IADsLargeInteger 接口 (iads.h)

IADsLargeInteger 接口用于操作 LargeInteger 类型的 64 位整数。

继承

IADsLargeInteger 接口继承自 IDispatch 接口。

备注

由于 Visual Basic 没有本机无符号数值数据类型，因此难以处理 Visual Basic 中的 IADsLargeInteger 。 如果 LowPart 或 HighPart 具有高位集，这可能会导致数据转换出错，从而导致 Visual Basic 将数字处理为负数。 下面的 Visual Basic 代码示例演示如何在 Visual Basic 中正确处理 IADsLargeInteger 。

示例

以下示例演示如何将 IADsLargeInteger 对象转换为十六进制字符串。

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，可以使用 FileTimeToSystemTime 和 SystemTimeToVariantTime API 将表示日期和时间的 IADsLargeInteger 对象转换为时间变体。 下面的代码示例对此进行了演示。

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

以下示例演示如何将 IADsLargeInteger 转换为 64 位整数。

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;
}

要求

最低受支持的客户端	Windows Vista
最低受支持的服务器	Windows Server 2008
目标平台	Windows
标头	iads.h

另请参阅

IADsLargeInteger 属性方法

IDispatch