The array of items to virtualize.

Compared by reference: mutating the array in place (data.push(...)) causes no update. Assign a new array instead. The dataRequest flow also expects a new array.

Emitted when the rendered window comes within a few items of the end of data. Also emitted on the first render, when the loaded items do not fill the viewport. Listen to this event to append more items (infinite / remote scrolling).

A loaded page of a larger collection, for data that arrives a page at a time.

Takes the place of data while it is set. The list is as long as totalCount, so the scrollbar spans the whole collection while only the page is in memory. Indices the page does not cover render nothing; use stateChange to see which range is wanted and supply the page that covers it.

Measured sizes are kept per index across pages while totalCount holds: the indices still mean the same records. A page with another totalCount is a different collection, and every size is measured again. A page that keeps the count but puts different records at the same indices keeps the sizes measured for the previous ones until those rows render.

Estimated item size in pixels used before an item is measured in the DOM. The engine replaces this with the actual measured size after the first render of each item. Unmeasured items then take the average measured size. Default is 50 pixels. Setting this to a value close to the actual average item size can improve initial rendering performance.

Item template provided programmatically. Takes precedence over a content ng-template[igxVirtualItem] when both are provided.

Items are measured by their border box, so margins accumulate as drift down the list. Use padding on the item, or a gap on a wrapper, instead.

Only the current window is in the DOM, so assistive technology cannot infer an item's position from the markup. Templates that render a role with set semantics (listitem, option, row, ...) should map the context's index and count onto aria-posinset and aria-setsize.

Item elements are recycled: bind all item state and write user changes back to the item, or unbound DOM state (e.g. a toggled checkbox) shows on another item. See keyFunction.

Returns a unique key from an item and its index in the whole collection. An item keeps its element while its key stays rendered. Defaults to the index; set it when items move within data (sort, insert, remove).

Scroll orientation of the virtual scroll. Can be either "vertical" or "horizontal". Default is "vertical".

Number of extra items to render beyond the visible area of the viewport. Higher values reduce blank flashes during fast scrolling but may impact performance. Default is 2.

Emitted when the rendered virtual window changes.