Question

I’ve got a problem with a binding in my windows phone project. I’m binding an class to a slider, but it won’t update the value. If I first start the app, the binding connection is established correctly and the slider does have its correct value. But if I change the “position” or “duration” value, the slider won’t update with it.

Can you please help me? I don’t have any clue, what I’m doing wrong 🙁

Class.cs:

public class Status : INotifyPropertyChanged
{
  public event PropertyChangedEventHandler PropertyChanged;
  private void PropChanged(string propName)
  {
    if (PropertyChanged != null)
    {
      PropertyChanged(this, new PropertyChangedEventArgs(propName));
    }
  }

  public double duration
  {
    get { return _duration; }
    set
    {
      if (this._duration == value)
        return;

      _duration = value;
      PropChanged("duration");
    }
  }

  public double position
  {
    get { return _position; }
    set
    {
      if (this._position == value)
        return;

      _position = value;
      PropChanged("position");
    }
  }
}

MainPage.xaml.cs:

public partial class MainPage : PhoneApplicationPage
{
  public MainPage()
  {
    this.ContentPanel.DataContext = _Status;
  }
}

MainPage.xaml:

 ...
<Grid x:Name="ContentPanel" Margin="12,12,12,0" Grid.RowSpan="2">
    <Slider x:Name="sl_PlayBackProgress"
            Value="{Binding Path=position}"
            Maximum="{Binding Path=duration}"
            Height="91"
            HorizontalAlignment="Left"
            Margin="0,40,0,0"
            VerticalAlignment="Top"
            Width="408"/>
</Grid>
...

Answer 1

Don’t know if it different from normal XAML/WPF. But in normal case I would recommend first to set up Binding.Mode to TwoWay and next just break on position.set entrance – and see the passed value