XML中特殊字符转义

 /// <summary>
 /// 特殊字符转义
 /// </summary>
 /// <param name="xml"></param>
 /// <returns></returns>
 public string XmlCharacterEscaping(string xml)
 {
     string xmlNew = xml;
     if (xml.IndexOf("&") != -)
     {
         xmlNew = xml.Replace("&", "&amp;");
     }
     if (xml.IndexOf("<") != -)
     {
         xmlNew = xml.Replace("<", "&lt;");
     }
     if (xml.IndexOf(">") != -)
     {
         xmlNew = xml.Replace(">", "&gt;");
     }
     if (xml.IndexOf('"') != -)
     {
         char c = '"';
         xmlNew = xml.Replace(c.ToString(), "&quot;");
     }
     return xmlNew;
 }