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| unit MethodAddress1;
(*
This sample shows how to call a funciton by name. We use MethodAddress to
retrive the name of a function, then we call it.
Since the method belongs to a class, we need to pass the class as a prameter,
too.
In gerneral, a function - declared in a class, that is defined as
procedure TFoo.foo(i : integer);
is called as
procedure TFoo.foo(obj : TObject; i : integer);
Normally, Delphi (as well as C++) automatically add the object parameter. Now
that we get a pointer to a function from MethodAddress, that does not belong to
any class, we need to pass the parameter by hand
(C) Thomas Quester
tquester@joice.net
http://arabella.joice.net
*)
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls;
type
TTest = class
public
Calls : integer;
published
Procedure Foo;
Procedure Test;
Procedure Bar;
procedure TestI(i : integer);
procedure TestS(s : string);
function Fak(i : integer) : integer;
end;
// For every combination of parameters, we define a prototype
TFunctionCall = procedure(obj : TObject);
TFunctionICall = procedure(obj : TObject; i : integer);
TFunctionSCall = procedure(obj : TObject; s : string);
TFunctionIICall = function (obj : TObject; i : integer) : integer;
TForm1 = class(TForm)
Label1: TLabel;
ComboBox1: TComboBox;
Button1: TButton;
Label2: TLabel;
Label3: TLabel;
EditPar: TEdit;
EditResult: TEdit;
procedure Button1Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
private
FTest:TTest;
{ Private-Deklarationen }
public
{ Public-Deklarationen }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.Button1Click(Sender: TObject);
var p : pointer;
ptr : TFunctionCall; // Without parametes
ptrI : TFunctionICall; // (i : integer);
ptrS : TFunctionSCall; // (s : string);
ptrII : TFunctionIICall; // (i : integer) : integer
s : string;
begin
s := combobox1.text;
p := FTest.MethodAddress(s); // Get the pointer
if p <> NIL then begin
ptr := p; // Assign it to every protorype
ptri := p;
ptrii := p;
ptrs := p;
s := Lowercase(s); // Now, we decide, what prototype to use.
if (s = 'foo') or (s = 'bar') or (s = 'test')
then ptr(FTest);
if (s = 'testi') then ptri(FTest,strtoint(editPar.text));
if (s = 'tests') then ptrs(Ftest,EditPar.text);
if (s = 'fak') then editResult.text := inttostr(ptrii(ftest,strtoint(editPar.text)));
end else
MessageBox(0,'Function not defined','',MB_OK);
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
FTest := TTest.Create;
FTest.Calls := 0;
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
FTest.Free;
end;
// ------------------------------------------------------------------------
// procedure TTest Foo
// Created : Quester 09.06.99 11:04:57
// ------------------------------------------------------------------------
Procedure TTest.Foo;
begin
messagebox(0,'foo',pchar(format('%d calls',[calls])),MB_OK);
inc(calls);
end;
// ------------------------------------------------------------------------
// procedure TTest Bar
// Created : Quester 09.06.99 11:05:08
// ------------------------------------------------------------------------
Procedure TTest.Bar;
begin
messagebox(0,'Bar',pchar(format('%d calls',[calls])),MB_OK);
inc(calls);
end;
procedure TTest.TestI(i : integer);
begin
messagebox(0,pchar(format('i = %d',[i])),pchar(format('%d calls',[calls])),MB_OK);
inc(calls);
end;
procedure TTest.TestS(s : string);
begin
messagebox(0,pchar(format('s = %s',[s])),pchar(format('%d calls',[calls])),MB_OK);
inc(calls);
end;
function TTest.Fak(i : integer) : integer;
var j : integer;
begin
result := 1;
for j := 1 to i do
result := result * j;
end;
// ------------------------------------------------------------------------
// procedure TTest Test
// Created : Quester 09.06.99 11:05:15
// ------------------------------------------------------------------------
Procedure TTest.Test;
begin
messagebox(0,'Test ',pchar(format('%d calls',[calls])),MB_OK);
inc(calls);
end;
end. |
Appel d'une fonction/TThread de façon paramétrique
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