When I serialize the value : If there is no value present in for data then it's coming like below format.
<Note>
<Type>Acknowledged by PPS</Type>
<Data />
</Note>
But what I want xml data in below format:
<Note>
<Type>Acknowledged by PPS</Type>
<Data></Data>
</Note>
Code For this i have written :
[Serializable]
public class Notes
{
[XmlElement("Type")]
public string typeName { get; set; }
[XmlElement("Data")]
public string dataValue { get; set; }
}
I am not able to figure out what to do for achieve data in below format if data has n't assign any value.
<Note>
<Type>Acknowledged by PPS</Type>
<Data></Data>
</Note>
You can do this by creating your own XmlTextWriter to pass into the serialization process.
public class MyXmlTextWriter : XmlTextWriter
{
public MyXmlTextWriter(Stream stream) : base(stream, Encoding.UTF8)
{
}
public override void WriteEndElement()
{
base.WriteFullEndElement();
}
}
You can test the result using:
class Program
{
static void Main(string[] args)
{
using (var stream = new MemoryStream())
{
var serializer = new XmlSerializer(typeof(Notes));
var writer = new MyXmlTextWriter(stream);
serializer.Serialize(writer, new Notes() { typeName = "Acknowledged by PPS", dataValue="" });
var result = Encoding.UTF8.GetString(stream.ToArray());
Console.WriteLine(result);
}
Console.ReadKey();
}
If you saved your string somewhere (e.g a file) you can use this simple Regex.Replace:
var replaced = Regex.Replace(File.ReadAllText(name), #"<([^<>/]+)\/>", (m) => $"<{m.Groups[1].Value.Trim()}></{m.Groups[1].Value.Trim()}>");
File.WriteAllText(name, replaced);
IMO it's not possibe to generate your desired XML using Serialization. But, you can use LINQ to XML to generate the desired schema like this -
XDocument xDocument = new XDocument();
XElement rootNode = new XElement(typeof(Notes).Name);
foreach (var property in typeof(Notes).GetProperties())
{
if (property.GetValue(a, null) == null)
{
property.SetValue(a, string.Empty, null);
}
XElement childNode = new XElement(property.Name, property.GetValue(a, null));
rootNode.Add(childNode);
}
xDocument.Add(rootNode);
XmlWriterSettings xws = new XmlWriterSettings() { Indent=true };
using (XmlWriter writer = XmlWriter.Create("D:\\Sample.xml", xws))
{
xDocument.Save(writer);
}
Main catch is in case your value is null, you should set it to empty string. It will force the closing tag to be generated. In case value is null closing tag is not created.
Kludge time - see Generate System.Xml.XmlDocument.OuterXml() output thats valid in HTML
Basically after XML doc has been generated go through each node, adding an empty text node if no children
// Call with
addSpaceToEmptyNodes(xmlDoc.FirstChild);
private void addSpaceToEmptyNodes(XmlNode node)
{
if (node.HasChildNodes)
{
foreach (XmlNode child in node.ChildNodes)
addSpaceToEmptyNodes(child);
}
else
node.AppendChild(node.OwnerDocument.CreateTextNode(""))
}
(Yes I know you shouldn't have to do this - but if your sending the XML to some other system that you can't easily fix then have to be pragmatic about things)
You can add a dummy field to prevent the self-closing element.
[XmlText]
public string datavalue= " ";
Or if you want the code for your class then Your class should be like this.
public class Notes
{
[XmlElement("Type")]
public string typeName { get; set; }
[XmlElement("Data")]
private string _dataValue;
public string dataValue {
get {
if(string.IsNullOrEmpty(_dataValue))
return " ";
else
return _dataValue;
}
set {
_dataValue = value;
}
}
}
In principal, armen.shimoon's answer worked for me. But if you want your XML output pretty printed without having to use XmlWriterSettings and an additional Stream object (as stated in the comments), you can simply set the Formatting in the constructor of your XmlTextWriter class.
public MyXmlTextWriter(string filename) : base(filename, Encoding.UTF8)
{
this.Formatting = Formatting.Indented;
}
(Would have posted this as a comment but am not allowed yet ;-))
Effectively the same as Ryan's solution which uses the standard XmlWriter (i.e. there's no need for a derived XmlTextWriter class), but written using linq to xml (XDocument)..
private static void AssignEmptyElements(this XNode node)
{
if (node is XElement e)
{
e.Nodes().ToList().ForEach(AssignEmptyElements);
if (e.IsEmpty)
e.Value = string.Empty;
}
}
usage..
