Question

I have the following dependency property that works fine but it does not auto update.
The dependency properties are all properties of the RegistrationButton.cls class.

public static readonly DependencyProperty DuurStilstandProperty =
        DependencyProperty.Register("DuurStilstand", typeof(string), typeof(RegistrationButton), new UIPropertyMetadata(""));

.NET Wrapper public property:

 public string DuurStilstand
    {
        get { return (string)GetValue(DuurStilstandProperty); }
        set { SetValue(DuurStilstandProperty, value); }
    }

What i am basically doing is trying to display a time (DateTime with default 3 min) and after that the time keeps increasing by using a timer and increments the Datetime by 1 second every second.

So on the screen it should display 00:03:00 and starts incrementing every second.

I have tried TwoWay binding (not sure if this is the issue?) but when i try the following my application crashes:

public static readonly DependencyProperty DuurStilstandProperty =
       DependencyProperty.Register("DuurStilstand", typeof(string), typeof(RegistrationButton), new FrameworkPropertyMetadata(0, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));

The code that involved creating the button (where the time is being displayed) and the timer:

public void InitializeDispatcherTimerStilstand()
    {
        timerStilstand = new DispatcherTimer();
        timerStilstand.Tick += new EventHandler(timerStilstand_Tick);
        timerStilstand.Interval = new TimeSpan(0, 0, 1);
        timerStilstand.Start();
        timerStilstand.ToString();
    }

    private void timerStilstand_Tick(object sender, EventArgs e)
    {
        this.tijdStilStandRegistrationBtn.AddSeconds(1);
    }

Code that creates the button:

Btn.Duurstilstand is the property that holds the time (hh:mm:ss format).

tijdStilStandRegistrationBtn = new DateTime(DateTime.Now.Year, DateTime.Now.Month, DateTime.Now.Day, 0, 3, 0); 

        RegistrationButton btn = new RegistrationButton(GlobalObservableCollection.regBtns.Count.ToString());
        btn.RegistrationCount = GlobalObservableCollection.regBtnCount;
        btn.Title = "btnRegistration" + GlobalObservableCollection.regBtnCount;
        btn.BeginStilstand = btn.Time;
        btn.DuurStilstand = String.Format("{0:T}", this.tijdStilStandRegistrationBtn);

        GlobalObservableCollection.regBtns.Add(btn);
        GlobalObservableCollection.regBtnCount++;

        InitializeDispatcherTimerStilstand();   

Currently it only seems to display 00:03:00 as time but it does not update when my program is running.

I also tried setting the UpDateSourceTrigger to PropertyChanged but it made no difference (this is located in a Style of type RegistrationButton).

<TextBlock x:Name="tbDuurStilstand" TextWrapping="Wrap" 
                                   Text="{Binding DuurStilstand, UpdateSourceTrigger=PropertyChanged}" 
                                   HorizontalAlignment="Center"
                                   VerticalAlignment="Center" 
                                   Margin="7.5,5,0,0" Height="24.8266666666667"/>

EDIT

public void CreateRegistrationButton()
    {
        tijdStilStandRegistrationBtn = new DateTime(DateTime.Now.Year, DateTime.Now.Month, DateTime.Now.Day, 0, 3, 0); 

        RegistrationButton btn = new RegistrationButton(GlobalObservableCollection.regBtns.Count.ToString());
        btn.RegistrationCount = GlobalObservableCollection.regBtnCount;
        btn.Title = "btnRegistration" + GlobalObservableCollection.regBtnCount;
        btn.BeginStilstand = btn.Time;
        //btn.DuurStilstand = String.Format("{0:T}", this.tijdStilStandRegistrationBtn);

        GlobalObservableCollection.regBtns.Add(btn);
        GlobalObservableCollection.regBtnCount++;

        InitializeDispatcherTimerStilstand(btn);     
    }

EDIT 2:

timerStilstand.Tick += () => timerStilstand_Tick(btn); //error at ()

“Delegate ‘System.EventHandler’ does not take 0 arguments”

Kind Regards.

Answer 1

DateTime is an immutable struct. You have to catch the result.
I think you need:

private void timerStilstand_Tick(object sender, EventArgs e)
{
    this.tijdStilStandRegistrationBtn = 
        this.tijdStilStandRegistrationBtn.AddSeconds(1);

    btn.DuurStilstand = 
        String.Format("{0:T}", this.tijdStilStandRegistrationBtn);

}

---

Take 2

public void InitializeDispatcherTimerStilstand(RegistrationButton btn)
{
    timerStilstand = new DispatcherTimer();
    //timerStilstand.Tick += new EventHandler(timerStilstand_Tick);
    timerStilstand.Tick += (aa, bb) => timerStilstand_Tick(btn);   // use capturing to pass btn

    timerStilstand.Interval = new TimeSpan(0, 0, 1);
    timerStilstand.Start();
    //timerStilstand.ToString();
}

private void timerStilstand_Tick(RegistrationButton btn)
{
   this.tijdStilStandRegistrationBtn = 
        this.tijdStilStandRegistrationBtn.AddSeconds(1);

    btn.DuurStilstand = 
        String.Format("{0:T}", this.tijdStilStandRegistrationBtn);
}