Currently, the code below omits null properties during serialization. I want null valued properties in the output xml as empty elements. I searched the web but didn't find anything useful. Any help would be appreciated.
var serializer = new XmlSerializer(application.GetType());
var ms = new MemoryStream();
var writer = new StreamWriter(ms);
serializer.Serialize(writer, application);
return ms;
Sorry, I forgot to mention that I want to avoid attribute decoration.
Can you control the items that have to be serialized?
Using
[XmlElement(IsNullable = true)]
public string Prop { get; set; }
you can represent it as <Prop xsi:nil="true" />
You can use also use the following code. The pattern is ShouldSerialize{PropertyName}
public class PersonWithNullProperties
{
public string Name { get; set; }
public int? Age { get; set; }
public bool ShouldSerializeAge()
{
return true;
}
}
PersonWithNullProperties nullPerson = new PersonWithNullProperties() { Name = "ABCD" };
XmlSerializer xs = new XmlSerializer(typeof(nullPerson));
StringWriter sw = new StringWriter();
xs.Serialize(sw, nullPerson);
XML
<?xml version="1.0" encoding="utf-16"?>
<Person xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://
www.w3.org/2001/XMLSchema">
<Name>ABCD</Name>
<Age xsi:nil="true" />
</Person>
Set the XmlElementAttribute.IsNullable property:
https://msdn.microsoft.com/en-us/library/system.xml.serialization.xmlelementattribute.isnullable(v=vs.110).aspx
Related
I want to create a serialisable class to represent an xml envelope that can contain arbitrary message content. Example xml (simplified) below:
<?xml version="1.0" encoding="utf-8"?>
<Envelope>
<MessageA>
<Url></Url>
</MessageA>
</Envelope>
<?xml version="1.0" encoding="utf-8"?>
<Envelope>
<MessageB>
<Value></Value>
</MessageB>
</Envelope>
My idea is to use a generic envelope class to handle this:
[Serializable]
[XmlRoot(ElementName="Envelope")]
public class Envelope<TContent> where TContent : new()
{
public Envelope()
{
Content = new TContent();
}
public TContent Content { get; set; }
}
[Serializable]
public class MessageA
{
public string Url { get; set; }
}
[Serializable]
public class MessageB
{
public string Value { get; set; }
}
These could be serialised so:
var envelope = new Envelope<MessageA>();
envelope.Content.Url = "http://www.contoso.com";
string xml = envelope.ToXml();
However, instead of the xml message that I want (per examples above), I get the following. How can I change the classes or the serialisation process to rename the Content element to the name of the Message itself?
<?xml version="1.0" encoding="utf-8"?>
<Envelope>
<Content>
<Url>http://www.contoso.com</Url>
</Content>
</Envelope>
Found that the XmlAttributeOverrides class has a solution for this problem. Adding the following method to the Envelope class causes the ToXml() extension method to serialise the object as required.
public string ToXml()
{
return ToXml(typeof(TContent).Name);
}
public string ToXml(string contentElementName)
{
XmlElementAttribute element = new XmlElementAttribute(contentElementName, typeof(TContent));
XmlAttributes attributes = new XmlAttributes();
attributes.XmlElements.Add(element);
XmlAttributeOverrides overrides = new XmlAttributeOverrides();
overrides.Add(typeof(Envelope<TContent>), "Content", attributes);
return ToXml(this, overrides);
}
public string ToXml(Envelope<TContent> value, XmlAttributeOverrides overrides)
{
using (var sw = new Utf8StringWriter())
{
var settings = new XmlWriterSettings
{
OmitXmlDeclaration = omitXmlDeclaration,
Indent = true
};
XmlSerializer xs = new XmlSerializer(typeof(Envelope<TContent>), overrides);
using (XmlWriter writer = XmlWriter.Create(sw, settings))
{
xs.Serialize(writer, value);
}
return sw.ToString();
}
}
When using a standard .NET Xml Serializer, is there any way I can hide all null values? The below is an example of the output of my class. I don't want to output the nullable integers if they are set to null.
