读取xml文件时路径错误中有非法字符

我正在尝试读取XML文件的内容。它在加载xml文件的行上抛出错误。
这是一个xml文件的示例

<?xml version="1.0" encoding="ISO-8859-1"?> 
<user userID="1356748"> 
<name first="Joe" last="Sample" /> 
<version>MACHVR</version> 
<aptitude name="Mental Acuity" id="A1">4</aptitude> 
<aptitude name="Business Terms" id="A2">3</aptitude> 
<aptitude name="Memory Recall" id="A3">9</aptitude> 
<aptitude name="Vocabulary" id="A4">4</aptitude> 
<aptitude name="Numerical Perception" id="A5">3</aptitude> 
<aptitude name="Mechanical Interest" id="A6">4</aptitude> 
<aptitude name="Math" id="A7">7</aptitude> 
</user>

这是我用来阅读它的代码

public Assessment GetXMLData(string UserId, string Secondary, string FirstName, string LastName, string AcctPassword)
{
    string URL = "http://www.myurl.com";
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL);
    request.Method = "POST";
    string postdata = "UserId=" + UserID + "&FirstName=" + FirstName +
        "&LastName=" + LastName + "&SecondaryAccount=" + Secondary +
        "&Password=" + AcctPassword;

    byte[] byteArray = Encoding.UTF8.GetBytes(postdata);
    request.ContentType = "application/x-www-form-urlencoded";
    request.ContentLength = byteArray.Length;

    Assessment test = new Assessment();
    Stream dataStream = request.GetRequestStream();
    dataStream.Write(byteArray, 0, byteArray.Length);
    dataStream.Close();
    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
    using (StreamReader streamReader = new StreamReader(response.GetResponseStream()))
    {
        string ResponseFromServer = streamReader.ReadToEnd();

        XDocument doc = XDocument.Load(ResponseFromServer);
        var query = from c in doc.Descendants("aptitude")
                    select c;
                    
        //some more code            
    }
}

错误正在被抛出 XDocument doc = XDocument.Load(ResponseFromServer)

我试着加上@符号,结果是

XDocument doc = XDocument.Load(@ResponseFromServer);

然后我尝试用它来转义字符串中的引号,并保留@符号

ResponseFromServer = ResponseFromServer.Replace("\"","\"\"") XDocument-doc=XDocument。加载(@ResponseFromServer);

我仍然得到错误