Ghi log lỗi
try
            {
                // Lỗi runtime~
                int a = 10;
                int b = 0;
                
                int c = a / b;
            }
            catch (Exception ex)
            {
                Console.WriteLine("Opps! Co loi xay ra! Vui long lien he Quan tri he thong (0915659223)!");
                Console.WriteLine("Vui long goi file log trong thu muc logs den Nha cung cap de khac phuc su co!");

                // Ghi log
                string logFolderName = "logs/";
                if (!Directory.Exists(logFolderName))
                {
                    // Kiểm tra thư mục log có tồn tại không? Nếu chưa có thì tạo mới
                    Directory.CreateDirectory(logFolderName);
                }
                string logFileName = ""; //2019_11_16_log.txt
                DateTime now = DateTime.Now;
                logFileName = String.Format("{0}_{1}_{2}_log.txt",
                    now.Year, now.Month, now.Day);

                //                     logs/2019_11_16_log.txt
                //string fullFileLog = logFolderName + "/" + logFileName;
                string fullFileLog = Path.Combine(logFolderName, logFileName);

                using (StreamWriter sw = new StreamWriter(fullFileLog))
                {
                    sw.WriteLine(String.Format("Loi xay ra vao luc: {0}", now));
                    sw.WriteLine(String.Format("Loi cu the: {0}", ex.Message));
                }

                // Tu dong am tham goi file log nay ve Server cua ban~
            }