/// <summary>
/// Remove an item from the direct children of a group.
/// </summary>
/// <param name="group">Group to remove item from</param>
/// <param name="item">Item to remove</param>
/// <returns>True if item could not be removed</returns>
private bool RemoveFromGroupDirectly(CollectionViewGroupInternal group, object item)
{
int leafIndex = group.Remove(item, true);
if (leafIndex >= 0)
{
this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, item, leafIndex));
return(false);
}
else
{
return(true);
}
}
/// <summary>
/// Add an item to the desired subgroup(s) of the given group
/// </summary>
/// <param name="item">Item to add</param>
/// <param name="group">Group to add item to</param>
/// <param name="level">The level of grouping</param>
/// <param name="loading">Whether we are currently loading</param>
/// <param name="insertedBefore">The item to insert this item before,
/// or <c>null</c> if the item should be added at the end.</param>
private void AddToSubgroups(object item, CollectionViewGroupInternal group, int level, bool loading, object insertedBefore)
{
object name = this.GetGroupName(item, group.GroupBy, level);
ICollection nameList;
if (name == UseAsItemDirectly)
{
// the item belongs to the group itself (not to any subgroups)
if (loading)
{
group.Add(item);
}
else
{
int localIndex = -1;
// If we were given an item to insert before, find its index
// within the target group. If it's not in the group, we'll
// get -1 back, which we'll translate into putting the item
// at the end of the list.
if (insertedBefore != null)
{
localIndex = group.LeafIndexOf(insertedBefore);
}
if (localIndex == -1)
{
localIndex = group.ItemCount;
}
group.Insert(item, localIndex);
int index = group.LeafIndexFromItem(item, localIndex);
this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, item, index));
}
}
else if ((nameList = name as ICollection) == null)
{
// the item belongs to one subgroup
this.AddToSubgroup(item, group, level, name, loading, insertedBefore);
}
else
{
// the item belongs to multiple subgroups
foreach (object o in nameList)
{
this.AddToSubgroup(item, group, level, o, loading, insertedBefore);
}
}
}
//------------------------------------------------------
//
// Private Methods
//
//------------------------------------------------------
/// <summary>
/// Removes an empty group from the PagedCollectionView grouping
/// </summary>
/// <param name="group">Empty subgroup to remove</param>
private static void RemoveEmptyGroup(CollectionViewGroupInternal group)
{
CollectionViewGroupInternal parent = group.Parent;
if (parent != null)
{
GroupDescription groupBy = parent.GroupBy;
int index = parent.ProtectedItems.IndexOf(group);
// remove the subgroup unless it is one of the explicit groups
if (index >= groupBy.GroupNames.Count)
{
parent.Remove(group, false);
}
}
}
/// <summary>
/// The item did not appear in one or more of the subgroups it
/// was supposed to. This can happen if the item's properties
/// change so that the group names we used to insert it are
/// different from the names used to remove it. If this happens,
/// remove the item the hard way.
/// </summary>
/// <param name="group">Group to remove item from</param>
/// <param name="item">Item to remove</param>
private void RemoveItemFromSubgroupsByExhaustiveSearch(CollectionViewGroupInternal group, object item)
{
// try to remove the item from the direct children
// this function only returns true if it failed to remove from group directly
// in which case we will step through and search exhaustively
if (this.RemoveFromGroupDirectly(group, item))
{
// if that didn't work, recurse into each subgroup
// (loop runs backwards in case an entire group is deleted)
for (int k = group.Items.Count - 1; k >= 0; --k)
{
CollectionViewGroupInternal subgroup = group.Items[k] as CollectionViewGroupInternal;
if (subgroup != null)
{
this.RemoveItemFromSubgroupsByExhaustiveSearch(subgroup, item);
}
}
}
}
/// <summary>
/// Initialize the given group
/// </summary>
/// <param name="group">Group to initialize</param>
/// <param name="level">The level of grouping</param>
/// <param name="seedItem">The seed item to compare with to see where to insert</param>
private void InitializeGroup(CollectionViewGroupInternal group, int level, object seedItem)
{
// set the group description for dividing the group into subgroups
