Использовать формы, объявленные в DLL

 
  In the example that follows the exe only sees a totally "virtual 
  abstract" interface to the object as is being exported from the dll 
  but it still can create the object and use it. 
  Of course the exe can not see or execute any methods declared in the 
  exe but that is the whole purpose of implementing them in a custom dll 
  to begin with. 

  Im folgenden Beispiel sieht die Exe-Datei nur ein total "virtuelles, abstraktes" 
  Interface zum Objekt, welches aus der Dll importiert wird aber es 
  kann doch dieses Objekt erzeugen und es gebrauchen. 
}


 // Example code: 

program
 Dlloader;

 uses

   Sharemem,
   Forms,
   exeunit1 in
 'exeunit1.pas' {Form1},
   DllIntfu in
 'DllIntfu.pas';

 {$R *.RES}

 begin

   Application.Initialize;
   Application.CreateForm(TForm1, Form1);
   Application.Run;
 end
.

 //-------------------------- 

unit
 DllIntfu;

 interface


 type

   TDllobject = class

   protected

     function
 Get_UserName: string
; virtual
; abstract
;
     procedure
 Set_UserName(Value: string
); virtual
; abstract
;
   public

     property
 UserName: string
 read
 Get_UserName write
 Set_UserName;
   end
;
   TDllobjectClass = class
 of
 TDllobject;

 implementation


 end
.

 //--------------------------- 

unit
 exeunit1;

 interface


 uses

   Windows, Messages, SysUtils, Classes, Graphics,
   Controls, Forms, Dialogs, DllIntfu, StdCtrls;

 type

   TForm1 = class
(TForm)
     Button1: TButton;
     procedure
 Button1Click(Sender: TObject);
   private

     { Private declarations }
   public

     { Public declarations }
   end
;

 var

   Form1: TForm1;

 implementation


 {$R *.DFM}

 type

   TDllfunc = function
: TDllobjectClass;
    stdcall
;

 procedure
 TForm1.Button1Click(Sender: TObject);
 var

   i: DWORD;
   fHandle: THandle;
   fDllfunc: TDllfunc;
   fDllobject: TDllobject;
   fUserName: string
;
 begin

   fHandle := LoadLibrary('UserName.dll');
   if
 (fHandle <> 0) then

   begin
 @fDllfunc := GetProcAddress(fHandle, 'Dllfunc');
     if
 Assigned(@fDllfunc) then

     begin

       i := 255;
       SetLength(fUserName, i);
       GetUserName(PChar(fUserName), i);
       fUserName           := StrPas(PChar(fUserName));
       fDllobject          := fDllfunc.Create;
       fDllobject.UserName := fUserName;
       ShowMessage(fDllobject.UserName);
       fDllobject.Free;
     end
;
     FreeLibrary(fHandle);
   end
;
 end
;

 end
.

 //------------------------------- 

library
 UserName;

 uses

   Sharemem,
   Sysutils,
   DllIntfu;

 type

   TCustomDllobject = class
(TDllobject)
   private

     fUserName: string
;
     function
 Getfilecount: Integer;
   protected

     function
 Get_UserName: string
; override
;
     procedure
 Set_UserName(Value: string
); override
;
   end
;

   TCustomDllobjectclass = class
 of
 TCustomDllobject;

 function
 TCustomDllobject.Getfilecount: Integer;
 var

   doserr: Integer;
   fsrch: TSearchRec;
 begin

   Result := 0;
   doserr := FindFirst('*.*', faanyfile, fsrch);
   if
 (doserr = 0) then

   begin

     while
 (doserr = 0) do

     begin

       if
 (fsrch.attr and
 faDirectory) = 0 then

         Inc(Result);
       doserr := findnext(fsrch);
     end
;
     FindClose(fsrch);
   end
;
 end
;

 function
 TCustomDllobject.Get_UserName: string
;
 begin

   Result := 'You signed on as ''' + fUserName + '''' +
     ' and there ' + IntToStr(Getfilecount) +
     ' files in this directory.';
 end
;

 procedure
 TCustomDllobject.Set_UserName(Value: string
);
 begin

   fUserName := Value;
 end
;

 function
 Dllfunc: TCustomDllobjectClass; stdcall
;
 begin

   Result := TCustomDllobject; // class type only 
end
;

 exports

   Dllfunc name 'Dllfunc';

 begin

 end
.

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