在WPF中暂停和恢复执行

Question

Is there any way to pause and resume the execution in WPF App [especially in ViewModel class]? I have tried with Auto and ManualResetEvent class. But it is not pausing at the point where I want to pause. The waitone method is not pausing the execution.

In my viewmodel, i have a method which calls the web service. The result of the web service will be coming in another method [ie, the call back method]. After getting the result from the web service, i want to continue the execution.

public void Method1()
{
   for(int i=0; i<5; i++)
   {
      // Call the web service. No waiting for the result.
      // Block the execution here....
   }
}

public void CallBackMethod(int serviceResult)
{
   // After getting the result...
   // I want to continue with Method1...
}

Is there any way to do it in WPF ?

Answer 1

You're talking about a ManualResetEvent :

private ManualResetEvent _reset;

public void Method1()
{  
   _reset = new ManualResetEvent(true);
   for(int i=0; i<5; i++)
   {
       // Call the web service.

       // WaitOne blocks the current thread 
       _reset.WaitOne();
   }
}

public void CallBackMethod(int serviceResult)
{
   // After getting the result...

   // Set allows waiting threads to continue
   _reset.Set();
}

Answer 2

But why do you need to do this in a loop? Simply run the service again when the callback method is called:

int count =0;
const int MAX_CALLS = 5;

public void RunService()
{
    //do service stuff
}

public void CallBackMethod(int serviceResult)
{
    if (count++ < MAX_CALLS)
        RunService ();
}
public static void Main (string[] args)
{
    RunService ();
}