Gets the collection of DocumentTableColumn objects representing columns of
the corresponding table.
Remarks
For documents of Spreadsheet file formats, a DocumentTable instance represents a single sheet.
For documents of other file formats, a DocumentTable instance represents a single table.
To access data of the corresponding table while assembling a document, pass an instance of this class as
a data source to one of DocumentAssembler.
overloads.
In template documents, a DocumentTable instance should be treated in the same way as if it was
a DataTable instance. See template syntax reference for more information.