Exception Handling in .net and Sharepoint

using System.IO;

using Microsoft.SharePoint.Administration;

//Below are the methods can be used to log exception in files or in ULS logs

private void WriteLog(string LogText)
        {
            try
            {
                SPSecurity.RunWithElevatedPrivileges(delegate()
                {
                    string fullFileName = GetValueByKey(CONFIG_LOG_FILEPATH);
                    string folderpath = string.Empty;
                    string fileName = string.Empty;
                    string ext = string.Empty;
 
                    string file = fullFileName;
 
                    folderpath = file.Remove(file.LastIndexOf("\\") + 1);
                    fileName = file.Substring(file.LastIndexOf("\\") + 1);
                    ext = fileName.Substring(fileName.LastIndexOf("."));
                    fileName = fileName.Remove(fileName.LastIndexOf("."));
 
                    string LogFilePath = folderpath + fileName + ext; ;
                    if (File.Exists(fullFileName))
                    {
                        FileInfo fi = new FileInfo(fullFileName);
                        long size = fi.Length;
 
                        if (size > 10485760)
                        {
                            string date = DateTime.Today.Year.ToString() + DateTime.Today.Month.ToString() + DateTime.Today.Day.ToString();
                            string time = DateTime.Now.TimeOfDay.Hours.ToString() + DateTime.Now.TimeOfDay.Minutes.ToString() + DateTime.Now.TimeOfDay.Seconds.ToString();
                            string dateTime = date + "T" + time;
                            string newPath = folderpath + fileName + "_" + dateTime + ext;
                            File.Copy(LogFilePath, newPath);
                            File.Delete(LogFilePath);
 
                        }
                    }
 
                    StreamWriter SW;
 
                    SW = File.AppendText(LogFilePath);
                    SW.WriteLine(DateTime.Now + ":~Workflow Round 2~:" + LogText);
                    SW.Close();
                });
 
            }
            catch (Exception ex)
            {
                LogMessage(ex);
 
            }
        }
 
        /// <summary>
        /// Private method Logs Error Message
        /// </summary>
        /// <param name="severity">TraceSeverity severity</param>
        /// <param name="message">String Message</param>
        private void LogMessage(TraceSeverity severity, string message)
        {
            try
            {
                uint uintEventID = 8000;//event ID
                string CategoryName = "Log Message";
                SPDiagnosticsCategory category = new SPDiagnosticsCategory(CategoryName, TraceSeverity.Medium, EventSeverity.Error);
                SPDiagnosticsService.Local.WriteTrace(uintEventID, category, TraceSeverity.Unexpected, message);
            }
            catch (Exception ex)
            {
                WriteLog(ex.Message.ToString());
                LogMessage(ex);
 
            }
 
 
        }
        /// <summary>
        /// Log Error Message
        /// </summary>
        /// <param name="ex">Exception ex</param>
        public void LogMessage(Exception ex)
        {
            LogMessage(TraceSeverity.High, ex.Message + ex.StackTrace);
        }
        /// <summary>
        /// Log Message
        /// </summary>
        /// <param name="message">string</param>
        public void LogMessage(string message)
        {
            LogMessage(TraceSeverity.Medium, message);
        }