combobox를 win32api로 만들어봤습니다.

#include <windows.h>
#include <tchar.h>
#include <string.h>
#define ID_COMBOBOX 100
TCHAR *items[]={TEXT("APPLE"), TEXT("Orange"), TEXT("Melon"), TEXT("Grape"), TEXT("Strawberry")};
HWND hCombo;
HINSTANCE hgInstance;
LRESULT CALLBACK WndProc(HWND hwnd , UINT message, WPARAM wparam, LPARAM lparam) {
	int i;
	TCHAR str[128];
	static TCHAR tmbuffer[128];
	switch(message) {
		case WM_CREATE:
			hCombo=CreateWindow(TEXT("combobox"), TEXT(""), WS_CHILD | WS_VISIBLE | CBS_DROPDOWN | WS_OVERLAPPED | CBS_HASSTRINGS,10, 10, 100, 200, hwnd, (HMENU)ID_COMBOBOX, hgInstance, NULL);
			tmbuffer[0]=TEXT('\0');
			for(i=0;i<5;i++) {
				SendMessage(hCombo, (UINT)CB_ADDSTRING, (WPARAM)0, (LPARAM)items[i]);
				_stprintf(tmbuffer, TEXT("%s %d"), tmbuffer, i);
			}
			//SendMessage(hCombo, CB_SETCURSEL, (WPARAM)2, (LPARAM)0);
			//ShowWindow(hCombo, SW_SHOWNORMAL);
 
			return 0;
		case WM_COMMAND:
			switch(LOWORD(wparam)) {
			case ID_COMBOBOX:
				switch(HIWORD(wparam)) {
					case CBN_SELCHANGE:
						i=SendMessage(hCombo, CB_GETCURSEL, 0, 0);
						SendMessage(hCombo, CB_GETLBTEXT, i, (LPARAM)str);
						SetWindowText(hwnd, str);
						break;
					case CBN_EDITCHANGE:
						GetWindowText(hCombo, str, 128);
						SetWindowText(hwnd, str);
						break;
				}
			}
			return 0;
		case WM_PAINT:
			{
				PAINTSTRUCT pst;
				HDC hdc=BeginPaint(hwnd, &pst);
				TextOut(hdc, 50, 400, tmbuffer, _tcslen(tmbuffer));
				EndPaint(hwnd, &pst);
				return 0;
			}
		case WM_DESTROY:
			PostQuitMessage(0);
			return 0;
	}
	return DefWindowProc(hwnd, message, wparam, lparam);
}
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) {
	WNDCLASS WndCls;
	WndCls.cbClsExtra=0;
	WndCls.cbWndExtra=0;
	WndCls.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
	WndCls.hCursor=LoadCursor(NULL, IDC_ARROW);
	WndCls.hIcon=NULL;
	WndCls.hInstance=hgInstance=hInstance;
	WndCls.lpfnWndProc=WndProc;
	LPCTSTR clsname=TEXT("combobox");
	WndCls.lpszClassName=clsname;
	WndCls.lpszMenuName=NULL;
	WndCls.style=CS_HREDRAW | CS_VREDRAW;
	RegisterClass(&WndCls);
	HWND hwnd=CreateWindow(clsname, TEXT("Displaying combobox"), WS_OVERLAPPEDWINDOW, 300, 300, 500, 500, NULL, NULL, hInstance, NULL);
	ShowWindow(hwnd, nShowCmd);
	MSG message;
 
	while( GetMessage(&message, NULL, 0, 0)  ) {
		TranslateMessage(&message);
		DispatchMessage(&message);
	}
 
	return (int)message.wParam;
}