编码转换（UTF8->GBK）

WCHAR woutstr[256];
char outch[256];
int len = MultiByteToWideChar(CP_UTF8, 0, value, -1, NULL, 0);
MultiByteToWideChar(CP_UTF8, 0, value, -1, woutstr, len);
len = WideCharToMultiByte(CP_ACP, 0, woutstr, -1, NULL, 0, NULL, NULL); 
WideCharToMultiByte(CP_ACP, 0, woutstr, -1, outch , len, 0, 0);