如何在序列化时加入encoding属性？

Question

代码如下：        public static string ToXml(object o)
        {
            var returnval = string.Empty;
            XmlSerializer xs = new XmlSerializer(typeof(PGFF));
            using (MemoryStream ms = new MemoryStream())
            {
                xs.Serialize(ms, o);
                returnval = System.Text.Encoding.UTF8.GetString(ms.ToArray());
                ms.Close();
            }
            return returnval;
        }
返回的xml<?xml version="1.0"?>
<PGFF version="0.0.1">
  <Guid>00000000-0000-0000-0000-000000000000</Guid>
  <Screens>
......
这里第一行 <?xml 里没有 Encoding属性，如何在序列化时加入?

Answer 1

用 XmlWriter + XmlWriterSetting
var result = string.Empty;
XmlSerializer xs = new XmlSerializer(obj.GetType());
XmlWriterSettings xws = new XmlWriterSettings();
Encoding utf8 = Encoding.UTF8;
xws.Encoding = utf8;
using (MemoryStream ms = new MemoryStream())
{
    using (XmlWriter xw = XmlWriter.Create(ms, xws))
    {
        xs.Serialize(xw, obj);
        result = utf8.GetString(ms.ToArray());
    }
}
return result;

Answer 2

上面的代码生成的XML在ie中无法浏览，重写了一下：
     public new string ToXml()
        {
            var result = string.Empty;
            XmlSerializer xs = new XmlSerializer(typeof(PGFF));
            using (MemoryStream ms = new MemoryStream())
            {
                using (TextWriter tw = new StreamWriter(ms, new UTF8Encoding()))
                {
                    xs.Serialize(tw, this);
                    result = Encoding.UTF8.GetString(ms.ToArray());
                }
            }
            return result;
        }