How to add attributes for C# XML Serialization

Question

I am having an issue with serializing and object, I can get it to create all the correct outputs except for where i have an Element that needs a value and an attribute. Here

Answer 1

It sounds like you need an extra class:

public class Document
{
    [XmlAttribute("type")]
    public string Type { get; set; }
    [XmlText]
    public string Name { get; set; }
}

Where an instance (in the example) would have Type = "word" and Name = "document name"; documents would be a List<Document>.

By the way - public fields are rarely a good idea...

Answer 2

You can use XmlWriter instead XmlSerialization to get this effect. It is more complex but if you have a lot of strings in model it will be cleaner solution.

Create your own CustomeAttribute, for example:

[System.AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
public class MyCustomAttribute : System.Attribute
{
    public MyCustomAttribute (string type)
    {
        MyType = type;
    }
    public string MyType { get; set; }
}

Then in model add it, like that:

public class MyModel
{
    [MyCustom("word")]
    public string Document { get; set; }
    [MyCustom("time")]
    public string Time { get; set; }
}

The last part is to create xml with this arguments. You can do it likes that:

        var doc = new XmlDocument();
        MyModel myModel = new MyModel();//or get it from somewhere else
        using (Stream s = new MemoryStream())
        {
            var settings = new XmlWriterSettings();
            settings.Async = true;
            settings.Indent = true;
            var writer = XmlTextWriter.Create(s, settings);
            await writer.WriteStartDocumentAsync();
            await writer.WriteStartElementAsync(null,"Root", null);

            myModel.GetType().GetProperties().ToList().ForEach(async p =>
            {
                dynamic value = p.GetValue(myModel);
                writer.WriteStartElement(p.Name);
                var myCustomAttribute = p.GetCustomAttributes(typeof(MyCustomAttribute), false).FirstOrDefault() as MyCustomAttribute;
                if(myCustomAttribute != null)
                {
                    await writer.WriteAttributeStringAsync(null, "MyType", null, myCustomAttribute.MyType );
                }

                writer.WriteValue(value);
                await writer.WriteEndElementAsync();
            });

            await writer.WriteEndElementAsync();
            await writer.FlushAsync();
            s.Position = 0;
            doc.Load(s);                
            writer.Close();
        }
        string myXml = doc.OuterXml

In myXml should be something like that: (values are examples)

<?xml version="1.0" encoding="utf-8"?>
<Root>
    <Document MyType="word">something</Document>
    <Time MyType="time">11:31:29</Time>
</Root>

You can do it in other way, of course. Here you have some docs which helped me: https://docs.microsoft.com/en-us/dotnet/api/system.xml.xmlwriter?view=netframework-4.8#writing_elements

Answer 3

Where do you have the type stored?

Normally you could have something like:

class Document {
    [XmlAttribute("type")]
    public string Type { get; set; }
    [XmlText]
    public string Name { get; set; }
}


public class _Filter    
{
    [XmlElement("Times")]    
    public _Times Times;    
    [XmlElement("Document")]    
    public Document Document;    
}

Answer 4

The string class doesn't have a type property, so you can't use it to create the desired output. You should create a Document class instead :

public class Document
{
    [XmlText]
    public string Name;

    [XmlAttribute("type")]
    public string Type;
}

And you should change the Document property to type Document