HI!
I'm doing my work of thesis on a c++ project using C++ Builder 5.
My tutor has obliged me to do a thing (that I've had yet in a simpler way) using a DLL.
Here come the problems.
In fact in a common application like this:
PHP Code:
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
Application->OnShortCut = Key;
}
void __fastcall TForm1::KeyEvent(TWMKey &Msg, bool &Handled)
{
if (Msg.CharCode == VK_RETURN)
{
ShowMessage("Enter disabled");
Handled = true;
}
}
, I'm able to use the command Application->OnShortCut. And the application does what required (the message is displayed).
Instead if I try to do a similar thing using a DLL, everything is harder (actually too hard for me).
In fact I think it's not possible to use a declaration like
void __fastcall TForm1::KeyEvent(TWMKey &Msg, bool &Handled)
in the body of the DLL, because of the fact that I cannot declare it anywhere (there isn't a header file to do this like in common applications).
So to avoid this problem I decided to add to my DLL a fictitious Form (Form2) where I declared the event KeyEvent: in the main body of the DLL I used the command Application->OnShortCut=Form2->KeyEvent.
According to me, everything should work, but it seems that the pushing of the key is not recognized. But I don't know why.
PHP Code:
//---------------------------------------------------------------------------
/* Unit1.cpp ----it's the body of the DLL*/
#include <vcl.h>
#include <windows.h>
#pragma hdrstop
//---------------------------------------------------------------------------
#pragma argsused
#include "Unit2.h"
int WINAPI DllEntryPoint(HINSTANCE hinst, unsigned long reason, void* lpReserved)
{
Form2 = new TForm2(NULL);
Application->OnShortCut = Form2->KeyEvent;
return 1;
}
//---------------------------------------------------------------------------
extern "C"
{
bool __export GetEvent()
{
bool ret = false;
if (come == true)
{
ret=true;
}
return ret;
}
}
/* Unit2.h ------ it's the header file of Form2 */
//---------------------------------------------------------------------------
#ifndef Unit2H
#define Unit2H
//---------------------------------------------------------------------------
#include <Classes.hpp>
#include <Controls.hpp>
#include <StdCtrls.hpp>
#include <Forms.hpp>
//---------------------------------------------------------------------------
class TForm2 : public TForm
{
__published: // IDE-managed Components
private: // User declarations
public: // User declarations
__fastcall TForm2(TComponent* Owner);
void __fastcall TForm2::KeyEvent(Messages::TWMKey &Msg, bool &Handled);
};
//---------------------------------------------------------------------------
extern PACKAGE TForm2 *Form2;
extern bool come;
//---------------------------------------------------------------------------
#endif
/* Unit2.cpp */
//---------------------------------------------------------------------------
#include <vcl.h>
#pragma hdrstop
#include "Unit2.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm2 *Form2;
bool come;
//---------------------------------------------------------------------------
__fastcall TForm2::TForm2(TComponent* Owner)
: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm2::KeyEvent(Messages::TWMKey &Msg, bool &Handled)
{
if (Msg.CharCode==VK_RETURN)
come=true;
else
come=false;
}
This simple application should return true if the RETURN key has been pushed, false in the other cases.
Any ideas?
Thanx
Dev Shed Forums Sponsor:
November 17th, 2003, 11:39 AM
using event in DLL
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