How to show a MessageBox in a interval with condition

Question

How can I call a MessageBox.Show command when the time is exactly 5pm in C#?

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

    const double interval60Minutes = 1000; // milliseconds to one hour
    System.Timers.Timer checkForTime = new System.Timers.Timer(interval60Minutes);

    string Check = null;
    private void Form1_Load(object sender, EventArgs e)
    {
        checkForTime.Elapsed += new ElapsedEventHandler(checkForTime_Elapsed);
        checkForTime.Enabled = true;
    }


    public void checkForTime_Elapsed(object sender, ElapsedEventArgs e)
    {

        DateTime target = new DateTime(2016, 5, 8, 11, 58, 0);
        DateTime now = DateTime.Now;

        if (target.ToString("HH:mm:ss") == now.ToString("HH:mm:ss") && (Check == null))
        {
            MessageBox.Show("Welcome Admin");
            checkForTime.Stop();
            checkForTime.Enabled = false;
        }
    }
}

If I put just MessageBox.Show without the if statement it works, but when I put a condition nothing happens. The timer won't stop I used both enabled = false and stop function.

The odds that the time matches *exactly* within 100 nanoseconds are very, very low. Also rather a bad idea to use System.Timers.Timer, good odds that the message box disappears behind another window since the Elapsed event runs on a worker thread. Drop a Timer from the toolbox. Calculate the Interval so you need only one Tick. And use NotifyIcon.ShowBalloonTip() to tell the user. — Hans Passant, May 08 '16 at 15:45
Look at this answer to a similar question: http://stackoverflow.com/a/18270238/820068 — Wesley Long, May 08 '16 at 16:05
@MostafizurRahman - actually the question is closed because of a user not demonstrating minimal understanding, not because it is off-topic. Hopefully it will someday get addressed, but I understand the mods have a lot more to deal with on stackoverflow than we do over in workplace. However, the answer I provided the link to is almost exactly what I was going to answer with, so it is, IMO, a duplicate. — Wesley Long, May 08 '16 at 16:13
@MostafizurRahman For some reason I can't access the checkForTime.Stop(); in the method checkForTimeElapsed — Ryze2, May 08 '16 at 16:39
@MostafizurRahman brother I used your answer but it wont stop the timer. It keep showing the messagebox. Please see my updated question.. — Ryze2, May 08 '16 at 16:52
@Ryze2 brother I have just check your code and its working fine here, please look carefully if the is problem in somewhere else — Mostafiz, May 08 '16 at 17:01
move your target time outside the `checkForTime_Elapsed` method because both target time and present time is initialize inside the `checkForTime_Elapsed` so everytime it true, for this messegebox will show up every time, move outside then it will only show whne the time match — Mostafiz, May 08 '16 at 17:07
@MostafizurRahman I put all the code in the question box please tell me what I did wrong thank you brother — Ryze2, May 08 '16 at 17:10
got it you are stoping the timer insdie the callback function for that you have to set `checkForTime.AutoReset = false;` in your code see my latest update — Mostafiz, May 08 '16 at 17:33

Mostafiz · Accepted Answer · 2016-05-08T17:32:49.553

Use this, this code will check if your target time and present time is same or not if same then it will run the MessageBox

if (target.ToString("HH:mm:ss") == now.ToString("HH:mm:ss"))
   {
       MessageBox.Show("It's Time");
   }

use

checkForTime.Stop();

where you want to stop the timer

to access the timer from another method put your timer in the global scope

    const double interval60Minutes = 1000; // milliseconds to one hour
    System.Timers.Timer checkForTime = new System.Timers.Timer(interval60Minutes);

    string Check = null;
    private void Form1_Load(object sender, EventArgs e)
    {
        checkForTime.Elapsed += new ElapsedEventHandler(checkForTime_Elapsed);
        checkForTime.Enabled = true;
        checkForTime.AutoReset = false;
    }


    public void checkForTime_Elapsed(object sender, ElapsedEventArgs e)
    {

        DateTime target = new DateTime(2016, 5, 8, 11, 58, 0);
        DateTime now = DateTime.Now;

        if (target.ToString("HH:mm:ss") == now.ToString("HH:mm:ss") && (Check == null))
        {
            MessageBox.Show("Welcome Admin");
            checkForTime.Stop();
        }

    }

Directly comparing times like that is sketchy. Comparing whole seconds will probably work, but there's no guarantee that the program/system won't choke and miss the time. A better way is to check whether the current time is past or equal to a certain time. Also converting to strings and comparing seems like a waste of resources. — Chris, May 08 '16 at 16:56

How to show a MessageBox in a interval with condition

1 Answers1