How to: Get or Set the System Time

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To get or set the system time of the device, use platform invoke to call the native GetSystemTime or SetSystemTime functions.

Note that the GetSystemTime function returns Coordinated Universal Time (UTC, also known as Greenwich Mean Time). To get your local time, you must add or subtract the number of hours between your time zone and UTC. For example, 24:00 (midnight) in UTC is 19:00 in New York--an offset of minus 5 hours (UTC–5).

To determine the UTC offset for your time zone, see the Time Zone tab of Date and Time Properties.

Some device emulators do not initially set daylight-saving time correctly, which could affect your result.

This code example defines the following:

  • Platform invoke declarations for the native methods in Windows Embedded CE.

  • A structure to pass to and receive from the native methods.

  • A managed method named GetTime, which displays the current time.

  • A managed method named SetTime, which sets the system clock ahead one hour.


Public Structure SYSTEMTIME
    Public wYear As UInt16
    Public wMonth As UInt16
    Public wDayOfWeek As UInt16
    Public wDay As UInt16
    Public wHour As UInt16
    Public wMinute As UInt16
    Public wSecond As UInt16
    Public wMilliseconds As UInt16
End Structure

Declare Function GetSystemTime Lib "CoreDll.dll" _
    (ByRef lpSystemTime As SYSTEMTIME) As UInt32

Declare Function SetSystemTime Lib "CoreDll.dll" _
    (ByRef lpSystemTime As SYSTEMTIME) As UInt32

Public Sub GetTime
    ' Call the native GetSystemTime method
    ' with the defined structure.
    Dim st As New SYSTEMTIME
    GetSystemTime(st)

    ' Show the current time.
    MessageBox.Show("Current Time: "  & st.wHour.ToString() _
        & ":" & st.wMinute.ToString())
End Sub

Public Sub SetTime
    ' Call the native GetSystemTime method
    ' with the defined structure.
   Dim st As New SYSTEMTIME
    GetSystemTime(st)

    ' Set the system clock ahead one hour.
    st.wHour = Convert.ToUInt16(((CInt(st.wHour) + 1)) Mod 24)
    SetSystemTime(st)

End Sub





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