VirtualList Class
Creates a collection of very large data sets, slow-acquiring data, or a combination of both. A virtual list is request based; the entire list is not loaded, but rather portions of it are loaded, allowing you to work with very large sets of data.
public class VirtualList : ModelItem, System.Collections.IList, System.Collections.ICollection, System.Collections.IEnumerable
Public Instance Constructors
| Constructor | Description |
| VirtualList() | Initializes a new instance of the VirtualList class. |
| VirtualList(ItemCountHandler) | Initializes a new instance of the VirtualList class. |
| VirtualList(IModelItemOwner, ItemCountHandler) | Initializes a new instance of the VirtualList class. |
Public Instance Methods
| Method | Description |
| Add | Adds an item to the end of the list. |
| Clear | Empties the contents of the list. |
| Contains | Determines whether a given item is in the list. |
| CopyTo | Copies the contents of this list to an array. |
| GetEnumerator | Gets an IEnumerator object for this collection. |
| IndexOf | Determines the index of a specific item in the list. |
| Insert | Inserts an item at the specified index. |
| IsItemAvailable | Determines whether an item at the specified index is available for query (the item can be located by index). |
| Modified | Indicates that the item at the given index has been modified, but the new value is not yet known. |
| Move | Moves an item to a different location within the list. |
| Remove | Removes the specified item from the list. |
| RemoveAt | Removes the item at the specified index. |
| RequestItem | Requests an item from the specified index. |
Protected Instance Methods
| Method | Description |
| ContainsDataForIndex | Determines whether a specified index has a corresponding data item in the list. |
| Dispose | Releases all the resources used by VirtualList. |
| OnRequestItem | Gets the item at the specified index. |
| OnRequestSlowData | Gets an item that is slow to acquire. |
| OnVisualsCreated | Notifies derived classes that the visual elements associated with the item in the specified index have been created. |
| OnVisualsReleased | Notifies derived classes that the visual elements associated with the item in the specified index have been released. |
Public Instance Properties
| Property | Description |
| Count | Gets or sets the number of items in the VirtualList object. |
| EnableSlowDataRequests | Gets or sets a value that indicates whether the slow data requests feature is enabled. |
| IsFixedSize | Gets a value that indicates whether the VirtualList object is a fixed size. |
| IsReadOnly | Gets a value that indicates whether the VirtualList object is read-only. |
| IsSynchronized | Gets a value that indicates whether the VirtualList object is thread-safe. |
| Item | Gets or sets an item from the VirtualList object. |
| RequestItemHandler | Gets or sets the item query handler, which allows for customized "get" logic without deriving and overriding the OnRequestItem method. |
| RequestSlowDataHandler | Gets or sets the event handler, which is raised when one of the items has been displayed on screen and is ready for deferred (partial) data updates. |
| StoreQueryResults | Determines whether the result of a RequestItem query should be stored in the VirtualList, which causes future queries to be faster. |
| SyncRoot | Gets the thread synchronization root. |
| UnavailableItem | Gets the object from a RequestItem query to inform the caller that the item cannot be retrieved. |
| VisualReleaseBehavior | Gets or sets the policy for data items after the visual items that were created for that item have been released. |
Remarks
This class also includes services for slow partial data loads.
Requirements
Reference: Microsoft.MediaCenter.UI
Namespace: Microsoft.MediaCenter.UI
Assembly: Microsoft.MediaCenter.UI.dll
Platform: Windows Vista Ultimate, Windows Vista Home Premium, and later
See Also