The generic name #Com_Owner can be used to refer to the current component. In the context of inheritance there are two other generic names you can use for components: #Com_Ancestor and #Com_Self.
#Com_Ancestor is a generic reference to the ancestor of the current component and #Com_Self is a generic reference to the currently executing component.
#Com_Owner and #Com_Self
To see in what way #Com_Owner and #Com_Self differ create two reusable parts with this code:
Button 3 |
This button reusable part contains a method MethodOne which displays a message saying Hello. The message is displayed when this button (Button3, in other words #Com_Owner) is clicked. FUNCTION options(*DIRECT) BEGIN_COM role(*EXTENDS #PRIM_PHBN) CAPTION('Button 3') HEIGHT(24) WIDTH(185)
MTHROUTINE name(MethodOne) USE builtin(MESSAGE_BOX_SHOW) with_args(OK OK INFO '' 'Hello') to_get(#STD_OBJ) ENDROUTINE
EVTROUTINE handling(#COM_OWNER.Click) INVOKE method(#com_owner.methodone) ENDROUTINE
END_COM
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Button 4 |
This button reusable part inherits from Button3 and redefines MethodOne so that the message says Bye. FUNCTION options(*DIRECT) BEGIN_COM role(*EXTENDS #BUTTON3) CAPTION('Button 4') HEIGHT(26) WIDTH(176)
MTHROUTINE name(MethodOne) options(*redefine) USE builtin(MESSAGE_BOX_SHOW) with_args(OK OK INFO '' 'Bye') to_get(#STD_OBJ) ENDROUTINE
END_COM
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Add these buttons to a form and compile and execute the form. Click on both buttons. They both display a message saying 'Hello':
In other words the redefined method which would display the message 'Bye' is not used for Button 4 because the Click event defined in Button 3 invokes the method in the component where it is defined (#Com_Owner):
INVOKE method(#com_owner.methodone)
Next change the invoke command in the Click event of Button 3 to use #Com_Self instead of #Com_Owner so that the Click event invokes the method in the component where the event is executed:
INVOKE method(#com_self.methodone)
Compile Button 3 and execute your form again. This time when you click on Button 4, the redefined method is used and the message 'Bye' is displayed:
#Com_Ancestor
If you want to invoke a method in an ancestor component, you can refer to it by qualifying the name of the method using the generic name #com_ancestor.
For example, to continue with the above example, you can invoke the MethodOne method in Button 3 from the redefined MethodOne in Button 4 like this:
MTHROUTINE name(MethodOne) options(*redefine)
INVOKE method(#com_ancestor.methodone)
USE builtin(MESSAGE_BOX_SHOW) with_args(OK OK INFO '' 'Bye') to_get(#STD_OBJ)
ENDROUTINE
Compile Button 4 and run your test form. When you click on Button 4 first the MethodOne from the ancestor Button 3 is invoked:
And then when you click OK, the Message_Box_Show Built-In Function showing the text 'Bye' defined in Button 4 is displayed:
