小弟我按照教程编写的程序如何跑不出可视窗口，但进程中有了哈

我按照教程编写的程序怎么跑不出可视窗口，但进程中有了哈~
#include<windows.h>
#include<tchar.h>
#include<stdio.h>
LRESULT CALLBACK Winselfact(
  HWND hwnd, 
  UINT uMsg, 
  WPARAM wParam, 
  LPARAM lParam 
);

int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance,
  LPSTR lpCmdLine, int nCmdShow )
{
WNDCLASS wls;

wls.style=CS_VREDRAW;
wls.lpfnWndProc=Winselfact;
wls.cbClsExtra=0;
wls.cbWndExtra=0;
wls.hInstance=hInstance;
wls.hIcon=LoadIcon(NULL,IDI_QUESTION);
wls.hCursor=LoadCursor(NULL,IDC_HAND);
wls.hbrBackground=(HBRUSH)GetStockObject(LTGRAY_BRUSH); 
wls.lpszMenuName=NULL;
wls.lpszClassName=_T("天才程序");

RegisterClass(&wls);

HWND hwnd;
hwnd=CreateWindow( _T("天才程序"), _T("天才程序"), WS_CAPTION|WS_MAXIMIZEBOX|WS_MAXIMIZE , CW_USEDEFAULT,CW_USEDEFAULT, CW_USEDEFAULT,CW_USEDEFAULT, 
NULL,NULL, hInstance,NULL); 
ShowWindow(hwnd,SW_SHOWNORMAL); 
UpdateWindow(hwnd);

MSG msg;
while(GetMessage(&msg,NULL,0,0))
{
TranslateMessage(&msg); 
DispatchMessage(&msg);
}

return 0;
}

LRESULT CALLBACK Winselfact(
  HWND hwnd, 
  UINT uMsg, 
  WPARAM wParam, 
  LPARAM lParam 
  )
{
switch(uMsg)
{
case WM_CHAR :
char Sizechar[20];
sprintf(Sizechar,"it is c%",wParam);
MessageBoxA(hwnd,Sizechar,"字母",MB_OK); 
}
return 0;
}

孙鑫的教程是VC6S上跑的，我用的VC2010,但是运行后没出现我想看到的窗口啊~ 我是菜鸟哈，见笑个~

[解决办法]
Winselfact函数中的最有一句return 0;改成return DefWindowProc(hwnd, uMsg, wParam, lParam);
[解决办法]
你没细心的看呀