一个值得大家来考虑的dll问题

在MDI窗体类型的编程中，主窗体（fsMDIForm）怎样调用子窗体（fsMDIChild，此子窗体为DLL）。

以下是我的原代码：

==========================================================================================

DPR  单元代码

program Mdiform;

uses

Forms,

UMdiform in ‘UMdiform.pas‘ {Mainform},

UDM in ‘UDM.pas‘ {GlobalDM: TDataModule},

UFun in ‘UFun.pas‘;

{$R *.res}

begin

Application.Initialize;

Application.CreateForm(TMainform, Mainform);

Application.Run;

end.

===============================================================================================

主窗体代码：

unit UMdiform;

interface

uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

Dialogs, Udm,StdCtrls;

type

TMainform = class(TForm)

Button1: TButton;

procedure Button1Click(Sender: TObject);

procedure FormCreate(Sender: TObject);

private

{ Private declarations }

public

MyHandle:HWND;

{ Public declarations }

end;

var

Mainform: TMainform;

type

T_ShowTestMng=function (var adm:TMainform) : Boolean; StdCall;

implementation

{$R *.dfm}

procedure TMainform.Button1Click(Sender: TObject);

var

Lib_         :THandle;

_ShowTestMng :T_ShowTestMng;

begin

Lib_:=LoadLibrary(pchar(‘MdiChild.dll‘));

try

@_ShowTestMng:=GetProcAddress(Lib_,‘_ShowTestMng‘);

if not(@_ShowTestMng=nil) then

_ShowTestMng(Mainform);

finally

FreeLibrary(Lib_);

end;

end;

procedure TMainform.FormCreate(Sender: TObject);

begin

MyHandle:=Application.Handle;

end;

end.

==============================================================================================

子窗体DLL代码：

library MdiChild;

uses

ShareMem,

UMdiform,  //此单元为父窗体单元，在顶目设置中我已经设置了搜索此单元在路径。

Forms,

SysUtils,

Classes,

UChild in ‘UChild.pas‘ {FrmChild};//FrmChild子窗体的FormStyle属性为FsMDIChild

{$R *.res}

function _ShowTestMng(var adm:TMainform) : Boolean; StdCall;

begin

result:=true;

Application.Handle:=adm.MyHandle;

Application.CreateForm(TFrmChild,FrmChild);   //程序就出错在此：出错原因是：Cannot create form. No MDI Forms are currently active.

FrmChild.Show;

end;

exports

_ShowTestMng;

end.

CSDN 网友 ( 2004-09-26)

垃圾

fugongming ( 2004-06-09)

将主窗体的application.Handle传入Dll中，并用它替换Dll中的Application，然后创建子窗体。就Ok了

lihaijiang ( 2004-05-31)

哈哈,没什么值得评价的呢

cybercake ( 2004-05-29)

算不上什么值得深思的问题，还是发到论坛上比较好。

CoolSlob ( 2004-05-28)

就这么几行简单的代码也要解释？~