Task , Thread 学习
1.任务StartNew后就开始执行，使用Wait()来确保任务结束后继续
static void Main(string[] args)
{
try
{
int numberOfUsers = 100;
var users = new string[20];
for (int i = 0; i < 20; i++)
{
users[i] = string.Format("LoadTest{0}", i + 1);
}
Task t = Task.Factory.StartNew(() => WriteLog(users[5]));
Thread.Sleep(5000);
Console.WriteLine("Is first one start?");
Task t1 = Task.Factory.StartNew(() => WriteLog(users[6]));
Thread.Sleep(5000);
Console.WriteLine("Are they start?");
Thread.Sleep(5000);
t1.Wait();
Console.WriteLine("Will End soon!");
t.Wait();
Thread.Sleep(500000000);
}
catch (Exception ex)
{
Console.WriteLine(string.Format("Time {0}:{1}",DateTime.Now, ex.Message));
Thread.Sleep(500000000);
}
}
private static void WriteLog(string userName)
{
Console.WriteLine(string.Format("Begin Time {0}:ProcessId {2} ThreadId {3} {1}", DateTime.Now, userName, System.Diagnostics.Process.GetCurrentProcess().Id, Thread.CurrentThread.ManagedThreadId));
Thread.Sleep(5000);
if (userName == "LoadTest2")
{
Thread.Sleep(5000);
throw new Exception("Lazy!");
}
Console.WriteLine(string.Format("End Time {0}:ProcessId {2} ThreadId {3} {1}", DateTime.Now, userName, System.Diagnostics.Process.GetCurrentProcess().Id, Thread.CurrentThread.ManagedThreadId));
}
执行效果：
使用ThreadPool也是同样效果：
foreach (string user in users)
{
ThreadPool.QueueUserWorkItem(arg =>
{
WriteLog(user);
});
}
2.10个任务一起执行,须注意WriteLog的参数不能直接使用i,因为在实际开始工作的时候i值已经变成了10
Task[] ts = new Task[10];
for(int i=0;i < numberOfUsers ; i++ )
{
ts[i] = Task.Factory.StartNew((object obj) => {
int j = (int)obj;
WriteLog(users[j]); }, i);
}
Task.WaitAll(ts);
Console.WriteLine("Will End soon!");
Thread.Sleep(500000000);3.总共20个人，后10个人接着前面10个人后干活，使用ContinueWith , 其中传的prevTask可以得到前面任务的状态
static void Main(string[] args)
{
try
{
int numberOfUsers = 10;
var users = new string[20];
for (int i = 0; i < 20; i++)
{
users[i] = string.Format("LoadTest{0}", i + 1);
}
Task[] ts = new Task[numberOfUsers];
for (int i = 0; i < numberOfUsers; i++)
{
ts[i] = Task.Factory.StartNew((object obj) =>
{
int j = (int)obj;
WriteLog(users[j]);
}, i).ContinueWith((prevTask) =>
{
string exp = string.Empty;
if (prevTask.Exception!=null ) exp = "Exception:" + prevTask.Exception.Message;
Console.WriteLine(string.Format("ID:{0} Status:{1} IsCanceled:{2} IsCompleted:{3} {4}", prevTask.Id, prevTask.Status, prevTask.IsCanceled, prevTask.IsCompleted, exp));
WriteLog(users[9 + prevTask.Id]);
});
}
Task.WaitAll(ts);
Console.WriteLine("Will End soon!");
Thread.Sleep(500000000);
}
catch (Exception ex)
{
Console.WriteLine(string.Format("Time {0}:{1}",DateTime.Now, ex.Message));
Thread.Sleep(500000000);
}
}4.获取UI上的值来控制是否cancel一个任务下面的所有子任务,使用CancellationTokenSource
static void Main(string[] args)
{
try
{
int numberOfUsers = 10;
var users = new string[numberOfUsers];
for (int i = 0; i < numberOfUsers; i++)
{
users[i] = string.Format("LoadTest{0}", i + 1);
}
CancellationTokenSource tokenSource = new CancellationTokenSource();
CancellationToken token = tokenSource.Token;
ConcurrentBag<Task> ts = new ConcurrentBag<Task>();
Console.WriteLine("Press any key to begin tasks...");
Console.WriteLine("To terminate the example, press 'c' to cancel and exit...");
Console.ReadKey();
Console.WriteLine();
//Task t = Task.Factory.StartNew(() => WriteLog(users[0], token), token);
//Console.WriteLine("Task {0} executing", t.Id);
//ts.Add(t);
Task t = Task.Factory.StartNew(() =>
{
Task tc;
for (int i = 0; i < numberOfUsers; i++)
{
tc = Task.Factory.StartNew((object obj) =>
{
int j = (int)obj;
WriteLog(users[j], token);
}, i, token);
ts.Add(tc);
}
},token);
ts.Add(t);
if (Console.ReadKey().KeyChar == 'c')
{
tokenSource.Cancel();
Console.WriteLine("\nTask cancellation requested.");
}
try
{
