I'm trying to make a countdown timer on Windows Phone 7, which is really important for my application. But I can't find any method to update text in UI regullary every one second.

```
Timer dt = new System.Threading.Timer(delegate
{
 Dispatcher.BeginInvoke(() =>
   {
      newtime = oldtime--;
      System.Diagnostics.Debug.WriteLine("#" + counter.ToString() + 
                                         " new: " + newtime.ToString() + 
                                         " old: " + oldtime.ToString());
      counter++;
      oldtime = newtime;
   }
}, null, 0, 1000);

```

After running my app console output seems like this:

> 
> 
> ```
> #1 new: 445 old: 446
> #2 new: 444 old: 445
> #3 new: 445 old: 446
> #4 new: 443 old: 444
> #5 new: 444 old: 445
> #6 new: 442 old: 443
> #7 new: 443 old: 444
> #8 new: 441 old: 442
> 
> ```
> 
> 

I can't figure out how to get rid of that unwanted invokes (#3, #5, #7, etc.)

Thank you for any advice.