如何向XML元素添加xsi:type属性

Question

如何在xml元素中添加xsi:type

我正在用c#写一个例程，它使用XmlSerializer序列化Xml文件。一切似乎都很好，只是有一件事我起初以为是小事，结果却不是。

这是我的代码，

public class OuterElement
        {
            public string firstElement { get; set; }
            public string secondElement { get; set; }
            public InnerElement innerElement = new InnerElement();
        }
        public class InnerElement
        {            
            [XmlAttribute(AttributeName="xsi:type")]
            public string type { get; set; }
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            XmlSerializer serializer = new XmlSerializer(typeof(OuterElement));
            OuterElement outerElement = new OuterElement();
            outerElement.firstElement = "name";
            outerElement.secondElement = "CD";
            outerElement.innerElement.type = "testsample";
            using (TextWriter writer = new StreamWriter(@"G:abc.xml"))
            {
                serializer.Serialize(writer, outerElement);
            }
        }

我想要这样的xml，

<OuterElement xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" lns:xsd="http://www.w3.org/2001/XMLSchema">
    <innerElement xsi:type="testsample">     
    </innerElement>
    <firstElement>name</firstElement> 
    <secondElement>CD</secondElement> 
</OuterElement>

Answer 1

您需要为属性声明正确的名称空间，如下所示:

public class InnerElement
{
    [XmlAttribute(Namespace = "http://www.w3.org/2001/XMLSchema-instance")]
    public string type = "bla";
}

这将产生您想要的输出:

<OuterElement xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <innerElement xsi:type="testsample" />
    <firstElement>name</firstElement>
    <secondElement>CD</secondElement>
</OuterElement>

Answer 2

您需要使用XmlTypeAttribute

[XmlType("testsample")]
public class InnerElement
{
} 

这将产生如下结果:

<innerElement xsi:type="testsample" />