我有以下类(class)定义
[XmlRoot(ElementName = "person",Namespace = "MyNamespace")]
public class Person : IXmlSerializable
{
public string FirstName { get; set; }
[XmlNamespaceDeclarations]
public XmlSerializerNamespaces Namespaces
{
get
{
var xmlSerializerNamespaces = new XmlSerializerNamespaces();
xmlSerializerNamespaces.Add("My", "MyNamespace");
return xmlSerializerNamespaces;
}
}
public string LastName { get; set; }
public XmlSchema GetSchema()
{
return null;
}
/// <exception cref="NotSupportedException"/>
public void ReadXml(XmlReader reader)
{
throw new NotSupportedException();
}
public void WriteXml(XmlWriter writer)
{
writer.WriteElementString("firstName",FirstName);
writer.WriteElementString("lastName", LastName);
}
}
一个我想用 My:MyNamespace的前缀序列化它,所以当我调用代码时
var xmlSerializer = new XmlSerializer(typeof(Person));
var person = new Person
{ FirstName = "John",LastName = "Doe"};
xmlSerializer.Serialize(Console.Out, person, person.Namespaces);
我期望以下输出:
<?xml version="1.0" encoding="ibm850"?>
<My:person xmlns:My="MyNamespace">
<My:firstName>John</My:firstName>
<My:lastName>Doe</My:lastName>
</My:person>
但是取而代之的是,我得到以下输出:
<?xml version="1.0" encoding="ibm850"?>
<person xmlns="MyNamespace">
<firstName>John</firstName>
<lastName>Doe</lastName>
</person>
我知道当我使用 SerializableAttribute 属性而不是从 IXmlSerializable 继承时,写前缀是可行的,但是我在项目中的类复杂得多,并且我不能使用默认的XmlSerializer。
最佳答案
XmlSerializer
类型不提供任何开箱即用的功能来处理此问题。
如果您确实需要使用XmlSerializer
,那么您将获得一个自定义的XmlSerializer
实现,该实现还没有扩展的余地。因此,下面的实现更多是概念验证,只是为了给您一个想法或起点。
为了简洁起见,我省略了任何错误处理,仅关注您问题中的Person
类。还有一些工作要做,以处理任何嵌套的复杂属性。
由于Serialize
方法不是virtual
,我们将不得不对其进行阴影处理。主要思想是将所有重载定向到具有自定义实现的单个重载。
由于是自定义的,因此在通过指定要应用的xml命名空间为其属性编写xml元素时,我们必须在Person
类中更加明确。
下面的代码
PrefixedXmlSerializer xmlSerializer = new PrefixedXmlSerializer(typeof(Person));
Person person = new Person {
FirstName = "John",
LastName = "Doe"
};
xmlSerializer.Serialize(Console.Out, person, person.Namespaces);
结果是
<My:person xmlns:My="MyNamespace">
<My:firstName>John</My:firstName>
<My:lastName>Doe</My:lastName>
</My:person>
您可以考虑这一切是否可以接受。
最后,
<My:person xmlns:My="MyNamespace">
等于<person xmlns="MyNamespace">
。人
[XmlRoot(ElementName = "person", Namespace = NAMESPACE)]
public class Person : IXmlSerializable
{
private const string NAMESPACE = "MyNamespace";
public string FirstName { get; set; }
[XmlNamespaceDeclarations]
public XmlSerializerNamespaces Namespaces
{
get
{
var xmlSerializerNamespaces = new XmlSerializerNamespaces();
xmlSerializerNamespaces.Add("My", NAMESPACE);
return xmlSerializerNamespaces;
}
}
public string LastName { get; set; }
public XmlSchema GetSchema()
{
return null;
}
/// <exception cref="NotSupportedException"/>
public void ReadXml(XmlReader reader)
{
throw new NotSupportedException();
}
public void WriteXml(XmlWriter writer)
{
// Specify the xml namespace.
writer.WriteElementString("firstName", NAMESPACE, FirstName);
writer.WriteElementString("lastName", NAMESPACE, LastName);
}
}
PrefixedXmlSerializer
public class PrefixedXmlSerializer : XmlSerializer
{
XmlRootAttribute _xmlRootAttribute;
public PrefixedXmlSerializer(Type type) : base(type)
{
this._xmlRootAttribute = type.GetCustomAttribute<XmlRootAttribute>();
}
public new void Serialize(TextWriter textWriter, Object o, XmlSerializerNamespaces namespaces)
{
// Out-of-the-box implementation.
XmlTextWriter xmlTextWriter = new XmlTextWriter(textWriter);
xmlTextWriter.Formatting = Formatting.Indented;
xmlTextWriter.Indentation = 2;
// Call the shadowed version.
this.Serialize(xmlTextWriter, o, namespaces, null, null);
}
public new void Serialize(XmlWriter xmlWriter, Object o, XmlSerializerNamespaces namespaces, String encodingStyle, String id)
{
// Lookup the xml namespace and prefix to apply.
XmlQualifiedName[] xmlNamespaces = namespaces.ToArray();
XmlQualifiedName xmlRootNamespace =
xmlNamespaces
.Where(ns => ns.Namespace == this._xmlRootAttribute.Namespace)
.FirstOrDefault();
// Write the prefixed root element with its xml namespace declaration.
xmlWriter.WriteStartElement(xmlRootNamespace.Name, this._xmlRootAttribute.ElementName, xmlRootNamespace.Namespace);
// Write the xml namespaces; duplicates will be taken care of automatically.
foreach (XmlQualifiedName xmlNamespace in xmlNamespaces)
{
xmlWriter.WriteAttributeString("xmlns", xmlNamespace.Name , null, xmlNamespace.Namespace);
}
// Write the actual object xml.
((IXmlSerializable)o).WriteXml(xmlWriter);
xmlWriter.WriteEndElement();
}
}
关于xml-serialization - 如何为IXmlSerializable类型添加 namespace 前缀,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/51590112/