如何在DialogBox对话框里增加一个子窗口

小弟第一次在DialogBox对话框里增加一个子窗口,但是代码运行就只显示对话框,代码如下:请高手指点#include <windows.h>
#include "resource.h"
HINSTANCE hInst;
char szClassName[] = "BASEWND";LRESULT CALLBACK WindowProc(HWND hwnd,UINT uMsg,WPARAM wParam,LPARAM lParam){return DefWindowProc(hwnd, uMsg, wParam, lParam);}
LRESULT CALLBACK MainProc(HWND hWndDlg, UINT uMsg, WPARAM wParam, LPARAM lParam);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
hInst = hInstance;
DialogBox(hInstance, (LPCTSTR)IDD_MAIN, NULL, (DLGPROC)MainProc);
return 0;
}LRESULT CALLBACK MainProc(HWND hWndDlg, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch(uMsg)
{ case WM_INITDIALOG:
{
SetWindowText(hWndDlg,"第一个对话框"); HWND hWnd;
WNDCLASSEX wc = 
{
sizeof(wc),
CS_HREDRAW | CS_VREDRAW,
WindowProc,
0,0,
hInst,
LoadIcon(NULL,IDI_APPLICATION),
LoadCursor(NULL,IDC_ARROW),
(HBRUSH)(COLOR_WINDOW+1),
NULL,
szClassName,
LoadIcon(NULL,IDI_APPLICATION)
};
RegisterClassEx(&wc); hWnd = CreateWindowEx(
0,
//窗口注册名
szClassName,"TheTestWindow",
WS_CHILD|WS_VISIBLE,
//WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,100,CW_USEDEFAULT,100,
hWndDlg,NULL,hInst,NULL); SetParent(hWnd,hWndDlg); ShowWindow(hWnd,SW_SHOW);
UpdateWindow(hWnd); }
break;
case WM_COMMAND:
switch(LOWORD(wParam))
{
case IDOK:
EndDialog(hWndDlg,IDOK);
break;
case IDCANCEL:
EndDialog(hWndDlg,IDCANCEL);
break;
}
break;
}
return 0;
}