Task.WaitAll(ts.ToArray());
}
catch (AggregateException e)
{
foreach (var v in e.InnerExceptions)
{
if (v is TaskCanceledException)
Console.WriteLine(" TaskCanceledException: Task {0}",
((TaskCanceledException)v).Task.Id);
else
Console.WriteLine(" Exception: {0}", v.GetType().Name);
}
}
Console.WriteLine("Will End soon!");
Thread.Sleep(500000000);
}
catch (Exception ex)
{
Console.WriteLine(string.Format("Time {0}:{1}",DateTime.Now, ex.Message));
Thread.Sleep(500000000);
}
}
private static void WriteLog(string userName, CancellationToken ct)
{
Console.WriteLine(string.Format("Begin Time {0}:ProcessId {2} ThreadId {3} {1}", DateTime.Now, userName, System.Diagnostics.Process.GetCurrentProcess().Id, Thread.CurrentThread.ManagedThreadId));
if (userName != "LoadTest1" && userName != "LoadTest2" && userName != "LoadTest3")
{
Thread.Sleep(5000);
}
if (ct.IsCancellationRequested)
{
Console.WriteLine(string.Format("Cancel :{0} ThreadId {1}", userName, Thread.CurrentThread.ManagedThreadId));
ct.ThrowIfCancellationRequested();
}
Console.WriteLine(string.Format("End Time {0}:ProcessId {2} ThreadId {3} {1}", DateTime.Now, userName, System.Diagnostics.Process.GetCurrentProcess().Id, Thread.CurrentThread.ManagedThreadId));
}5.总共10个任务，每次最多3个任务，每当这3个任务中任何一个完成，就会从后续任务中拿出任务来做
static void Main(string[] args)
{
try
{
int numberOfUsers = 10;
var users = new string[numberOfUsers];
for (int i = 0; i < numberOfUsers; i++)
{
users[i] = string.Format("LoadTest{0}", i + 1);
}
Action[] aArr = new Action[numberOfUsers];
int j = 0 ;
for (int i = 0; i < numberOfUsers; i++){
aArr[i] = new Action(() => WriteLog(users[j++]));
}
System.Threading.Tasks.ParallelOptions po = new ParallelOptions();
po.MaxDegreeOfParallelism = 3;
try
{
System.Threading.Tasks.Parallel.Invoke(po, aArr);
}
catch (AggregateException e)
{
foreach (var v in e.InnerExceptions)
{
if (v is TaskCanceledException)
Console.WriteLine(" TaskCanceledException: Task {0}",
((TaskCanceledException)v).Task.Id);
else
Console.WriteLine(" Exception: {0}", v.Message);
}
}
Console.WriteLine("Will End soon!");
Thread.Sleep(500000000);
}
catch (Exception ex)
{
Console.WriteLine(string.Format("Time {0}:{1}",DateTime.Now, ex.Message));
Thread.Sleep(500000000);
}
}6.总共10个任务，每次最多3个任务，而且每次必须3个一起开始
static void Main(string[] args)
{
try
{
int numberOfUsers = 10;
int maxConcurrent = 3;
var users = new string[numberOfUsers];
for (int i = 0; i < numberOfUsers; i++)
{
users[i] = string.Format("LoadTest{0}", i + 1);
}
int itemProcessed = 0;
int loopCnt = 0;
do
{
List<Task> taskList = new List<Task>();
for (int i = 0; i < maxConcurrent; i++)
{
taskList.Add(Task.Factory.StartNew((object obj) =>
{
int j = (int)obj;
try
{
if (loopCnt * maxConcurrent + j < numberOfUsers)
{
WriteLog(users[loopCnt * maxConcurrent + j]);
}
}
catch (Exception ex)
{
Console.WriteLine(string.Format("{0} encounter error :{1}", users[loopCnt * maxConcurrent + j],ex.Message ));
}
}
,i));
Interlocked.Increment(ref itemProcessed);
}
Task.WaitAll(taskList.ToArray());
loopCnt++;
} while (itemProcessed < numberOfUsers);
Console.WriteLine("Will End soon!");
Thread.Sleep(500000000);
}
catch (Exception ex)
{
Console.WriteLine(string.Format("Time {0}:{1}",DateTime.Now, ex.Message));
Thread.Sleep(500000000);
}
}
7.每次最多３个user一起干活
!wrong
static void Main(string[] args)
{
ThreadPool.SetMaxThreads(1, 100);
int numberOfUsers = 10;
int maxWorkUsers = 3;
var users = new string[numberOfUsers];
for (int i = 0; i < numberOfUsers; i++)
{
users[i] = string.Format("LoadTest{0}", i + 1);
}
var options = new ParallelOptions();
options.MaxDegreeOfParallelism = maxWorkUsers;
Parallel.ForEach(users, options,
(user) =>
{
WriteLog(user);
});
Thread.Sleep(500000000);
}
correct
