You can use this method to clear the entire collection of tree nodes from a tree view.
To remove an individual tree node from the collection, use the TreeNodeCollection.Remove(TreeNode) or TreeNodeCollection.RemoveAt(int) methods.
To add new System.Windows.Forms.TreeNode objects to the collection, use the TreeNodeCollection.Add(string), TreeNodeCollection.AddRange(TreeNode[]), or TreeNodeCollection.Insert(int, TreeNode) methods.