1、新建Dll工程
2、Dll工程全部代码
library SubMain;
{ Important note about DLL memory management: ShareMem must be the
first unit in your library's USES clause AND your project's (select
Project-View Source) USES clause if your DLL exports any procedures or
functions that pass strings as parameters or function results. This
applies to all strings passed to and from your DLL--even those that
are nested in records and classes. ShareMem is the interface unit to
the BORLNDMM.DLL shared memory manager, which must be deployed along
with your DLL. To avoid using BORLNDMM.DLL, pass string information
using PChar or ShortString parameters. }
uses
SysUtils, Forms,
Classes, Windows, Dialogs,
SubMain_Unit in 'SubMain_Unit.pas' {Frm_SubMain};
var
AppHnd: Thandle;//应用程序的句柄变量
AppScr: TScreen;//应用程序的环境变量
{$R *.res}
procedure DllEntryPoint(dwReason: DWord);
begin
case dwReason of
DLL_PROCESS_ATTACH:
begin
AppHnd := Application.Handle;//备份Exe句柄
AppScr := Screen;//备份Exe环境
end;
DLL_THREAD_ATTACH: ShowMessage('Create Thread'); //Dll文件中最好用Messagebox，ShowMessage部分环境中容易抽风
DLL_THREAD_DETACH: ShowMessage('Free Thread'); //Dll文件中最好用Messagebox，ShowMessage部分环境中容易抽风
DLL_PROCESS_DETACH:
begin
if Frm_SubMain <> nil then FreeAndNil(Frm_SubMain);//防止Dll窗体未释放干净
Application.Handle := AppHnd; //恢复Exe句柄
Screen := AppScr;//恢复Exe环境
end;
end;
end;
exports
CreateFrm,DropFrm;//输出函数接口
begin
DllProc := @DllEntryPoint;
DllEntryPoint(DLL_PROCESS_ATTACH);
end.
3、SubMain_Unit.pas源码
unit SubMain_Unit; interface uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, FyFun_Unit; type
TFrm_SubMain = class(TForm)
procedure FormClose(Sender: TObject; var Action: TCloseAction);
procedure FormDestroy(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
procedure CreateFrm(AppHnd: THandle);export;stdcall;//接口函数声明
procedure DropFrm; export;stdcall;//接口函数声明
var
Frm_SubMain: TFrm_SubMain; implementation {$R *.dfm}
procedure CreateFrm(AppHnd: THandle);//窗体创建函数
begin
Application.Handle := AppHnd; if not Assigned(Frm_SubMain) then
Frm_SubMain := TFrm_SubMain.Create(Application); Frm_SubMain.Show;
end; procedure DropFrm;//窗体释放函数
begin
if Frm_SubMain <> nil then
FreeAndNil(Frm_SubMain);
end;
procedure TFrm_SubMain.FormClose(Sender: TObject; var Action: TCloseAction);
begin
Action := caFree;//dll窗体关闭自动释放
end; procedure TFrm_SubMain.FormDestroy(Sender: TObject);
begin
Frm_SubMain := nil;//dll窗体关闭自动释放
end; end.
4、调用文件Main.pas代码
unit Main_Unit; interface uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls; type
TCreateFrm = procedure(AppHnd: THandle); stdcall;
TDropFrm = procedure; stdcall;
TFrm_Main = class(TForm)
Btn_1: TButton;
Btn_2: TButton;
Btn_3: TButton;
Btn_4: TButton;
procedure Btn_1Click(Sender: TObject);
procedure Btn_2Click(Sender: TObject);
procedure Btn_3Click(Sender: TObject);
procedure Btn_4Click(Sender: TObject);
private
LibHandle: THandle;
FormRef: LongInt;
{ Private declarations }
public
{ Public declarations }
end; var
Frm_Main: TFrm_Main; implementation {$R *.dfm} procedure TFrm_Main.Btn_1Click(Sender: TObject); //动态加载Dll文件
begin
if LibHandle = 0 then
begin
LibHandle := SafeLoadLibrary('SubMain.dll');
if LibHandle = 0 then
raise Exception.Create('Not Found Dll File')
else
ShowMessage('Dll Loaded');
end;
end; procedure TFrm_Main.Btn_2Click(Sender: TObject); //释放Dll文件
begin
if LibHandle > 0 then
begin
FreeLibrary(LibHandle);
LibHandle := 0;
ShowMessage('Dll UnLoaded');
end;
end; procedure TFrm_Main.Btn_3Click(Sender: TObject); //读取Dll文件窗体并显示
var
CreateFrm: TCreateFrm;
begin
if LibHandle = 0 then
raise Exception.Create('Place Load Dll File First'); @CreateFrm := GetProcAddress(LibHandle,PChar('CreateFrm'));
if @CreateFrm = nil then
raise Exception.Create('Function Error'); CreateFrm(Application.Handle);
end; procedure TFrm_Main.Btn_4Click(Sender: TObject); //释放Dll窗体
var
DropFrm: TDropFrm;
begin
@DropFrm := GetProcAddress(LibHandle,PChar('DropFrm'));
if @DropFrm = nil then
raise Exception.Create('Function Error'); DropFrm;
end; end.