How to use the .NET Timer class to trigger an event at a specific time?

Question

I would like to have an event triggered in my app which runs continuously during the day at a certain time, say at 4:00pm. I thought about running the timer every second and

Answer 1

Echo to Dan's solution, using Timercallback is a quick and neat solution. Inside the method you want to schedule a task or subroutine to be run, use the following:

    t = New Timer(Sub()
                        'method call or code here'
                  End Sub, Nothing, 400, Timeout.Infinite)

use of 'Timeout.Infinite' will ensure the callback will be executed only once after 400ms. I am using VB.Net.

Answer 2

Taking VoteCoffees lead, here is a compact event based solution:

public class DailyTrigger 
{
    readonly TimeSpan triggerHour;  

    public DailyTrigger(int hour, int minute = 0, int second = 0)
    {
        triggerHour = new TimeSpan(hour, minute, second);
        InitiateAsync();        
    }

    async void InitiateAsync()
    {
        while (true)
        {
            var triggerTime = DateTime.Today + triggerHour - DateTime.Now;
            if (triggerTime < TimeSpan.Zero)
                triggerTime = triggerTime.Add(new TimeSpan(24,0,0));
            await Task.Delay(triggerTime);
            OnTimeTriggered?.Invoke();
        }
    }

    public event Action OnTimeTriggered;
}

Consumer:`

void Main()
{
    var trigger = new DailyTrigger(16); // every day at 4:00pm

    trigger.OnTimeTriggered += () => 
    {
        // Whatever
    };  

    Console.ReadKey();
}

Answer 3

Task scheduler is a better option, and it can be easily used in C#, http://taskscheduler.codeplex.com/