DispatcherTimer doesn't allow event subscription after timer is started

03-25-2008 5:21 PM |

In the following code snippet. the _timer_Tick event will never be called. Obviously
Silverlight doesn't allow to subscribe to a DispatcherTimer once it runs.

_timer = new DispatcherTimer();
_timer.Interval = TimeSpan.FromSeconds(0.5);
_timer.Start();
_timer.Tick += new EventHandler(_timer_Tick);

This is quite confusing until you figure it out...
Florian

 

Re: DispatcherTimer doesn't allow event subscription after timer is started

03-27-2008 4:24 AM |

Hi:

  Thanks for reproting this issue and sorry for confusing you so much. But it's by design and from the msdn we can see the example also attach the event before calling Start method:

http://msdn2.microsoft.com/en-us/library/system.windows.threading.dispatchertimer.aspx

  However it's very kind of you to point it out, which may save other's time.

Thanks again.

Re: Re: DispatcherTimer doesn't allow event subscription after timer is started

03-27-2008 6:37 AM |

It is confusing, because in WPF proper you can attach an event handler once
the timer is running!