The Categories property defines the number of leading columns in Data that represent the categories. The ViewChange event is triggered whenever there is a change in the control's view.

Once the ViewChange event occurs the following properties are updated:

• Data, retrieves the data to be represented (the pivot-table) as a 2-dimensional array
• Columns, retrieves the names of the columns, represented as a comma-separated list
• Categories,  retrieves the number of leading columns in Data that represent the categories
• Series,  defines the number of trailing columns in Data that represent the series
• Stack, retrieves the name of the stack for each exported column (columns generated from the same pivot-column are grouped together in a stack), represented as a comma-separated list.
• Items, retrieves the number of rows in Data

Similarly, the internal eXGraph control is updated automatically based on this information. (only if the ControlID property is "exontrol.graph")