timer - if specific time passed show messagebox in C# -

so, want this: if specific time passed (for example 9 hours) loading form, want show messagebox said "9 hours passed". code this:

public partial class form1 : form {     stopwatch stopwatch = new stopwatch();      public form1()     {         initializecomponent();         stopwatch.start();     }      private void button1_click(object sender, eventargs e)     {         double sec = stopwatch.elapsedmilliseconds / 1000;         double min = sec / 60;         double hour = min / 60;         if (hour == 9.00d)         {             stopwatch.stop();             messagebox.show("passed: " + hour.tostring("0.00"));         }     } } 

and problem don't know write part of code:

if (hour == 9.00d)         {             stopwatch.stop();             messagebox.show("passed: " + hour.tostring("0.00"));         } 

so, write code? if have better way of doing this, please show me.

what people not appreciating is unlikely double hours 9.00! why not ask timer fire once, after time want, 9 hours.

timer timer; public form1() {     initializecomponent();     timer.tick += timer_tick;     timer.interval = timespan.fromhours(9).totalmilliseconds;     timer.start(); }  void timer_tick(object sender, eventargs e) {     timer.stop();     messagebox.show("9 hours passed"); }