C＃序列化xmlwriter字符串编写器内存不足，无法使用大型对象

Question

I am managing a large project and need to serialize and send an object in xml format. The object is ~130 mb.

(NOTE: I did not write this project, so making edits outside of this method, or drastically changing the architecture is not an option. It works great normally, but when the object is this large, it throws out of memory exception. I need to do it another way to handle large objects.)

The current code is this:

public static string Serialize(object obj)
{
    string returnValue = null;

    if (null != obj)
    {
        System.Runtime.Serialization.DataContractSerializer formatter = new System.Runtime.Serialization.DataContractSerializer(obj.GetType());

        XDocument document = new XDocument();

        System.IO.StringWriter writer = new System.IO.StringWriter();
        System.Xml.XmlTextWriter xmlWriter = new XmlTextWriter(writer);

        formatter.WriteObject(xmlWriter, obj);
        xmlWriter.Close();

        returnValue = writer.ToString();
    }

    return returnValue;
}

It is throwing an out of memory exception right at returnValue = writer.ToString().

I rewrote it to use "using" blocks which I prefer:

public static string Serialize(object obj)
    {
        string returnValue = null;
        if (null != obj)
        {
            System.Runtime.Serialization.DataContractSerializer formatter = new System.Runtime.Serialization.DataContractSerializer(obj.GetType());
            using (System.IO.StringWriter writer = new System.IO.StringWriter())
            {
                using (System.Xml.XmlTextWriter xmlWriter = new XmlTextWriter(writer))
                {
                    formatter.WriteObject(xmlWriter, obj);
                    returnValue = writer.ToString();
                }
            }
        }
        return returnValue;
    }

researching this, it appears the ToString method on StringWriter actually uses double the RAM. (I actually have plenty of RAM free, over 4 gb, so not really sure why I am getting an out of memory error).

Answer 1

Well, I found the best solution was to serialize to a file directly, then instead of passing a string along, I pass the file:

public static void Serialize(object obj, FileInfo destination)
{
    if (null != obj)
    {
        using (TextWriter writer = new StreamWriter(destination.FullName, false))
        {
            XmlTextWriter xmlWriter = null;
            try
            {
                xmlWriter = new XmlTextWriter(writer);
                DataContractSerializer formatter = new DataContractSerializer(obj.GetType());
                formatter.WriteObject(xmlWriter, obj);
            }
            finally
            {
                if (xmlWriter != null)
                {
                    xmlWriter.Flush();
                    xmlWriter.Close();
                }
            }
        }
    }
}

Of course, now I have another problem which I will post ... and that is deserializing the file!