Use the Clear method to clear the entire nodes collection. Use the Remove method to remove a specific node in the collection. The ClearAssistants method clears the assistant nodes collection. Use the ShowAssistants property to hide all assistant nodes. Use the Expanded property to expand or collapse a node. Use the Count property to count the nodes in the collection. Use the Item property to access a node giving its index or its key. Use the Index property to get the index of the node. Use the Key property to specify the key of the node.