hi,
I've made a little example that works fine, but i don't know if it is what
you were expecting.
The problem is :
if you replace all my "class function" with simple functions, it still
works...
so my example do not show the using of generic reference of class you were
attending ;-)
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls;
type
enumFormatter = (
ftArrangementNumber,
ftCustomerNumber
);
TForm1 = class(TForm)
btnFormat: TButton;
rgFormatType: TRadioGroup;
procedure btnFormatClick(Sender: TObject);
private
{ Déclarations privées }
procedure Test(AFormatType : enumFormatter);
public
{ Déclarations publiques }
end;
TFormatter = class
public
class function FormatString(aString: String): string; virtual;
end;
TFormatterClass = class of TFormatter;
TCustomerNumberFormatter = class (TFormatter)
public
class function FormatString(aString: String): string; override;
end;
TArrangementNumberFormatter = class (TFormatter)
public
class function FormatString(aString: String): string; override;
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
class function TFormatter.FormatString(aString: String): string;
begin
end;
class function TCustomerNumberFormatter.FormatString(aString: String):
string;
begin
Result := 'CUST : ' + aString + '*';
end;
class function TArrangementNumberFormatter.FormatString(aString: String):
string;
begin
Result := 'ARR : ' + aString + '*';
end;
procedure TForm1.Test(AFormatType : enumFormatter);
var
myClass : TFormatterClass;
ftClass : TFormatter;
begin
myClass := nil;
case AFormatType of
ftArrangementNumber : myClass := TArrangementNumberFormatter;
ftCustomerNumber : myClass := TCustomerNumberFormatter;
end;
ftClass := myClass.Create;
ShowMessage(ftClass.FormatString('Text to format'));
end;
procedure TForm1.btnFormatClick(Sender: TObject);
begin
Test(enumFormatter(rgFormatType.ItemIndex));
end;
end.
Cédric
----- Original Message -----
From: "Jesper Stenlund" <jes...@handelsbanken.se>
To: <delphi@elists.org>
Sent: Tuesday, May 12, 2009 1:20 PM
Subject: Class method
>I have a bunch of classes that formats a string in different ways.
> Today I have to create an instance of a specific "formattingobject" and
> then run the formattingmethod.
> Instead of that behaviour I now want make the formattingmethod a class
> method.
>
> But that causes me some other problems.
> Here's a small example:
>
> TCustomerNumberFormatter = class (TObject)
> private
> class function FormatString(aString: String): string;
> end;
>
> TArrangementNumberFormatter = class (TObject)
> private
> class function FormatString(aString: String): string;
> end;
>
>
> Then I want to do something like this but I don't know exactly how to
> write my code.
>
> case FormatType of
> ftArrangementNumber: myClass := TArrangementNumberFormatter;
> ftCustomerNumber: myClass := TCustomerNumberFormatter;
> end;
>
> TEdit1.Caption := myClass.FormatString(myObject.StringToFormat);
>
>
> I know that last row isn't correct, but how can I do this?
>
> I hope you understand what I'm looking for.
> I want to use the classname that I get from the case-sentence and then run
> the class function on that particular class.
> Is it possible to do it like this?
>
>
> //Jesper
> _______________________________________________
> Delphi mailing list -> Delphi@elists.org
> http://lists.elists.org/cgi-bin/mailman/listinfo/delphi
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