Hi
Thanks to you all for your help and the tutorial on interfaces which was very handy as
I'm still wrapping my mind around them (apart from this problem).
I decided to use Kyley's RTTI interrogation technique - I understand what it's doing
whereas my OO development is still digesting interfaces. In due course I may go the
interface way, but for the moment, the RTTI method will suffice.
I decided to check the functions worked as I expected by creating my own object
(rather than using Form/Panel, Font background ...)
I defined a minimal object with get/set properties and tried to use it (see skeletal
code below). Compiled fine but gave a "Doesn't have a Colour Property" message, which
means that IsPublishedProp is returning nil.
After wandering around the help system on RTTI I went home and the answer (well a
solution anyway) came while I was driving. I was pondering on why the system-defined
objects were fine and mine wasn't. Answer - they're all derived from TComponent. Even
though the property is public and published, for "IsPublishedProp()" to work, the
class (apparently) has to be a descendent of TComponent, TObject won't work.
So now I have a method I can use for both VCL objects and those I create.
I greatly appreciate your help
Thank you all
Giovanni
CompSci - Massey Uni
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// TMyColourSetTester = class(TObject) <= FAILS AT RUNTIME
TMyColourSetTester = class(TComponent) <= WORKS FINE
private
MyColour : TColor;
function GetCol : TColor;
procedure SetCol (value : TColor);
public
constructor create; // just calls inherited create
published
property
color : TColor read GetCol write SetCol;
end;
procedure SetObjectColour (name : string;
AObject : TObject;
newColour : TColor);
var result : boolean;
propinfo : PPropInfo;
classTypeInfo : PTypeInfo;
begin
result := IsPublishedProp(AObject,'color');
If result then SetOrdProp(AObject,'Color',newColour)
else showmessage(name+' doesn''t have a Color property');
end;
var Coltester : TMyColourSetTester;
ColTester:= TMyColourSetTester.create;
ColTester.color:= clYellow; // Make sure it goes
setObjectColour('ColTester', ColTester, clAqua);
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