Accessing Attributes with ADSI

You can use the IADs::Get or the IADs::GetEx functions to access attribute values. Both functions return a variant value. These functions are only available for directories that support a schema. When using a directory without a schema you must use the IADsProperty interfaces to manipulate data.

IADs::Get returns a variant which may or may not be a variant array depending on the number of values returned by the server. For example, if only one value is returned from the server, regardless of whether it is a single or multiple valued attribute, IADs::Get returns a non-variant array. On the other hand, if more than one value is returned, a variant array is returned.

IADs::Get can also return a variant which contains another COM object (via IDispatch).

In other words, IADs::Get always returns one of three types of variant:

• Simple variant (which may contain VT_BSTR, VT_DISPATCH).

  This is normally set when a single value is returned.

• Variant array of variants (VT_ARRAY | VT_VARIANT).

  This is normally set when multiple values are returned.

• Variant array of bytes (VT_ARRAY | VT_UI1).

  This is normally set when binary data is returned.

Note  The Visual Basic Scripting Language supports variant and variant arrays of variants. Hence, you cannot use VBScript to read binary data. The ADSI SDK includes a sample program called the Octet String Converter that allows you to read binary data from VBScript. Visual Basic does not have this limitation.