截取中文输入法输入的字符串，更改编码为ANSI

在全英文的XP中，在非unicode的程序中输入的中文会转为“？？”。

通过截获WM_IME_COMPOSITION消息得到输入的字符串
ImmGetCompositionStringW得到Unicode
WideCharToMultiByte转换为ANSI

BOOL CchartestDlg::PreTranslateMessage(MSG* pMsg)
{
	if (pMsg->message == WM_IME_COMPOSITION)
	{
		HIMC hIMC;
		HWND hWnd=pMsg->hwnd;
		DWORD dwSize;
		WCHAR lpWideStr[20];

		hIMC = ImmGetContext(hWnd);

		dwSize = ImmGetCompositionStringW(hIMC, GCS_RESULTSTR, NULL, 0);

		dwSize += sizeof(WCHAR);

		memset(lpWideStr, 0, 20);

		//get string in Unicode
		ImmGetCompositionStringW(hIMC, GCS_RESULTSTR, lpWideStr, dwSize);

		//transfer to ANSI code
		int   iSize;
		LPSTR   pszMultiByte;
		int ChineseSimpleAcp = 936;
		
		iSize = WideCharToMultiByte(ChineseSimpleAcp,0,lpWideStr,-1,NULL,0, NULL,NULL);

		pszMultiByte = new char[iSize+1]/**sizeof(char)*/;

		WideCharToMultiByte(ChineseSimpleAcp, 0, lpWideStr, -1,	pszMultiByte, iSize, NULL, NULL );

		CString strText = pszMultiByte;

		delete pszMultiByte;

		ImmReleaseContext(hWnd, hIMC);

		return TRUE;
	}
		
	return Default();	
}