How to remove all elements from NSTreeController with NSOutlineController

I am using NSTreeController with NSOutlineController to display contents in 1parent-1child hierarchy. My structure is like this:

- parent

- child

- parent

- child

Now when user press a refresh button, I want to remove all the nodes and refill it again.

[[treeController arrangedObjects] removeAllItems];
[[treeController arrangedObjects] removeAllObjects];

but nothings seems to be working.

I guess binging NSTreeControll开发者_JS百科er with NSArrayController should help but I really don't know steps to bind -NSArrayController-NSTreeController-NSOutlineController.

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I do it all the time with unbound lists.

Simple to clear the list:

[treeController setContent:nil];

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From the documentation for the content property:

The value of this property can be an array of objects, or a single root object. The default value is nil.

If your content is an array (presumably an NSMutableArray), then

[treeController.content removeAllObjects];

would be appropriate. Setting it to nil removes the underlying container. If your content is a single object, then

treeController.content = nil;

is the correct choice.