Current Xml output:
<?xml version="1.0" encoding="utf-8"?>
<myClass>
<myNullableInt p2:nil="true" xmlns:p2="http://www.w3.org/2001/XMLSchema-instance" />
<myOtherInt>-1</myOtherInt>
</myClass>
What I want:
<?xml version="1.0" encoding="utf-8"?>
<myClass>
<myOtherInt>-1</myOtherInt>
</myClass>
You can create a function with the pattern ShouldSerialize{PropertyName} which tells the XmlSerializer if it should serialize the member or not.
For example, if your class property is called MyNullableInt you could have
public bool ShouldSerializeMyNullableInt()
{
return MyNullableInt.HasValue;
}
Here is a full sample
public class Person
{
public string Name {get;set;}
public int? Age {get;set;}
public bool ShouldSerializeAge()
{
return Age.HasValue;
}
}
Serialized with the following code
Person thePerson = new Person(){Name="Chris"};
XmlSerializer xs = new XmlSerializer(typeof(Person));
StringWriter sw = new StringWriter();
xs.Serialize(sw, thePerson);
Results in the followng XML - Notice there is no Age
<Person xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<Name>Chris</Name>
</Person>
Additionally to what Chris Taylor wrote: if you have something serialized as an attribute, you can have a property on your class named {PropertyName}Specified to control if it should be serialized. In code:
public class MyClass
{
[XmlAttribute]
public int MyValue;
[XmlIgnore]
public bool MyValueSpecified;
}
It exists a property called XmlElementAttribute.IsNullable
If the IsNullable property is set to true, the xsi:nil attribute is generated for class members that have been set to a null reference.
The following example shows a field with the XmlElementAttribute applied to it, and the IsNullable property set to false.
public class MyClass
{
[XmlElement(IsNullable = false)]
public string Group;
}
You can have a look to other XmlElementAttribute for changing names in serialization etc.
You can define some default values and it prevents the fields from being serialized.
[XmlElement, DefaultValue("")]
string data;
[XmlArray, DefaultValue(null)]
List<string> data;
I prefer creating my own xml with no auto-generated tags. In this I can ignore creating the nodes with null values:
public static string ConvertToXML<T>(T objectToConvert)
{
XmlDocument doc = new XmlDocument();
XmlNode root = doc.CreateNode(XmlNodeType.Element, objectToConvert.GetType().Name, string.Empty);
doc.AppendChild(root);
XmlNode childNode;
PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(typeof(T));
foreach (PropertyDescriptor prop in properties)
{
if (prop.GetValue(objectToConvert) != null)
{
childNode = doc.CreateNode(XmlNodeType.Element, prop.Name, string.Empty);
childNode.InnerText = prop.GetValue(objectToConvert).ToString();
root.AppendChild(childNode);
}
}
return doc.OuterXml;
}
In my case the nullable variables/elements were all String type. So, I simply performed a check and assigned them string.Empty in case of NULL. This way I got rid of the unnecessary nil and xmlns attributes (p3:nil="true" xmlns:p3="http://www.w3.org/2001/XMLSchema-instance)
// Example:
myNullableStringElement = varCarryingValue ?? string.Empty
// OR
myNullableStringElement = myNullableStringElement ?? string.Empty
private static string ToXml(Person obj)
{
XmlSerializerNamespaces namespaces = new XmlSerializerNamespaces();
namespaces.Add(string.Empty, string.Empty);
string retval = null;
if (obj != null)
{
StringBuilder sb = new StringBuilder();
using (XmlWriter writer = XmlWriter.Create(sb, new XmlWriterSettings() { OmitXmlDeclaration = true }))
{
new XmlSerializer(obj.GetType()).Serialize(writer, obj,namespaces);
}
retval = sb.ToString();
}
return retval;
}
I'm serializing a class like below
XmlSerializerNamespaces namespaces = new XmlSerializerNamespaces();
namespaces.Add(string.Empty, string.Empty);
StringWriter sw = new StringWriter();
XmlSerializer serializer1 = new XmlSerializer(typeof(List<student>), new XmlRootAttribute("Response"));
XmlTextWriter xmlWriter = new XmlTextWriter(sw);
serializer1.Serialize(xmlWriter, ls, namespaces);
sw.ToString()
The result string below
<?xml version="1.0" encoding="utf-16"?>
<Response><student><name>xxx</name></student></Response>
but, How can i add an attribute to the root element(Response)?
like below one
<?xml version="1.0" encoding="utf-16"?>
<Response status="1"><student><name>xxx</name></student></Response>
You just need to mark that property of the class with XmlAttribute, i.e.
class MyClass{
[XmlAttribute("status")]
public string ErrorStatus { get; set; }
}
Edit:
Just realised you are serializing the list directly. Put your list inside a parent class, Response, and add the above attribute to this Response class, then serialise the Response object.
