perun/02_Windows_App/Perun_v1/01_Classes/LogController.cs

using System;
using System.IO;

// Singleton class - log controller
class LogController
{
    private static LogController _instance = new LogController();   // Singleton instance
    public int level;   // Level of logging

    public static LogController instance
    {
        get
        {
            return _instance;   // Return current instance
        }
    }

    public void WriteLog(int logLevel, string strLog)
    {
        if (logLevel > this.level) return;  // Check if we shall log it with the current log level, if not - exit

        StreamWriter LogStreamWriter;
        FileStream LogFileStream = null;
        DirectoryInfo LogDirectoryInfo = null;
        FileInfo LogFileInfo;

        string LogFilePath = Path.Combine(Environment.ExpandEnvironmentVariables("%userprofile%"), "Documents") + "\\Perun\\";
        LogFilePath = LogFilePath + "Perun_Log_" + Globals.AppInstanceID + "_" + System.DateTime.Today.ToString("yyyyddMM") + "." + "txt";
        LogFileInfo = new FileInfo(LogFilePath);
        LogDirectoryInfo = new DirectoryInfo(LogFileInfo.DirectoryName);
        if (!LogDirectoryInfo.Exists) LogDirectoryInfo.Create();
        if (!LogFileInfo.Exists)
        {
            LogFileStream = LogFileInfo.Create();
        }
        else
        {
            try
            {
                LogFileStream = new FileStream(LogFilePath, FileMode.Append);
            }
            catch
            {
                // Do nothing 
            }
        }
        try
        {
            LogStreamWriter = new StreamWriter(LogFileStream);
            LogStreamWriter.WriteLine(strLog);
            LogStreamWriter.Close();
        }
        catch
        {
            // Do nothing
        }

        // TBD: log rotation
    }
}