将 System::Datetime 转换为 QDateTime
Convert System::Datetime to QDateTime
如何转换 System::Datetime to QDateTime?
也许这是一种简单的方法,但它很容易被低估:
a) 使用 DateTime.ToString()
将 System::Datetime 转换为字符串
b) 使用 QDateTime::fromString()
将字符串转换为 QDateTime
或考虑使用 QDateTime::fromTime_t()
(参见 Datetime to time_t conversion 的示例)
使用 Win32 API
#define WINDOWS_TICKS_PER_SEC 10000000
#define EPOCH_DIFFERENCE 11644473600LL
QDatetime getQDatetime(){
FILETIME ft = {0};
::GetSystemTimeAsFileTime(&ft); //Retrieves the current system date and time.
LARGE_INTEGER li = {0};
li.LowPart = ft.dwLowDateTime;
li.HighPart = ft.dwHighDateTime;
long long int hns = li.QuadPart;
wprintf(L"Windows API time: %lli\n", hns);
long long int utm ;
utm=(hns / WINDOWS_TICKS_PER_SEC - EPOCH_DIFFERENCE);
wprintf(L"Unix time: %lli\n", utm);
return QDateTime::fromTime_t(utm);
}
您可以使用 ISO 8601 规范作为中间格式:
/* not tested */
System::DateTime date;
QString str(date.ToString("O")); // "O" for ISO format
QDateTime qdt = QDateTime::fromString(str, Qt::ISODate);
请参阅 QDateTime::fromString
and DateTime::ToString
文档
QDateTime::fromString(QString::fromStdWString(msclr::interop::marshal_as<std::wstring>(systemDateTime.ToString("ddMMyyyy HH:mm:ss"))), "ddMMyyyy HH:mm:ss"))
如何转换 System::Datetime to QDateTime?
也许这是一种简单的方法,但它很容易被低估:
a) 使用 DateTime.ToString()
b) 使用 QDateTime::fromString()
或考虑使用 QDateTime::fromTime_t()
(参见 Datetime to time_t conversion 的示例)
使用 Win32 API
#define WINDOWS_TICKS_PER_SEC 10000000
#define EPOCH_DIFFERENCE 11644473600LL
QDatetime getQDatetime(){
FILETIME ft = {0};
::GetSystemTimeAsFileTime(&ft); //Retrieves the current system date and time.
LARGE_INTEGER li = {0};
li.LowPart = ft.dwLowDateTime;
li.HighPart = ft.dwHighDateTime;
long long int hns = li.QuadPart;
wprintf(L"Windows API time: %lli\n", hns);
long long int utm ;
utm=(hns / WINDOWS_TICKS_PER_SEC - EPOCH_DIFFERENCE);
wprintf(L"Unix time: %lli\n", utm);
return QDateTime::fromTime_t(utm);
}
您可以使用 ISO 8601 规范作为中间格式:
/* not tested */
System::DateTime date;
QString str(date.ToString("O")); // "O" for ISO format
QDateTime qdt = QDateTime::fromString(str, Qt::ISODate);
请参阅 QDateTime::fromString
and DateTime::ToString
文档
QDateTime::fromString(QString::fromStdWString(msclr::interop::marshal_as<std::wstring>(systemDateTime.ToString("ddMMyyyy HH:mm:ss"))), "ddMMyyyy HH:mm:ss"))