C# Definition:
[StructLayout(LayoutKind.Sequential)]
public struct FILETIME {
public uint DateTimeLow;
public uint DateTimeHigh;
}
VB.Net Definition:
<StructLayout(LayoutKind.Sequential)> _
Public Structure FILETIME
Public dwLowDateTime As UInteger
Public dwHighDateTime As UInteger
Public ReadOnly Property Value() As ULong
Get
Return CType(dwHighDateTime << 32, ULong) + dwLowDateTime
End Get
End Property
End Structure
Alternative Managed Definition:
System.Runtime.InteropServices.FILETIME (obsolete), or System.Runtime.InteropServices.ComTypes.FILETIME in the .NET Framework 2.0.
Notes:
None.
Sample Code:
There is no reason not to use System.Runtime.InteropServices.ComTypes.FILETIME, but there still is a need for conversion to DateTime:
C#
public static DateTime FiletimeToDateTime(FILETIME fileTime) {
long hFT2 = (((long) fileTime.dwHighDateTime) << 32) | ((uint) fileTime.dwLowDateTime);
return DateTime.FromFileTimeUtc(hFT2);
}
public static FILETIME DateTimeToFiletime(DateTime time) {
FILETIME ft;
long hFT1 = time.ToFileTimeUtc();
ft.dwLowDateTime = (int) (hFT1 & 0xFFFFFFFF);
ft.dwHighDateTime = (int) (hFT1 >> 32);
return ft;
}
Actually, this is NOT working. The only solution I've found so far is using the API Kernel32.dll function FileTimeToSystemTime, then transforming from that into a regular DateTime.
The reason it was not working, is the + operator between "((long) high) << 32" and "low". I changed this to the | operator.
* Note that System.Runtime.InteropServices.FILETIME is now obsolete. Changed to use System.Runtime.InteropServices.ComTypes.FILETIME instead.
This works for me in vb.net:
Private Shared Function ConvertFileTimeToDateTime(input As FILETIME) As DateTime
Dim longTime As ULong = (CType(input.dwHighDateTime, ULong) << 32) Or input.dwLowDateTime
Return DateTime.FromFileTime(longTime)
End Function
-
Completely without any error-prone bit shift operations:
C#
[StructLayout(LayoutKind.Sequential)]
struct FILETIME {
private long timestamp;
public DateTime Local {
get { return DateTime.FromFileTime(this.timestamp); }
set { this.timestamp = value.ToFileTime(); }
}
public DateTime Utc {
get { return DateTime.FromFileTimeUtc(this.timestamp); }
set { this.timestamp = value.ToFileTimeUtc(); }
}
}
