>>>As I am learning VFP, I discovered how to add an object to a form programmatically. What I’m struggling with is, how do you capture event processing for this object? I.e. when a command button receives a double click. Any help is appreciated.
>>
>>The button has a DoubleClick() that can be extended by subclassing the base class and adding code to the method. For example:
>>
>>
DEFINE CLASS ObnoxiousButton as CommandButton
>> PROCEDURE DoubleClick
>> ?? CHR(7)
>> WAIT WINDOW 'Hey dummy, you double-clicked!!!'
>> ENDPROC
>>ENDDEFINE
>>
>>To create a command button programmatically with this, you ADD OBJECT not from the class CommandButton, but from the subclass you've created called ObnoxiousButton...
>>
>>You can make subclasses using the Visual Class Designer, too.
>
>I tried something like this in my form init procedure but I get the message "methods and events cannot contain nested procedures or class defintions". I kinda want to create the object and its procedures on the fly while the program is running. Is this possible?
Not really. You could put a reference to an external .PRG or another object in a method, and build that at runtime, or build the subclass and compile it before executing it (requires VFP6 SP3 or a development copy of VFP to do) by creating a text file that would contain the class definition, compiling it and then firing the compiled .FXP - the subclass needs to exist before you can instantiate it, and you can't bury an object definition inside a method of an object (creates problems since the object definition is only visible in that method execution, so VFP doesn't allow it.)
example:
DEFINE CLASS FlexibleButtonDef AS CommandButton
icDoubleClickPrgToRun = 'ObnoxiousDoubleClick.FXP'
PROCEDURE DoubleClick
IF FILE(thisform.icDoubleClickPrgToRun)
DO (thisform.icDoubleClickPrgToRun)
ELSE
WAIT WINDOW 'Hey dummy, I can't find my DoubleClick Code!!!!'
ENDIF
ENDPROC
ENDDEFINE
You could then create the program to run for the DubleClick as a text file, compile it, and stick the name of the program to run in the propery you create to hold the name. it's not what I'd do, since i usually know the basic behavior I want well in advance, and might just need to set a couple of properties to get my subclass to behave, but this approach does work with SP3's new ability to compile a .PRG on the fly...
