{ 
 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.