static void Main(string[] args)
{
try
{
int numberOfUsers = 10;
var users = new string[numberOfUsers];
for (int i = 0; i < numberOfUsers; i++)
{
users[i] = string.Format("LoadTest{0}", i + 1);
}
Action[] aArr = new Action[numberOfUsers];
int j = 0 ;
for (int i = 0; i < numberOfUsers; i++){
aArr[i] = new Action(() => WriteLog(users[j++]));
}
System.Threading.Tasks.ParallelOptions po = new ParallelOptions();
po.MaxDegreeOfParallelism = 3;
try
{
System.Threading.Tasks.Parallel.Invoke(po, aArr);
}
catch (AggregateException e)
{
foreach (var v in e.InnerExceptions)
{
if (v is TaskCanceledException)
Console.WriteLine(" TaskCanceledException: Task {0}",
((TaskCanceledException)v).Task.Id);
else
Console.WriteLine(" Exception: {0}", v.Message);
}
}
Console.WriteLine("Will End soon!");
Thread.Sleep(500000000);
}
catch (Exception ex)
{
Console.WriteLine(string.Format("Time {0}:{1}",DateTime.Now, ex.Message));
Thread.Sleep(500000000);
}
}
private static void WriteLog(string userName)
{
Console.WriteLine(string.Format("Begin Time {0}:ProcessId {2} ThreadId {3} {1}", DateTime.Now, userName, System.Diagnostics.Process.GetCurrentProcess().Id, Thread.CurrentThread.ManagedThreadId));
Thread.Sleep(5000);
if (userName == "LoadTest2")
{
Thread.Sleep(5000);
throw new Exception("Lazy!");
}
Console.WriteLine(string.Format("End Time {0}:ProcessId {2} ThreadId {3} {1}", DateTime.Now, userName, System.Diagnostics.Process.GetCurrentProcess().Id, Thread.CurrentThread.ManagedThreadId));
}
8.多線程改變某值
private static List<string> testList = new List<string>();
private static void AddList(string name)
{
testList.Add(name);
}
static void test2()
{
int threadcount = 10;
List<Thread> threads = new List<Thread>();
for (int i = 0; i < threadcount; i++)
{
Thread t = new Thread(delegate(object parameter)
{
EmpServiceDataContext db = new EmpServiceDataContext();
int _i = (int)parameter;
int index = 0;
for( int k = 0 ; k < 20000 ; k++)
{
if (index % threadcount == _i)
{
try
{
AddList("Thread" + k);
}
catch (Exception ex)
{
}
}
index++;
}
});
t.Name = string.Format("SendEmailThread_{0}", i);
threads.Add(t);
t.Start(i);
}
foreach (Thread t in threads)
{
t.Join();
}
}
Task t = Task.Factory.StartNew(() => test2());
t.Wait();
9.volatile 和 Interlocked
http://baike.baidu.com/view/608706.htm?fr=aladdin
1）. 并行设备的硬件寄存器（如：状态寄存器）
2）. 一个中断服务子程序中会访问到的非自动变量（Non-automatic variables)
3）. 多线程应用中被几个任务共享的变量
Interlocked.Decrement(ref JOB_COUNT);
10. ThreadStartStop
如何：创建和终止线程（C# 编程指南）
http://msdn.microsoft.com/zh-cn/library/7a2f3ay4(VS.80).aspx
public class Worker
{
// This method will be called when the thread is started.
public void DoWork()
{
while (!_shouldStop)
{
Console.WriteLine("worker thread: working...");
}
Console.WriteLine("worker thread: terminating gracefully.");
}
public void RequestStop()
{
_shouldStop = true;
}
// Volatile is used as hint to the compiler that this data
// member will be accessed by multiple threads.
private volatile bool _shouldStop;
}
public class WorkerThreadExample
{
static void Main()
{
// Create the thread object. This does not start the thread.
Worker workerObject = new Worker();
Thread workerThread = new Thread(workerObject.DoWork);
// Start the worker thread.
workerThread.Start();
Console.WriteLine("main thread: Starting worker thread...");
// Loop until worker thread activates.
while (!workerThread.IsAlive);
// Put the main thread to sleep for 1 millisecond to
// allow the worker thread to do some work:
Thread.Sleep(1);
// Request that the worker thread stop itself:
workerObject.RequestStop();
// Use the Join method to block the current thread
// until the object's thread terminates.
workerThread.Join();
Console.WriteLine("main thread: Worker thread has terminated.");
}
}
