Xamarin Forms Using Reflexion to get Property of Bindable Property - xaml

Question

What i want is, when the value is changed, it should call CreateChart()and use the new values.
I try to call in an onPropertyChange method OnValueChanged a bindable Property with reflection, but the property is always null and i dont get the value of the property Value
public partial class CorrectWrongRingChart : ContentView
{
public CorrectWrongRingChart()
{
InitializeComponent();
}
public static readonly BindableProperty ChartProperty =
BindableProperty.Create(
nameof(CorrectWrongChart),
typeof(Chart),
typeof(CorrectWrongRingChart));
public Chart CorrectWrongChart
{
get { return (Chart)GetValue(ChartProperty); }
set => SetValue(ChartProperty, value);
}
public static readonly BindableProperty ValueProperty =
BindableProperty.Create(
nameof(Value),
typeof(CorrectWrongValue),
typeof(CorrectWrongRingChart),
propertyChanged: OnValueChanged);/*(b, o, n) => { ((CorrectWrongRingChart)b).OnPropertyChanged("Text");});*/
public CorrectWrongValue Value
{
get { return (CorrectWrongValue)GetValue(ValueProperty); }
set => SetValue(ValueProperty, value);
}
private static void OnValueChanged(BindableObject bindable, object oldValue, object newValue)
{
((CorrectWrongRingChart)bindable).OnPropertyChanged("Text");
//((CorrectWrongRingChart)bindable).OnPropertyChanged("Correct");
//((CorrectWrongRingChart)bindable).OnPropertyChanged("Wrong");
var valueProperty = ValueProperty.GetType().GetProperty("Value");
var value = (CorrectWrongValue)valueProperty.GetValue("Value");
var ChartProperty = ValueProperty.GetType().GetProperty("CorrectWrongChart");
if (value != null)
{
ChartProperty.SetValue("CorrectWrongChart", CreateChart(value));
}
}
public static readonly BindableProperty TextProperty =
BindableProperty.Create(
nameof(Text),
typeof(string),
typeof(CorrectWrongRingChart),
defaultValue: string.Empty);
public string Text => $"{Value?.CorrectCount ?? 0}/{Value?.TotalCount ?? 0}";
//public double Correct => Value.CorrectPercentage;
//public double Wrong => Value.WrongPercentage;
private static Chart CreateChart(CorrectWrongValue value)
{
var chart = new Microcharts.DonutChart();
chart.IsAnimated = false;
ChartEntry corretEntry = new ChartEntry((float)value.CorrectPercentage)
{
Color = SKColor.Parse("#00FF00")
};
ChartEntry wrongEntry = new ChartEntry((float)value.WrongPercentage)
{
Color = SKColor.Parse("#FF0000")
};
chart.Entries = new List<ChartEntry>() { corretEntry, wrongEntry };
return chart;
}
}
Xaml:
<Grid >
<forms:ChartView x:Name="chart1" WidthRequest="130" HeightRequest="130" Chart="{Binding CorrectWrongChart, Source={x:Reference Root}}">
</forms:ChartView>
<Label Text="{ Binding Text, Source={x:Reference Root} }"
VerticalOptions="Center"
HorizontalOptions="Fill"
HorizontalTextAlignment="Center"
TextColor="Black"
FontSize="19"
FontFamily="{ StaticResource AppBoldFontFamily }" />
</Grid>

Answer 1

If you want to get Value when the value is changed , you could get it directly like following
private static void OnValueChanged(BindableObject bindable, object oldValue, object newValue)
{
var currentValue = newValue;
// do something you want
// you could get other property like following
// var view = bindable as CorrectWrongRingChart;
// var currentText = view.Text;
}
The property Value will change automatically when we change the value of it source .So we don't need to invoke the following lines any more , which maybe will lead to infinite loop .
if (value != null)
{
ChartProperty.SetValue("CorrectWrongChart", CreateChart(value));
}