Field components methods available at runtime enable you to convert field values from one data type to another, and enable you to set focus to the first data-aware control in a form that is associated with a field component. 

Controlling the focus of data-aware components associated with a field is important when your application performs record-oriented data validation in a dataset event handler (such as BeforePost). Validation may be performed on the fields in a record whether or not its associated data-aware control has focus. Should validation fail for a particular field in the record, you want the data-aware control containing the faulty data to have focus so that the user can enter corrections. 

You control focus for a field's data-aware components with a field's FocusControl method. FocusControl sets focus to the first data-aware control in a form that is associated with a field. An event handler should call a field's FocusControl method before validating the field. The following code illustrates how to call the FocusControl method for the Company field in the Customers table:

CustomersCompany.FocusControl;

CustomersCompany->FocusControl();

The following table lists some other field component methods and their uses. For a complete list and detailed information about using each method, see TField.  

Selected field component methods