/// <summary>
/// Expands a node recursively till all child/grandchild nodes are expanded.
/// All its parent nodes up to root must already be expanded.
/// Otherwise there is no effect.
/// </summary>
/// <param name="data">The data object that the target node contains</param>
public void ExpandItemRecursive(object data)
{
int index;
TreeGridViewItemInfo itemInfo = this.FindItemInfoForData(data, out index);
ExpandItemRecursiveInternal(itemInfo, index);
}
/// <summary>
/// Collapse a node containing the given data.
/// All its parent nodes up to root must already be expanded, including itself.
/// Otherwise there is no effect.
/// </summary>
/// <param name="data">The data object that the target node contains</param>
public void CollapseItem(object data)
{
// Collapse a node is a simple operation as to remove any following nodes whose level
// is bigger than this one, until a node with equal or smaller level value is reached.
// in the process if a removed node was expanded, we keep it in orphanExpandedItemsStore
int index;
TreeGridViewItemInfo itemInfo = this.FindItemInfoForData(data, out index);
bool focusRemoved = false;
if (itemInfo != null && itemInfo.IsExpanded)
{
int n = index + 1;
int count = 0;
while (n < this.itemInfoFlatList.Count)
{
var childInfo = this.itemInfoFlatList[n];
n++;
if (childInfo.Level > itemInfo.Level)
{
count++;
// before remove it, check if its selected or focused on
if (base.SelectedItem == childInfo)
{
// selected item is removed, select the parent item instead
base.SelectedItem = itemInfo;
}
if (this.focusItemInfo == childInfo)
{
this.focusItemInfo = null;
focusRemoved = true;
}
if (childInfo.IsExpanded)
{
this.orphanExpandedItemsStore.Add(childInfo.Data);
}
}
else
{
// equal or smaller Level value reached, no more child nodes
break;
}
}
if (count > 0)
{
itemInfo.IsExpanded = false;
if (focusRemoved)
{
this.restoreFocusItemInfo = itemInfo;
}
else
{
this.restoreFocusItemInfo = this.focusItemInfo;
}
this.itemInfoFlatList.RemoveRange(index + 1, count);
}
}
}
/// <summary>
/// Clean up the item container
/// </summary>
/// <param name="element">The TreeGridViewItem to be discarded</param>
/// <param name="item">The associated data object (TreeGridViewItemInfo)</param>
protected override void ClearContainerForItemOverride(DependencyObject element, object item)
{
TreeGridViewItemInfo info = item as TreeGridViewItemInfo;
TreeGridViewItem tgvi = element as TreeGridViewItem;
tgvi.ParentView = null;
base.ClearContainerForItemOverride(element, item);
}
public void ScrollItemIntoView(object data)
{
int index;
// Consider optimizing this for large lists...
