Creating Error-log in C# to write errors in Event Viewer as well in directory.

ErrorLog.CS

using Microsoft.SharePoint;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Application1
{
    public class ErrorLog
    {
        public class ErrorLog
        {
            /// <summary>
            /// WriteToEventLog
            /// </summary>
            /// <param name="message"></param>
            /// <param name="sourcename"></param>
            /// <param name="logName"></param>

            #region WriteToEventLog
            public void WriteToEventLog(string message, string sourcename, string logName, EventLogEntryType ErrorType)
            {
                try
                {
                    SPSecurity.RunWithElevatedPrivileges(delegate()
                    {
                        EventLog elog = new EventLog();
                        if (!EventLog.SourceExists(sourcename))
                        {
                            EventLog.CreateEventSource(sourcename, logName);
                        }
                        elog.Source = sourcename;
                        elog.Log = logName;
                        elog.EnableRaisingEvents = true;
                        elog.WriteEntry(message, ErrorType);
                    });
                }

                catch (Exception ex)
                {
                    writeErrors(ex.ToString());
                }
            }
            #endregion

            /// <summary>
            /// writeErrors
            /// </summary>
            /// <param name="msg"></param>

            #region writeErrors
            public void writeErrors(string msg)
            {
                try
                {
                    SPSecurity.RunWithElevatedPrivileges(delegate()
                    {
                        string dir = @"c:\\ Error LOG";
                        Directory.CreateDirectory(dir);
                        TextWriter tw = new StreamWriter(@"c:\\ Error LOG\Error.txt", true);
                        tw.WriteLine(System.DateTime.Now.ToString() + "  Error : " + msg);
                        tw.Close();
                    });
                }
                catch (Exception ex)
                {
                    //writeErrors(ex.ToString());

                }
            }
            #endregion
        }
    }
}

 

Application1.cs 

Creating Error Log  variables 
      #region ErrorLog Variables
        public string sourceName = "Application1";
        public string logName = "Application";
        ErrorLog el = new ErrorLog();
        #endregion

Writing ErrorLog method
 /// <summary> ErrorLogMethod
        /// ErrorLogMethod
        /// </summary>
        /// <param name="ex"></param>

        private void ErrorLogMethod(Exception ex)
        {
            //Catching error in Event viewer
            el.writeErrors(ex.ToString());
            el.WriteToEventLog(ex.ToString(), sourceName, logName, EventLogEntryType.Error);
            //Displaying the Error Message   
             lblerror.Text = ex.Message;
         }
        protected void Page_Load(object sender, EventArgs e)
        {
            try
            {
            }
           catch (Exception ex)
            {
                ErrorLogMethod(ex);
            }
        }