AssignEmptyElements(document.FirstNode);
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 searched and tried some attributes but none of them worked for my below scenario:
public class ObjSer
{
[XmlElement("Name")]
public string Name
{
get; set;
}
}
//Code to serialize
var obj = new ObjSer();
obj.Name = "<tag1>Value</tag1>";
var stringwriter = new System.IO.StringWriter();
System.Xml.Serialization.XmlSerializer serializer = new System.Xml.Serialization.XmlSerializer(obj.GetType());
serializer.Serialize(stringwriter, obj);
Output would be as follows:
<ObjSer><Name><tag1>Value</tag1></Name></ObjSer>
But I need output as:
<ObjSer><Name><tag1>Value</tag1></Name></ObjSer>
Scenario 2: In some cases I need to set:
obj.Name = "Value";
Is there any attribute or method I can override to make it possible?
You can't with default serializer. XmlSerializer does encoding of all values during serialization.
If you want your member to hold xml value, it must be XmlElement. Here is how you can accomplish it
public class ObjSer
{
[XmlElement("Name")]
public XmlElement Name
{
get; set;
}
}
var obj = new ObjSer();
// <-- load xml
var doc = new XmlDocument();
doc.LoadXml("<tag1>Value</tag1>");
obj.Name = doc.DocumentElement;
// --> assign the element
System.Xml.Serialization.XmlSerializer serializer = new System.Xml.Serialization.XmlSerializer(obj.GetType());
serializer.Serialize(Console.Out, obj);
Output:
<?xml version="1.0" encoding="IBM437"?>
<ObjSer xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<Name>
<tag1>Value</tag1>
</Name>
</ObjSer>
UPDATE:
In case if you want to use XElement instead of XmlElement, here is sample on how to do it
public class ObjSer
{
[XmlElement("Name")]
public XElement Name
{
get; set;
}
}
static void Main(string[] args)
{
//Code to serialize
var obj = new ObjSer();
obj.Name = XDocument.Parse("<tag1>Value</tag1>").Document.FirstNode as XElement;
System.Xml.Serialization.XmlSerializer serializer = new System.Xml.Serialization.XmlSerializer(obj.GetType());
serializer.Serialize(Console.Out, obj);
}
No, you can't. It is the natural and usual behaviour of the xml serializer. The serializer doesn't have to handle within the XML strings. So, it escapes the xml as expected.
You should decode the escaped string again while deserializing it.
If you want to add dynamically elements in the XML I suggest you to use Linq to XML and you can create tag1 or another kind of elements easily.
I would suggest serializing to an XDocument then converting that to a string and manually unescaping the desired part and writing it to a file. I would say this would give you the least headache it shouldn't be more than a couple lines of code. If you need it I can provide some code example if needed.
I found one more way of changing the type
public class NameNode
{
public string tag1
{
get; set;
}
[XmlText]
public string Value
{
get; set;
}
}
public class ObjSer
{
[XmlElement("Name")]
public NameNode Name
{
get; set;
}
}
To set value of Name:
var obj = new ObjSer();
var valueToSet = "<tag1>Value</tag1>";
//or var valueToSet = "Value";
//With XML tag:
if (valueToSet.Contains("</"))
{
var doc = new XmlDocument();
doc.LoadXml(valueToSet);
obj.Name.tag1 = doc.InnerText;
}
else //Without XML Tags
{
obj.Name.Value = senderRecipient.Name;
}
This solution will work in both cases, but has limitation. It will work only for predefined tags (ex. tag1)
I have a bunch of C# classes, which are auto generated from an XSD. Then I generate XML files based on those C# classes. Nothing existing so far.
