Threadpool's queueuserworkitem method (waitcallback) and queueuserworkitem method (waitcallback, object)

Note: to use this method, you must introduce the application: using system. Threading; // introduce the application.

It indicates that the method to be executed is queued for execution,WaitcallbackIndicates the method to be executed;ObjectThe object that contains the data used by the method. If the method is successfully queuedTrueOtherwiseFalse.

1. The following is the sample code of the threadpool. queueuserworkitem method (waitcallback:

1 using system; 2 using system. collections. generic; 3 using system. LINQ; 4 using system. text; 5 using system. threading; // introduce application 6 7 namespace queueuserworkitem_waitcallback _ 8 {9 class program10 {11 static void main (string [] ARGs) 12 {13 // queue the task.14 threadpool. queueuserworkitem (New waitcallback (threadproc); 15 16 console. writeline ("main thread does some work, then sleeps. "); 17 // If you comment out of the sleep, the main thread exits before18 // The thread pool task runs. the thread pool uses background19 // threads, which do not keep the application running. (this20 // is a simple example of a race condition .) 21 thread. sleep (1000); 22 23 console. writeline ("main thread exits. "); 24} 25 26 // This thread procedure performs the task.27 static void threadproc (Object stateinfo) 28 {29 // No State object was passed to queueuserworkitem, so 30 // stateinfo is null.31 console. writeline ("Hello from the thread pool. "); 32} 33} 34}

After running the above Code:

2. The following is the sample code of the threadpool. queueuserworkitem method (waitcallback, object:

1 using system; 2 using system. collections. generic; 3 using system. LINQ; 4 using system. text; 5 using system. threading; 6 7 namespace queueuserworkitem _ waitcallback _ OBJECT _ 8 {9 // queue the method for execution and specify the object containing the data used by the method. This method is executed when a thread pool thread becomes available. 10/* 11*12 * Public static bool queueuserworkitem (waitcallback callback, object state) 13*14*15 * callback type: system. threading. waitcallback16 * waitcallback, which indicates the method to be executed. 17*18*19 * State type: system. object20 * indicates the object that contains the data used by the method. 21*22*23 * return value type: system. boolean24 * true if this method is successfully queued; notsupportedexception is thrown if this work item cannot be queued. 25*26*27 * Note: If the callback method requires complex data, you can define classes containing the data. 28*29 */30 class program31 {32 static void main (string [] ARGs) 33 {34 // create an object containing the information needed for the task.35 taskinfo Ti = new taskinfo ("This report displays the number {0 }. ", 42); 36 37 // queue the task and data.38 threadpool. queueuserworkitem (New waitcallback (threadproc), Ti); 39 40 console. writeline ("main thread does some work, then sleeps. "); 41 42 // If you comment out the sleep, the main thread exits before43 // The threadpool task has a chance to run. threadpool uses 44 // background threads, which do not keep the Application 45 // running. (This is a simple example of a race condition .) 46 thread. sleep (1000); 47 48 console. writeline ("main thread exits. "); 49} 50 51 // The thread procedure performs the independent task, in this case52 // formatting and printing a very simple report.53 // 54 static void threadproc (Object stateinfo) 55 {56 taskinfo Ti = (taskinfo) stateinfo; 57 console. writeline (TI. boilerplate, Ti. value ); 58} 59} 60 61 // taskinfo holds state information for a task that will be62 // executed by a threadpool thread.63 public class taskinfo64 {65 // state information for the task. these members66 // can be implemented as read-only properties, read/write67 // properties with validation, and so on, as required.68 Public String boilerplate; 69 public int value; 70 71 // public constructor provides an easy way to supply all72 // the information needed for the task.73 public taskinfo (string text, int number) 74 {75 boilerplate = text; 76 value = number; 77} 78} 79}

After running the above Code: