XElement.ToString() 默认会把\r\n, \n转化成默认换行符（有的环境是\n，也有的环境是\r\n），若不想自动转化可以采用 NewLineHandling.None：

 1 string xmlString;
 2 
 3 var settings = new XmlWriterSettings
 4 {
 5     OmitXmlDeclaration = true,
 6     NewLineHandling = NewLineHandling.None
 7 };
 8 
 9 using (var sw = new StringWriter())
10 {
11     using (var xw = XmlWriter.Create(sw, settings))
12     {
13         node.WriteTo(xw);
14     }
15 
16     xmlString = sw.ToString();
17 }
Write with NewLineHandling.None

测试代码：

转义字符：

\r: 

\n: 


&: &

<: &lt;

>: &gt;

 

 1 public static void TestXml()
 2 {
 3     var str = "<Root><string>Value1a&#xA;Value1b&#xD;&#xA;Value1c</string></Root>";
 4     
 5      var xDoc = XDocument.Parse(str);
 6     var element = xDoc.Descendants("string").First();
 7     var value = element.Value;
 8     Console.WriteLine("1. Element plain value: {0}", value);
 9     Console.WriteLine("\r\nBelow log will show \\r \\n as visible characters.\r\n");
10     Console.WriteLine("2. Element Value Show new line character: {0}", value.Replace("\r", "\\r").Replace("\n", "\\n"));
11     
12     Console.WriteLine("3. Element.ToString(): {0}", element.ToString().Replace("\r", "\\r").Replace("\n", "\\n"));
13     
14     var settings = new XmlWriterSettings
15     {
16         OmitXmlDeclaration = true,        
17         NewLineHandling =  NewLineHandling.None
18     };
19     
20     string xmlStr;
21     using (var sw = new StringWriter())
22     {
23         using (var xw = XmlWriter.Create(sw, settings))
24         {
25             element.WriteTo(xw);                    
26         }
27         
28         xmlStr = sw.ToString();
29         Console.WriteLine("4. Serialize with NewLineHandling.None: {0}", xmlStr.Replace("\r", "\\r").Replace("\n", "\\n"));
30     }    
31     
32     using (var reader = new StringReader(xmlStr)) // If only use StringReader, it will convert \r\n to \n
33     {
34         var ser = new XmlSerializer(typeof(string));
35         value = (string)ser.Deserialize(reader);
36         Console.WriteLine("5. Deserialize with StringReader: {0}", value.Replace("\r", "\\r").Replace("\n", "\\n"));
37     }
38     
39     using (var reader = new XmlTextReader(new StringReader(xmlStr))) // If use XmlTextReader it will keep \r and \n
40     {
41         var ser = new XmlSerializer(typeof(string));
42         value = (string)ser.Deserialize(reader);
43         Console.WriteLine("6. Deserialize with XmlTextReader: {0}", value.Replace("\r", "\\r").Replace("\n", "\\n"));
44     }
45 }

 

在windows 10 上测试：

1. Element plain value: Value1a
Value1b
Value1c

Below log will show \r \n as visible characters.

2. Element Value Show new line character: Value1a\nValue1b\r\nValue1c
3. Element.ToString(): <string>Value1a\r\nValue1b\r\nValue1c</string>
4. Serialize with NewLineHandling.None: <string>Value1a\nValue1b\r\nValue1c</string>
5. Deserialize with StringReader: Value1a\nValue1b\nValue1c
6. Deserialize with XmlTextReader: Value1a\nValue1b\r\nValue1c