_bstr_t与CString相互转换

_bstr_t与CString相互转换


_bstr_t bstr;


CString strSql;


CString -> _bstr_t: bstr = (_bstr_t)strSql;


_bstr_t -> CString: strSql = (LPCSTR)bstr;


BSTR宽字符串与CString相互转换


BSTR bstr;


CString strSql;


CString -> BSTR: bstr = strSql.AllocSysString();


BSTR -> CString: strSql = (LPCSTR)bstr;


1、_variant_t


(1)、一般传给这3个指针的值都不是MFC直接支持的数据类型,而要用_variant_t转换一下


_variant_t(XX)可以把大多数类型的变量转换成适合的类型传入：


(2)、_variant_t var;_variant_t -> long: (long)var;


_variant_t -> CString: CString strValue = (LPCSTR)_bstr_t(var);


CString -> _variant_t: _variant_t(strSql);