See Also: ICancelAddNew Members
The System.ComponentModel.ICancelAddNew interface enables a collection to add a new item in an extensible way. The new item subsequently can be committed or rolled back. The IBindingList.AddNew method of the collection is used to tentatively add the item, which is subsequently transacted through the following operations:
The ICancelAddNew.EndNew(int) method will explicitly commit the pending addition.
Performing another collection operation, such as an insertion, removal, or move will implicitly commit the pending addition.
The ICancelAddNew.CancelNew(int) method will roll back the pending addition if it has not already been committed.
In some scenarios, such as Windows Forms complex data binding, the collection may receive ICancelAddNew.CancelNew(int) or ICancelAddNew.EndNew(int) calls for items other than the newly added item. (Each item is typically a row in a data view.) Ignore these calls; cancel or commit the new item only when that item's index is specified.
There are two models that allow transactional addition of an item to a data-bound collection:
The older model relies directly on a collection that implements the System.ComponentModel.IBindingList interface and is data-bound directly using the System.Windows.Forms.CurrencyManager class. The System.Windows.Forms.CurrencyManager.AddNew, System.Windows.Forms.CurrencyManager.EndCurrentEdit, and System.Windows.Forms.CurrencyManager.CancelCurrentEdit methods of the System.Windows.Forms.CurrencyManager class are responsible for transactional support for adding new items. However, this functionality depends upon the items supporting transactional behavior through the System.ComponentModel.IEditableObject interface. If the items do not support this interface, the item will always be added to the list, regardless of subsequent calls to System.Windows.Forms.CurrencyManager.CancelCurrentEdit.
The newer model supports a more robust data-binding scenario through the generic System.ComponentModel.BindingList`1 class, which implements the System.ComponentModel.IBindingList and System.ComponentModel.ICancelAddNew interfaces. In this case, the transactional support is managed by the System.ComponentModel.BindingList`1 collection directly.