The doughnut chart can be a pie plot such as the one shown in this figure.
Each point in a pie series has a single data value. Each point is visualized as a pie slice.
The HoleSize property is used to create the doughnut chart. If this property is not set when using the PieSeries class, the chart would be a pie chart.
A pie series can be assigned a border and fill effect for the pie slices. Assigning null for a border or fill effect indicates that the property is null.
Each point can be assigned a border, fill effect, and a detachment distance for the pie slice. Detachment distance is measured relative to pie radius (0 = no detachment, 1 = detachment is length of pie radius). The detachment distance (PieDetachments property) is used to create an exploded doughnut chart.
For more information on the pie series object in the API, refer to the PieSeries class.