XmlWriter.Create 返回包装在 XmlWellFormedWriter 中的特定 XmlRawWriter，所有这些都定义为内部的，因此您无法扩展它们。
但是，您可以扩展 XmlTextWriter，但与格式良好的编写器相比，它的功能集非常有限。
所以...
这是我为处理此问题而制作的自定义 XmlTextWriter，它具有格式良好的编写器所缺少的大部分功能，但 XmlWriterSettings 除外：
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
namespace System.Xml
{
public class CustomXmlTextWriter : XmlTextWriter
{
internal class CustomStreamWriter : StreamWriter
{
public CustomStreamWriter(Stream stream, Encoding encoding) : base(stream) { }
// This prevents the XmlTextWriter from writing the extra space before attributes, and the short EndElement " />"
public bool DisableSpace { get; set; }
public override void Write(char value)
{
if (DisableSpace && value == ' ') return;
else base.Write(value);
}
public override void Write(string value)
{
if (DisableSpace && value == " /") base.Write('/');
else base.Write(value);
}
}
public CustomXmlTextWriter(string filename, XmlWriterSettings settings) : this(new FileStream(filename, FileMode.Create, FileAccess.Write, FileShare.Read), settings) { }
public CustomXmlTextWriter(Stream stream, XmlWriterSettings settings) : this(new CustomStreamWriter(stream, settings.Encoding), settings) { }
internal CustomXmlTextWriter(CustomStreamWriter writer, XmlWriterSettings settings)
: base(writer)
{
m_Writer = writer;
m_Settings = settings;
if (m_Settings.OmitXmlDeclaration == false)
{
string encoding = (m_Writer.Encoding.CodePage == 1201) ? "UTF-16BE" : m_Writer.Encoding.WebName;
m_Writer.WriteLine("<?xml version=\"1.0\" encoding=\"{0}\"?>", encoding);
}
}
private bool m_HasAttributes = false;
private Stack<bool> m_HasAttributesStack = new Stack<bool>();
private CustomStreamWriter m_Writer;
private XmlWriterSettings m_Settings;
public override XmlWriterSettings Settings { get { return m_Settings; } }
public override void WriteStartElement(string prefix, string localName, string ns)
{
if (WriteState == WriteState.Element)
{
if (m_HasAttributes && Settings.NewLineOnAttributes) { WriteIndent(m_HasAttributesStack.Count); }
WriteRaw(""); // Trick the XmlTextWriter into closing the previous element, and updating the WriteState
m_Writer.DisableSpace = false;
}
int indentLevel = m_HasAttributesStack.Count;
if (indentLevel > 0)
{
WriteIndent(indentLevel);
}
m_HasAttributesStack.Push(m_HasAttributes);
m_HasAttributes = false;
base.WriteStartElement(prefix, localName, ns);
}
public override void WriteEndElement()
{
if (m_HasAttributes && Settings.NewLineOnAttributes)
{
WriteIndent(m_HasAttributesStack.Count - 1);
}
m_HasAttributes = m_HasAttributesStack.Pop();
base.WriteEndElement();
m_Writer.DisableSpace = false;
}
public override void WriteFullEndElement()
{
m_HasAttributes = m_HasAttributesStack.Pop();
WriteIndent(m_HasAttributesStack.Count);
base.WriteFullEndElement();
}
public override void WriteStartAttribute(string prefix, string localName, string ns)
{
if (Settings.NewLineOnAttributes)
{
WriteIndent(m_HasAttributesStack.Count);
m_Writer.DisableSpace = true;
}
m_HasAttributes = true;
base.WriteStartAttribute(prefix, localName, ns);
}
public override void WriteString(string text)
{
if (m_Settings.NewLineHandling == NewLineHandling.Replace)
{
text = Regex.Replace(text, @"\r\n?|\n", m_Settings.NewLineChars);
}
else if (m_Settings.NewLineHandling == NewLineHandling.Entitize)
{
text = Regex.Replace(text, @"\n|\r", m => String.Format("&#x{0:X};", (int)m.Value[0]));
}
base.WriteString(text);
}
private void WriteIndent(int indentLevel)
{
if (Settings.Indent == false) return;
m_Writer.Write(Settings.NewLineChars);
for (int i = 0; i < indentLevel; ++i)
{
m_Writer.Write(Settings.IndentChars);
}
}
}
}
只需在您的项目中创建一个包含上述代码的文件，然后像这样使用它：
// Create the XmlWriter Settings as you normally would
// *Note: You can change or omit these, they are just for an example of what I supported
XmlWriterSettings settings = new XmlWriterSettings()
{
Encoding = Encoding.UTF8,
//OmitXmlDeclaration = true,
Indent = true,
//IndentChars = " ",
IndentChars = "\t",
NewLineOnAttributes = true,
//NewLineHandling = NewLineHandling.Entitize,
//NewLineHandling = NewLineHandling.Replace,
//NewLineChars = @"\n",
};
// Replace XmlWriter.Create with new CustomXmlTextWriter
//using (XmlWriter writer = XmlWriter.Create(path, settings))
using (XmlWriter writer = new CustomXmlTextWriter(path, settings))
{
xml.WriteTo(writer);
}
如果这个功能只是作为 XmlWriterSettings 中的一个选项添加到格式良好的编写器中，那就太好了。
有时更改 diff 工具不是一个选项（甚至不是问题所在） 当使用像 perforce 这样的系统通过工具自动合并更改时，最好使更改尽可能原子化。
例如...如果最后一个属性被一个人更改，而另一个属性被另一个人添加到末尾，则没有理由根据哪一行应该包含结束 >（或 /> ）。这种情况的最佳解决方案是，如果右括号在自己的行上，并且一起避免冲突。