玩轉C#之【執行序-實際實作】

介紹

定義

執行緒帶來的負擔

Thread

Thread.CurrentThread.ManagedThreadId

演示用的函示

private void doSomething(string name)
        {
            Console.WriteLine($"doSomething {name}Start 執行緒：{Thread.CurrentThread.ManagedThreadId}");
            long lRestul = 0;
            for (int i = 0; i < 1000000; i++)
            {
                lRestul++;
            }
            Thread.Sleep(2000);
            Console.WriteLine($"doSomething {name}End 執行緒：{Thread.CurrentThread.ManagedThreadId}");
        }

建立執行緒、並啟動執行

// Action action = () => this.doSomething("button3");
 ThreadStart threadStart = () => this.doSomething("button3");//委派
 //Thread thread =new Thread(action);
 Thread thread = new Thread(threadStart);
 thread.Start();//啟動

執行緒暫停、喚醒、銷毀

thread.Suspend();//執行緒暫停  舊方法-被遺棄了-不建議使用-容易造成死鎖
 thread.Resume();//執行緒喚醒   舊方法-被遺棄了-不建議使用

try
            {
                thread.Abort();//銷毀，方式是拋棄異常 也不建議 不一定及時
            }
            catch (Exception)
            {
                Thread.ResetAbort();//取消異常
            }

執行緒等待

while (thread.ThreadState != ThreadState.Stopped)
            {
                Thread.Sleep(100);//當前執行緒 休息100ms
            }

//執行緒等待
   thread.Join(500);//最多等待500
   Console.WriteLine("最多等待500ms");
   thread.Join();//當前執行緒等待thread完成

Thread的特點IsBackground

//IsBackground 是Thread的特點 只有thread可以設定前台，後台
 Console.WriteLine(thread.IsBackground);
 //默認是前台線程，啟動後一定要先完成任務的，阻止進程退出
 thread.IsBackground = true;//指定後台線程 隨者程式退出

設定執行緒優先級別

thread.Priority = ThreadPriority.Highest;//設定線程優先級別
  //CPU會依優先執行Highest 不代表Highest 就最先結束

ThreadPool-執行緒集區(大陸:線程池)

執行方式

ThreadPool.QueueUserWorkItem(t => this.doSomething("button4_Click"));

取得環境中最大可以使用的執行緒數量

public static void GetMaxThreads (out int workerThreads, out int completionPortThreads);

ThreadPool.GetAvailableThreads(out int workerThreads, 
            out int portThreads);

設定線程池最大數量跟最小數量

ThreadPool.SetMaxThreads(16, 16);
   ThreadPool.SetMinThreads(8, 8);

執行緒等待

ManualResetEvent manualResetEvent = new ManualResetEvent(false);
ThreadPool.QueueUserWorkItem(t =>
{
    this.doSomething("btnThreadPool");
    manualResetEvent.Set();
    //manualResetEvent.Reset();
});
manualResetEvent.WaitOne();

Console.WriteLine("等待QueueUserWorkItem完成後才執行");

Thread Callback範例

無返回值的非同步Callback

var fun = this.ThreadWidthReturn<int>(() =>
            {
                Console.WriteLine($"fun 執行緒：{Thread.CurrentThread.ManagedThreadId}");
                Thread.Sleep(2000);
                return DateTime.Now.Millisecond;
            });
            Console.WriteLine("123");

            int iResult = fun.Invoke();
            Console.WriteLine($"{iResult}");
private void ThreadWithCallback(Action act, Action callback)
        {
            Thread thread = new Thread(() =>
              {
                  act.Invoke();
                  callback.Invoke();
              });
            thread.Start();
        }

有返回值的非同步Callback

var fun = this.ThreadPoolWidthReturn<int>(() =>
            {
                Console.WriteLine($"fun 執行緒：{Thread.CurrentThread.ManagedThreadId}");
                Thread.Sleep(2000);
                return DateTime.Now.Millisecond;
            });
            Console.WriteLine("123");

            int iResult = fun.Invoke();
            Console.WriteLine($"{iResult}");
private Func<T> ThreadWidthReturn<T>(Func<T> func)
        {
            T t = default(T);
            Thread thread = new Thread(() =>
            {
                t = func.Invoke();
            });
            Console.WriteLine($"ThreadWidthReturn 執行緒：{Thread.CurrentThread.ManagedThreadId}");
            thread.Start();

            return () =>
            {
                thread.Join();
                Console.WriteLine($"return 執行緒：{Thread.CurrentThread.ManagedThreadId}");
                return t;
            };
        }

參考資料