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Every object you see on your screen that can be
located, can be clicked, or moved, is called a window. As you may imagine,
these window objects can be as different as the human eye can
distinguished them. Some of these objects are icons, buttons, pictures,
menu items, etc. As different as they are, there are also various ways of
creating them.
There are three main ways you create a window, as we
will learn throughout this site. One of the techniques you can use
consists of creating a script in a resource file, as we have introduced
scripts in lessons 1 and 2. Another technique you can use consists of
calling one of the Win32 functions such as CreateWindow() or CreateWindowEx()
to create a window; we have introduced it when creating the main window in
all previous applications. The last option you have is to use your own
class and customize the creation of a window. |
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In C++, you probably learned that it is a good idea to
make sure that the main() function be not crowded, which can make your
program easier to read and troubleshoot when problems happen. You can also
apply this to Win32 programming by separating tasks in their own units.
Based on this, you can define functions that perform specific tasks such
as creating or registering the window
To apply object oriented programming (OOP) to a Win32
application, you can create a class for each window you use in your
application. Since each object is primarily a window, you can start with a
general window that lays a foundation for other windows. Such a class can
be created as follows (this is a primary window class; we will add methods
to it as needed: |
#ifndef WINCTRLS_H
#define WINCTRLS_H
#include <windows.h>
//---------------------------------------------------------------------------
class WControl
{
public:
WControl();
virtual ~WControl();
HWND Create(HINSTANCE hinst, LPCTSTR clsname,
LPCTSTR wndname, HWND parent = NULL,
DWORD dStyle = WS_OVERLAPPEDWINDOW,
int x = CW_USEDEFAULT, int y = CW_USEDEFAULT,
int width = 450, int height = 380);
BOOL Show(int dCmdShow = SW_SHOWNORMAL);
operator HWND();
protected:
HWND hwnd;
HINSTANCE mhInst;
public:
HINSTANCE GetInstance();
private:
};
//---------------------------------------------------------------------------
#endif // WINCTRLS_H
This class can be implemented as follows:
#include "winctrl.h"
//---------------------------------------------------------------------------
WControl::WControl()
: hwnd(0)
{
}
//---------------------------------------------------------------------------
WControl::~WControl()
{
}
//---------------------------------------------------------------------------
WControl::operator HWND()
{
return hwnd;
}
//---------------------------------------------------------------------------
HWND WControl::Create(HINSTANCE hinst, LPCTSTR clsname,
LPCTSTR wndname, HWND parent,
DWORD dStyle,
int x, int y,
int width, int height)
{
hwnd = CreateWindow(clsname, wndname, dStyle,
x, y, width, height, parent, NULL, hinst, NULL);
return hwnd;
}
//---------------------------------------------------------------------------
BOOL WControl::Show(int dCmdShow)
{
BOOL CanShow = ::ShowWindow(hwnd, dCmdShow);
if( CanShow )
return TRUE;
return FALSE;
}
//---------------------------------------------------------------------------
HINSTANCE WControl::GetInstance()
{
return mhInst;
}
//---------------------------------------------------------------------------
To use this class, simply declare it in your application and
call the necessary methods. Here is an example:
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Practical Learning: Initializing an Application