As of the latest release (10/04/2019) RadPieChart with a PieSeries having LabelBinding set to a property name, and ShowLabels set to True, with the list of data bound to ItemsSource containing one or more empty pie slices (a null in the list), causes a System.Reflection.TargetException to be thrown on load of the page containing the chart in iOS (this scenario works fine in UWP).

I am using the latest available Visual Studio 2019 (16.3.5) and the latest available Xamarin.Forms package (4.2.0.848062) and testing on an iPad with iOS 13.1.  The reason I need to have a null value in the list is so that the custom color palette I'm applying will always apply the same colors to the same data points (pie slices), even though in some cases, zero or one or two of the three pie slices will have no data value (and so should not appear in the chart, but still "use up" the corresponding color in the 3 colors of the palette).

In the 08/02/2019 release, this scenario worked fine in iOS (the 09/13/2019 release had the https://feedback.telerik.com/xamarin/1431067-chart-ios-invalidcastexception-is-thrown-when-the-chart-is-loaded issue, which is now resolved in the 10/04/2019 release, but which prevented my testing in iOS since in my app I had RadCartesianCharts on the same pages as the RadPieCharts).

The newly broken functionality in iOS could possibly be related to two other items that are marked completed:
https://feedback.telerik.com/xamarin/1366403-piechart-tooltip-behavior-is-not-working-properly (in 10/04/2019 release)
https://feedback.telerik.com/xamarin/1365842-chart-null-value-support (in R3 2018 SP release)

When the series data is updated and axis labels are redrawn, occasionally the default DateTime format is shown in DateTimeContinuousAxis.

When you update the data in the chart so that the vertical axis values are changed - the annotation does not properly update and stays at the same location.

Loading Chart on iOS raises an exception of type InvalidCastException.

Using the RadPieChart and PieSeries (UI for Xamarin v2019.2.802.1 from NuGet), I can currently set the LabelBinding (or LabelFormat or LabelFormatter) to adjust the strings displayed in the labels on the slices of the pie chart, but unlike other chart controls, I currently have no way to modify the styling of those labels like I can in every other chart control I've used from Telerik UI for Xamarin.

It seems to me that it would be best to have more properties on the PieSeries class, like LabelFontSize, LabelFontAttributes, LabelFontFamily, LabelTextColor, and LabelMargin (Label prefix to distinguish from LegendTitleBinding could be kept or discarded as desired on some of these names).

LabelMargin would be particularly helpful to eliminate the UWP situation wherein currently all pie slice labels overlap with the outer lighter ring of the pie chart (see image from UWP).  The others just seem needed to maintain a consistent appearance of charts within an app - if all my chart labels are dark blue and a different font size and style except for the not-style-able black labels in pie charts, that makes pie charts hard to incorporate without looking bad or forcing styling elsewhere to match the pie charts' fixed values.

Allow customers to set rotation of the labels of the separate bars in a similar manner as their format.

When you set custom stroke to ScatterLineSeries, the colors in the RadLegend are not updated.

If you have a Chart with BarSeries and TooltipBehavior defined, the tooltip of each bar is shown only when the user taps in the area around the tip of the bar.

The expected behavior is the tooltip to be displayed when clicking anywhere on the bar.

In the case of multiple axes, provide the possibility to add a third y-axis in the middle of a RadCartesianChart.

When you set RadLegend`s VerticalOptions or HorizontalOptions to Center - the control disappears. This can be easily observed when the Orientation of the legend is horizontal, but can be reproduced in vertical mode too by setting the HorizontalOptions to Center.

When you have some Series defined and dynamically clear and add new Series, those are not displayed correctly on iOS - it seems the vertical axis is not extended, and all the data points are visualized on the horizontal axis.

If the user pinches in the vertical direction, only the Y-Axis should zoom and the x-axis scale should remain the same.

If the user pinches in the horizontal direction, only the X-Axis should zoom and the y-axis scale should remain the same.

Setting SelectedPointOffset and RadiusFactor in DonutSeries or PieSeries causes unexpected behavior when selecting a pie piece in the chart.

Hi there,

 

I would like to have support for selecting a slice of the piechart from code-behind. I have have looked into the chart and series properties but found no selectable datapoints property. The chartSelectionBehavior offers a ClearSelection method and the readonly SelectedPoints property, but nothing to add a selected point.

 

Once the data of the bar chart is changed, the selection behavior does not fire. The issue is reproducible when the chart is placed inside AnimationPanel,

The issue seems to be down to the width - either calculated or set. Some widths seem to cause the lines to appear - refer to the attached chart_grey_lines.png file.

Workaround: manually calculate the screen width upon load and to set the width to a corresponding lookup value

SelectionChanged event of the Chart SelectionBehavior is not raised for LineSeries when DataPointSelectionMode is "Single" and  SeriesSelectionMode is "None".  

If we have a Chart with combined barseries and lineseries, and the lineseries is added first, the bars are misaligned - they are not placed in the center of the axis label on Android.

As a workaround, make sure to add first the barseries, then the lineseries.

When Custom Palette is used and FillColor is set, the color is not applied to the line series.

As a workaround set the both properties of the PaletteEntry: FillColor and SrtokeColor: 

<telerikChart:PaletteEntry  FillColor="Red" StrokeColor="Red" />

The iOS Chart raises an exception when null values are added at runtime