Hierarchical data sources

There are two classes in the FastReport Business Graphics standard set that provide data representation for hierarchical charts.

HierarchicalRecordsSource

This class allows specifying data manually. To do this, fill the Records collection with HierarchicalRecord elements, each with Text and Value fields to define the text and value of the record, and the Children collection in which child records are placed.

Thus, the Children and Parentfields (filled automatically) build a hierarchical relationship between records.

In the following example, we create an instance of HierarchicalRecordsSource and add to it the Bakery productsrecord, which in turn contains three child records: Ciabatta, Bread and Croissant.

HierarchicalRecordsSource recordsSource = new HierarchicalRecordsSource();

// Creating a "Bakery products" record. The constructor for creating a record may not take a value if it is a record containing child nodes
HierarchicalRecord r = new HierarchicalRecord("Bakery products");
// Creating child records. Text and value are passed to the constructor
r.Children.Add(new HierarchicalRecord("Ciabatta", 3));
r.Children.Add(new HierarchicalRecord("Bread", 5));
r.Children.Add(new HierarchicalRecord("Croissant", 1));

// Adding a parent record to the list of source records  
recordsSource.Records.Add(r);

Some charts, such as Sunburst, can display a root element. To set the parameters of the root element, the Root property must be filled in.

recordsSource.Root.Text = "Root element";

HierarchicalListSource

This class allows building a hierarchical structure based on tabular sources (System.Data.DataSet, System.Array) using the standard DataBinding procedure.

To build a hierarchy, set the LevelTextMembers collection with field names in nesting order.

For example:

listSource.LevelTextMembers.Add("Country");
listSource.LevelTextMembers.Add("City");

The ValueMember field specifies the field that will be used to define the record value.

Suppose you have a DataTable with the Country and City fields setting the hierarchy and the Population field setting the value. To load the data from DataTable , we need the following code:

listSource = new HierarchicalListSource();
listSource.BeginInit();
listSource.DataSource = dataTable;
listSource.LevelTextMembers.Add("Country");
listSource.LevelTextMembers.Add("City");
listSource.ValueMember = "Population";
listSource.EndInit();

Note that we use the BeginInit() and EndInit() calls to disable events triggering during property setup.