The problem:
The generated XML files are going through validation and the validation requires an extra attribute to all XML tags with xsi:nil="true". Basically the tags should look like : <testTag.01 xsi:nil="true" NV="123123" />, but I can't achieve that in C#. My code is:
if (myObject.TestTag.HasValue)
{
t.testTag01 = new testTag01();
t.testTag01.Value = myObject.TestTag.Value;
}
//else
//{
// t.testTag01 = new testTag01();
// t.testTag01.NV = "123123";//Not Recorded
//}
This code generates <testTag.01>SomeValue</testTag.01> or <testTag.01 xsi:nil="true"/>.
If I uncomment the ELSE, the result would be: <testTag.01>SomeValue</testTag.01> or <testTag.01 NV="123123" />.
So I have no idea how to get to the format, which is required by the validation tool. Any ideas ?
P.S.
Here is the auto-generated C# class:
/// [System.CodeDom.Compiler.GeneratedCodeAttribute("xsd",
"4.0.30319.33440")] [System.SerializableAttribute()]
[System.Diagnostics.DebuggerStepThroughAttribute()]
[System.ComponentModel.DesignerCategoryAttribute("code")]
[System.Xml.Serialization.XmlTypeAttribute(AnonymousType=true,
Namespace="http://www.blabla.org")]
public partial class testTag01 {
private string nvField;
private SomeEnum valueField;
/// <remarks/>
[System.Xml.Serialization.XmlAttributeAttribute()]
public string NV {
get {
return this.nvField;
}
set {
this.nvField = value;
}
}
/// <remarks/>
[System.Xml.Serialization.XmlTextAttribute()]
public SomeEnum Value {
get {
return this.valueField;
}
set {
this.valueField = value;
}
} }
I wouldn't like to alter that part, but I understand it is impossible without doing it. Also I have tried to set SomeEnum to be Nullable. public SomeEnum? Value, but is throwing an exception:
Cannot serialize member 'Value' of type System.Nullable`1[]. XmlAttribute/XmlText cannot be used to encode complex types.
XmlSerializer doesn't directly support binding to elements that simultaneously have xsi:nil="true" along with other attribute values; see Xsi:nil Attribute Binding Support: The nil attribute and other attributes.
Thus, you need to emit the attribute manually.
If you want to be able to generate an element with no content and two attributes, one named NV and the other always being xsi:nil="true", you can modify your testTag01 class to have the NV property as well as a synthetic property having the correct namespace and name:
public class testTag01
{
[XmlAttribute]
public string NV { get; set; }
[XmlAttribute("nil", Namespace = "http://www.w3.org/2001/XMLSchema-instance")]
public string Nil { get { return "true"; } set { } }
}
If you sometimes want to have xsi:nil="true" but at other times want the element to have content corresponding to your SomeEnum, you need to do something a bit more complicated, since the xsi:nil="true" must be suppressed when the element has content:
public class testTag01
{
[XmlAttribute]
public string NV { get; set; }
[XmlAttribute("nil", Namespace = "http://www.w3.org/2001/XMLSchema-instance")]
public string Nil { get { return SomeEnum == null ? "true" : null; } set { } }
public bool ShouldSerializeNil() { return SomeEnum == null; }
[XmlIgnore]
public SomeEnum? SomeEnum { get; set; }
[XmlText]
public string SomeEnumText
{
get
{
if (SomeEnum == null)
return null;
return SomeEnum.Value.ToString();
}
set
{
// See here if one needs to parse XmlEnumAttribute attributes
// http://stackoverflow.com/questions/3047125/retrieve-enum-value-based-on-xmlenumattribute-name-value
value = value.Trim();
if (string.IsNullOrEmpty(value))
SomeEnum = null;
else
{
try
{
SomeEnum = (SomeEnum)Enum.Parse(typeof(SomeEnum), value, false);
}
catch (Exception)
{
SomeEnum = (SomeEnum)Enum.Parse(typeof(SomeEnum), value, true);
}
}
}
}
}
(An element that simultaneously has both xsi:nil="true" and content would be a violation of the XML standard; hopefully you don't have that.)
