What is and how to fix System.TypeInitializationException error?

Question

private static void Main(string[] args)
{
    string str = null;
    Logger.InitUserLogWithRotation();            // <--- error occur
    ...
}

When I build project, it has no error. But When I execute it, it always aborted.

I tried to debug project , but System.TypeInitializationException error occurred at first line.

I've already tried to googling , yet found no solution.

It seems like any variable initialize code is wrong , but can't find it.

Please help me. I'm new to C#.

Thanks.

※ Here is Logger Class Code

public class Logger
{
    private static int HDLOG_PRIORITY_DEBUG = 4;
    private static int HDLOG_PRIORITY_ERROR = 1;
    private static int HDLOG_PRIORITY_FATAL = 0;
    private static int HDLOG_PRIORITY_INFO = 3;
    private static int HDLOG_PRIORITY_WARNING = 2;
    public static int LOG_LEVEL_DEBUG = 4;
    public static int LOG_LEVEL_ERROR = 2;
    public static int LOG_LEVEL_FATAL = 1;
    public static int LOG_LEVEL_INFO = 5;
    public static int LOG_LEVEL_WARNING = 3;
    private static string s_bstCommonAppData = Path.Combine(s_commonAppData, "XXXX");
    private static string s_bstUserDataDir = Path.Combine(s_bstCommonAppData, "UserData");
    private static string s_commonAppData = Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData);
    private static bool s_consoleLogging = false;
    private static FileStream s_fileStream;
    public static HdLoggerCallback s_HdLoggerCallback;
    private static string s_logDir = null;
    private static string s_logFileName = "XXXX";
    private static string s_logFilePath = null;
    public static int s_logFileSize = 0xa00000;
    private static bool s_loggerInited = false;
    private static string s_logLevels = null;
    private static int s_logRotationTime = 0x7530;
    private static string s_logStringDebug = "DEBUG";
    private static string s_logStringError = "ERROR";
    private static string s_logStringFatal = "FATAL";
    private static string s_logStringInfo = "INFO";
    private static string s_logStringWarning = "WARNING";
    private static int s_processId = -1;
    private static string s_processName = "Unknown";
    private static object s_sync = new object();
    public static int s_totalLogFileNum = 5;
    private static TextWriter writer = Console.Error;

    private static void Close()
    {
        if (!s_consoleLogging)
        {
            writer.Close();
            s_fileStream.Dispose();
            writer.Dispose();
        }
    }

    public static void Debug(string msg)
    {
        Debug("{0}", new object[] { msg });
    }

    public static void Debug(string fmt, params object[] args)
    {
        Print(LOG_LEVEL_DEBUG, s_processName, fmt, args);
    }

    private static void DoLogRotation()
    {
    Label_0000:
        Thread.Sleep(s_logRotationTime);
        try
        {
            lock (s_sync)
            {
                FileInfo info = new FileInfo(s_logFilePath);
                if (info.Length >= s_logFileSize)
                {
                    string destFileName = s_logFilePath + ".1";
                    string path = s_logFilePath + "." + s_totalLogFileNum;
                    if (File.Exists(path))
                    {
                        File.Delete(path);
                    }
                    for (int i = s_totalLogFileNum - 1; i >= 1; i--)
                    {
                        string str3 = s_logFilePath + "." + i;
                        string str4 = s_logFilePath + "." + (i + 1);
                        if (File.Exists(str3))
                        {
                            File.Move(str3, str4);
                        }
                    }
                    File.Move(s_logFilePath, destFileName);
                }
            }
            goto Label_0000;
        }
        catch (Exception)
        {
            goto Label_0000;
        }
    }

    public static void Error(string msg)
    {
        Error("{0}", new object[] { msg });
    }

    public static void Error(string fmt, params object[] args)
    {
        Print(LOG_LEVEL_ERROR, s_processName, fmt, args);
    }

    public static void Fatal(string msg)
    {
        Fatal("{0}", new object[] { msg });
    }

    public static void Fatal(string fmt, params object[] args)
    {
        Print(LOG_LEVEL_FATAL, s_processName, fmt, args);
    }

