Can't access class in form

[nikel]

Hello, I'm trying to call my class in form create event. I declated a variable named D however can't access it. Here's my code so far:

Code: Pascal  [Select][+][-]

1. var
2.   D       : TDownload;
3.  
4. implementation
5.  
6. {$R *.lfm}
7.  
8. { TForm1 }
9.  
10. procedure TForm1.FormCreate(Sender: TObject);
11. begin
12.   ShowMessage(Assigned(D).ToString()); // Outputs 0
13. end;

I create the class as:

Code: Pascal  [Select][+][-]

1.   TDownload = class(TForm1)
2.   private
3.     LinkToFile    : string;
4.     TaskToKill    : shortstring;
5.   public
6.     constructor Create(AOwner: TComponent); reintroduce;
7.     constructor Create(AOwner: TComponent; L: string; T: shortstring); reintroduce;
8.     destructor Destroy; override;

I'm calling the create event in main lpr file. How can I use classes and forms correctly?

[ASerge]

Where D assigned?

[Nicole]

What happens, if you put this not in the create event but in OnResize?
This event is just the first one I came across, which happens "later".

[Handoko]

I'm calling the create event in main lpr file.

It might (???) work but because D is declared inside TForm1, it makes more sense calling D := TDownload(self) in TForm1's OnCreate event.

[Paolo]

Out of curiosity, why are you using "reintroduce" ?

[Nicole]

@Handoko
I would give it a try. Just half a minute of work.

Some days ago I had a similar problem.
If the tests is positive, I explain it in detail. If not, it would be a waste.

[jamie]

You need to use "Override" not "Reintroduced"

The first create should be ok with that but the section which does not have a Constructor of that type you simply use "Virtual" and use the
CTRL+Shift+C to auto generate the body code.

 In the Override version, you need to call the inherited Create(aowner) .... etc.

in the non, overridden on you still need to call the Create(....) constructor.

As for your Assigned returning 0 instead of a Boolean word, maybe you don't have the SysUtils in the uses list, those are helpers?

Jamie
 

[egsuh]

TForm1 is the anscestor class of TDownload.
D must be instantiated somewhere else.