Hope this helps.
You can create another object that contains the list, and then create a property to add the attribute to the root node.
The trick is to preface the list in this new class with an explicit type assignment to the Student type to avoid having your list nested within another parent node.
[XmlType(TypeName = "Response")]
public class ResponseObject
{
[XmlAttribute("status")]
public string file { get; set; }
[XmlElement("Student", Type = typeof(Student))]
public List<Student> studentList { get; set; }
}
Your code would then look like the following
XmlSerializerNamespaces namespaces = new XmlSerializerNamespaces();
namespaces.Add(string.Empty, string.Empty);
StringWriter sw = new StringWriter();
XmlSerializer serializer1 = new XmlSerializer(typeof(ResponseObject));
XmlTextWriter xmlWriter = new XmlTextWriter(sw);
//Creating new object and assign the existing list and status
ResponseObject resp = new ResponseObject();
resp.studentList = ls;
resp.status = 1;
//Serialize with the new object
serializer1.Serialize(xmlWriter, resp, namespaces);
sw.ToString()
When using a standard .NET Xml Serializer, is there any way I can hide all null values? The below is an example of the output of my class. I don't want to output the nullable integers if they are set to null.
Current Xml output:
<?xml version="1.0" encoding="utf-8"?>
<myClass>
<myNullableInt p2:nil="true" xmlns:p2="http://www.w3.org/2001/XMLSchema-instance" />
<myOtherInt>-1</myOtherInt>
</myClass>
What I want:
<?xml version="1.0" encoding="utf-8"?>
<myClass>
<myOtherInt>-1</myOtherInt>
</myClass>
You can create a function with the pattern ShouldSerialize{PropertyName} which tells the XmlSerializer if it should serialize the member or not.
For example, if your class property is called MyNullableInt you could have
public bool ShouldSerializeMyNullableInt()
{
return MyNullableInt.HasValue;
}
Here is a full sample
public class Person
{
public string Name {get;set;}
public int? Age {get;set;}
public bool ShouldSerializeAge()
{
return Age.HasValue;
}
}
Serialized with the following code
Person thePerson = new Person(){Name="Chris"};
XmlSerializer xs = new XmlSerializer(typeof(Person));
StringWriter sw = new StringWriter();
xs.Serialize(sw, thePerson);
Results in the followng XML - Notice there is no Age
<Person xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<Name>Chris</Name>
</Person>
Additionally to what Chris Taylor wrote: if you have something serialized as an attribute, you can have a property on your class named {PropertyName}Specified to control if it should be serialized. In code:
public class MyClass
{
[XmlAttribute]
public int MyValue;
[XmlIgnore]
public bool MyValueSpecified;
}
It exists a property called XmlElementAttribute.IsNullable
If the IsNullable property is set to true, the xsi:nil attribute is generated for class members that have been set to a null reference.
The following example shows a field with the XmlElementAttribute applied to it, and the IsNullable property set to false.
public class MyClass
{
[XmlElement(IsNullable = false)]
public string Group;
}
You can have a look to other XmlElementAttribute for changing names in serialization etc.
You can define some default values and it prevents the fields from being serialized.
