Module list_data_source 

ListDataSource — read-and-command interface for a flat collection behind a ListView / TableView.

ListDataSource is the flat-list peer of TreeDataSource: a positional read API plus the capability protocol (identity, DnD validation, lazy loading). It is the input every flat data view reads through. The built-in ListModel<T> and SortFilterListModel<T> implement it; an external/huge source (a paged database cursor, a 1M-row windowed feed) implements it directly and owns its own paging behind row_state/request_window/fetch_more.

Not object-safe (associated types + generic with_item); ListView consumes it generically via ListView::from_source and erases it into a closure bundle. The DnD and lazy methods default to inert / fully-resident, so a read-only in-memory source implements only len + with_item + observe_changes.

When to use

Prefer ListModel<T> when your data fits in memory and you want automatic DataChange notifications with no extra work. Implement ListDataSource directly when the source is external, huge, or requires lazy window-based loading — the view calls request_window each build pass and fetch_more near the end.

// ListModel<T> implements ListDataSource — pass it directly to any flat view.
let model = ListModel::from_vec(vec!["alpha", "beta", "gamma"]);
// Access via the ListDataSource interface:
let _len = model.len();
let _first = model.with_item(0, |s| *s);
assert_eq!(_len, 3);
assert_eq!(_first, Some("alpha"));

Traits

ListDataSource

A data source for a flat collection viewed by ListView, TableView, and GridView.