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GUI Customisation

This document summarises the points at which you can easily customise gui integration behaviour.

There are a number of protected virtual methods provided in the helper classes. Simply override these methods to provide your own processing.

CLASS dbEditHelper User Hook Methods

EnteringAboutToLoad

Called just before copying record values into controls. Controls should be fully constructed at this point, by the mechanism specific to the particular GUI, and probably initialised to default values.

 

EnteringAfterLoad

Called after record values are loaded into controls. If you have any unlinked controls which have values derived from the database values, this is where you'd set them. (Alternatively, once we implement virtual fields, you could have a virtual field linked to the control.)

 

CanLeaveRecord

Called by all movement buttons and OK button. Default allows departure from record but you can override for complex validation.

 

ConfirmSave

Called to provide user interaction to confirm a save, typically if record is dirty. Returns a tri-state YNCancelT.

 

CLASS dbEditHelper Messages - alternative way to react

Some people may not want to subclass dbEditHelper and override the above messages. You can also set messages of type unsigned long which will be broadcast along the normal message handling for your framework.

The accessor functions for the optional GUI messages are the public methods with the same names as the above hook methods, with the prefix msg. eg:

msgEnteringAboutToLoad(yourMessageNum)

sets the message broadcast by the default EnteringAboutToLoad

 

unsigned long getMsg = msgEnteringAboutToLoad()

gets the message broadcast by the default EnteringAboutToLoad

 

Note that if you override the user hooks, the above messages won't be broadcast unless you do so, or call the dbEditHelper original method.

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