Create Log File in Asp.Net using C#

In this article we will cover how to Create and Write Log File in Asp.Net Application using c#.

Create Log

This method will create log file with given name if it does not exists.

public void CreateLog(string logFileName)
{
    string directory = HttpContext.Current.Server.MapPath("~/App_Data/");
    string logFile = directory + "/" + logFileName;
 
    if (!File.Exists(logFile))
    {
        var file = File.Create(logFile);
        file.Close();
    }
}

Write Log

This method will create log file with given name if it does not exists and write data to it.

public void WriteLog(string logFileName)
{
    string directory = HttpContext.Current.Server.MapPath("~/App_Data/");
    string logFile = directory + "/" + logFileName;
 
    // Create file if it does not exists
    if (!File.Exists(logFile))
        CreateLog(logFileName);
 
    StreamWriter sw = new StreamWriter(logFile, true);
    sw.WriteLine("********** Application Start Time**********");
    sw.WriteLine("********** {0} **********", DateTime.Now + " (System Time)");
    sw.Dispose();
    sw.Close();
}

Example

CreateLog("log.txt"); // Create Log File

WriteLog("log.txt"); // Write Log File

WriteLog("ErrorLog.txt"); // Create and Write Log File