C # program Singleton log output,

C # program Singleton log output,

For a complete program system, a log record is essential. You can use it to record the running status and error information of a program during running. For example, errors that do not want to be prompted through the dialog box, exceptions caught during program execution, etc.

First, create a new class in the appropriate directory in your solution, such as LogManager:

Write the following code:

1 /// <summary> 2 /// log management 3 /// </summary> 4 public class LogManager 5 {6 private string _ logDir; // log file storage directory 7 8 private static LogManager m_LogInstance; // static singleton object 9 // static constructor 10 static LogManager () 11 {12 m_LogInstance = new LogManager (); 13} 14 // private constructor (required function, which cannot be instantiated externally) 15 private LogManager () 16 {17 _ logDir = Environment. currentDirectory + "\ Log"; 18 this. delOldFile (); 19} 20 // <summary> 21 // /Attribute get singleton object 22 // </summary> 23 public static LogManager LogInstance24 {25 get {return m_LogInstance ;} 26} 27 28 /// <summary> 29 // write a log record 30 /// </summary> 31 /// <param name = "pLog"> log record content </param> 32 public void WriteLog (string pLog) 33 {34 lock (this. _ logDir) // exclusive lock: prevents multiple threads in the main program from simultaneously accessing the same file. Error 35 {36 // create a log file 37 var vDT = DateTime according to the time. now; 38 string vLogFile = string. format ("{0} \ Log {1} {2} {3 }. log ", _ logD Ir, vDT. year, vDT. month, vDT. day); 39 // create a file stream for writing 40 using (FileStream fs = new FileStream (vLogFile, FileMode. append) 41 {42 StreamWriter sw = new StreamWriter (fs); 43 sw. writeLine ("{0 }>>{ 1}", vDT. toString ("yyyy-MM-dd HH: mm: ss"), pLog); 44 sw. flush (); 45 sw. close (); 46 fs. close (); 47} 48} 49} 50 51 // Delete the expired file 52 private void DelOldFile () 53 {54 // traverse all the sub-files in the specified folder, delete the log files before a certain period of time. 55 if (! Directory. exists (this. _ logDir) 56 {57 // If the folder Directory does not exist 58 Directory. createDirectory (this. _ logDir); 59 return; 60} 61 62 var vFiles = (new DirectoryInfo (this. _ logDir )). getFiles (); 63 for (int I = vFiles. length-1; I> = 0; I --) 64 {65 // specify the condition, and then delete 66 if (vFiles [I]. name. contains ("Log") 67 {68 if (DateTime. now-vFiles [I]. lastWriteTime ). days> 7) 69 {70 vFiles [I]. delete (); 71} 72} 73} 74} 75 76} // end class

Among them, rows 8th-26th are a way to implement the singleton mode. In this way, execute at the location where your program needs:

LogManager. LogInstance. WriteLog ("A log record is generated ");

It will record the parameters in the specified file one day.

That is, 23:53:45> A log record is generated.