Asp.net Create an error log file

Introduction: In this article I will explain how to create an error log file in asp.net

Description:

Error log file is useful to capture runtime errors and exceptions of website to a file. In this example I will create a text error log file. Follow the below given steps to implement:

Step 1: Add a Global.asax file to Project/website if not exist.

Step 2: Now add the namespace to Global.asax file.

<%@ Import Namespace="System.IO" %>

Step 3: After that write the below given code in Application_Error event of Global file: 

void Application_Error(object sender, EventArgs e)

    {

        // Code that runs when an unhandled error occurs

        Exception ex = new Exception();

        ex = Server.GetLastError().GetBaseException();

        FileStream fs = new FileStream(Server.MapPath("~/ErrorLOG.txt"), FileMode.OpenOrCreate, FileAccess.ReadWrite);

        StreamWriter sw = new StreamWriter(fs);

        sw.BaseStream.Seek(0, System.IO.SeekOrigin.End);

        sw.WriteLine("ERROR DATE: " + System.DateTime.Now.ToString(System.Globalization.CultureInfo.InvariantCulture));

        sw.Write("\r\n");

        sw.Write("ERROR MESSAGE: " + ex.Message);

        sw.Write("\r\n");

        sw.Write("SOURCE: " + ex.Source);

        sw.Write("\r\n");

         sw.Write("FORM NAME: " + System.Web.HttpContext.Current.Request.Url.ToString());

         sw.Write("\r\n");

         sw.Write("QUERYSTRING: " + Request.QueryString.ToString());

         sw.Write("\r\n");

         sw.Write("TARGETSITE: " + ex.TargetSite.ToString());

         sw.Write("\r\n");

         sw.Write("STACKTRACE: " + ex.StackTrace + System.Diagnostics.EventLogEntryType.Error);

         sw.Write("\r\n");

        sw.WriteLine("-----------------------------------------------------------------------------------------");

        sw.Close();

      }

When any error or exception occurs in website/project, error writes to ErrorLOG text file.