[This topic is pre-release documentation and is subject to change in future releases. Blank topics are included as placeholders.]

Tag interface for data window views. Data window views follow the view interface but keep a window over the data received by their parent view. Data window view may keep length windows or time windows or other windows. Data window views generally follow the following behavior: They publish the data that was received as new data from their parent view directly as new data to child views. They publish the data that expires out of the window (for length or time reasons or other reasons) as old data to their child views. They remove the data they receive as old data from their parent view out of the window and report the data removed as old data to child views. Certain views may decide to attach only to data window views directly. One reason for this is that window limit the number of event instances kept in a collection. Without this limitation some views may not work correctly over time as events accumulate but are not removed from the view by means old data updates received from a parent data window.

The following tables list the members exposed by the DataWindowView type.

Public Methods

  NameDescription
AddView
Add a view to the viewable object.
(Inherited from Viewable.)
AttachesTo
Return null if the view will accept being attached to a particular object.
(Inherited from View.)
GetEnumerator
Returns an enumerator that iterates through the collection.
(Inherited from IEnumerable<(Of T>).)
GetEnumerator
Returns an enumerator that iterates through a collection.
(Inherited from IEnumerable.)
GetViews
Returns all added views.
(Inherited from Viewable.)
RemoveView
Remove a view.
(Inherited from Viewable.)
Update
Notify that data has been added or removed from the Viewable parent. The last object in the newData array of objects would be the newest object added to the parent view. The first object of the oldData array of objects would be the oldest object removed from the parent view.

If the call to update contains new (inserted) data, then the first argument will be a non-empty list and the second will be empty. Similarly, if the call is a notification of deleted data, then the first argument will be empty and the second will be non-empty. Either the newData or oldData will be non-null. This method won't be called with both arguments being null, but either one could be null. The same is true for zero-length arrays. Either newData or oldData will be non-empty. If both are non-empty, then the update is a modification notification.

When update() is called on a view by the parent object, the data in newData will be in the collection of the parent, and its data structures will be arranged to reflect that. The data in oldData will not be in the parent's data structures, and any access to the parent will indicate that that data is no longer there.

(Inherited from View.)