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;  //定义函数类型
  var
    x,y,z:integer;

{$R *.dfm}

Function Calculate(FunName:Pchar):integer;
var
  Dllname:string; //存放动态链接库文件名
  Hinst:Thandle;  // 加载动态链接库文件的句柄
  ProcName:Pchar;   //要调用的函数或过程名
  Fpointer:TFarProc; //函数指针
  MyFunct:TintFunction;  //函数变量
begin
  getdir(0,dllname);
  dllname:=dllname+'\EXAM_10_1.dll';   //形成动态链接库文件名
  ProcName:=FunName;
  Hinst:=SafeLoadLibrary(Dllname);//加载动态链接库
   if Hinst>0 then     //加载成功
      try
         Fpointer:=GetProcAddress(HInst,ProcName);//得到要调用过程的地址
         if Fpointer<>Nil then
            begin
               Myfunct:=TIntFunction(Fpointer);//形成函数名
               Calculate:=Myfunct(x,y,z); //调用相应函数
            end
           else
              showmessage('DLL Function not found.');
      Finally
         FreeLibrary(Hinst);   //卸载动态链接库
      end
      else
         ShowMessage(Dllname+' Library not Found');
end;


procedure TForm1.Button1Click(Sender: TObject);
  Var
    Funname:Pchar;//函数名
    Res:integer;  //调用动态链接库的结果
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.