Menggunakan IADs::GetInfoEx untuk Pengambilan Rentang

Metode IADs.GetInfoEx dapat digunakan untuk mengambil rentang nilai atribut. Rentang nilai yang akan diambil ditentukan dalam array nama atribut yang diteruskan ke metode .

Penentu rentang untuk kueri properti memerlukan formulir berikut:

<property name>;range=<low range>-<high range>

di mana "<nama> properti" adalah ldapDisplayName dari atribut, "<rentang> rendah" adalah indeks berbasis nol dari nilai atribut pertama yang diambil dan "<rentang> tinggi" adalah indeks berbasis nol dari nilai atribut terakhir yang akan diambil. Nol digunakan untuk "<rentang> rendah" untuk menentukan entri pertama. Karakter kartubebas (*) dapat digunakan untuk "<rentang> tinggi" untuk menentukan semua entri yang tersisa.

Contoh kode berikut berisi fungsi yang menunjukkan cara menggunakan pengambilan rentang dengan IAD::GetInfoEx untuk menghitung anggota grup.

HRESULT EnumGroupWithGetInfoEx(LPCWSTR pwszGroupDN, 
                               LPCWSTR pwszUsername, 
                               LPCWSTR pwszPassword)
{
    if(NULL == pwszGroupDN)
    {
        return E_POINTER;
    }
    
    HRESULT hr;
    IADs *pads;

    hr = ADsOpenObject( pwszGroupDN,
                        pwszUsername,
                        pwszPassword,
                        ADS_SECURE_AUTHENTICATION,
                        IID_IADs, 
                        (void**)&pads);

    if(SUCCEEDED(hr))
    {
        const DWORD dwStep = 1000;
        DWORD dwLowRange;
        DWORD dwHighRange;
        WCHAR wszAttr[MAX_PATH];
        LPWSTR rgAttrs[1];

        rgAttrs[0] = wszAttr;

        dwLowRange = 0;
        dwHighRange = dwLowRange + (dwStep - 1);

        do
        {
            VARIANT var;

            // Perform this query with the "range=<lowRange>-<highRange>" range.
            swprintf_s(wszAttr, L"member;range=%d-%d", dwLowRange, dwHighRange);
    
            hr = ADsBuildVarArrayStr(rgAttrs, 1, &var);
            if(SUCCEEDED(hr))
            {
                hr = pads->GetInfoEx(var, 0);
                
                VariantClear(&var);

                if(SUCCEEDED(hr))
                {
                    hr = pads->Get(CComBSTR("member"), &var);
                    if(SUCCEEDED(hr))
                    {
                        if(var.vt == (VT_VARIANT | VT_ARRAY))
                        {
                            VARIANT *pVar;
                            long lLBound, lUBound;

                            // Get the array of VARIANTs.
                            hr = SafeArrayAccessData((SAFEARRAY*)(var.pparray), (void HUGEP* FAR*)&pVar);
                            if(SUCCEEDED(hr))
                            {
                                // Get the bounds for the array.
                                hr = SafeArrayGetLBound((SAFEARRAY*)(var.pparray), 1, &lLBound);
                                hr = SafeArrayGetUBound((SAFEARRAY*)(var.pparray), 1, &lUBound);

                                // Get the number of elements.
                                long cElements = lUBound - lLBound + 1;

                                // Enumerate the elements.
                                for(long i = 0; i < cElements; i++)
                                {
                                    switch(pVar[i].vt)
                                    {
                                    case VT_BSTR:
                                        wprintf(pVar[i].bstrVal); 
                                        wprintf(L"\n"); 
                                        break;
                                    }
                                }

                                // Release the array.
                                SafeArrayUnaccessData((SAFEARRAY*)(var.pparray));
                            }
                        }
                        // This occurs only if one element is retrieved.
                        else if (var.vt == VT_BSTR)
                        {
                            wprintf(var.bstrVal); 
                            wprintf(L"\n"); 
                        }

                        VariantClear(&var);
                    }

                    // Increment the high and low ranges to query for the next block of objects.
                    dwLowRange = dwHighRange + 1;
                    dwHighRange = dwLowRange + (dwStep - 1);
                }
            }
        }while(SUCCEEDED(hr));

        pads->Release();
    }

    return hr;
}

Contoh kode berikut berisi fungsi yang menunjukkan cara menggunakan pengambilan rentang dengan IADs.GetInfoEx untuk menghitung anggota grup.

Private Sub EnumGroupMembersWithGetInfoEx(strGroupDN As String, strUsername As String, strPassword As String)
    Dim oGroup As IADs
    Dim dso As IADsOpenDSObject
    
    On Error GoTo quit
        
    strPath = "LDAP://" & strGroupDN
    
    If "" <> strUsername Then
        ' Bind to the group with the specified user name and password.
        Set dso = GetObject("LDAP:")
        Set oGroup = dso.OpenDSObject(strPath, strUsername, strPassword, 1)
    Else
        ' Bind to the group with the current credentials.
        Set oGroup = GetObject(strPath)
    End If
    
    ' For compatibility with all operating systems, the number of objects
    ' retrieved by each query should not exceed 999. The number of objects
    ' to retrieve should be as close as possible to 999 to reduce the number
    ' of round trips to the server necessary to retrieve the objects.
    rangeStep = 999
    lowRange = 0
    highRange = lowRange + rangeStep
    
    Do
        ' Use the "member;range=<lowRange>-<highRange>" syntax.
        strCommandText = "member;range=" & lowRange & "-" & highRange
        Debug.Print "Current search command: " & strCommandText
        
        ' Load the specified range of members into the local cache. This will
        ' throw an error if the range exceeds the properties contained in the
        ' object. The "On Error GoTo quit" error handler will cause the loop
        ' to terminate when this happens.
        On Error GoTo quit
        oGroup.GetInfoEx Array(strCommandText), 0
        
        ' Enumerate the retrieved members.
        oMembers = oGroup.Get("member")
        If vbArray And VarType(oMembers) Then
            For Each oMember In oMembers
                ' Add the member.
                Debug.Print oMember
                nRetrieved = nRetrieved + 1
            Next
        Else
            ' oGroup.Get returned only one member, so add it to the list.
            Debug.Print oMembers
            nRetrieved = nRetrieved + 1
        End If
        
        ' Increment the high and low ranges to query for the next block of objects.
        lowRange = highRange + 1
        highRange = lowRange + rangeStep
    Loop While True
    
quit:
End Sub