Sets or returns whether lines from the slices to their data labels will be shown.

 public boolean ShowLeaderLines{ get; set; }

Public Property ShowLeaderLines() As Boolean

This defaults to true when creating a new pie series.
The lines themselves can be customized using the LeaderLines property.

This property is linked for series in the same group. See SettingsPieDoughnut for more information on how linking works.
For doughnut series, setting this will have no effect and it will always return false.