Binding programmatically to a syncfusion NeedPointer

Question

I am trying to bind without success a property called PointerValue to a NeedlePointer.Value progmatically but seem to have got lost somewhere.

The xamarin app basically has a gauge and a start button when the start button is pressed I start the timer. Upon timer elapsed the needle value should increase by on. Easy in XAML but cant figure out how to convert this to code <gauge:NeedlePointer Value="{Binding PointerValue}"

public class StopWatchPage : BaseContentPage
{
    private Timer timer;

    private double PointerValue
    {
        get => (double)GetValue(PointerValueProperty);
        set => SetValue(PointerValueProperty, value);
    }

    private static readonly BindableProperty PointerValueProperty =
        BindableProperty.Create("PointerValue", 
           typeof(double), typeof(StopWatchPage), 0d);

    public StopWatchPage()
    {
        this.BindingContext = this;

        var needlePointer = new NeedlePointer
        {
            Value = PointerValue
        };
        needlePointer.SetBinding(
            PointerValueProperty, nameof(PointerValue));

        var scale = new Scale{...};
        scale.Pointers.Add(needlePointer);
        scales.Add(scale);
        circularGauge.Scales = scales;

        ... add gauge to Content etc...
    }

    private void Timer_Elapsed(object sender, ElapsedEventArgs e)
    {
        this.PointerValue += 1;
    }
}

Answer 1

this should work, although the actual name of ValueProperty might be different depending on how NeedlePointer is implemented. The first argument is the name of the control property that you are binding to (the target), and the second is the name of the value property acts as the source.

needlePointer.SetBinding(NeedlePointer.ValueProperty, "PointerValue");

however, if you want the UI to update dynamically, you will also need to have your BindingContext implement INotifyPropertyChanged

There is no need to create a BindableProperty