背景： 我正在开发一个控制台应用程序，每行保存到指定的日期日志文件（例如2017年1月5日是01_05_2017_log_.txt）
每个日志都按其应有的方式添加，但我似乎无法弄清楚的问题是为什么它会再次添加包含日志值的List的所有先前值。
因此，当调用CurrentLogs.Add("Some log here")时，它会将Some log here添加到CurrentLogs列表中。
让我们再次调用它，但这次使用的字符串是another log here。列表中的项目如下：
如果我再次尝试使用.Add方法，则会重新添加3个
我看了看周围的方式，bing，google，无济于事。
// This is the List object I'm using.
public class LoggerList<T> : List<T>
{
public event EventHandler OnAdd;
public new void Add(T item)
{
OnAdd?.Invoke(this, null);
base.Add(item);
}
}
现在这里是Logger类，其中Logger.CurrentLogs.Add()被称为f rom
public class Logger
{
// Directory in which logs are stored
private static string _loggerPath = "Logs/";
// Used to check if the Old Logs have already been added to the OldLogs Object
private static bool _alreadyPulled = false;
// Previously saved logs before the current use of the console app
private static readonly List<string> OldLogs = new List<string>();
// Current logs to be added here
public static LoggerList<string> CurrentLogs = new LoggerList<string>();
//EventHandler to Save Logs on add
public static void OnAdd(object sender, EventArgs e)
{
SaveLog();
}
/// <summary>
/// Saves the logs
/// </summary>
public static void SaveLog()
{
if (!Directory.Exists(_loggerPath))
{
Directory.CreateDirectory(_loggerPath);
}
string fileName = _loggerPath + DateTime.Now.ToString("MM_dd_yyyy") + "_log_.txt";
// If the File Exists, contiue with loading
if (File.Exists(fileName))
{
// If the OldLogs have not already been pulled, pull them
if (!_alreadyPulled)
{
var oldLogs = File.ReadAllLines(fileName).ToList();
foreach (var i in oldLogs)
{
OldLogs.Add(i);
}
_alreadyPulled = true; // Let know that the OldLogs have already been pulled this instance
}
List<string> lines = OldLogs;
lines.AddRange(CurrentLogs);
File.Delete(fileName);
var sr = File.CreateText(fileName);
foreach (string x in lines)
{
sr.WriteLine(x);
}
sr.Flush();
sr.Close();
}
// Only go here if the file doesn't exist
else
{
var sr = File.CreateText(fileName);
foreach (string x in CurrentLogs)
{
sr.WriteLine(x);
}
sr.Flush();
sr.Close();
}
}
}
这是Program.cs（添加此项，因为这是调用Messenger类的地方
课程
{
static void Main（string [] args）
{
Logger.CurrentLogs.OnAdd + = Logger.OnAdd;
CommandManager.InitCommands（）;
CheckForEntries（）;
}
private static void CheckForEntries()
{
while (true)
{
Console.ForegroundColor = ConsoleColor.White;
var text = Console.ReadLine();
try
{
if (!SendEntry(text))
{
Console.WriteLine("Failed to send");
}
}
catch (CommandNotFoundException ex)
{
Messenger.Send("Commmand does not exist (" + text.GetWords()[0] + ")");
}
}
}
private static bool SendEntry(string text)
{
try
{
if (text.FirstCharacter() != "/")
{
return false;
}
else
{
string text2 = text.Substring(1);
string commandname = text2.GetWords()[0];
foreach (Command c in CommandManager.RegisteredCommands)
{
if (c.Name.ToLower() == commandname.ToLower())
{
c.Run(text2.Substring(commandname.Length));
return true;
}
else
{
foreach (string alias in c.Aliases)
{
if (alias.ToLower() == commandname.ToLower())
{
c.Run(text2.Substring(commandname.Length + 1));
return true;
}
}
}
}
throw new CommandNotFoundException();
}
}
catch (CommandNotFoundException ex)
{
throw ex; // Placed here so that the catch (Exception) does not go beyond
}
catch (Exception ex)
{
Console.WriteLine(ex);
return false;
}
}
}
这里是Messenger.cs（.Add直接发生的地方）
// Color codes
private static readonly string[] codes =
{
"0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
"a", "b", "c", "d", "e", "f"
};
private static string Format(string rawText)
{
return "&e" + TimeStamp() + " " + rawText;
}
public static string TimeStamp()
{
return "<" + DateTime.Now.ToString("MM/dd/yyyy hh:mm:ss") + ">";
}
public static void Send(string textRaw)
{
Logger.CurrentLogs.Add(Format(textRaw).Substring(2));
string text = Format(textRaw);
List<int> skipOver = new List<int>();
for (int txt = 0; txt <= text.Length - 1; txt++)
{
char[] chars = text.ToCharArray();
if (chars[txt].ToString() == "&")
{
List<string> hi = codes.ToList();
if (hi.Contains(chars[txt + 1].ToString().ToLower()))
{
skipOver.Add(txt);
skipOver.Add(txt + 1);
}
}
}
for (int x = 0; x <= text.Length - 1; x++)
{
char[] chars = text.ToCharArray();
if (chars[x] == "&".ToCharArray()[0]) continue;
if (x <= 1 || skipOver.Contains(x)) continue;
char behind2 = chars[x - 2];
char behind1 = chars[x - 1];
if (behind2.ToString() == "&")
{
bool isGoodCode = false;
foreach (string s in codes)
{
if (s.ToLower() == behind1.ToString().ToLower())
{
isGoodCode = true;
}
}
if (isGoodCode)
{
skipOver.Add(x - 2);
skipOver.Add(x - 1);
if (x < text.Length - 1)
{
Color baseColor = ToColor(behind1.ToString());
ConsoleColor cColor = ToConsoleColor(baseColor);
Console.ForegroundColor = cColor;
Console.Write(chars[x]);
}
else if (x == text.Length - 1)
{
Color baseColor = ToColor(behind1.ToString());
ConsoleColor cColor = ToConsoleColor(baseColor);
Console.ForegroundColor = cColor;
Console.WriteLine(chars[x]);
}
}
else
{
if (x < text.Length - 1)
{
Console.Write(chars[x - 2]);
Console.Write(chars[x - 1]);
Console.Write(chars[x]);
}
else if (x == text.Length - 1)
{
Console.Write(chars[x - 2]);
Console.Write(chars[x - 1]);
Console.WriteLine(chars[x]);
}
}
}
else
{
if (x < text.Length - 1)
{
Console.Write(chars[x]);
}
else if (x == text.Length - 1)
{
Console.WriteLine(chars[x]);
}
}
}
}
答案 0 :(得分：2)
在这些行中
List<string> lines = OldLogs;
lines.AddRange(CurrentLogs);
＆＃34;线＆＃34;指向与＃34; OldLogs＆＃34;相同的对象。因此，您不断在同一列表中添加条目。
您可以尝试复制：
var lines = new List<string>(OldLogs);