按照@EBrown的建议，一种可能性是读取字符串变量中的文件内容，并用正确的& 符号替换表示XML & ，然后解析XML结构.可能的解决方案如下所示:

As @EBrown suggested, one possibility would be read the file content in a string variable and replace the & symbol with the correct representation for propert XML & and then parse the XML structure. A possible solution could look like this:

var xmlContent = File.ReadAllText(@"nuevo.xml");
XmlDocument doc;
doc = new XmlDocument();
doc.LoadXml(xmlContent.Replace("&", "&"));

XmlNodeList Xpersonas = doc.GetElementsByTagName("personas");
XmlNodeList Xlista = ((XmlElement)Xpersonas[0]).GetElementsByTagName("edad");

foreach (XmlElement nodo in Xlista)
{
    string edad = nodo.GetAttribute("edad");
    string nombre = nodo.InnerText;
    Console.WriteLine(nodo.InnerXml.Replace("&", "&"));
}

输出为:

34 & 34 

如果可以使用LINQ2XML，则解决方案甚至更短，并且无需编写反向(第二)替换，因为LINQ2XML会自动为您做到这一点:

If it is ok to use LINQ2XML, then the solution is even shorter, and there is no need to write the reverse(second) replace, because LINQ2XML make this for you automatically:

var xmlContent = File.ReadAllText(@"nuevo.xml");
var xmlDocument = XDocument.Parse(xmlContent.Replace("&", "&"));
var edad = xmlDocument.Root.Element("edad").Value;
Console.WriteLine(edad);

输出与上面相同.