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Extension Methods
Posted: Tue Aug 07, 2018 4:53 pm
by Karl-Heinz
Hi Wolfgang,
i read your answer in the italian forum - with a little help of Google
- about Extensions. I´ve tested it with a Vulcan class and i´m impressed how seamless it works ! Sure, you can´t access class vars, but better that route than no way to go
Code: Select all
BEGIN NAMESPACE ControlExtensions
STATIC CLASS TabcontrolExtensions
STATIC METHOD GetAllControlsFromPage( SELF o AS Tabcontrol, iIndex AS INT ) AS ARRAY
LOCAL symPage AS SYMBOL
IF ( symPage := o:__GetSymbolFromIndex( iIndex - 1 )) != NULL_SYMBOL
RETURN o:GetAllControlsFromPage( symPage )
ELSE
RETURN {}
ENDIF
STATIC METHOD GetAllControlsFromPage( SELF o AS Tabcontrol, symPage AS SYMBOL ) AS ARRAY
LOCAL oWin AS Window
IF ( oWin := (Window) o:GetTabPage( symPage ) ) != NULL_OBJECT
RETURN oWin:GetAllChildren()
ELSE
RETURN {}
ENDIF
END CLASS
END NAMESPACE
regards
Karl-Heinz
Extension Methods
Posted: Tue Aug 07, 2018 5:09 pm
by wriedmann
Hi Karl-Heinz,
yes, it works like a charm. I can give you a bit more code - written before the X# runtime was available:
Code: Select all
static class StringExtensions
static method IsDigitsOnly( self cString as string ) as logic
local lReturn as logic
lReturn := true
foreach cChar as Char in cString
if cChar < '0' .or. cChar > '9'
lReturn := false
exit
endif
next
return lReturn
static method IsDecimalDigitsOnly( self cString as string ) as logic
local lReturn as logic
lReturn := true
foreach cChar as Char in cString
if ( cChar < '0' .or. cChar > '9' ) .and. ! cChar == '.' .and. ! cChar == ','
lReturn := false
exit
endif
next
return lReturn
end class
I have extended several base classes, not only string, but also object:
Code: Select all
class ObjectExtensions
static method PropertyNames( self oObject as object ) as string[]
local aReturn as string[]
local nLen as int
local nI as int
local oProperties as System.Reflection.PropertyInfo[]
oProperties := oObject:GetType():GetProperties()
nLen := oProperties:Length
aReturn := string[]{nLen}
for nI := 1 upto nLen
aReturn[nI] := oProperties[nI]:Name
next
oProperties := null_object
return aReturn
end class
It is a very powerful possibility, and for sure you will find some of these extension methods also in the XSharp Tools library.
Wolfgang
Extension Methods
Posted: Thu Aug 09, 2018 6:05 pm
by PaulB
Wolfgang,
Thanks so much for sharing this.
So the "SELF" parameter declaration can extend the class. Class variables follow the behavior as if a subclass?
Paul Bartlett
Extension Methods
Posted: Thu Aug 09, 2018 6:13 pm
by wriedmann
Hi Paul,
Class variables follow the behavior as if a subclass?
unfortunately not. Extension methods are added externally to the class so they have no access to the class internals.
Wolfgang