我创建了一个类-WhiteList - 包含从xml文件中读取的数据。我想列出这些元素，但是在第一个元素添加到列表后，我创建了一个新的数据元素，它删除了列表中第一个元素的争用。 I.E.似乎新的（元素）重新创建了对列表中元素的引用。
代码段：
namespace WhiteList
{
public class WhiteListElement
{
private const byte EQL = 0;
private const byte CTN = 1;
private const byte COMMON_NAME = 0;
private const byte ORG = 1;
private const byte ORG_UNIT = 2;
private const byte LOC = 3;
private const byte STATE = 4;
private const byte COUNTRY = 5;
private static string[,] Subject;
private static string[,] Issuer;
private static string MinTlsLevel;
private static string Customer;
public WhiteListElement()
{
Subject = new string[6, 2];
Issuer = new string[6, 2];
Customer = "";
MinTlsLevel = "";
}
//---- set/get functions ---- example
public string GetCommonName(bool SubjectVal, bool Name)
{
if (true == SubjectVal) { if (true == Name) return Subject[COMMON_NAME, 0]; else return Subject[COMMON_NAME, 1]; }
else { if (true == Name) return Issuer[COMMON_NAME, 0]; else return Issuer[COMMON_NAME, 1]; }
}
public void SetCommonName(bool SubjectVal, bool Name, string NewValue)
{
if (true == SubjectVal) { if (true == Name) Subject[COMMON_NAME, 0] = NewValue; else Subject[COMMON_NAME, 1] = NewValue; }
else { if (true == Name) Issuer[COMMON_NAME, 0] = NewValue; else Issuer[COMMON_NAME, 1] = NewValue; }
}
}
class Program
{
public static void CreateWhiteList()
{
try
{
using (XmlReader reader = XmlReader.Create("WhiteList.xml"))
{
while (reader.Read())
{
if (reader.NodeType == XmlNodeType.Element)
{
if (reader.Name == "Kunder")
{
while (reader.Read())
{
if (reader.NodeType == XmlNodeType.Element)
{
XElement el = (XElement)XNode.ReadFrom(reader);
if (el != null)
{
WhiteListElement elem = new WhiteListElement();
var noderef = el.FirstNode;
elem.SetCustomer(el.Name.ToString());
while (noderef.NextNode != null)
{
noderef = noderef.NextNode;
string nodestring = noderef.ToString();
if (nodestring[0] == '<')
{
int startindx, stopindx;
string tag = nodestring.Substring(3);
string data;
tag = tag.Substring(0, tag.IndexOf('_'));
startindx = nodestring.IndexOf('\"') + 1;
stopindx = (nodestring.Substring(startindx)).IndexOf('\"');
data = nodestring.Substring(startindx, stopindx);
switch (tag)
{
case "CERTLVL": elem.SetCertLvl(data); break;
case "CN": if (nodestring[1] == 'S') elem.SetCommonName(true, true, data); if (nodestring[1] == 'I') elem.SetCommonName(false, true, data); break;
case "OU": if (nodestring[1] == 'S') elem.SetOrgUnit(true, true, data); if (nodestring[1] == 'I') elem.SetOrgUnit(false, true, data); break;
case "O": if (nodestring[1] == 'S') elem.SetOrg(true, true, data); if (nodestring[1] == 'I') elem.SetOrg(false, true, data); break;
case "L": if (nodestring[1] == 'S') elem.SetLocation(true, true, data); if (nodestring[1] == 'I') elem.SetLocation(false, true, data); break;
case "S": if (nodestring[1] == 'S') elem.SetState(true, true, data); if (nodestring[1] == 'I') elem.SetState(false, true, data); break;
case "C": if (nodestring[1] == 'S') elem.SetCountry(true, true, data); if (nodestring[1] == 'I') elem.SetCountry(false, true, data); break;
}
}
}
CustomerList.Add(elem);
}
}
}
}
}
}
}
}
catch (Exception ex) { Console.WriteLine(ex.Message); throw (ex); }
}
public static List<WhiteListElement>CustomerList = null;
static void Main(string[] args)
{
CustomerList = new List<WhiteListElement>();
CreateWhiteList();
}
}
}
------------- Code snippet end。
将第一个元素放入列表（CustomerList.Add（elem））并返回到“WhiteListElement elem = new WhiteListElement（）;”行后出现问题。这将删除CustomerList [0]中的元素，并且在将数据放入elem之后，它将被插入elem和CustomerList [0]，最后在列表中以两个相同的元素结束。
我甚至试图在添加elem之后添加elem = null只是为了尝试擦除引用，但是这不起作用
我做错了什么？
/卡斯滕
答案 0 :(得分：2)
private static string[,] Subject;
private static string[,] Issuer;
private static string MinTlsLevel;
private static string Customer;
你的问题来自这里，静态成员通过类的所有实例共享，因此当你编辑第二个时，你擦除第一个，你的类应该是这样的
public class WhiteListElement
{
private const byte EQL = 0;
private const byte CTN = 1;
private const byte COMMON_NAME = 0;
private const byte ORG = 1;
private const byte ORG_UNIT = 2;
private const byte LOC = 3;
private const byte STATE = 4;
private const byte COUNTRY = 5;
private string[,] Subject;
private string[,] Issuer;
private string MinTlsLevel;
private string Customer;
public WhiteListElement()
{
Subject = new string[6, 2];
Issuer = new string[6, 2];
Customer = "";
MinTlsLevel = "";
}
//---- set/get functions ---- example
public string GetCommonName(bool SubjectVal, bool Name)
{
if (true == SubjectVal) { if (true == Name) return Subject[COMMON_NAME, 0]; else return Subject[COMMON_NAME, 1]; }
else { if (true == Name) return Issuer[COMMON_NAME, 0]; else return Issuer[COMMON_NAME, 1]; }
}
public void SetCommonName(bool SubjectVal, bool Name, string NewValue)
{
if (true == SubjectVal) { if (true == Name) Subject[COMMON_NAME, 0] = NewValue; else Subject[COMMON_NAME, 1] = NewValue; }
else { if (true == Name) Issuer[COMMON_NAME, 0] = NewValue; else Issuer[COMMON_NAME, 1] = NewValue; }
}
}
编辑：您可以在参考资料中阅读有关静态的更多内容：https://msdn.microsoft.com/fr-fr/library/98f28cdx.aspx
特别是：
虽然类的实例包含该类的所有实例字段的单独副本，但每个静态字段只有一个副本。
无法使用它来引用静态方法或属性访问器。
答案 1 :(得分：1)
首先，我认为Boo的答案可以解决您的问题，但我认为我至少会建议采用更加面向对象的方法，以便将来更轻松地使用/调试此问题：
cmd.exe可以用作：
public class WhiteListElement
{
public string CertLevel;
public static WhiteListElement Create(XElement xml)
{
WhiteListElement element = new WhiteListElement();
element.CertLevel = xml.Attribute("CERTLVL").Value;
// Put data into object...
return element;
}
}
public class WhiteList
{
public List<WhiteListElement> Elements = new List<WhiteListElement>();
public static WhiteList Create(string xmlUri)
{
WhiteList whiteList = new WhiteList();
whiteList.Elements.AddRange(XElement.Load(xmlUri).Descendants("Kunder")
.Where(xmlElement => xmlElement != null)
.Select(xmlElement => WhiteListElement.Create(xmlElement)));
return whiteList;
}
}
使用示例XML：
WhiteList list = WhiteList.Create("WhiteList.xml");
string certLevel1 = list.Elements[0].CertLevel;