Michael Van Canneyt wrote:
On Wed, 20 Jun 2007, Marc Weustink wrote:
Michael Van Canneyt wrote:
On Wed, 20 Jun 2007, Marc Weustink wrote:
Michael Van Canneyt wrote:
On Wed, 20 Jun 2007, Micha Nelissen wrote:
Michael Van Canneyt wrote:
This is due to a Delphi compatibility fix. Component names must be
valid
identifiers. Logical, since the name must match the field name in
the
form,
Why *must* it match a field name in the form ?
Because the streaming depends on it.
The stream contains the component name. The streaming mechanism creates
a
component, sets it's name and then matches this name with the list of
published fields of TForm, and then fills in the pointer.
And what if a published field isn't found ?
Nothing. Since there is no pointer to fill in, nothing happens.
And this is right, because if you were to create everything run-time, and
stream
that, there are no pointers to fill in when the stream is being read again.
:)
then back to Michas question: why must ?
Because in the form declaration, the fieldname must match the name.
Given
TMyForm = Class(TForm)
MyButton : TButton;
end;
and a form file
Object TmYForm
Object MyButton : TButton
Caption = 'Click here'
end
end
The MyButton (=component name) in the form file is used to look up the MyButton
field in TMyForm. If it doesn't find that, then things in code like
MyButton.Enabled:=False;
Would lead to a nice access violation, if the instance pointer is Nil...
Yes, I do understand this. An ide (or someone doing this manually)
should handle this. And for components which are streamed this way its a
requirement.
However, it is IMO a bit strange that there are limitations on some
property, only because some usage indirectly requires a valid
identifier. IMO, the creator of this usage is responsible for that, not
the component itself.
Marc
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