[XmlElement, DefaultValue("")]
string data;
[XmlArray, DefaultValue(null)]
List<string> data;
I prefer creating my own xml with no auto-generated tags. In this I can ignore creating the nodes with null values:
public static string ConvertToXML<T>(T objectToConvert)
{
XmlDocument doc = new XmlDocument();
XmlNode root = doc.CreateNode(XmlNodeType.Element, objectToConvert.GetType().Name, string.Empty);
doc.AppendChild(root);
XmlNode childNode;
PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(typeof(T));
foreach (PropertyDescriptor prop in properties)
{
if (prop.GetValue(objectToConvert) != null)
{
childNode = doc.CreateNode(XmlNodeType.Element, prop.Name, string.Empty);
childNode.InnerText = prop.GetValue(objectToConvert).ToString();
root.AppendChild(childNode);
}
}
return doc.OuterXml;
}
In my case the nullable variables/elements were all String type. So, I simply performed a check and assigned them string.Empty in case of NULL. This way I got rid of the unnecessary nil and xmlns attributes (p3:nil="true" xmlns:p3="http://www.w3.org/2001/XMLSchema-instance)
// Example:
myNullableStringElement = varCarryingValue ?? string.Empty
// OR
myNullableStringElement = myNullableStringElement ?? string.Empty
private static string ToXml(Person obj)
{
XmlSerializerNamespaces namespaces = new XmlSerializerNamespaces();
namespaces.Add(string.Empty, string.Empty);
string retval = null;
if (obj != null)
{
StringBuilder sb = new StringBuilder();
using (XmlWriter writer = XmlWriter.Create(sb, new XmlWriterSettings() { OmitXmlDeclaration = true }))
{
new XmlSerializer(obj.GetType()).Serialize(writer, obj,namespaces);
}
retval = sb.ToString();
}
return retval;
}
I have a problem with CDATA deserialization using standard .Net XmlSerializer.
Update: I get XML from external system and I can't influence it's format so I can't make CData be enclosed in a separate Element of Attribute.
Serialization gives this:
<?xml version="1.0" encoding="utf-16"?>
<MyClass xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><![CDATA[Hello, world!]]></MyClass>
Deserialization does not restore object to it's original state.
Here's class that is being serialized:
public class MyClass
{
string _data;
[XmlIgnore]
public string Data
{
get { return _data; }
set { _data = value; }
}
[XmlAnyElement]
public XmlCDataSection CData
{
get { return new XmlDataDocument().CreateCDataSection(Data); }
set { Data = value.Value; }
}
}
Here's the test which fails:
[Test]
public void CData_as_inner_text_test()
{
MyClass item = new MyClass();
item.Data = "Hello, world!";
XmlSerializer serializer = new XmlSerializer(item.GetType());
string serialized;
using (StringWriter sw = new StringWriter())
{
serializer.Serialize(sw, item);
serialized = sw.GetStringBuilder().ToString();
}
MyClass deserialized;
using (StringReader sr = new StringReader(serialized))
{
deserialized = (MyClass)serializer.Deserialize(sr);
}
Assert.AreEqual(item.Data, deserialized.Data); // For some reason, deserialized.Data == null
}
I found the same problem here but there's no answer:
XmlSerializer, XmlAnyElement and CDATA
The CData property ends up null, because the content of the CDATA section ends up in the Data property, where it is being ignored...
<MyClass><![CDATA[Hello, world!]]></MyClass>
is absolutely equivalent to:
<MyClass>Hello, world!</MyClass>
You shouldn't care whether the external app writes the content of MyClass as CData or not. Likewise, the external app shouldn't care how you write it out.
IOW, this should be all you need:
public class MyClass
{
string _data;
[XmlText]
public string Data
{
get { return _data; }
set { _data = value; }
}
}
First declare a property as XmlCDataSection
public XmlCDataSection ProjectXml { get; set; }
in this case projectXml is a string xml
ProjectXml = new XmlDocument().CreateCDataSection(projectXml);
when you serialize your message you will have your nice format (notice )
<?xml version="1.0" encoding="utf-16"?>
<MessageBase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xsi:type="Message_ProjectStatusChanged">
<ID>131</ID>
<HandlerName>Plugin</HandlerName>
<NumRetries>0</NumRetries>
<TriggerXml><![CDATA[<?xml version="1.0" encoding="utf-8"?><TmData xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" Version="9.0.0" Date="2012-01-31T15:46:02.6003105" Format="1" AppVersion="10.2.0" Culture="en-US" UserID="0" UserRole=""><PROJECT></PROJECT></TmData>]]></TriggerXml>
<MessageCreatedDate>2012-01-31T20:28:52.4843092Z</MessageCreatedDate>
<MessageStatus>0</MessageStatus>
<ProjectId>0</ProjectId>
<UserGUID>8CDF581E44F54E8BAD60A4FAA8418070</UserGUID>
<ProjectGUID>5E82456F42DC46DEBA07F114F647E969</ProjectGUID>
<PriorStatus>0</PriorStatus>
<NewStatus>3</NewStatus>
<ActionDate>0001-01-01T00:00:00</ActionDate>
</MessageBase>