iads.h (iads.h) 的 IADsLargeInteger 介面

IADsLargeInteger介面是用來操作LargeInteger類型的 64 位整數。

繼承

IADsLargeInteger介面繼承自 IDispatch 介面。

備註

在 Visual Basic 中處理 IADsLargeInteger 很困難，因為 Visual Basic 沒有原生無符號數值資料類型。 如果 LowPart 或 HighPart 已設定高位，這可能會導致 Visual Basic 將數位當做負數來處理，這可能會導致資料轉換發生錯誤。 下列 Visual Basic 程式碼範例示範如何在 Visual Basic 中正確處理 IADsLargeInteger 。

範例

下列範例示範如何將 IADsLargeInteger 物件轉換成十六進位字串。

Dim oDomain As IADs
Dim oLargeInt As LargeInteger

Set oDomain = GetObject("LDAP://DC=fabrikam,DC=com")
Set oLargeInt = oDomain.Get("creationTime")

Debug.Print oLargeInt.HighPart
Debug.Print oLargeInt.LowPart

strTemp = "&H" + CStr(Hex(oLargeInt.HighPart)) + _
     CStr(Hex(oLargeInt.LowPart))
Debug.Print strTemp

在 Visual Basic 中，您可以使用FileTimeToSystemTime 和 SystemTimeToVariantTime API，將代表日期和時間的IADsLargeInteger物件轉換成 Time Variant。 這顯示在下列程式碼範例中。

Public Declare Function FileTimeToSystemTime Lib "kernel32" _
   (lpFileTime As FILETIME, _
   lpSystemTime As SYSTEMTIME) As Long

Public Declare Function SystemTimeToVariantTime Lib "oleaut32.dll" _
    (lpSystemTime As SYSTEMTIME, _
    dbTime As Double) As Long

Public Type SYSTEMTIME
    wYear As Integer
    wMonth As Integer
    wDayOfWeek As Integer
    wDay As Integer
    wHour As Integer
    wMinute As Integer
    wSecond As Integer
    wMilliseconds As Integer
End Type

Public Type FILETIME
    dwLowDateTime As Long
    dwHighDateTime As Long
End Type


' This function will convert the ADSI data type LargeInteger to
' a Variant time value in Greenwich Mean Time (GMT).
Function LargeInteger_To_Time(oLargeInt As LargeInteger, vTime As Variant)_
              As Boolean
    On Error Resume Next
    Dim pFileTime As FILETIME
    Dim pSysTime As SYSTEMTIME
    Dim dbTime As Double
    Dim lResult As Long
    
    If (oLargeInt.HighPart = 0 And oLargeInt.LowPart = 0) Then
        vTime = 0
        LargeInteger_To_Time = True
        Exit Function
    End If
    
    If (oLargeInt.LowPart = -1) Then
        vTime = -1
        LargeInteger_To_Time = True
        Exit Function
    End If
    
    pFileTime.dwHighDateTime = oLargeInt.HighPart
    pFileTime.dwLowDateTime = oLargeInt.LowPart
    
    ' Convert the FileTime to System time.
    lResult = FileTimeToSystemTime(pFileTime, pSysTime)
    If lResult = 0 Then
        LargeInteger_To_Time = False
        Debug.Print "FileTimeToSystemTime: " + Err.Number + "  - "_
                   + Err.Description
        Exit Function
    End If
    
    ' Convert System Time to a Double.
    lResult = SystemTimeToVariantTime(pSysTime, dbTime)
    If lResult = 0 Then
        LargeInteger_To_Time = False
        Debug.Print "SystemTimeToVariantTime: " + Err.Number + _
                 "  - " + Err.Description
        Exit Function
    End If
    
    ' Place the double in the variant.
    vTime = CDate(dbTime)
    LargeInteger_To_Time = True

End Function

下列範例示範如何將 IADsLargeInteger 轉換為 64 位整數。

HRESULT PrintAccountExpires(LPCWSTR pwszADsPath)
{
    if(!pwszADsPath)
    {
        return E_INVALIDARG;
    }
    
    HRESULT hr;
    CComPtr<IADs> spads;

    // Bind to the object.
    hr = ADsGetObject(pwszADsPath, IID_IADs, (LPVOID*)&spads);
    if(FAILED(hr))
    {
        return hr;
    }

    /*
    Get the accountExpires attribute, which is an
    IDispatch that contains an IADsLargeInteger.
    */
    CComVariant svar;
    hr = spads->Get(CComBSTR("accountExpires"), &svar);
    if(FAILED(hr))
    {
        return hr;
    }

    // Get the IADsLargeInteger interface.
    CComPtr<IADsLargeInteger> spli;
    hr = svar.pdispVal->QueryInterface(IID_IADsLargeInteger, 
                                      (LPVOID*)&spli);
    if(FAILED(hr))
    {
        return hr;
    }

    // Get the high and low parts of the value.
    long lHigh;
    long lLow;
    hr = spli->get_HighPart(&lHigh);
    hr = spli->get_LowPart(&lLow);

    // Convert the high and low parts to an __i64.
    __int64 i64;
    i64 = (ULONG)lHigh;
    i64 = (i64 << 32);
    i64 = i64 + (ULONG)lLow;
    
    // Print all of the values.
    wprintf(L"HighPart = %u, LowPart = %u, Combined = %I64d\n", 
            lHigh, lLow, i64);

    return hr;
}

規格需求

最低支援的用戶端	Windows Vista
最低支援的伺服器	Windows Server 2008
目標平臺	Windows
標頭	iads.h

另請參閱

IADsLargeInteger 屬性方法

IDispatch