Win32 window wrapper class

#pragma once
#include <Windows.h>
class Display
{
private:
	char* mWindowTitle;
	WNDCLASSEX mWndClass;
	HWND mHwnd;
	MSG mMsg;
	int mWidth;
	int mHeight;
public:
	Display(int width, int height, char* windowtitle, WNDPROC messagefunc, HINSTANCE hinst);
	~Display(void);
	bool InitializeWindow();
	HWND GetWindowHandle();
	MSG GetMessageHandler();
};

#include "display.h"

Display::Display(int width, int height,char* windowtitle, WNDPROC messagefunc, HINSTANCE hinst)
{
	mWindowTitle = windowtitle;
	mWidth = width;
	mHeight = height;
	mHwnd = 0;

	//Step 1 register the window class
	mWndClass.cbSize = sizeof(WNDCLASSEX); //the size of the structure
	mWndClass.style = 0; //Style of the class
	mWndClass.lpfnWndProc = messagefunc; // function pointer to the callback function
	mWndClass.cbClsExtra = 0;
	mWndClass.cbWndExtra = 0;
	mWndClass.hIcon = LoadIcon(hinst, IDI_APPLICATION);
	mWndClass.hCursor = LoadCursor(hinst,IDC_ARROW);
	mWndClass.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
	mWndClass.lpszClassName = "EngineGameWindow";
	mWndClass.lpszMenuName = NULL;
	mWndClass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
	mWndClass.hInstance =  hinst;
}

Display::~Display(void)
{
}

bool Display::InitializeWindow()
{
	if(!RegisterClassEx(&mWndClass))
		MessageBox(NULL,"Sorry could not register window class",
						"Window Registration Error", MB_ICONEXCLAMATION | MB_OK);

	//Step 2 creating the window
	mHwnd = CreateWindowEx(WS_EX_CLIENTEDGE,"EngineGameWindow", mWindowTitle,
		WS_OVERLAPPEDWINDOW,GetSystemMetrics(SM_CXSCREEN)/4,
							GetSystemMetrics(SM_CYSCREEN)/8, 
							mWidth, mHeight,NULL,NULL,mWndClass.hInstance,NULL);
	if(mHwnd == NULL)
		MessageBox(mHwnd,"Window not created","Window Creation Error",MB_ICONEXCLAMATION | MB_OK);

	return true;
}

HWND Display::GetWindowHandle()
{
	return mHwnd;
}

MSG Display::GetMessageHandler()
{
	return mMsg;
}

LRESULT CALLBACK WndProc(HWND hwnd,UINT msg,WPARAM wparam,LPARAM lparam)
{
	if(msg == WM_CHAR && wparam == VK_ESCAPE)
	{
		PostQuitMessage(0);
		return 0;
	}
	switch(msg)
	{
	case WM_CLOSE: //when the window is to be closed
		//close the window 
		DestroyWindow(hwnd);
		break;
	case WM_DESTROY: // When the entire window class is destroyed
		// 
		PostQuitMessage(0);
		break;
	case WM_PAINT:
		ValidateRect(hwnd, 0);
		break;
	default:
		return DefWindowProc(hwnd,msg,wparam,lparam);
	}
	return DefWindowProc(hwnd, msg, wparam, lparam);
}

int WINAPI WinMain(HINSTANCE hinst, HINSTANCE hPrevinstance, LPSTR lpcmdline, int ncmdshow)
{
	Display display = Display(800, 600, "Engine",WndProc,hinst);
	if(!display.InitializeWindow())
		return 0;

	Directx9Api api = Directx9Api();
	if(!api.InitializeApi())
		return 0;

	ShowWindow(display.GetWindowHandle(), SW_SHOW);
	UpdateWindow(display.GetWindowHandle());

	//Step 3 the Message loop
	while (GetMessage(&display.GetMessageHandler(),display.GetWindowHandle(),0,0) > 0)
	{
		TranslateMessage(&(display.GetMessageHandler()));
		DispatchMessage(&(display.GetMessageHandler()));
	}
	return 0;
}

int WINAPI WinMain(HINSTANCE hinst, HINSTANCE hprevinst,LPSTR lpcmdline, int ncmdshow)
{
	WNDCLASSEX wndclassex;
	HWND hwnd;
	MSG msg;

	//Step 1 register the window class
	wndclassex.cbSize = sizeof(WNDCLASSEX); //the size of the structure
	wndclassex.style = CS_DROPSHADOW; //Style of the class
	wndclassex.lpfnWndProc = WndProc; // function pointer to the callback function
	wndclassex.cbClsExtra = 0;
	wndclassex.cbWndExtra = 0;
	wndclassex.hIcon = LoadIcon(hinst, IDI_APPLICATION);
	wndclassex.hCursor = LoadCursor(hinst,IDC_ARROW);
	wndclassex.hbrBackground = (HBRUSH)(COLOR_WINDOW);
	wndclassex.lpszClassName = wndclassname;
	wndclassex.lpszMenuName = NULL;
	wndclassex.hIconSm = LoadIcon(hinst, IDI_APPLICATION);
	wndclassex.hInstance =  hinst;

	if(!RegisterClassEx(&wndclassex))
	{
		MessageBox(NULL, "Sorry could not register window class",
			"Window Registration Error", MB_ICONEXCLAMATION | MB_OK);
		return 0;
	}

	//Step 2 creating the window
	hwnd = CreateWindowEx(WS_EX_CLIENTEDGE,wndclassname,"A simple window",
		WS_OVERLAPPEDWINDOW,((GetSystemMetrics(SM_CXSCREEN)/2)/2), ((GetSystemMetrics(SM_CYSCREEN)/2)/2), 300, 300,NULL,NULL,hinst,NULL);
	
	if(hwnd == NULL)
	{
		MessageBox(hwnd,"Sorry could not create a window","Window Creation Error",MB_ICONEXCLAMATION | MB_OK);
		return 0;
	}

	ShowWindow(hwnd, ncmdshow);
	UpdateWindow(hwnd);

	//Step 3 the Message loop
	while (GetMessage(&msg,hwnd,0,0) > 0)
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);

	}

	return msg.wParam;
}