如何在任务运行时将一些数据从TPL任务传播到主进程

我有一种情况，我创建了一个长时间运行的任务列表，它监视一些系统/网络资源，然后发送电子邮件， 日志到一个txt文件，并且调用web服务当某些条件得到满足。然后再次开始监控。这些任务是在windows服务中创建的，因此将一直运行。

我希望它们引发事件或其他东西来通知父类(创建它们的类)，它将执行上面提到的3个操作，而不是任务中的每个对象自己执行。

以及如何控制只有一个任务在一个时间使用父类的方法。由于涉及电子邮件和web服务调用，因此两个并发请求可能会影响代码。

这些观察者有三种类型，每种类型实现以下接口。

public interface IWatcher
{
    void BeginWatch();        
}

实现的类是

//this watcher is responsible for watching over a sql query result
public class DBWatcher : IWatcher
{
    ....
    void BeginWatch()
    {
        //Here a timer is created which contiously checks the SQL query result.
        //And would Call SERVICE, send an EMAIL and LOG into a file
        Timer watchIterator = new Timer(this._intervalMinutes * 60000);
        watchIterator.Elapsed += new ElapsedEventHandler(_watchIterator_Elapsed);
        watchIterator.Start();
    }
    void _watchIterator_Elapsed(object sender, ElapsedEventArgs e)
    {
        //1. Check Query result
        //3. Call SERVICE, send an EMAIL and LOG into a file if result is not as was expected
        //I have done the work to this part!
        //And I can do the functions as follows .. it should be simple.
        //*********************
        //SendEmail();
        //LogIntoFile();
        //CallService();
        //But I want the above three methods to be present in one place so i dont have to replicate same functionality in different watcher.
        //One approach could be to create a seperate class and wrape the above mentioned functions in it, create an instance of that class here and call them.
        //Second option, which I am interested in but dont know how to do, is to have this functionality in the parent class which actually creates the tasks and have each watcher use it from HERE ...
    }
    ....
}

//this watcher is responsible for watching over Folder
public class FolderWatcher : IWatcher
{
    ....
    void BeginWatch()
    {
         ///Same as above
    }
    ....
}

首先，我从一个XML文件创建一个List。这可以包含DBWatcher的多个实例，DBWatcher将连续观察不同的查询结果，FolderWatcher将连续观察不同的文件夹。

创建List之后，我调用下面的函数来创建一个单独的Task。我多次调用这个函数来创建一组不同的观察者。

    private void _createWatcherThread(IWatcher wat, CancellationTokenSource cancellationToken)
    {
        //This represents a watcher that will watch some specific area for any activities
        IWatcher watcher = wat.Copy();
        bool hasWatchBegin = false;
        try
        {
            //run forever
            for (;;)
            {
                //dispose the watcher and stop this thread if CANCEL token has been issued
                if (cancellationToken.IsCancellationRequested)
                {
                    ((IDisposable)watcher).Dispose();
                    break;
                }
                else if (!hasWatchBegin)
                {
                    //This method of a watcher class creates a timer. which will
                    //continously check the status after a few minutes... So its the 
                    //timer's elapsed method in Watcher object which will send the mail 
                    //& call service etc to update the admin of current status of the watcher.
                    //this will be called only once in a watcher!
                    watcher.BeginWatch();
                    hasWatchBegin = true;
                }
            }
        }
        catch (Exception ex)
        {
            //Watcher has thrown an exception. 
            //Again, do the following operations
            //*********************
            //SendEmail();
            //LogIntoFile();
            //CallService();
        }
    }

...
void Email(string message){}
void Log(string message){}
void CallWebService(string message){}

void RunMonitoringTask()
{
    var task = Task.TaskFactory.StartNew(() =>
    {
        string message = Monitor();
        if( ShouldNotify(message))
           {
              Email(mesasge);
              Log(message);
              CallWebService(message);
           }
    }
)
}
...

...
void Email(string message){}
void Log(string message){}
void CallWebService(string message){}

void Monitor()
{
    while(true)
    {
          string message = Monitor();
          if(ShouldNotify(message))
          { 
              var task = Task.TaskFactory.StartNew(() =>
              {
                  Email(mesasge);
                  Log(message);
                  CallWebService(message);
              }
         }
    }
)
}
...

Progress<string> progress = new Progress<string>();
progress.ProgressChanged += (s, data) => Console.WriteLine(data);
for (int i = 0; i < 2; i++)
    Task.Run(() => DoWork(progress));

public static void DoWork(IProgress<string> progress)
{
    int i = 0;
    while (true)
    {
        Thread.Sleep(500);//placeholder for real work
        progress.Report(i++.ToString());
    }
}