How to update a Chart's data?

[Ghostbird]

How do I update the data of a Chart?

I'm using MAUI and I have a ChartView that has a rendered Chart, but at a later point in time, the data changes.

I can't bind the Entries of any type of Chart, so I opted to bind the ChartView.ChartProperty and generate a completely new chart, but this method will not clear the canvas before redrawing, it will simply draw an additional copy of the chart somewhere on the canvas, it does in fact seem to attempt to avoid drawing over the previous chart if possible.

The canvas is not accessible, so I can't manually erase it.

In the context where the update comes in, I do not know the exact subclass of the current Chart. Chart itself has no Entries property, so I can't change that.

Even if I first change the ChartView.Chart to null, the canvas is not erased.

UPDATE:

Turns out the canvas is only erased when you set the Chart to null. However when you use MVVM and bindings in MAUI, it won't work well together:

1. View model value changes
2. Set the value to null to clear canvas
3. Set the value to draw a new graph
4. Binding fires twice, both passing the latest value
5. Graph gets drawn on top of the previous drawing

I tried a different step 2 where I set the ChartView.Graph to null, but that doesn't work either.

I managed to get it to work when I introduced a delay between 2 and 3, but that's ugly and not guaranteed to work.

[mikiNoz]

same problem. did you find a solution?
your solution dind twork for me. it is still drawing on top of the old drawing:

private void ReasignChart()
{
    chartView.Chart = ((YieldPageViewModel)BindingContext).ResultsbarChart;
}

private void SetChartToNull()
{
    chartView.Chart = null;
    //add  delay to give the chart time to clear
    Task.Delay(5000).Wait();
}

[Ghostbird]

I suspect your solution is not working because you're using .Wait() which locks up the thread for 5 seconds, and causes no time at all to pass from the point of view of the frozen control. I'm using await Task.Delay(100);

As a rule, you should never use Task.Wait()