使用DLL檔案中封裝的視窗

使用DLL檔案中封裝的視窗徐長友

文章摘要：
     編寫軟體時常常使用到DLL檔案，本文就使用DLL檔案中封裝的視窗來說說Delphi中在DLL如何封裝視窗，如何調用DLL中封裝的視窗，及MDI-Child在DLL中載入並使用

一、在DLL中封裝視窗
    開啟Delphi建立一個DLL工程，儲存為usedll，產生代碼

library usedll; { 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, Classes; {$R *.res} begin end.

建立一個表單，添加一個Label和Button，設定如下：

object Form1: TForm1 Left = 192 Top = 133 Width = 334 Height = 221 Caption = 'DLL'#20013#20351#29992#31383#20307 Color = clBtnFace Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -11 Font.Name = 'MS Sans Serif' Font.Style = [] OldCreateOrder = False PixelsPerInch = 96 TextHeight = 13 object Label1: TLabel Left = 104 Top = 80 Width = 80 Height = 13 Caption = 'DLL'#20013#20351#29992#31383#20307 end object Button1: TButton Left = 120 Top = 152 Width = 75 Height = 25 Caption = #30830#23450 TabOrder = 0 OnClick = Button1Click end end

添加一過程：procedure LoadForm; export;
procedure LoadForm;
begin
Form1 := TForm1.Create(Application);
try
Form1.ShowModal;
finally
Form1.Free;
end;
end;

全部完整的代碼：

library usedll; uses SysUtils, Classes, Form_Unit in 'Form_Unit.pas' {Form1}; {$R *.res} exports LoadForm index 1; begin end.

 

unit Form_Unit; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls; type TForm1 = class(TForm) Label1: TLabel; Button1: TButton; procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form1: TForm1; ApplicationName: String; procedure LoadForm(Handle: THandle; AppName: ShortString); export; implementation {$R *.dfm} procedure LoadForm(Handle: THandle; AppName: ShortString); begin Application.Handle := Handle; ApplicationName := AppName; Form1 := TForm1.Create(Application); try Form1.ShowModal; finally Form1.Free; end; end; procedure TForm1.Button1Click(Sender: TObject); begin self.close; end; end.

編譯後產生usedll.dll檔案，至此DLL檔案就完成了

二、調用DLL中封裝的視窗

    建立一個工程，添加一個Button，表單布局如下：

object Form1: TForm1 Left = 192 Top = 133 Width = 336 Height = 222 Caption = 'Form1' Color = clBtnFace Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -11 Font.Name = 'MS Sans Serif' Font.Style = [] OldCreateOrder = False PixelsPerInch = 96 TextHeight = 13 object Button1: TButton Left = 128 Top = 88 Width = 75 Height = 25 Caption = #25171#24320#31383#20307 TabOrder = 0 OnClick = Button1Click end end

完整的代碼如下：

unit Use_Unit; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls; type TForm1 = class(TForm) Button1: TButton; procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form1: TForm1; procedure LoadForm; external 'usedll.dll' index 1; implementation {$R *.dfm} procedure TForm1.Button1Click(Sender: TObject); begin LoadForm; end; end.

三、MDI-Child在DLL中載入並使用
    如果是MDI-Child又如何在DLL中載入並使用呢，下面就這個問題說說使用DLL檔案中封裝的視窗。
建立一個DLL工程，儲存為mdidll，再建立一個表單，FormStyle設為fsMDIChild，如下：
object Form1: TForm1
Left = 192
Top = 133
Width = 344
Height = 234
Caption = 'MDI'
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'MS Sans Serif'
Font.Style = []
FormStyle = fsMDIChild
OldCreateOrder = False
Position = poDefault
Visible = True
OnClose = FormClose
PixelsPerInch = 96
TextHeight = 13
end

代碼如下：

unit mdi_Unit; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs; type TForm1 = class(TForm) procedure FormClose(Sender: TObject; var Action: TCloseAction); private { Private declarations } public { Public declarations } MyParentForm: TForm; MyParentApplication: TApplication; end; var DllApplication: TApplication; implementation {$R *.dfm} procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction); begin Action:=caFree; end; end.

library mdidll; uses Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, mdi_Unit in 'mdi_Unit.pas' {Form1}; procedure LoadChild(ParentApplication: TApplication; ParentForm: TForm); export; stdcall; var Form1: TForm1; DllProc: Pointer; begin Application:=ParentApplication; Form1:=TForm1.Create(ParentForm); Form1.MyParentForm:=ParentForm; Form1.MyParentApplication:=ParentApplication; Form1.Show; end; procedure DLLUnloadProc(Reason: Integer); register; begin if Reason = DLL_PROCESS_DETACH then Application:=DllApplication; end; {$R *.res} exports LoadChild; begin DllApplication:=Application; DLLProc := @DLLUnloadProc; end.

編譯後產生mdidll.dll檔案。
使用DLL中的MDI-Child視窗如下：

    建立一個工程，主視窗設定如下FormStyle設為fsMDIForm：
object Form1: TForm1
Left = 192
Top = 133
Width = 544
Height = 375
Caption = 'Form1'
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'MS Sans Serif'
Font.Style = []
FormStyle = fsMDIForm
Menu = MainMenu1
OldCreateOrder = False
PixelsPerInch = 96
TextHeight = 13
object MainMenu1: TMainMenu
Left = 72
Top = 136
object N1: TMenuItem
Caption = #26032#24314'(&N)'
OnClick = N1Click
end
end
end
代碼：

unit usemdi_Unit; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, Menus; type TForm1 = class(TForm) MainMenu1: TMainMenu; N1: TMenuItem; procedure N1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; T_ProvaChild = procedure (ParentApplication: TApplication; ParentForm: TForm); stdcall; var Form1: TForm1; implementation {$R *.dfm} procedure TForm1.N1Click(Sender: TObject); var DllHandle: THandle; ProcAddr: FarProc; ProvaChild: T_ProvaChild; begin DllHandle := LoadLibrary('mdidll'); ProcAddr := GetProcAddress(DllHandle, 'LoadChild'); if ProcAddr <> nil then begin ProvaChild := ProcAddr; ProvaChild(Application,Self); end; end; end.

結束語：
    到這裡你應該會用Delphi調用DLL檔案中封裝的視窗了吧，如果還有不明白的話請與我聯絡(首頁: http://yousoft.home.chinaren.com ,郵箱:yousoft@chinaren.com)