Standard tooltips are implemented by the Chart control using two properties:

  1. ToolTip: allows for both design-time and run-time tooltips for DataPoint, Series and LegendItem objects. Special formatting can be used for these tooltips.
  2. LegendToolTip: used to set or get the tooltips of default legend items created for DataPoint or Series objects, depending on the chart type displayed. Special formatting can also be used for these tooltips.

Custom tooltips are implemented via the GetToolTipText event, which can be used to display a tooltip for a chart element that doesn't have a tooltip property and also to override the tooltip for a chart element that does have a tooltip property.