Countdown timer system.timers problem xamarin forms

Question

Now i updated the code and im not getting errors, problem is its not counting

   private System.Timers.Timer _timer;
    private int _countSeconds;
    public MainPage()
    {
        InitializeComponent();
        _timer = new System.Timers.Timer();
        _timer.Interval = 1000;
        _timer.Elapsed += _timer_Elapsed;
        _countSeconds = 5;
        _timer.Enabled = true;
    }
                          
    private void _timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
    {
        _countSeconds--;
        CountLabel.Text = _countSeconds.ToString();

        if (_countSeconds == 0)
        {
            _timer.Stop();
        }
        throw new NotImplementedException();
        
       
    }
                     
    }
}

I think it has something to do with the OnTimedEvent method i need to specify arguments when calling it. I just dont know what to pass in but i would like it to be called from a button but no clue what system timers elapsedeventargs e is. Looked on youtube, reddit, stackoverflow and microsoft. No real explanation or help anywhere.

Heres my MainPage.xaml

<Label Text="Count" x:Name="CountLabel"  HorizontalTextAlignment="Center" VerticalTextAlignment="Center" FontSize="Large"></Label>

When are you getting the error? On build or run? Try giving the whole error message. In your example you have one curly brace `}` more than you should. — Michael, Aug 10 '20 at 20:04
What is the specific error code/message and what line is causing it? Why do you have a `void Main` in a XF Page? — Jason, Aug 10 '20 at 20:04
Visual Studio can typical help writing event handler methods. After typing `+=´ press TAB once or twice. But the methods seems correct. — Michael, Aug 10 '20 at 20:05
@Michael removed main and put the code in mainpage. i did autocomplete thank you. Now its not counting tho — Christian Khalil, Aug 10 '20 at 20:12
you need to update your Label on the main thread - see https://learn.microsoft.com/en-us/xamarin/essentials/main-thread — Jason, Aug 10 '20 at 20:17
@Jason This shit just made my day, thank you all for the help! — Christian Khalil, Aug 10 '20 at 20:22

score 2 · Accepted Answer · 2020-08-11T01:16:51.013

2

You can use Device.Timer instead of System.Timers in Xamarin.Forms.

public partial class MainPage : ContentPage
{
    private int _countSeconds  = 5 ;

    public MainPage()
    {
        InitializeComponent();

        Device.StartTimer(TimeSpan.FromSeconds(1), () =>
         {
             _countSeconds--;
             CountLabel.Text = _countSeconds.ToString();
             return Convert.ToBoolean(_countSeconds);
         });
    }

I think this question and answers help you. How do I add a timer in Xamarin?

edited Aug 11 '20 at 01:16

answered Aug 11 '20 at 01:08

return Convert.ToBoolean(_countSeconds); is this for checking if the timer is running or what? – Christian Khalil Aug 11 '20 at 16:21
Convert.ToBoolean() returns true if value is not zero; otherwise, false. So , the timer is running while _countseconds > 0. When _countseconds reach 0 , the timer stop. – Aug 12 '20 at 22:47
There's also `System.Threading.Timer`. It's an absolutely horrible API, but it can at least be cancelled. – BlueRaja - Danny Pflughoeft Mar 05 '21 at 23:18

score -1 · Answer 2 · answered Aug 10 '20 at 20:27

-1

Visual Studio can typical help writing event handler methods. After typing `+=´ press TAB once or twice. But the methods seems correct. – Michael

you need to update your Label on the main thread - see learn.microsoft.com/en-us/xamarin/essentials/main-thread – Jason

answered Aug 10 '20 at 20:27

Christian Khalil

15
1
5

1

Please see [How do I write a good answer?](https://stackoverflow.com/help/how-to-answer). – Andrew Aug 10 '20 at 20:57
@Andrew dont know how to mark a comment as solution so i thought id comment and mark it as the solution to end post – Christian Khalil Aug 11 '20 at 16:20

Countdown timer system.timers problem xamarin forms

2 Answers2