"C # Advanced Programming version Seventh" Multiple Threads events

Following the example, the code is slightly changed and typed, as shown below

Using system;using system.collections.generic;using system.linq;using system.threading;using System.Threading.Tasks  Using System.text;namespace demo2{class Program {static void Main (string[] args) {const            int taskcount = 10;            Event array, logging thread execution status var mevents = new Manualreseteventslim[taskcount];            Wait for array, receive event signal from var waithandles = new Waithandle[taskcount];            Classes that perform specific tasks var Calcs = new Calculator[taskcount];            Task Factory TaskFactory tf = new TaskFactory (); for (int i = 0; i < Taskcount; i++) {//Initialize event Mevents[i] = new Manualreseteven                Tslim (FALSE); Bind event with wait binding waithandles[i] = Mevents[i].                WaitHandle;                Initializes the class that performs the task calcs[i] = new Calculator (mevents[i]); Start a task tf. StartNew (Calcs[i].            Calculation, tuple.create (i + 1, i + 3));       }     Thread.Sleep (5000);            Console.Write ("task is running\r\n");                for (int i = 0; i < Taskcount; i++) {//returns the index of the wait array that performed the operation, gets a specific event based on the index, and then issues a reset signal from the event                int index = WaitHandle.WaitAny (waithandles);                if (index = = waithandle.waittimeout) {console.write ("timeout\r\n"); } else {Mevents[index].                    Reset (); Console.Write ("finished task for {0}\r\n", Calcs[index].                TaskID);        }} Console.readkey (True);        }} public class Calculator {//Log event status private ManualResetEventSlim mevent; public int?        TaskID {get; private set;}        Public Calculator (ManualResetEventSlim ev) {this.mevent = EV;        public void calculation (object obj) {tuple<int, int> data = (tuple<int, int>) obj;    Console.Write ("Task {0} starts calculation\r\n", Task.currentid); Thread.Sleep (New Random ().            Next (3000));            TaskID = Task.currentid;            Console.Write ("Task {0} is ready\r\n", Task.currentid); Mevent.        Set (); }    }}

　　

After this sentence is masked, "finished task for" is often a fixed value and does not quite understand why this is the case.
I don't know if it is reset, WaitHandle will fail, WaitHandle.WaitAny (waithandles) will not get duplicate records

"C # Advanced Programming version Seventh" Multiple Threads events