Being a descendent of IBasic the interface "IList" is the base
interface for all kinds of list interfaces. Only the properties that apply
to all list interfaces are introduced here. If you want to have a good
overview you might want to look at the IList Reference.
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type IList = interface (IBasic) ['{F6B8D483-40DB-11D3-A52D-00005A180D69}'];
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The most important property of a list is probably, how many items it
contains:
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property IList. ItemCount : integer;
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Then we have the "Capacity" property, which tells us how many items our list
can hold without being forced to reallocate. Generally this property should
not be very interesting for you. It's important only if you build your own
descendents from IList.
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property IList.Capacity : integer;
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Some lists may happen to have "nil" items, some may not. Anyway, the
following method removes all "nil" items, if any:
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procedure IList. Pack;
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One important feature of lists is sorting. However, sorting is quite
dependent of the list type. So in our base interface we can only introduce
some parts of sorting mechanism. The property "SortDown" says whether the
list is sorted normally or upside down. The property "SortInfo" has no
special meaning. It can be set and then later asked by the custom sorting
procedure.
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property IList. SortDown : boolean;
property IList.SortInfo : integer;
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If you're using the same list object in more than one thread at the same
time, you need to synchronize access to it. For this purpose you can use the
both built in functions "Lock" and "Unlock". They're realized internally
by a ICriticalSection object.
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procedure IList.Lock;
function IList.Unlock : boolean;
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The following properties are useful mainly when you show the list's items in
a TListView. "SelectedCount" tells you how many items are selected in the
TListView component. "FocusedItem" tells you which of the items is currently
focused. And "LastFocusedItem" is needed for multiple selections.
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property IList.SelectedCount : integer;
property IList.FocusedItem : IBasic;
property IList.LastFocusedItem : IBasic;
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