    private static string GetLogDir(bool userSpecificLog)
    {
        string str;
        if (s_logDir != null)
        {
            return s_logDir;
        }
        try
        {
            if (userSpecificLog)
            {
                str = Path.Combine(s_bstUserDataDir, "Logs");
            }
            else
            {
                str = (string) Registry.LocalMachine.OpenSubKey(@"Software\XXXX").GetValue("LogDir");
            }
        }
        catch (Exception)
        {
            str = Path.Combine(s_bstUserDataDir, "Logs");
        }
        s_logDir = str;
        return str;
    }

    private static string GetPrefix(string tag, string logLevel)
    {
        int managedThreadId = Thread.CurrentThread.ManagedThreadId;
        DateTime now = DateTime.Now;
        return string.Format("{0:D4}-{1:D2}-{2:D2} {3:D2}:{4:D2}:{5:D2}.{6:D3} {7}:{8:X8} ({9}). {10}: ", new object[] { now.Year, now.Month, now.Day, now.Hour, now.Minute, now.Second, now.Millisecond, s_processId, managedThreadId, tag, logLevel });
    }

    public static TextWriter GetWriter()
    {
        return new Writer(delegate (string msg) {
            Print(msg);
        });
    }

    private static void HdLogger(int prio, uint tid, string tag, string msg)
    {
        int level = 0;
        if (prio == HDLOG_PRIORITY_FATAL)
        {
            level = LOG_LEVEL_FATAL;
        }
        else if (prio == HDLOG_PRIORITY_ERROR)
        {
            level = LOG_LEVEL_ERROR;
        }
        else if (prio == HDLOG_PRIORITY_WARNING)
        {
            level = LOG_LEVEL_WARNING;
        }
        else if (prio == HDLOG_PRIORITY_INFO)
        {
            level = LOG_LEVEL_INFO;
        }
        else if (prio == HDLOG_PRIORITY_DEBUG)
        {
            level = LOG_LEVEL_DEBUG;
        }
        Print(level, tag, "{0:X8}: {1}", new object[] { tid, msg });
    }

    public static void Info(string msg)
    {
        Info("{0}", new object[] { msg });
    }

    public static void Info(string fmt, params object[] args)
    {
        Print(LOG_LEVEL_INFO, s_processName, fmt, args);
    }

    public static void InitConsoleLog()
    {
        InitLog("-", true, false);
    }

    public static void InitLog(string logFileName, bool userSpecificLog, bool doLogRotation)
    {
        s_loggerInited = true;
        s_HdLoggerCallback = new HdLoggerCallback(Logger.HdLogger);
        s_processId = Process.GetCurrentProcess().Id;
        s_processName = Process.GetCurrentProcess().ProcessName;
        if (logFileName == "-")
        {
            writer = Console.Error;
            s_consoleLogging = true;
        }
        else
        {
            if (logFileName == null)
            {
                logFileName = s_logFileName;
            }
            if (userSpecificLog)
            {
                logFileName = logFileName + "Users";
            }
            string logDir = GetLogDir(userSpecificLog);
            string str2 = string.Format(@"{0}\{1}.log", logDir, logFileName);
            if (!Directory.Exists(logDir))
            {
                Directory.CreateDirectory(logDir);
            }
            s_logFilePath = str2;
            LogLevelsInit();
            lock (s_sync)
            {
                Open();
            }
            if (doLogRotation)
            {
                new Thread(() => DoLogRotation()) { IsBackground = true }.Start();
            }
        }
    }

    public static void InitSystemLog()
    {
        InitLog(null, false, false);
    }

    public static void InitSystemLogWithRotation()
    {
        InitLog(null, false, true);
    }

    public static void InitUserLog()
    {
        InitLog(null, true, false);
    }

    public static void InitUserLogWithRotation()
    {
        InitLog(null, true, true);
    }

    private static bool IsLogLevelEnabled(string tag, string level)
    {
        if (s_logLevels == null)
        {
            return false;
        }
        return (s_logLevels.StartsWith("ALL") || s_logLevels.Contains((tag + ":" + level).ToUpper()));
    }

