validate xml during serialization

问题

This post https://stackoverflow.com/a/1708614/5333340 gives a solution on how to validate an xml during deserialization. It also says that similar code can be written for serialization, but I was not able to figure it out.

Can someone give a hint?

I want to do the validation during serialization, so that, if the validation fails at some point, the serialization stops immediately.

---

Based on the linked answer my deserialization code, where validation takes place, looks like this:

private static readonly XmlSerializer _topSerializer = new XmlSerializer(typeof(top));
private static readonly XmlSettings _settings = ...
    // same as in the linked post, only without `ValidationEventHandler` set

public static top Deserialize(Stream strm)
{
    using (StreamReader input = new StreamReader(strm))
    {
        using (XmlReader reader = XmlReader.Create(input, _settings))
        {
            return (top)_topSerializer.Deserialize(reader);
        }
    }
}

The class top is the class representing the root element of my xml schema; I created the classes with xsd.exe.

This works perfectly; when the xml does not conform to the schema, I get an XmlSchemaValidationException.

---

In order to transfer this approach to my curent serialization code (where no validation takes place), which looks like this

public static void Serialize(top t, Stream strm)
{
    using (XmlWriter wr = XmlWriter.Create(strm))
    {
        _topSerializer.Serialize(wr, t);
    }
}

, I would need to put the XmlReader somewhere, since it's the XmlReader that is needed for validation. But where and how? The XmlReader.Create method takes a TextReader or a Stream as input, so I assume I need to have already put something into the stream before the XmlReader can read it. So

using (XmlReader reader = XmlReader.Create(strm, _settings))
{
    using (XmlWriter wr = XmlWriter.Create(strm))
    {
        _topSerializer.Serialize(wr, t);
    }
}

won't validate the generated xml since the stream is still empty when it goes through the XmlReader. The stream will only be filled AFTER the call of _topSerializier.Serialize, so doing the reading after it makes kind of sense. But then, what to put in there?

using (XmlWriter wr = XmlWriter.Create(strm))
{
    _topSerializer.Serialize(wr, t);

    using (XmlReader reader = XmlReader.Create(strm, _settings))
    {
        // what to do here?
    }
}

(This code also does not validate.)

来源：https://stackoverflow.com/questions/53168867/validate-xml-during-serialization