dynacall.~pas

本光盘是《Delphi 7应用教程》一书的配套光盘

unit DynaCall;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    GroupBox1: TGroupBox;
    Label1: TLabel;
    Edit1: TEdit;
    Label2: TLabel;
    Edit2: TEdit;
    Label3: TLabel;
    Edit3: TEdit;
    Label4: TLabel;
    Edit4: TEdit;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
   private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;


implementation
  type
    TintFunction=Function(x,y,z:integer):integer;stdcall;
  var
    x,y,z:integer;

{$R *.dfm}

Function Calculate(FunName:Pchar):integer;
var
  Dllname:string;
  Hinst:Thandle;
  ProcName:Pchar;
  Fpointer:TFarProc;
  MyFunct:TintFunction;
begin
  getdir(0,dllname);
  dllname:=dllname+'\EXAM_10_1.dll';
  ProcName:=FunName;
  Hinst:=SafeLoadLibrary(Dllname);
   if Hinst>0 then
      try
         Fpointer:=GetProcAddress(HInst,ProcName);
         if Fpointer<>Nil then
            begin
               Myfunct:=TIntFunction(Fpointer);
               Calculate:=Myfunct(x,y,z);
            end
           else
              showmessage('DLL Function not found.');
      Finally
         FreeLibrary(Hinst);
      end
      else
         ShowMessage(Dllname+' Library not Found');
end;


procedure TForm1.Button1Click(Sender: TObject);
  Var
    Funname:Pchar;
    Res:integer;
begin
    Funname:='Max';
    x:=strtoint(Edit1.text);
    y:=strtoint(Edit2.text);
    z:=strtoint(edit3.Text );
    Res:=Calculate(FunName);
    Edit4 .text:=IntTostr(Res) ;
end;

procedure TForm1.Button2Click(Sender: TObject);
  Var
    Funname:Pchar;
    Res:Integer;
begin
    Funname:='Min';
    x:=strtoint(Edit1.text);
    y:=strtoint(Edit2.text);
    z:=strtoint(edit3.Text );
    Res:=Calculate(FunName);
    Edit4 .text:=IntTostr(Res) ;
end;

end.