GroupDescription groupDescription = this.GetGroupDescription(group, level);
group.GroupBy = groupDescription;
// create subgroups for each of the explicit names
ObservableCollection <object> explicitNames =
(groupDescription != null) ? groupDescription.GroupNames : null;
if (explicitNames != null)
{
for (int k = 0, n = explicitNames.Count; k < n; ++k)
{
CollectionViewGroupInternal subgroup = new CollectionViewGroupInternal(explicitNames[k], group);
this.InitializeGroup(subgroup, level + 1, seedItem);
group.Add(subgroup);
}
}
group.LastIndex = 0;
}
/// <summary>
/// Returns the index of the given item within the list of leaves governed
/// by this group
/// </summary>
/// <param name="item">Item we are looking for</param>
/// <returns>Number of items under that leaf</returns>
internal int LeafIndexOf(object item)
{
int leaves = 0; // number of leaves we've passed over so far
for (int k = 0, n = Items.Count; k < n; ++k)
{
CollectionViewGroupInternal subgroup = Items[k] as CollectionViewGroupInternal;
if (subgroup != null)
{
int subgroupIndex = subgroup.LeafIndexOf(item);
if (subgroupIndex < 0)
{
leaves += subgroup.ItemCount; // item not in this subgroup
}
else
{
return(leaves + subgroupIndex); // item is in this subgroup
}
}
else
{
// current item is a leaf - compare it directly
if (Object.Equals(item, Items[k]))
{
return(leaves);
}
else
{
leaves += 1;
}
}
}
// item not found
return(-1);
}
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
/// <summary>
/// Initializes a new instance of the <see cref="CollectionViewGroupInternal"/> class.
/// </summary>
/// <param name="name">Name of the CollectionViewGroupInternal</param>
/// <param name="parent">Parent node of the CollectionViewGroup</param>
internal CollectionViewGroupInternal(object name, CollectionViewGroupInternal parent)
: base(name)
{
this._parentGroup = parent;
}
//------------------------------------------------------
//
// Private Methods
//
//------------------------------------------------------
/// <summary>
/// Add an item to the subgroup with the given name
/// </summary>
/// <param name="item">Item to add</param>
/// <param name="group">Group to add item to</param>
/// <param name="level">The level of grouping.</param>
/// <param name="name">Name of subgroup to add to</param>
/// <param name="loading">Whether we are currently loading</param>
/// <param name="insertedBefore">The item to insert this item before,
/// or <c>null</c> if the item should be added at the end.</param>
private void AddToSubgroup(object item, CollectionViewGroupInternal group, int level, object name, bool loading, object insertedBefore)
{
CollectionViewGroupInternal subgroup;
int index = (this._isDataInGroupOrder) ? group.LastIndex : 0;
// find the desired subgroup
for (int n = group.Items.Count; index < n; ++index)
{
subgroup = group.Items[index] as CollectionViewGroupInternal;
if (subgroup == null)
{
continue; // skip children that are not groups
}
if (group.GroupBy.NamesMatch(subgroup.Name, name))
{
group.LastIndex = index;
this.AddToSubgroups(item, subgroup, level + 1, loading, insertedBefore);
return;
}
}
// the item didn't match any subgroups. Create a new subgroup and add the item.
subgroup = new CollectionViewGroupInternal(name, group);
this.InitializeGroup(subgroup, level + 1, item);
if (loading)
{
group.Add(subgroup);
group.LastIndex = index;
}
else
{
if (insertedBefore != null && group.ItemCount > 0)
{
index = 0;
// If we were given an item to insert before, find its index
// within the target group. If it's not in the group, we'll
// get -1 back, which we'll translate into putting the item
// at the end of the list.
int itemIndex = group.LeafIndexOf(insertedBefore);
if (itemIndex == -1)
{
index = group.ItemCount;
}
else
{
// But if the item to be inserted before is within this
// group, then we need to find the correct group position
// for the insert. Iterate through the groups, finding
// the correct insert position.
CollectionViewGroupInternal nextGroup = ((CollectionViewGroupInternal)group.Items[index]);
while (itemIndex >= nextGroup.ItemCount)
{
itemIndex -= nextGroup.ItemCount;
// Increment the index and set the next group
nextGroup = ((CollectionViewGroupInternal)group.Items[++index]);
}
}
}
group.Insert(subgroup, index);
}
this.AddToSubgroups(item, subgroup, level + 1, loading, insertedBefore);
}
