1();
}
else
{
return "file does not exist";
}
}
And the serializing and the serialized object get called by a menu that has this 2 buttons:
if(GUI.Button(new Rect(10,50,300,100),"Save"))
{
SaveXml saver = new SaveXml();
information infol = new information();
infol.Data1("textone");
infol.Data2("texttwo");
infol.Data3( "textthree");
saver.SaveData(infol, "accdata.xml");
}
if(GUI.Button(new Rect(500,50,300,100),"Load"))
{
SaveXml saver1 = new SaveXml();
text = saver1.Load();
}
so the variable text that is declared in the class menu, should be "textone", after i clicked the Save Button and the LoadButton. The Savebutton creates a file that is empty.
The Deserialization seems to work but of course there is no String in the data1 variable in Information so the variable in the menu called text is empty too. I get no errors and i can work with the object after serialization.
So why doesnt my serialization work? Please help me. I excuse for my bad english and mistakes, i am new to stackoverflow.
Xml serializer serializes public fields/properties not methods. Change your methods to properties. For ex,
public string Data2
{
set { data2 = value; }
get { return data2; }
}
So your information class can be
public class Information
{
public string Data1 { get; set; }
public string Data2 { get; set; }
public string Data3 { get; set; }
}
BTW: you don't need this Serializable attribute. It is only used by BinaryFormatter
I'm not sure but from what i see you don't have any public fields... Take a look here
And also, why don't you just use auto getter/setter ?
According to this MSDN support article, using XmlSerializer the way you have performs only "shallow" serialization - it only serializes public fields/properties. To serialize private data requires "deep" serialization which appears to be a whole other animal.