Hab ein kleines Problem:
Ich will eine Art Plugin für meine Anwendung schreiben.
Das Tutorial, dass hier so oft genannt wird habe ich schon.
Also, inch habe ein Hauptprogramm, eine
dll und eine
Unit, auf die Beide zugreifen.
Code in der
Unit:
Delphi-Quellcode:
unit testUnit;
interface
type
TTestObjekt =
class
public
String1:
String;
Strign2:
String
end;
implementation
end.
Text in der
dll:
Delphi-Quellcode:
library Project1;
{ Important note about DLL memory management: ShareMem must be the
first unit in your library's USES clause AND your project's (select
Project-View Source) USES clause if your DLL exports any procedures or
functions that pass strings as parameters or function results. This
applies to all strings passed to and from your DLL--even those that
are nested in records and classes. ShareMem is the interface unit to
the BORLNDMM.DLL shared memory manager, which must be deployed along
with your DLL. To avoid using BORLNDMM.DLL, pass string information
using PChar or ShortString parameters. }
uses
SysUtils,
Classes,
testUnit
in '
..\shared Units\testUnit.pas';
procedure test;
stdcall;
var obj:TTestObjekt;
begin
obj.Create;
obj.String1:='
FUNKTIONIERT!!!!!!!';
end;
exports
test;
{$R *.res}
begin
end.
Text im Programm:
Delphi-Quellcode:
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TShellexecute =
procedure;
stdcall;
TForm1 =
class(TForm)
Button1: TButton;
Button2: TButton;
Button3: TButton;
procedure Button3Click(Sender: TObject);
procedure Button1Click(Sender: TObject);
procedure calldll;
procedure Button2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
uses testUnit;
procedure TForm1.calldll;
var
hLib: cardinal;
MyShellExecute: TShellexecute;
begin
hLib := LoadLibrary('
test.dll');
if hLib<>0
then
begin
@MyShellexecute := GetProcAddress(hLib, '
test');
if not Assigned(MyShellexecute)
then
begin
RaiseLastOSError;
exit;
end;
end
else
begin
RaiseLastOSError;
exit;
end;
MyShellexecute;
end;
{$R *.dfm}
procedure TForm1.Button3Click(Sender: TObject);
begin
Close;
end;
procedure TForm1.Button1Click(Sender: TObject);
var Obj:TTestObjekt;
begin
Obj.Create;
showmessage(obj.String1);
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
Form1.calldll;
end;
end.
FreeandNil(obj)
hab ich erstmal mit absicht weggelassen.
Jedesmal wenn ich auf Button2 clicke bekomme ich folgende Fehlermeldung:
"Acess vialation at adress 00000000. Read of adress 00000000."
Wo liegt der Fehler?
PS: Bin noch neu im
OOP und
dll-Programmieren!