TreeGridViewItemInfo info = this.FindItemInfoForData(data, out index);
if (info != null)
{
this.ScrollIntoView(info);
}
}
void ExpandFully()
{
if (this.ParentView != null)
{
TreeGridViewItemInfo info = this.DataContext as TreeGridViewItemInfo;
if (info != null)
{
this.ParentView.ExpandItemRecursive(info.Data);
this.IsExpanded = true;
}
}
}
void ExpandItemRecursiveInternal(TreeGridViewItemInfo itemInfo, int index)
{
// Expand a node recursively till the whole subtree under it are expanded
// this occurs when user press '*' on a node
// handling should be careful since the subtree may already be partially expanded
int partialExpandedCount = 0;
if (itemInfo != null)
{
var itemsToInsert = new List <TreeGridViewItemInfo>();
if (!itemInfo.IsExpanded)
{
this.GetChildItemInfoRecursive(itemInfo, itemsToInsert);
partialExpandedCount = 0;
}
else
{
int x = index + 1;
while (x < this.itemInfoFlatList.Count)
{
var childInfo = this.itemInfoFlatList[x];
x++;
if (childInfo.Level > itemInfo.Level)
{
partialExpandedCount++;
itemsToInsert.Add(childInfo);
if (!childInfo.IsExpanded)
{
this.GetChildItemInfoRecursive(childInfo, itemsToInsert);
}
}
else
{
break;
}
}
}
if (partialExpandedCount < itemsToInsert.Count)
{
// save focus
this.restoreFocusItemInfo = this.focusItemInfo;
// first collapse the item (in case it is partially expanded already)
if (partialExpandedCount > 0)
{
this.itemInfoFlatList.RemoveRange(index + 1, partialExpandedCount);
}
// insert the whole sub tree
this.itemInfoFlatList.InsertRange(index + 1, itemsToInsert);
}
}
}
// find parent item of specified item;
// look back to find the first item whose Level value is smaller than this one
private TreeGridViewItemInfo GetParentItemInfo(TreeGridViewItemInfo childInfo)
{
int childIndex = this.itemInfoFlatList.IndexOf(childInfo);
if (childIndex >= 0 && childIndex < this.itemInfoFlatList.Count)
{
for (int i = childIndex - 1; i >= 0; i--)
{
var parentInfo = this.itemInfoFlatList[i];
if (parentInfo.Level < childInfo.Level)
{
return(parentInfo);
}
}
}
return(null);
}
/// <summary>
/// Prepare the item container.
/// This is after ItemContainerGenerator created a TreeGridViewItem, and we have a chance to
/// do some intialization work
/// </summary>
/// <param name="element">The TreeGridViewItem that is newly created (or recycled)</param>
/// <param name="item">The data object associated (a TreeGridViewItemInfo object)</param>
protected override void PrepareContainerForItemOverride(DependencyObject element, object item)
{
TreeGridViewItemInfo info = item as TreeGridViewItemInfo;
TreeGridViewItem container = element as TreeGridViewItem;
if (info != null)
{
container.ParentView = this;
// initialize necessary properties
container.Level = info.Level;
container.IsExpanded = info.IsExpanded;
container.HasChildren = this.DataHasChildren(info.Data);
base.PrepareContainerForItemOverride(element, info.Data);
}
}
private void GetChildAndOrphanItemInfo(TreeGridViewItemInfo itemInfo, List <TreeGridViewItemInfo> appendList)
{
List <TreeGridViewItemInfo> childrenInfo = this.CreateChildItemInfoCollection(itemInfo);
if (childrenInfo != null && childrenInfo.Count > 0)
{
itemInfo.IsExpanded = true;
foreach (var c in childrenInfo)
{
appendList.Add(c);
if (this.orphanExpandedItemsStore.Contains(c.Data))
{
this.orphanExpandedItemsStore.Remove(c.Data);
this.GetChildAndOrphanItemInfo(c, appendList);
}
}
}
}
private void ItemContainerGenerator_StatusChanged(object sender, EventArgs e)
{
if (this.ItemContainerGenerator.Status == System.Windows.Controls.Primitives.GeneratorStatus.ContainersGenerated)
{
if (this.restoreFocusItemInfo != null)
{
TreeGridViewItem tgvi = this.ItemContainerGenerator.ContainerFromItem(this.restoreFocusItemInfo) as TreeGridViewItem;
if (tgvi != null)
{
if (this.IsFocused)
{
tgvi.Focus();
this.restoreFocusItemInfo = null;
}
}
}
}
}
/// <summary>
/// Move focus to parent item
/// </summary>
/// <param name="childItem">The currently focused item</param>
/// <returns>true if succeeds; otherwise false</returns>
internal bool FocusToParentItem(TreeGridViewItem childItem)
{
TreeGridViewItemInfo childInfo = this.ItemContainerGenerator.ItemFromContainer(childItem) as TreeGridViewItemInfo;
if (childInfo != null)
{
var parentInfo = this.GetParentItemInfo(childInfo);
if (parentInfo != null)
{
this.ScrollIntoView(parentInfo);
TreeGridViewItem parentContainer = this.ItemContainerGenerator.ContainerFromItem(parentInfo) as TreeGridViewItem;
if (parentContainer != null)
{
return(parentContainer.Focus());
}
}
}
return(false);
}
/// <summary>
/// Expands a node containing the given data.
