[c#] How to write log file in c#?

How would I write a log file in c#?

Currently i have a timer with this statement which ticks every 20 secs:

File.WriteAllText(filePath+"log.txt", log);

For everything that i want logged i do this:

log += "stringToBeLogged";

As you can assume the string log just grows and grows as the program runs. (I don't even know if there is a maximum chars per string?)

I assume that there must be better ways of doing this. i just thought that it would be heavy to write the whole file again and again for every time something is added to the log.

public static void WriteLog(string strLog)
    {
        StreamWriter log;
        FileStream fileStream = null;
        DirectoryInfo logDirInfo = null;
        FileInfo logFileInfo;

        string logFilePath = "C:\\Logs\\";
        logFilePath = logFilePath + "Log-" + System.DateTime.Today.ToString("MM-dd-yyyy") + "." + "txt";           
        logFileInfo = new FileInfo(logFilePath);
        logDirInfo = new DirectoryInfo(logFileInfo.DirectoryName);
        if (!logDirInfo.Exists) logDirInfo.Create();
        if (!logFileInfo.Exists)
        {
            fileStream = logFileInfo.Create();
        }
        else
        {
            fileStream = new FileStream(logFilePath, FileMode.Append);
        }
        log = new StreamWriter(fileStream);
        log.WriteLine(strLog);
        log.Close();
    }   

Refer Link: blogspot.in

as posted by @randymohan, with using statements instead

public static void WriteLog(string strLog)
{
    string logFilePath = @"C:\Logs\Log-" + System.DateTime.Today.ToString("MM-dd-yyyy") + "." + "txt";
    FileInfo logFileInfo = new FileInfo(logFilePath);
    DirectoryInfo logDirInfo = new DirectoryInfo(logFileInfo.DirectoryName);
    if (!logDirInfo.Exists) logDirInfo.Create();
    using (FileStream fileStream = new FileStream(logFilePath, FileMode.Append))
    {
        using (StreamWriter log = new StreamWriter(fileStream))
        {
            log.WriteLine(strLog);
        }
    }
}

Use File.AppendAllText instead:

File.AppendAllText(filePath + "log.txt", log);

create a class create a object globally and call this

using System.IO;
using System.Reflection;


   public class LogWriter
{
    private string m_exePath = string.Empty;
    public LogWriter(string logMessage)
    {
        LogWrite(logMessage);
    }
    public void LogWrite(string logMessage)
    {
        m_exePath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
        try
        {
            using (StreamWriter w = File.AppendText(m_exePath + "\\" + "log.txt"))
            {
                Log(logMessage, w);
            }
        }
        catch (Exception ex)
        {
        }
    }

    public void Log(string logMessage, TextWriter txtWriter)
    {
        try
        {
            txtWriter.Write("\r\nLog Entry : ");
            txtWriter.WriteLine("{0} {1}", DateTime.Now.ToLongTimeString(),
                DateTime.Now.ToLongDateString());
            txtWriter.WriteLine("  :");
            txtWriter.WriteLine("  :{0}", logMessage);
            txtWriter.WriteLine("-------------------------------");
        }
        catch (Exception ex)
        {
        }
    }
}

Add log to file with Static Class

 public static class LogWriter
        {
            private static string m_exePath = string.Empty;
            public static void LogWrite(string logMessage)
            {
                m_exePath = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);
                if (!File.Exists(m_exePath + "\\" + "log.txt"))
                    File.Create(m_exePath + "\\" + "log.txt");

                try
                {
                    using (StreamWriter w = File.AppendText(m_exePath + "\\" + "log.txt"))
                        AppendLog(logMessage, w);
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }

            }

            private static void AppendLog(string logMessage, TextWriter txtWriter)
            {
                try
                {
                    txtWriter.Write("\r\nLog Entry : ");
                    txtWriter.WriteLine("{0} {1}", DateTime.Now.ToLongTimeString(),DateTime.Now.ToLongDateString());
                    txtWriter.WriteLine("  :");
                    txtWriter.WriteLine("  :{0}", logMessage);
                    txtWriter.WriteLine("-------------------------------");
                }
                catch (Exception ex)
                {
                }
            }
        }

There are 2 easy ways

• StreamWriter - http://www.dotnetperls.com/streamwriter
• Log4Net like Log4j(Java) - http://www.codeproject.com/Articles/140911/log4net-Tutorial

if(!File.Exists(filename)) //No File? Create
{
    fs = File.Create(filename);
    fs.Close();
}
if(File.ReadAllBytes().Length >= 100*1024*1024) // (100mB) File to big? Create new
{
    string filenamebase = "myLogFile"; //Insert the base form of the log file, the same as the 1st filename without .log at the end
    if(filename.contains("-")) //Check if older log contained -x
    {
         int lognumber = Int32.Parse(filename.substring(filename.lastIndexOf("-")+1, filename.Length-4); //Get old number, Can cause exception if the last digits aren't numbers
         lognumber++; //Increment lognumber by 1
         filename = filenamebase + "-" + lognumber + ".log"; //Override filename
    }
    else 
    {
         filename = filenamebase + "-1.log"; //Override filename
    }
    fs = File.Create(filename);
    fs.Close();
}

Refer link:

http://www.codeproject.com/Questions/163337/How-to-write-in-log-Files-in-C

This is add new string in the file

using (var file = new StreamWriter(filePath + "log.txt", true))
        {
            file.WriteLine(log);
            file.Close();
        }

Very convenient tool for logging is http://logging.apache.org/log4net/

You can also make something of themselves less (more) powerful. You can use http://msdn.microsoft.com/ru-ru/library/system.io.filestream (v = vs.110). Aspx