A CustomDataSource is a clas that can be subclassed to create a custom/on-demand DataSource.

You can create a subclass of CustomDataSource and override methods as desired.

Browse the methods for brief documentation about each method available for overriding.

Important! - To create an on-demand dataSource, you must pass false when setting the count property, ie mydatasource.KeyCount(false)=0.
By doing this, you are responsible for keeping track of selections, and any row reordering that occurs.
This can be a much more complicated task and is only recommended if displaying data from a database.
Otherwise a "managed" DataView/DataSource is recommended.

See the examples CustomData,FileData and DBDataSource in the MainDemoItems, FileBrowserDemo and DataBaseDemo folders for examples.
DBDataSource is unmanaged, the others are custom managed DataSources.