Timer for alarm

Question

I want to make a simple program to make it run in the specific time. Here is my code:

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        Alarm ft = new Alarm(dateTimePicker1.Value);
    }
}

public class Alarm
{
    public Timer reminder = new Timer();
    public DateTime RemindAt;

    public Alarm(DateTime time)
    {
        RemindAt = time;

        reminder.Interval = (int)(RemindAt - DateTime.Now).TotalMilliseconds;
        reminder.Start();
        reminder.Tick += new EventHandler(reminder_Tick);
    }

    void reminder_Tick(object sender, EventArgs e)
    {
        if (RemindAt <= DateTime.Now)
        {
            reminder.Dispose();
            MessageBox.Show("W: " + RemindAt.ToString("dd MMMM yyyy, HH:mm:ss") + "\n" + "N: " + DateTime.Now.ToString("dd MMMM yyyy, HH:mm:ss") + "\n\n");
        }
    }

As you can seem I use timers, but it seems pretty inaccurate, I have no idea why. Here is the screenshot of 6 alarms: https://i.stack.imgur.com/IGzIh.png

Half of them are wrong. W stands for when it should work, N stands for now. The difference can be huge sometimes, why is that? How to fix that, or maybe there is a better way to make a simple alarm?

score 1 · Accepted Answer · answered Feb 10 '12 at 19:53

1

System.Windows.Forms.Timers aren't precise, especially for large numbers. Instead of calculating the value for Interval, set it to something constant, say 1000.

answered Feb 10 '12 at 19:53

Ry-

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Yeah, I tried to set timer interval to 1000, but it seems wrong to check it every second. I wanted a better way, so I came up with this code, which doesn't work properly. – irondsd Feb 11 '12 at 09:37
@irondsd: Don't worry, once every second won't hurt your processor, even if it does seem a little hackish. (Unless you run it for several weeks, then maybe it does seem a little wrong. But then why aren't you using the Task Scheduler? `taskschd.msc`) – Ry- Feb 11 '12 at 16:38

score 0 · Answer 2 · edited May 23 '17 at 11:56

0

Take a Look at Windows Task Schedular

Basically create your EXE and let Windows handle the time to run.

How to do it via UI

Install it Programmatically

edited May 23 '17 at 11:56

Community

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1

answered Feb 10 '12 at 19:54

Brad Semrad

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Timer for alarm

2 Answers2