c# - How to update label text from a timer event handler in a different class? -

i have form label in called labeltime. in class called timecalculate have timer timer_tick event handler. in class have function gettime() returns time in string format. want string appear in labeltime every timer_tick. there way achieve that?

public void mytimer(label o_timelabel)  {   timer clock = new timer();    clock.tag = o_timelabel.text;    clock.interval = 1000; clock.start();    clock.tick += new eventhandler(timer_tick);  }   private void timer_tick(object sender, eventargs eargs)  {    if (sender == clock)    {      //labeltime.text = gettime(); <-- want work!    }  } 

the timer , timer_tick event not need in same class label, can create simple custom event publish/subscribe timer_tick event.

your timecalculate class:

namespace stackoverflow.winforms {     using system;     using system.windows.forms;      public class timecalculate     {         private timer timer;          private string thetime;         public string thetime         {                         {                 return thetime;             }             set             {                 thetime = value;                 onthetimechanged(this.thetime);             }         }          public timecalculate()         {             timer = new timer();             timer.tick += new eventhandler(timer_tick);             timer.interval = 1000;             timer.start();         }          private void timer_tick(object sender, eventargs e)         {             thetime = datetime.utcnow.tostring("dd/mm/yyyy hh:mm:ss");         }          public delegate void timertickhandler(string newtime);         public event timertickhandler thetimechanged;          protected void onthetimechanged(string newtime)         {             if (thetimechanged != null)             {                 thetimechanged(newtime);             }         }     } } 

the extremely simplified example above shows how can use delegate , event publish notification when timer_tick timer object event fires.

any objects require notification when timer_tick event fires (i.e. time updated) need subscribe custom event publisher:

namespace stackoverflow.winforms {     using system.windows.forms;      public partial class form1 : form     {         private timecalculate timecalculate;          public form1()         {             initializecomponent();             this.timecalculate = new timecalculate();             this.timecalculate.thetimechanged += new timecalculate.timertickhandler(timehaschanged);          }          protected void timehaschanged(string newtime)         {             this.txtthetime.text = newtime;         }     } } 

we create instance of timecalcualte class before subscribing timertickhandler event specifying method (timehaschanged) handle notification. note txtthetime name gave textbox on form.