/// <summary>
/// Expands one path in the tree and selects a particular TreeViewItem.
/// </summary>
/// <param name="sender">The Button clicked.</param>
/// <param name="e">Parameters associated to the Button click.</param>
private void SelectOne(object sender, RoutedEventArgs e)
{
ObjectCollection treeOfLifeCollection = (ObjectCollection)this.Resources["treeOfLife"];
TaxonomyViewModel elementToExpand = (TaxonomyViewModel)((TaxonomyViewModel)treeOfLifeCollection[2]).Subclasses[3].Subclasses[0].Subclasses[0].Subclasses[0];
// This iterates through the three top-level items only.
foreach (TaxonomyViewModel item in treeView.Items)
{
if (item.ExpandSuperclasses(elementToExpand))
{
elementToExpand.IsSelected = true;
break;
}
}
}
/// <summary>
/// This helper method traverses the tree in a depth-first non-recursive way
/// and executes the action passed as a parameter on each item.
/// </summary>
/// <param name="itemAction">Action to be executed for each item.</param>
private void ApplyActionToAllItems(Action <TaxonomyViewModel> itemAction)
{
Stack <TaxonomyViewModel> dataItemStack = new Stack <TaxonomyViewModel>();
dataItemStack.Push(this);
while (dataItemStack.Count != 0)
{
TaxonomyViewModel currentItem = dataItemStack.Pop();
itemAction(currentItem);
foreach (TaxonomyViewModel childItem in currentItem.Subclasses)
{
dataItemStack.Push(childItem);
}
}
}
/// <summary>
/// This helper method uses recursion to look for the element passed as a parameter in the view model
/// hierarchy and executes the action passed as a parameter to its entire ancestor chain (excluding
/// the item itself).
/// </summary>
/// <param name="itemToLookFor">The element this method will look for.</param>
/// <param name="itemAction">Action to be executed on each superclass in the ancestor chain.</param>
/// <returns>True if it the itemToLookFor was found, false otherwise.</returns>
private bool ApplyActionToSuperclasses(TaxonomyViewModel itemToLookFor, Action <TaxonomyViewModel> itemAction)
{
if (itemToLookFor == this)
{
return(true);
}
else
{
foreach (TaxonomyViewModel subclass in this.Subclasses)
{
bool foundItem = subclass.ApplyActionToSuperclasses(itemToLookFor, itemAction);
if (foundItem)
{
itemAction(this);
return(true);
}
}
return(false);
}
}
/// <summary>
/// This method sets IsExpanded to true for each element in the ancestor chain of the item
/// passed as a parameter.
/// </summary>
/// <param name="itemToLookFor">The element this method will look for.</param>
/// <returns>True if it the itemToLookFor was found, false otherwise.</returns>
public bool ExpandSuperclasses(TaxonomyViewModel itemToLookFor)
{
return(ApplyActionToSuperclasses(itemToLookFor, superclass => superclass.IsExpanded = true));
}