Delphi 用DLL实现插件的简单实例
这是DLL的代码
实现代码：
library MyDll;
uses SysUtils, Dialogs, Classes;
procedure ShowInfo(info:PChar);
stdcall;
begin ShowMessage('您选择了【'+info+'】');
end;
function GetCaption:Pchar;
begin Result := '中国';
end;
exports ShowInfo, GetCaption;
{
$R *.res}
begin end.
这是调用窗体的代码
本例只使用了一个DLL，所以当有多个DLL时，需要循环DLL所在目录，依次加载DLL
unit Main;
interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, Menus, ExtCtrls;
type TShowInfo = procedure (info:PChar);
stdcall;
TGetCaption = function : PChar;
stdcall;
TForm1 = class(TForm) Button1: TButton;
Button2: TButton;
MainMenu1: TMainMenu;
Image1: TImage;
procedure Button2Click(Sender: TObject);
private {
Private declarations }
FHandel : THandle;
//DLL句柄 FProAddress: Pointer;
//DLL中ShowInfo的地址 showinfo: TShowInfo;
//为动态加载DLL而设 procedure LoadPlusIn;
//加载插件（DLL） procedure ItemClick(Sender: TObject);
//自定义菜单点击事件 public {
Public declarations }
end;
var Form1: TForm1;
implementation {
$R *.dfm}
procedure TForm1.Button2Click(Sender: TObject);
begin LoadPlusIn;
end;
procedure TForm1.ItemClick(Sender: TObject);
begin @showinfo := FProAddress;
//取地址 if @showinfo <> nil then showinfo(PWideChar(TMenuItem(Sender).Caption));
//执行DLL中的ShowInfo end;
procedure TForm1.LoadPlusIn;
var getcaption: TGetCaption;
item : TMenuItem;
begin FHandel := LoadLibrary('MyDll.dll');
//加载 if FHandel = 0 then begin ShowMessage('加载失败！');
Exit;
end else begin @getcaption := GetProcAddress(FHandel,'GetCaption');
//取DLL中GetCaption地址 if @getcaption <> nil then begin item := TMenuItem.Create(MainMenu1);
//创建一个菜单 item.Caption := getcaption;
//取Caption，即调用DLL中的GetCaption FProAddress := GetProcAddress(FHandel,'ShowInfo');
//取得DLL中ShowInfo的地址 item.OnClick := ItemClick;
//赋予菜单项的点击事件 MainMenu1.Items.Add(item);
//添加到主菜单 end;
end;
end;
end.
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