ic卡全自动洗衣机:Delphi应用程序和DLL的融合(MDI窗口)

***********************
main (mdi) form
***********************

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TShowFrm = procedure(App: TApplication; Scr:TScreen); stdcall;

type
TForm1 = class(TForm)
Button2: TButton;
procedure FormCreate(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
procedure Button2Click(Sender: TObject);
private
hInstance: THandle;
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
try
hInstance := SafeLoadLibrary(‘Mydll.dll‘, SEM_NOOPENFILEERRORBOX);
{load the library on form create as will need to know what forms are
available, so they can be listed for creation.}
except
on e: exception do ShowMessage(e.Message);
end;
end;

procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
try
if Form1.MDIChildCount = 1 then
begin
MDIChildren[0].Close;
end;
{This example only uses 1 form in a single dll. In reality would cycle
through all open children, closing as go}

FreeLibrary(hInstance);
{destroy reference to dll}
except
on e: exception do ShowMessage(e.Message);
end;
end;

procedure TForm1.Button2Click(Sender: TObject);
var
AFunc: Pointer;
begin
try
Pointer(AFunc) := GetProcAddress(hInstance, PChar (‘ShowFrm‘));
TShowFrm(AFunc)(Application, Screen);
{Open the child form}
except
on e: exception do ShowMessage(e.Message);
end;
end;

end.

***********************
dll file
***********************

library Mydll;

uses
SysUtils,
Classes,
Forms,
Windows,
Dialogs,
MyForm in ‘MyForm.pas‘ {Form2};

{$R *.res}

var
AppDLL: TApplication;
ScrDLL: TScreen;

procedure MyDLLProc(Reason: Integer);
begin
try
if Reason = DLL_PROCESS_DETACH then
begin
Application := AppDLL;
Screen := ScrDLL;
end;
except
on e: exception do ShowMessage(e.Message);
end;
end;

procedure ShowFrm(App:TApplication; Scr: TScreen); stdcall;
begin
Application := App;
Screen := Scr;
App.CreateForm(TForm2, Form2);
Form2.Show;
end;

exports
ShowFrm;

begin
try
AppDLL := Application;
ScrDLL := Screen;
DLLProc := @MyDLLProc;
except
on e: exception do ShowMessage(e.Message);
end;
end.

***********************
mdi-child form
***********************

unit MyForm;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TForm2 = class(TForm)
procedure FormClose(Sender: TObject; var Action: TCloseAction);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form2: TForm2;

implementation

{$R *.dfm}
procedure TForm2.FormClose(Sender: TObject; var Action: TCloseAction);
begin
try
Action := caFree;
except
on e: exception do ShowMessage(e.Message);
end;
end;
end.

主要是,将MDI的父窗口句柄传入.这样就可以正常建立DLL MDI窗口了.

注意.MDI窗口释放的时候,要用 Action:=caFree;