/// <summary>
/// Creates a legend item.
/// </summary>
/// <returns>A legend item for insertion in the legend items collection.
/// </returns>
protected virtual LegendItem CreateLegendItem()
{
LegendItem legendItem = new LegendItem();
if (this.LegendItemStyle != null)
{
legendItem.Style = LegendItemStyle;
}
return(legendItem);
}
/// <summary>
/// Updates the indexes of all legend items when a change is made to the collection.
/// </summary>
private void UpdateLegendItemIndexes()
{
int index = 0;
foreach (DataPoint dataPoint in ActiveDataPoints)
{
LegendItem legendItem = _dataPointLegendItems[dataPoint];
legendItem.Content = dataPoint.IndependentValue ?? (index + 1);
index++;
}
}
/// <summary>
/// Removes data point's legend item when the data point is removed.
/// </summary>
/// <param name="dataPoint">The data point to remove.</param>
protected override void RemoveDataPoint(DataPoint dataPoint)
{
base.RemoveDataPoint(dataPoint);
if (dataPoint != null)
{
LegendItem legendItem = _dataPointLegendItems[dataPoint];
_dataPointLegendItems.Remove(dataPoint);
LegendItems.Remove(legendItem);
UpdateLegendItemIndexes();
}
}
/// <summary>
/// Creates a legend item from a data point.
/// </summary>
/// <param name="dataPoint">The data point to use to create the legend item.</param>
/// <param name="index">The 1-based index of the Control.</param>
/// <returns>The series host legend item.</returns>
private LegendItem CreatePieLegendItem(DataPoint dataPoint, int index)
{
LegendItem legendItem = CreateLegendItem();
// Set the Content of the LegendItem
legendItem.Content = dataPoint.IndependentValue ?? index;
// Create a representative DataPoint for access to styled properties
DataPoint legendDataPoint = CreateDataPoint();
legendDataPoint.Style = dataPoint.Style;
legendItem.DataContext = legendDataPoint;
return(legendItem);
}
/// <summary>
/// Creates a legend item for each data point.
/// </summary>
/// <param name="dataPoint">The data point added.</param>
protected override void AddDataPoint(DataPoint dataPoint)
{
base.AddDataPoint(dataPoint);
int index = ActiveDataPoints.IndexOf(dataPoint) + 1;
Style style = NextStyle(typeof(PieDataPoint), true);
if (dataPoint.Style == null)
{
dataPoint.Style = style;
}
LegendItem legendItem = CreatePieLegendItem(dataPoint, index);
_dataPointLegendItems[dataPoint] = legendItem;
LegendItems.Add(legendItem);
UpdateLegendItemIndexes();
}