5.20193.637
ICollectionView Wijmo API Interface

ICollectionView Interface

Enables collections to have the functionalities of current record management, custom sorting, filtering, and grouping.

This is a JavaScript version of the ICollectionView interface used in Microsoft's XAML platform. It provides a consistent, powerful, and MVVM-friendly way to bind data to UI elements.

Wijmo includes several classes that implement ICollectionView. The most common is CollectionView, which works based on regular JavsScript arrays.

Type parameters

  • T

Heirarchy

Properties

canFilter

canFilter: boolean

Gets a value that indicates whether this view supports filtering via the filter property.

canGroup

canGroup: boolean

Gets a value that indicates whether this view supports grouping via the groupDescriptions property.

canSort

canSort: boolean

Gets a value that indicates whether this view supports sorting via the sortDescriptions property.

currentItem

currentItem: T

Gets the current item in the view.

currentPosition

currentPosition: number

Gets the ordinal position of the current item in the view.

filter

filter: IPredicate<T>

Gets or sets a callback used to determine if an item is suitable for inclusion in the view.

NOTE: If the filter function needs a scope (i.e. a meaningful 'this' value), then remember to set the filter using the 'bind' function to specify the 'this' object. For example:

  collectionView.filter = this._filter.bind(this);

groupDescriptions

groupDescriptions: ObservableArray<GroupDescription>

Gets a collection of GroupDescription objects that describe how the items in the collection are grouped in the view.

groups

groups: any[]

Gets the top-level groups.

isEmpty

isEmpty: boolean

Gets a value that indicates whether this view contains no items.

items

items: T[]

Gets the filtered, sorted, grouped items in the view.

sortDescriptions

sortDescriptions: ObservableArray<SortDescription>

Gets a collection of SortDescription objects that describe how the items in the collection are sorted in the view.

sourceCollection

sourceCollection: any

Gets or sets the collection object from which to create this view.

Methods

beginUpdate

  • beginUpdate(): void
  • Suspends refreshes until the next call to endUpdate.

    Returns void

contains

  • contains(item: T): boolean
  • Returns a value that indicates whether a given item belongs to this view.

    Parameters

    • item: T

      The item to locate in the collection.

    Returns boolean

deferUpdate

  • deferUpdate(fn: Function): void
  • Executes a function within a beginUpdate/endUpdate block.

    The collection will not be refreshed until the function has been executed. This method ensures endUpdate is called even if the function throws.

    Parameters

    • fn: Function

      Function to be executed within the beginUpdate/endUpdate block.

    Returns void

endUpdate

  • endUpdate(): void
  • Resumes refreshes suspended by a call to beginUpdate.

    Returns void

implementsInterface

  • implementsInterface(interfaceName: string): boolean
  • Returns true if the object implements a given interface.

    Parameters

    • interfaceName: string

      Name of the interface to look for.

    Returns boolean

moveCurrentTo

  • moveCurrentTo(item: T): boolean
  • Sets the specified item to be the current item in the view.

    Parameters

    Returns boolean

moveCurrentToFirst

  • moveCurrentToFirst(): boolean
  • Sets the first item in the view as the current item.

    Returns boolean

moveCurrentToLast

  • moveCurrentToLast(): boolean
  • Sets the last item in the view as the current item.

    Returns boolean

moveCurrentToNext

  • moveCurrentToNext(): boolean
  • Sets the item after the current item in the view as the current item.

    Returns boolean

moveCurrentToPosition

  • moveCurrentToPosition(index: number): boolean
  • Sets the item at the specified index in the view as the current item.

    Parameters

    • index: number

      The index of the item to set as the currentItem.

    Returns boolean

moveCurrentToPrevious

  • moveCurrentToPrevious(): boolean
  • Sets the item before the current item in the view as the current item.

    Returns boolean

refresh

  • refresh(): void
  • Re-creates the view using the current sort, filter, and group parameters.

    Returns void

Events

collectionChanged

Occurs when the collection changes.

currentChanged

currentChanged: Event<ICollectionView, EventArgs>

Occurs after the current item changes.

currentChanging

currentChanging: Event<ICollectionView, EventArgs>

Occurs before the current item changes.