Then use it like:
public class TestClass
{
[XmlElement("testTag.01")]
public testTag01 TestTag { get; set; }
public static void Test()
{
Test(new TestClass { TestTag = new testTag01 { NV = "123123" } });
Test(new TestClass { TestTag = new testTag01 { NV = "123123", SomeEnum = SomeEnum.SomeValue } });
}
private static void Test(TestClass test)
{
var xml = test.GetXml();
var test2 = xml.LoadFromXML<TestClass>();
Console.WriteLine(test2.GetXml());
Debug.WriteLine(test2.GetXml());
if (test2.TestTag.NV != test.TestTag.NV)
{
throw new InvalidOperationException("test2.TestTag.NV != test.TestTag.NV");
}
}
}
The XML output looks like:
<TestClass xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<testTag.01 NV="123123" xsi:nil="true" />
</TestClass>
Or
<TestClass xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<testTag.01 NV="123123">SomeValue</testTag.01>
</TestClass>
Prototype fiddle using these extension methods:
public static class XmlSerializationHelper
{
public static T LoadFromXML<T>(this string xmlString, XmlSerializer serializer = null)
{
T returnValue = default(T);
using (StringReader reader = new StringReader(xmlString))
{
object result = (serializer ?? new XmlSerializer(typeof(T))).Deserialize(reader);
if (result is T)
{
returnValue = (T)result;
}
}
return returnValue;
}
public static string GetXml<T>(this T obj, XmlSerializerNamespaces ns = null, XmlWriterSettings settings = null, XmlSerializer serializer = null)
{
using (var textWriter = new StringWriter())
{
settings = settings ?? new XmlWriterSettings() { Indent = true, IndentChars = " " }; // For cosmetic purposes.
using (var xmlWriter = XmlWriter.Create(textWriter, settings))
(serializer ?? new XmlSerializer(typeof(T))).Serialize(xmlWriter, obj, ns);
return textWriter.ToString();
}
}
}
As expected there is no solution for that case out of the box, so I improvise a bit and achieved my goal in a post processing logic.
I am parsing the generated XML and if I am looking for a node with xsi:nil attribute, but without NV attribute - I add NV attribute with default value.
Same for the nodes with NV attribute, but no xsi:nil.
Here is the code:
XmlDocument doc = new XmlDocument();// instantiate XmlDocument and load XML from file
doc.Load("somepath.xml");
//Get the nodes with NV attribute(using XPath) and add xsi:nill to that nodes
XmlNodeList nodes = doc.SelectNodes("//*[#NV]");
foreach (XmlNode node in nodes)
{
XmlAttribute nilAttr = doc.CreateAttribute("nil", "http://www.w3.org/2001/XMLSchema-instance");
nilAttr.Value = "true";
node.Attributes.Append(nilAttr);
}
//Get the nodes with xsi:nill attribute(using XPath) and add NV with default value to that nodes
XmlNamespaceManager nsManager = new XmlNamespaceManager(doc.NameTable);
nsManager.AddNamespace("xsi", "http://www.w3.org/2001/XMLSchema-instance");
XmlNodeList nilNodes = doc.SelectNodes("//*[#xsi:nil]", nsManager);
foreach (XmlNode node in nilNodes)
{
XmlAttribute nvAttr = doc.CreateAttribute("NV");
nvAttr.Value = "7701003";
node.Attributes.Append(nvAttr);
}
doc.Save("somepath.xml");
The upper answer makes totally sense, but since these classes are auto-generated I will do it my way with the post processing, cause if the provider changes the XSD schema, my solution doesn't need any extra work. Thanks anyway.
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());
}
}
}