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Setting Form1.BorderIcons in code

Posted on 2003-10-30
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Last Modified: 2007-12-19
I prefer to set properties in code rather than via the object inpsector as I find it more maintainable that way.

I want to set

  Form1.BorderIcons := [];
  Form1.Position       := poMainFormCenter;

in code. It gived a visiblity erro if I try and set them in my Form1.FormCreate, If I try in Form1.FormShow the assigments are not effective whereas they are if Is et them in the object inspector. How can I achieve this in code?

Thanks, Tom.
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Question by:tomcorcoran
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9 Comments
 
LVL 2

Assisted Solution

by:j42
j42 earned 50 total points
ID: 9651467
Hi,

I nearly always reintroduce the constructor of my forms. Thus you can't create them like
  myForm := Application.CreateForm(TMyForm, myForm);
Use
  myForm := TMyForm.Create(new parameter list);
instead.

type
  TMyForm = class(TForm)
  public
    contructor Create; reintroduce;
    ...
  end;

constructor TMyForm.Create;
begin
  inherited Create(Nil);  // Nil: no owner
  Self.BorderIcons := [];
  Self.Position := poWhatever;
end;

Don't forget to remove the Application.CreateForm(...) from your *.dpr file!

Cheers
0
 

Author Comment

by:tomcorcoran
ID: 9675501
Thanks for the post.

I did not have much luck with your method. I create all my forms ont he fly so did not have to change any CreateForms. I removed the FomrCreate event and tried adding :

   constructor Create; reintroduce;
 ..

constructor TMyForm1.Create;
begin
  inherited Create(Nil);  // Nil: no owner
 
  MyCombo.Style  := csDropDownList;
end;

This does not work. I have to set the style in the object inspector for the items dropdown to show.

Thanks, Tom.
0
 
LVL 27

Expert Comment

by:kretzschmar
ID: 9677253
works like a charme

procedure TForm1.FormCreate(Sender: TObject);
begin
  BorderIcons := [];  //just left out Form1
  Position       := poMainFormCenter;
  combobox1.Style := csDropDownList;
end;

?? didn't understand the question -> problem

meikl ;-)
0
 

Author Comment

by:tomcorcoran
ID: 9677452
So they all show for you? What if you do a combobox1.items.commatext := 'one,two,three'; Does that show too?

I wonder why they don't show for me unless thay are in the object inpector. From j42's comment above he would appear to know what I am talking about and has experienced the problem.

Confused now.

Cheers, Tom.
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LVL 27

Accepted Solution

by:
kretzschmar earned 50 total points
ID: 9677468
?? no prob

procedure TForm1.FormCreate(Sender: TObject);
begin
  BorderIcons := [];
  Position       := poMainFormCenter;
  combobox1.Style := csDropDownList;
  combobox1.items.commatext := 'one,two,three';
end;

meikl ;-)
0
 
LVL 2

Expert Comment

by:j42
ID: 9679944
> From j42's comment above he would appear to know what I am talking about and has experienced the problem.
Yep, I had similar problems but I can't remember exactly. The only thing I know is that sometimes the OnCreate event is
'too late', thus the hiding of the original constructor. And I can remember other members of EE asking qusetions about
the same topic.
I played a little with the BorderIcons property and it seams that you can use it in the OnCreate event. I don't know what's
wrong with your code. I tried SDI and MDI apps, Application.CreateForm and Form1 := TForm1.Create(Nil). Everything worked
ok...
Just another guess. Try to replace all the instances (Form1, Form2) by the Self keyword. If it works I will explain why. Sorry,
don't know what else to do.
0
 

Author Comment

by:tomcorcoran
ID: 9680392
thanks for the info. Not sure what you mean by "Try to replace all the instances (Form1, Form2) by the Self keyword". I create all froms on the fly, normally they are embeded in other forms so the create goes like
  TheForm := Self.Create(ParentPanel.Owner);
with TheForm reference being local only to a procedure and killed at the end.

Thanks for the testing. I'll have to figure out why mine does not get called.

Cheers, Tom.
0
 
LVL 2

Expert Comment

by:j42
ID: 9681947
Ok, maybe you are aware of all that stuff. If so, please kindly skip this comment ;-)

let's say you have a class TYourForm and a global variable YourForm in YourFormUnit.pas.
In your *.dpr file there is something like Appliaction.CreateForm(TYourForm, YourForm). In
your procedure you have a local variable theForm: TYourForm and you call
theForm := TYourForm.Create(ParentPanel.Owner). Your OnCreate handler looks something
like this:

procedure TYourForm.CreateForm(Sender...);
begin
  YourForm.BorderIcons := [];
end;
=> Error.

YourForm is not a dangling reference since the CreateForm in the *.dpr file but you don't
want to change any property of YourForm but of theForm (the local one).

procedure TYourForm.CreateForm(Sender...);
begin
  theForm.BorderIcons := [];
end;
will work but it's bad style.

procedure TYourForm.CreateForm(Sender...);
begin
  Self.BorderIcons := [];
end;
is what I prefer.

Hope this was clear enough.
0
 

Author Comment

by:tomcorcoran
ID: 9949708
This wasn't working and then started working again...one of those weird delphi problems.  I am trying to think of an example of why you would reinstroduce the form create.

chees, tom.
0

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