/// All its parent/grandparent nodes up to root must already be expanded.
/// Otherwise there is no effect.
/// </summary>
/// <param name="data">The data object that the target node contains</param>
/// <returns>true if the item is already expanded, or the expand succeeds</returns>
public bool ExpandItem(object data)
{
/*
* additionally handles a special scenario:
* Assume a tree like this (-> denotes parent-child relationship):
* A(expanded) -> B(expanded) -> C
*
* now user collapse A, all child/grandchild nodes (including B and C) are removed from the flat list;
* later user expands A again, B is created (but default collapsed) and
* inserted after A into the list, but user expects B to be expanded as it was.
* So we need to furthur expand B as well.
* orphanExpandedItems is used to remember nodes like B (expanded before removed),
* whenever an item is expanded, we'll check in to orphanExpandedItems to see if any
* of the child items need further expansion, and so on.
* (as a matter of fact WPF TreeView internally does similar things.)
*/
int index;
TreeGridViewItemInfo itemInfo = this.FindItemInfoForData(data, out index);
if (itemInfo == null)
{
return(false);
}
if (itemInfo.IsExpanded)
{
return(true);
}
var itemsToInsert = new List <TreeGridViewItemInfo>();
this.GetChildAndOrphanItemInfo(itemInfo, itemsToInsert);
if (itemsToInsert.Count > 0)
{
// save focus and restore later
this.restoreFocusItemInfo = this.focusItemInfo;
this.itemInfoFlatList.InsertRange(index + 1, itemsToInsert);
}
return(true);
}
/// <summary>
/// Select/unselect a node.
/// All parent nodes up to root must already be expanded.
/// Otherwise there is no effect.
/// </summary>
/// <param name="data">The data that the target node contains</param>
/// <param name="selected">true: select the node; false: unselect the node</param>
public void SelectItem(object data, bool selected)
{
int index;
TreeGridViewItemInfo info = this.FindItemInfoForData(data, out index);
if (info != null)
{
this.ScrollIntoView(info);
this.Dispatcher.BeginInvoke(
(Action)(() =>
{
TreeGridViewItem container = this.ItemContainerGenerator.ContainerFromIndex(index) as TreeGridViewItem;
if (container != null)
{
container.IsSelected = selected;
}
}),
System.Windows.Threading.DispatcherPriority.Background);
}
}
// Get children items of an item;
// The binding path is expected from TreeGridView.ItemsTemplate which should be a HierarchicalDataTemplate,
// Use reflection to get the property value
private List <TreeGridViewItemInfo> CreateChildItemInfoCollection(TreeGridViewItemInfo info)
{
List <TreeGridViewItemInfo> result = null;
if (info == null || info.Data == null)
{
return(result);
}
IEnumerable childCollection = this.GetChildCollection(info.Data);
if (childCollection != null)
{
foreach (var c in childCollection)
{
if (result == null)
{
result = new List <TreeGridViewItemInfo>();
}
result.Add(new TreeGridViewItemInfo(c, info.Level + 1));
}
}
return(result);
}
/// <summary>
/// Called by an item to notify the view when it gets focus
/// The view has to know the currently focused item
/// </summary>
/// <param name="childItem">the child item got focus</param>
internal void NotifyItemGotFocus(TreeGridViewItem childItem)
{
this.focusItemInfo = this.ItemContainerGenerator.ItemFromContainer(childItem) as TreeGridViewItemInfo;
// clear the pending focus restore since a new focus is set by user
this.restoreFocusItemInfo = null;
}
