如何等待任务执行结束以恢复程序执行

Question

I'm working on ac# program where I want to wait for the end of the execution of two tasks (which run a javscript script on a browser and then use the result) to resume the execution of the main program. I must do that because the rest of the program necesitates the informations obtained from the browser. I'm calling the method where the tasks are created from the main method.

I've tried to simply use the waitAll() method of the Task class however it seems that the execution of my program does not wait for the end of the execution of the tasks to resume.

public void method1 () {
  Task t1 = browser.EvaluateScriptAsync(myScript1).ContinueWith(x =>{... }});
  Task t2 = browser.EvaluateScriptAsync(myScript2).ContinueWith(x =>{...});
  Task.WaitAll(t1, t2);
}

static void main (){
  method1();
  //code which necessisates the information brought by method1
  ...

}

Answer 1

Your code seems correct to me. Could you try waiting the two tasks independently and see what happens?

public void Method1()
{
    Task t1 = browser.EvaluateScriptAsync(myScript1);
    t1.Wait();
    // Put here the code inside the ContinueWith(x => { ... });
    Task t2 = browser.EvaluateScriptAsync(myScript2)
    t2.Wait();
    // Put here the code inside the ContinueWith(x => { ... });
}

Another way to do it:

public async Task Method1Async()
{
    Task t1 = browser.EvaluateScriptAsync(myScript1);
    Task t2 = browser.EvaluateScriptAsync(myScript2);
    await t1;
    // Put here the code inside the ContinueWith(x => { ... });
    await t2;
    // Put here the code inside the ContinueWith(x => { ... });
}

static void Main()
{
    Method1Async().Wait();
    // Code which necessitates the information brought by Method1Async.
}