ComponentOne True DataControl 8.0
Implementing Handlers for User Events Mode

The most essential part of defining your custom data source is, of course, programming handlers for the True DataControl events: UserReadData, UserWriteData, UserAddData, UserDeleteRow, and UserFindData. Depending upon your application requirements, you may not have to provide handlers for all five events. For example, if your data source is read-only, implementing UserReadData alone is sufficient. The UserFindData event is optional in all cases, it is only used to improve search performance in large data sources.

See the Reference section for details on each of the following events used in the user events mode:

UserReadData

Fired when the control is requested to retrieve a bookmark or columns data.

UserWriteData

Fired when a row data has been modified and the user commits the changes by leaving the row or calling Recordset.Update.

UserAddData

Fired when a new row has been added and the user commits the changes by leaving the newly added row or calling Recordset.Update.

UserDeleteRow

Fired when a row has been deleted and the user commits the changes.

UserFindData

Gives you an opportunity to optimize performance of simple search in your data source.

 

 


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