[c#] What is and how to fix System.TypeInitializationException error?

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);
    }
}

The TypeInitializationException that is thrown as a wrapper around the exception thrown by the class initializer. This class cannot be inherited.

TypeInitializationException is also called static constructors.

System.TypeInitializationException happens when the code that gets executed during the process of loading the type throws an exception.

When .NET loads the type, it must prepare all its static fields before the first time that you use the type. Sometimes, initialization requires running code. It is when that code fails that you get a System.TypeInitializationException.

In your specific case, the following three static fields run some code:

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);

Note that s_bstCommonAppData depends on s_commonAppData, but it is declared ahead of its dependency. Therefore, the value of s_commonAppData is null at the time that the Path.Combine is called, resulting in ArgumentNullException. Same goes for the s_bstUserDataDir and s_bstCommonAppData: they are declared in reverse order to the desired order of initialization.

Re-order the lines to fix this problem:

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

I experienced the System.TypeInitializationException due to a different error in my .NET framework 4 project's app.config. Thank you to pStan for getting me to look at the app.config. My configSections were properly defined. However, an undefined element within one of the sections caused the exception to be thrown.

Bottom line is that problems in the app.config can generated this very misleading TypeInitializationException.

A more meaningful ConfigurationErrorsException can be generated by the same error in the app.config by waiting to access the config values until you are within a method rather than at the class level of the code.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;
using System.Collections.Specialized;

namespace ConfigTest
{
    class Program
    {
        public static string machinename;
        public static string hostname;
        public static NameValueCollection _AppSettings;

        static void Main(string[] args)
        {
            machinename = System.Net.Dns.GetHostName().ToLower();
            hostname = "abc.com";// System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName()).HostName.ToLower().Replace(machinename + ".", "");
            _AppSettings = ConfigurationManager.GetSection("domain/" + hostname) as System.Collections.Specialized.NameValueCollection;
        }
    }
}

These lines are your problem (or at least one of your problems, if there are more):

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);

You reference some static members in the initializers for other static members. This is a bad idea, as the compiler doesn't know in which order to initialize them. The result is that during the initialization of s_bstCommonAppData, the dependent field s_commonAppData has not yet been initialized, so you are calling Path.Combine(null, "XXXX") and this method does not accept null arguments.

You can fix this by making sure that fields used in the initialization of other fields are declared first:

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

Or use a static constructor to explicitly order the assignments:

private static string s_bstCommonAppData;
private static string s_bstUserDataDir;
private static string s_commonAppData;

static Logger()
{
    s_commonAppData = Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData);
    s_bstCommonAppData = Path.Combine(s_commonAppData, "XXXX");
    s_bstUserDataDir = Path.Combine(s_bstCommonAppData, "UserData");
}

I have the error of system.typeintialzationException, which is due to when I tried to move the file like:

 File.Move(DestinationFilePath, SourceFilePath)

That error was due to I had swapped the path actually, correct one is:

 File.Move(SourceFilePath, DestinationFilePath)

i. Please check the InnerException property of the TypeInitializationException

ii. Also, this may occur due to mismatch between the runtime versions of the assemblies. Please verify the runtime versions of the main assembly (calling application) and the referred assembly

Had a simular issue getting the same exception. Took some time locating. In my case I had a static utility class with a constructor that threw the exception (wrapping it). So my issue was in the static constructor.

I had this problem. As stated it is probably a static declaration issue. In my case it was because I had a static within a DEBUG clause. That is (in c#)

#if DEBUG
    public static bool DOTHISISINDEBUGONLY = false;
#endif

Everything worked fine until I complied a Release version of the code and after that I got this error - even on old release versions of the code. Once I took the variable out of the DEBUG clause everything returned to normal.

If you have custom attributes in appsetting. move your

     <configSections> 
     </configSections>

tag to the first child in the <confuguration>.

I know that this is a bit of an old question, but I had this error recently so I thought I would pass my solution along.

My errors seem to stem from a old App.Config file and the "in place" upgrade from .Net 4.0 to .Net 4.5.1.

When I started the older project up after upgrading to Framework 4.5.1 I got the TypeInitializationException... right off the bat... not even able to step through one line of code.

After creating a brand new wpf project to test, I found that the newer App.Config file wants the following.

  <configSections>
    <sectionGroup name="userSettings" type="System.Configuration.UserSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" >
      <section name="YourAppName.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" allowExeDefinition="MachineToLocalUser" requirePermission="false" />
    </sectionGroup>
  </configSections>  

Once I dropped that in, I was in business.

Note that your need might be slightly different. I would create a dummy project, check out the generated App.Config file and see if you have anything else missing.

Hope this helps someone. Happy Coding!