IEnumCERTVIEWEXTENSION::GetValue method (certview.h)

Article
10/13/2021

The GetValue method retrieves the value of the current extension in the extension-enumeration sequence.

Syntax

HRESULT GetValue(
  [in]  LONG    Type,
  [in]  LONG    Flags,
  [out] VARIANT *pvarValue
);

Parameters

[in] Type

Data type for the returned data. This parameter can be used to specify that the extension data be decoded before being returned. If PROPTYPE_BINARY is specified, the data is not decoded but instead returned in its raw format.

Specify one of the following values.

Value	Meaning
PROPTYPE_BINARY	The extension value is retrieved as is and is ASN.1 encoded if necessary.
PROPTYPE_DATE	Extension value is returned as a date/time.
PROPTYPE_LONG	Extension value is returned as a signed long.
PROPTYPE_STRING	The extension value is ASN.1 encoded as an IA5 string.

[in] Flags

Flag that denotes the output format for the returned data. This parameter can be one of the following values.

Value	Meaning
CV_OUT_BASE64	BASE64 without BEGIN/END
CV_OUT_BASE64HEADER	BASE64 with BEGIN CERTIFICATE and END CERTIFICATE
CV_OUT_BASE64REQUESTHEADER	BASE64 with BEGIN NEW CERTIFICATE REQUEST and END NEW CERTIFICATE REQUEST
CV_OUT_BINARY	Binary
CV_OUT_HEX	Hexadecimal string
CV_OUT_HEXADDR	Hexadecimal string with address/offset
CV_OUT_HEXASCII	Hexadecimal string with ASCII
CV_OUT_HEXASCIIADDR	Hexadecimal string with ASCII and address/offset

[out] pvarValue

A pointer to a value of VARIANT type that contains the data for the currently referenced extension. This method fails if the pvarValue parameter is NULL. Upon successful completion of this function, pvarValue contains the extension data currently referenced by the extension-enumeration sequence. The caller is responsible for calling VariantClear when done with the data in pvarValue.

Return value

C++

If the method succeeds, the method returns S_OK.

If the method fails, it returns an HRESULT value that indicates the error. For a list of common error codes, see Common HRESULT Values.

VB

The return value is a Variant that represents the data in the extension.

Remarks

This method is used to retrieve the data in the extension currently being referenced by the extension-enumeration sequence.

If the extension-enumeration sequence is not referencing a valid extension, GetValue fails. Use one of the following methods to navigate through the enumeration:

IEnumCERTVIEWEXTENSION::Reset: Moves to the next extension in the enumeration sequence.
IEnumCERTVIEWEXTENSION::Next: Moves to the next extension in the enumeration sequence.
IEnumCERTVIEWEXTENSION::Skip: Skips a specified number of extensions.

This method fails if the extension-enumeration sequence was obtained by a call to the ICertView::EnumCertViewColumn method because enumeration sequences obtained by that method contain only schema information.

Examples

VARIANT     var;
LONG        Index;
HRESULT     hr;
SYSTEMTIME  systime;

VariantInit(&var);

// Enumerate each extension
// pEnumExt is previously instantiated IEnumCERTVIEWEXTENSION object
while (S_OK == pEnumExt->Next(&Index))
{
    hr = pEnumExt->GetValue(PROPTYPE_BINARY, CV_OUT_HEX, &var);
    if (FAILED(hr))
    {
        printf("Failed GetValue - %x\n", hr);
        break;
    }
    switch(var.vt)
    {
        case VT_EMPTY:
            printf("VT_EMPTY\n");
            break;
        case VT_BSTR:
            printf("BSTR:%ws\n", var.bstrVal);
            break;
        case VT_DATE:
            VariantTimeToSystemTime(var.date, &systime);
            printf("%d.%d.%d %02d:%02d:%02d\n",
                   systime.wMonth,
                   systime.wDay,
                   systime.wYear,
                   systime.wHour,
                   systime.wMinute,
                   systime.wSecond );
            break;
        case VT_I2:
            printf("%d\n", var.iVal);
            break;
        case VT_I4:
            printf("%d\n", var.lVal);
            break;
        default:
            printf("type is:%i\n", var.vt);
            break;
    }
}
// Free resources.
VariantClear( &var );

Requirements

Requirement	Value
Minimum supported client	None supported
Minimum supported server	Windows Server 2003 [desktop apps only]
Target Platform	Windows
Header	certview.h (include Certsrv.h)
Library	Certidl.lib
DLL	Certadm.dll

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