asked on

Dynamic Creation of Objects

I need to create DYNAMICALLY some objects within other objects. The pseudocode I want goes something like this:

// on click of a button

For iLoop := 1 to iNoOfPanelsToDo do
begin
// Create a panel
// give it a cyclic name ('panel001')
// set its size and location on the form by Top := iLoop*20 etc.
// Create a child panel on the above panel
// give it a cyclic name ('innerpanel001')
// set its size and location on the form
// Create a button on the innerpanel
// Attach procedure 'InnerButtonPressed' to the button's OnClick event
end;

I've stumbled through the Delphi Help but I cant seem to find anything like this in terms I've guessed to put in the search, yet I suspect it is something the more experienced Delphi people will know like the back of their hand. I did it before ages ago; all I can remember is the bit about accessing the dynamically-created components by name with FindComponent.

Sample code is best; I learn well from plagiarism; oops, I mean example.

Martin C

ASKER CERTIFIED SOLUTION

kretzschmar

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MartinC

ASKER

Meikl:

I got all that to work - thx! - except the line:

onClick := YourPredefinedClickProc;

which says "[Error] uAssetFacet.pas(67): Incompatible types: 'method pointer and regular procedure'" ... I presume there is some way I am not defining the procedure ... I wrote it as:

procedure YourPredefinedClickProc;
begin
beep;
beep;
beep;
end;

... and I have no idea where I am supposed to store its top line:

procedure YourPredefinedClickProc;

... which I cuurently have above the form's type declaration:

type
TfrmAssetFacet = class(TForm)

... any idea where it should go?

kretzschmar

well, glad to hear

about the error you get

redefine your proc to

procedure TFormClassName.YourPredefinedClickProc(Sender : TObject);
begin
beep;
beep;
beep;
end;

you may notice TFormClassName
this means you should declare this procedure within your formtype like

type
TfrmAssetFacet = class(TForm)
.....
private //could also public
procedure YourPredefinedClickProc(Sender : TObject);
......
end;

so that your proc becomes

procedure TfrmAssetFacet.YourPredefinedClickProc(Sender : TObject);
begin
beep;
beep;
beep;
end;

hope you get it work

meikl ;-)

MartinC

ASKER

I tried that before ... I have the declaration like this:

type
TfrmAssetFacet = class(TForm)
procedure FormShow(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
procedure YourPredefinedClickProc;
end;

... then in the code I have:

onClick := YourPredefinedClickProc;

... and later I have:

procedure TfrmAssetFacet.YourPredefinedClickProc;
begin
beep;
beep;
beep;
end;

... but the compiler says:

[Error] uAssetFacet.pas(68): Incompatible types: 'Parameter lists differ'

... any clues?

kretzschmar

an easy one (you just not read my comment carfully ;-)

replace this
procedure TfrmAssetFacet.YourPredefinedClickProc;
begin
beep;
beep;
beep;
end;

with
procedure TfrmAssetFacet.YourPredefinedClickProc(Sender : TObject); //just add the sender
begin
beep;
beep;
beep;
end;

hope now you get it work

meikl ;-)

SOLUTION

ZhaawZ

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kretzschmar

good point, ZhaawZ, overlooked this

MartinC

ASKER

Sorry, normally I am a good copier but I missed that one. I've increased the points a bit (60 to 100) and chucked a tidbit to ZhaawZ for his correction, which no doubt would have tripped me up too.

Martin