WPF › Virtualizing Wrap Panel › AboutToRenderChildItemsEventArgs

AboutToRenderChildItemsEventArgs

class.NET 6 / 8 / 10.NET Framework 4.8Binarymission.WPF.Controls.Panels.VirtualizingWrapPanel

Provides the data for BinaryVirtualizingWrapPanel.AboutToRenderChildItems: the range of items the panel is about to show.

public class AboutToRenderChildItemsEventArgs : EventArgs

Inherits from / implements: EventArgs

Examples

// Fetch the thumbnails of the photos about to come into view, before their tiles are drawn.
panel.AboutToRenderChildItems += (sender, e) =>
{
    int first = (int)e.ChildItemIndicesToRender[0];
    int last = (int)e.ChildItemIndicesToRender[1];
    for (int index = first; index <= last; index++)
    {
        thumbnailCache.Request(photos[index].FilePath);
    }
};

Members at a glance

Constructors
`AboutToRenderChildItemsEventArgs`	Creates the event data with an empty `ChildItemIndicesToRender`; the panel fills it before raising the event.
Properties
`ChildItemIndicesToRender`	Gets the first and last index of the items about to be shown.

Constructors

AboutToRenderChildItemsEventArgs

public AboutToRenderChildItemsEventArgs() : base()

Creates the event data with an empty ChildItemIndicesToRender; the panel fills it before raising the event.

Properties

ChildItemIndicesToRender

public List<long> ChildItemIndicesToRender

Gets the first and last index of the items about to be shown.

Value: A list of two zero-based indices into the items control's Items: element 0 is the first item about to be shown and element 1 the last, inclusive. The last is never past the end of the list; with no items it is -1.