How to: Implement the Drill-Down Functionality in Sunburst

• Oct 02, 2023
• 2 minutes to read

Drill-Down allows users to change the detail level of data displayed in a sunburst. This example shows how to create a drill-down sunburst.

1. Subscribe the Sunburst control’s MouseUp event.

2. In the event hander, replace the existing adapter data source with data associated with the selected sunburst item’s Tag property to drill through the item. Tag stores user data objects that the Sunburst control uses to create the item and its child items.

3. You can use a stack to save the adapter data source’s states to implement the ‘Drill up’ action.

C#

void sunburstControl1_MouseUp(object sender, MouseEventArgs e) {
    SunburstHitInfo shi = sunburstControl1.CalcHitInfo(e.Location);
    if(shi.InSunburstItem) {
        TypeInfo drillDownDataSource = (TypeInfo)shi.SunburstItem.Tag;
        if(DataAdapter.DataSource != drillDownDataSource) {
            dataStack.Push(new DataSourceInfo(DataAdapter.DataSource, sunburstControl1.CenterLabel.TextPattern));
            DataAdapter.DataSource = drillDownDataSource;
            sunburstControl1.CenterLabel.TextPattern += "." + drillDownDataSource.NamespaceString;
        }
    }
    else if(shi.InCenterLabel && dataStack.Count > 0) {
        DataSourceInfo sourceInfo = dataStack.Pop();
        DataAdapter.DataSource = sourceInfo.Source;
        sunburstControl1.CenterLabel.TextPattern = sourceInfo.Label;
    }
}

VB.NET

Private Sub sunburstControl1_MouseUp(ByVal sender As Object, ByVal e As MouseEventArgs) Handles sunburstControl1.MouseUp
    Dim shi As SunburstHitInfo = sunburstControl1.CalcHitInfo(e.Location)
    If shi.InSunburstItem Then
        dataStack.Push(New DataSourceInfo(DataAdapter.DataSource, sunburstControl1.CenterLabel.TextPattern))
        Dim data As TypeInfo = CType(shi.SunburstItem.Tag, TypeInfo)
        DataAdapter.DataSource = data
        sunburstControl1.CenterLabel.TextPattern &= "." & data.NamespaceString
    ElseIf shi.InCenterLabel AndAlso dataStack.Count > 0 Then
        Dim sourceInfo As DataSourceInfo = dataStack.Pop()
        DataAdapter.DataSource = sourceInfo.Source
        sunburstControl1.CenterLabel.TextPattern = sourceInfo.Label
    End If
End Sub

The following table lists the API members the code above uses:

Member	Description
SunburstHitInfo	Contains information about the Sunburst element that is under the test point.
SunburstHitInfo.InSunburstItem	Returns the value that specifies whether the cursor is over a sunburst item.
SunburstHierarchicalDataAdapter.DataSource	Gets or sets the object that is the data adapter’s data source.
SunburstItem.Tag	Gets or sets the object that contains data related to a sunburst item.