Data label options for all series in the chart view are defined by the ChartView.DataLabels property.
The DataLabelCollection object is used to change the appearance of data labels of a particular series or for specific data points in the series. Use the Series.CustomDataLabels property to get access to the DataLabelCollection object . Use properties and methods of the DataLabelCollection object to specify options applied to all data points in the series.
To specify data label options for a specific data point, add an item to the DataLabelCollection at the index that is equal to the index of the selected data point, using the DataLabelCollection.Add method. The DataLabel object obtained allows you to change properties of the data label associated with the selected data point.