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23.3. Win32::OLE::Enum

The Win32::OLE::Enum module provides special support for collections. Collections are special automation data types that contain an array of objects or data. A collection supports enumeration; you can iterate through each item through a standard interface.

Collection objects should always provide a Count property (the number of items in the collection) and an Item method. The Item method is used to access a particular collection item using a subscript, which may be an integer or a string, depending on the server. Collection objects may also optionally contain an Add and a Remove method.

Collection objects also support a standard COM interface (IEnumVARIANT) that allows you to enumerate each item in a collection. It defines methods that let you advance the iteration to the next item, skip a given item, restart the enumeration, and create a new copy of the iterator. While all servers are supposed to provide this interface, some servers don't implement all of the methods (often Reset and Clone are not implemented).

Win32::OLE::Enum defines these methods for enumerating collections. The collection object should provide the Count and Item methods, which are often all you need to use on collections. For example:

$cnt = $coll->Count( );
if( $cnt) {
    $obj = $coll->Item(0);
    $obj->do_something( );

Count will tell you the number of items in the collection, and Item will return the desired item as a Win32::OLE object.

For the enumeration methods, you need to create an enumeration object for the collection object:

$coll = $obj->some_coll( );
$enum = Win32::OLE::Enum->new($coll);

Now you can use the enumeration methods on the object.

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