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Why does ListBox.ObjectCollection and ListView.ListViewItemCollection have AddRange but not InsertRange or RemoveRange?

So both ListBox.ObjectCollection

and ListView.ListViewItemCollection

implement a class IList

that provides methods Add

and Remove

, but not AddRange

, InsertRange

or RemoveRange

. However, ListBox.ObjectCollection

and ListView.ListViewItemCollection

also provide a method AddRange

- simply not InsertRange

or RemoveRange

.

Take a look at a class ArrayList

that, in addition to implementation IList

, also provides AddRange

, InsertRange

and RemoveRange

. The same difference exists between the generic forms of this class and the interface, List<T>

(which has AddRange

, InsertRange

and RemoveRange

) and IList<T>

(which only provides Add

and Remove

).

I can understand interfaces IList

and IList<T>

without providing AddRange

etc. is just an interface; All that exceeds the minimum requirements Add

, Remove

, RemoveAt

etc., is optional. But given the usefulness of methods *Range

for classes ArrayList

and List<T>

and considering how convenient they are for controls ListBox

and ListView

, I wonder why they don't exist for those controls.

Somebody knows? Is there something about internal implementation InsertRange

and RemoveRange

what makes these methods less efficient, more complex, or less suitable for ListBox.ObjectCollection

and with ListView.ListViewItemCollection

what AddRange

?

To be clear: I'm not looking for the speculation "Looks like somebody at Microsoft has gotten lazy"; rather, I'm wondering if anyone knows of a legitimate distinction between AddRange

and InsertRange

/ RemoveRange

that might explain the lack of these latter methods from ListBox.ObjectCollection

and ListView.ListViewItemCollection

.

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1 answer


  • In general, a rather rare scenario for using InsertRange and (even more so) RemoveRange. If RemoveRange, for example, removes a given range only if there is a contiguous range of elements similar to the given range, or should it delete these elements one by one?

  • These methods are usually easy to implement if you need them. With extension methods, you can make them look almost like native methods.

  • There are no signs in the code to indicate that it would be difficult to implement these methods (as well as thousands of other "useful" methods). In fact, the implementation ListView

    InsertItems

    even accepts an array of elements under the hood. Only the standard ListViewItemCollection.Insert()

    always provides an array with 1 element. Take a look with reflector at ListViewNativeItemCollection.Insert()

    :

     public ListViewItem Insert(int index, ListViewItem item)
 {
     //Various checks excluded ....
     this.owner.InsertItems(index, new ListViewItem[] { item }, true);
     //More code excluded .....
     return item;
 }

I guess it wasn't that important to the implementation of this feature ... so they didn't.



As Eric Lippert likes to say , "because no one has ever designed, defined, implemented, tested, documented or posted this feature."

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