C# Async Await用法示范

C# Async Await用法演示

public void Main()
{
    var result = LaunchTasks(new List<int>() { 5, 3 });
    Debug.WriteLine("The final result is {0}",result.Result);
}
 
public async Task<bool> LaunchTasks(List<int> waitTimes)
{
    bool result = false;
    List<Task> tasks = new List<Task>();
    try
    {
       foreach (int wait in waitTimes)
       {
           var task1 = FirstWait(wait);
           tasks.Add(task1);
           var task2 = SecondWait(wait);
           tasks.Add(task2);
       }
       Debug.WriteLine("About to await on {0} Tasks", tasks.Count);
       await Task.WhenAll(tasks);
       Debug.WriteLine("After WhenAll");
    }
    catch (Exception ex)
    {
    }
 
    return result;
}
 
private async Task<bool> FirstWait(int waitTime)
{
    var task = Task.Factory.StartNew<bool>((delay) => 
    {
        try
        {
            int count = (int)delay;
            for (int i = 0; i < count; i++)
            {
                Debug.WriteLine("FirstWait is at {0}", i);
            }
        }
        catch (Exception ex)
        {
            Debug.WriteLine(ex.Message);
        }
 
        return true;
    }, waitTime);
 
    await Task.WhenAll(task);
    Debug.WriteLine("After FirstWait");
    return task.Result;
}
 
 
private async Task<bool> SecondWait(int waitTime)
{
    var task = Task.Factory.StartNew<bool>((delay) =>
    {
        try
        {
            int count = (int)delay;
            for (int i = 0; i < count; i++)
            {
                Debug.WriteLine("SecondWait is at {0}", i);
            }
        }
        catch (Exception ex)
        {
            Debug.WriteLine(ex.Message);
        }
        return true;
    }, waitTime);
    await Task.WhenAll(task);
    Debug.WriteLine("After SecondWait");
    return task.Result;
}