    private static void LogLevelsInit()
    {
        string name = @"Software\XXXX\Config";
        try
        {
            using (RegistryKey key = Registry.LocalMachine.OpenSubKey(name))
            {
                s_logLevels = (string) key.GetValue("DebugLogs");
            }
        }
        catch (Exception)
        {
            return;
        }
        if (s_logLevels != null)
        {
            s_logLevels = s_logLevels.ToUpper();
        }
    }

    private static void Open()
    {
        if (!s_consoleLogging)
        {
            if (!s_loggerInited)
            {
                InitLog("-", false, false);
                s_loggerInited = true;
            }
            else
            {
                s_fileStream = new FileStream(s_logFilePath, FileMode.Append, FileAccess.Write, FileShare.Delete | FileShare.ReadWrite);
                writer = new StreamWriter(s_fileStream, Encoding.UTF8);
            }
        }
    }

    public static void Print(string msg)
    {
        Print("{0}", new object[] { msg });
    }

    public static void Print(string fmt, params object[] args)
    {
        Print(LOG_LEVEL_INFO, s_processName, fmt, args);
    }

    public static void Print(int level, string tag, string fmt, params object[] args)
    {
        string str = "UNKNOWN";
        if (level == LOG_LEVEL_FATAL)
        {
            str = s_logStringFatal;
        }
        else if (level == LOG_LEVEL_ERROR)
        {
            str = s_logStringError;
        }
        else if (level == LOG_LEVEL_WARNING)
        {
            str = s_logStringWarning;
        }
        else if (level == LOG_LEVEL_INFO)
        {
            str = s_logStringInfo;
        }
        else if (level == LOG_LEVEL_DEBUG)
        {
            str = s_logStringDebug;
        }
        if ((level != LOG_LEVEL_DEBUG) || IsLogLevelEnabled(tag, str))
        {
            lock (s_sync)
            {
                Open();
                writer.WriteLine(GetPrefix(tag, str) + fmt, args);
                writer.Flush();
                Close();
            }
        }
    }

    public static void SetLogDir(string logDir)
    {
        s_logDir = logDir;
    }

    public static void Warning(string msg)
    {
        Warning("{0}", new object[] { msg });
    }

    public static void Warning(string fmt, params object[] args)
    {
        Print(LOG_LEVEL_WARNING, s_processName, fmt, args);
    }

    public delegate void HdLoggerCallback(int prio, uint tid, string tag, string msg);

    public class Writer : TextWriter
    {
        private WriteFunc writeFunc;

        public Writer(WriteFunc writeFunc)
        {
            this.writeFunc = writeFunc;
        }

        public override void WriteLine(string msg)
        {
            this.writeFunc(msg);
        }

        public override void WriteLine(string fmt, object obj)
        {
            this.writeFunc(string.Format(fmt, obj));
        }

        public override void WriteLine(string fmt, object[] objs)
        {
            this.writeFunc(string.Format(fmt, objs));
        }

        public override System.Text.Encoding Encoding
        {
            get
            {
                return System.Text.Encoding.UTF8;
            }
        }

        public delegate void WriteFunc(string msg);
    }
}

Answer 1

Whenever a TypeInitializationException is thrown, check all initialization logic of the type you are referring to for the first time in the statement where the exception is thrown - in your case: Logger.

Initialization logic includes: the type's static constructor (which - if I didn't miss it - you do not have for Logger) and field initialization.

Field initialization is pretty much "uncritical" in Logger except for the following lines:

private static string s_bstCommonAppData = Path.Combine(s_commonAppData, "XXXX");
private static string s_bstUserDataDir = Path.Combine(s_bstCommonAppData, "UserData");
private static string s_commonAppData = Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData);

s_commonAppData is null at the point where Path.Combine(s_commonAppData, "XXXX"); is called. As far as I'm concerned, these initializations happen in the exact order you wrote them - so put s_commonAppData up by at least two lines ;)