Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
368 views
in Technique[技术] by (71.8m points)

c# - streaming XML serialization in .net

I'm trying to serialize a very large IEnumerable<MyObject> using an XmlSerializer without keeping all the objects in memory.

The IEnumerable<MyObject> is actually lazy..

I'm looking for a streaming solution that will:

  1. Take an object from the IEnumerable<MyObject> Serialize it to the underlying stream using the standard serialization (I don't want to handcraft the XML here!)
  2. Discard the in memory data and move to the next

I'm trying with this code:

using (var writer = new StreamWriter(filePath))
{
 var xmlSerializer = new XmlSerializer(typeof(MyObject));
  foreach (var myObject in myObjectsIEnumerable)
  {
   xmlSerializer.Serialize(writer, myObject);
  }
}

but I'm getting multiple XML headers and I cannot specify a root tag <MyObjects> so my XML is invalid.

Any idea?

Thanks

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

The XmlWriter class is a fast streaming API for XML generation. It is rather low-level, MSDN has an article on instantiating a validating XmlWriter using XmlWriter.Create().

Edit: link fixed. Here is sample code from the article:

async Task TestWriter(Stream stream) 
{
    XmlWriterSettings settings = new XmlWriterSettings();
    settings.Async = true;

    using (XmlWriter writer = XmlWriter.Create(stream, settings)) {
        await writer.WriteStartElementAsync("pf", "root", "http://ns");
        await writer.WriteStartElementAsync(null, "sub", null);
        await writer.WriteAttributeStringAsync(null, "att", null, "val");
        await writer.WriteStringAsync("text");
        await writer.WriteEndElementAsync();
        await writer.WriteCommentAsync("cValue");
        await writer.WriteCDataAsync("cdata value");
        await writer.WriteEndElementAsync();
        await writer.FlushAsync();
    }
}

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...