Delphi getting property value of a member from ClassType
- by Kayode Yusuf
I am implementing a Boilerplate feature - allow users to Change descriptions of some components - like Tlabels - at run time.
e.g.
TFooClass = Class ( TBaseClass)
Label : Tlabel;
...
End;
Var FooClass : TFooClass;
...
At Design time, the value Label's caption property is say - 'First Name', when the
application is run, there is a feature that allows the user to change the caption
value to say 'Other Name'. Once this is changed, the caption for the label for
the class instance of FooClass is updated immediately.
The problem now is if the user for whatever reason wants to revert back to the design
time value of say 'First Name' , it seems impossible.
I can use the RTTIContext methods and all that but I at the end of the day, it seems
to require the instance of the class for me to change the value and since this
has already being changed - I seem to to have hit a brick wall getting around it.
My question is this - is there a way using the old RTTI methods or the new RTTIContext
stuff to the property of a class' member without instantiating the class - i.e. getting
the property from the ClassType definition.
This is code snippet of my attempt at doing that :
c : TRttiContext;
z : TRttiInstanceType;
w : TRttiProperty;
Aform : Tform;
....
Begin
.....
Aform := Tform(FooClass);
for vCount := 0 to AForm.ComponentCount-1 do begin
vDummyComponent := AForm.Components[vCount];
if IsPublishedProp(vDummyComponent,'Caption') then begin
c := TRttiContext.Create;
try
z := (c.GetType(vDummyComponent.ClassInfo) as TRttiInstanceType);
w := z.GetProperty('Caption');
if w <> nil then
Values[vOffset, 1] := w.GetValue(vDummyComponent.ClassType).AsString
.....
.....
....
....
I am getting all sorts of errors and any help will be greatly appreciated.
