Mono - XDocument.Load因LoadOptions.PreserveWhitespace而失败

Question

使用Mono版本2.10.5，以下代码在任何XML文档上都会失败：

using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Xml.Linq;

namespace TestXDocument
{
    class MainClass
    {
        public static void Main (string[] args)
        {
            Stream s = File.Open("Settings.xml", FileMode.Open);
            XDocument d = XDocument.Load(s, LoadOptions.PreserveWhitespace);
            s.Close();
            d.Save("Settings.xml");
        }
    }
}

只有当XDocument.Load使用LoadOptions.PreserveWhitespace时，才会发生这种情况。对于如何解决这个问题，有什么想法吗？

在Linux Mint 12和Ubuntu 11.10上测试。

下面是一个例外：

 Unhandled Exception: System.InvalidOperationException: This XmlWriter does not accept Text at this state Prolog.
  at System.Xml.XmlTextWriter.ShiftStateContent (System.String occured, Boolean allowAttribute) [0x00000] in <filename unknown>:0 
  at System.Xml.XmlTextWriter.WriteString (System.String text) [0x00000] in <filename unknown>:0 
  at System.Xml.DefaultXmlWriter.WriteString (System.String text) [0x00000] in <filename unknown>:0 
  at System.Xml.Linq.XText.WriteTo (System.Xml.XmlWriter w) [0x00000] in <filename unknown>:0 
  at System.Xml.Linq.XDocument.WriteTo (System.Xml.XmlWriter w) [0x00000] in <filename unknown>:0 
  at System.Xml.Linq.XDocument.Save (System.Xml.XmlWriter w) [0x00000] in <filename unknown>:0 
  at System.Xml.Linq.XDocument.Save (System.String filename, SaveOptions options) [0x00000] in <filename unknown>:0 
  at System.Xml.Linq.XDocument.Save (System.String filename) [0x00000] in <filename unknown>:0 
  at TestXDocument.MainClass.Main (System.String[] args) [0x00000] in <filename unknown>:0 
[ERROR] FATAL UNHANDLED EXCEPTION: System.InvalidOperationException: This XmlWriter does not accept Text at this state Prolog.
  at System.Xml.XmlTextWriter.ShiftStateContent (System.String occured, Boolean allowAttribute) [0x00000] in <filename unknown>:0 
  at System.Xml.XmlTextWriter.WriteString (System.String text) [0x00000] in <filename unknown>:0 
  at System.Xml.DefaultXmlWriter.WriteString (System.String text) [0x00000] in <filename unknown>:0 
  at System.Xml.Linq.XText.WriteTo (System.Xml.XmlWriter w) [0x00000] in <filename unknown>:0 
  at System.Xml.Linq.XDocument.WriteTo (System.Xml.XmlWriter w) [0x00000] in <filename unknown>:0 
  at System.Xml.Linq.XDocument.Save (System.Xml.XmlWriter w) [0x00000] in <filename unknown>:0 
  at System.Xml.Linq.XDocument.Save (System.String filename, SaveOptions options) [0x00000] in <filename unknown>:0 
  at System.Xml.Linq.XDocument.Save (System.String filename) [0x00000] in <filename unknown>:0 
  at TestXDocument.MainClass.Main (System.String[] args) [0x00000] in <filename unknown>:0 

Answer 1

我可以在Ubuntu 11.10上的两个代码示例中重现相同的问题。如你所说，在Windows平台上没有问题。似乎Mono运行时在XDocument的Save方法中有某些bug，从而导致意外错误。我想向Mono运行时团队报告这个问题，以获取软件补丁。

然而，我可以在这里带来的可能的解决方案是，

d.Root.Save("Settings1.xml");

与我们在XDocument中遇到的问题一样，XElement中的保存方法似乎没有任何问题。