private void TheTreeView_PreviewSelectionChanged(object sender, PreviewSelectionChangedEventArgs e)
{
if (LockSelectionCheck.IsChecked == true)
{
// The current selection is locked by user request (Lock CheckBox is checked).
// Don't allow any changes to the selection at all.
e.CancelThis = true;
}
else
{
// Selection is not locked, apply other conditions.
// Require all selected items to be of the same type. If an item of another data
// type is already selected, don't include this new item in the selection.
if (e.Selecting && TheTreeView.SelectedItems.Count > 0)
{
e.CancelThis = e.Item.GetType() != TheTreeView.SelectedItems[0].GetType();
}
}
//if (e.Selecting)
//{
// System.Diagnostics.Debug.WriteLine("Preview: Selecting " + e.Item + (e.Cancel ? " - cancelled" : ""));
//}
//else
//{
// System.Diagnostics.Debug.WriteLine("Preview: Deselecting " + e.Item + (e.Cancel ? " - cancelled" : ""));
//}
}
public bool SelectCore(MultiSelectTreeViewItem item)
{
if (treeView.SelectedItems.Count > 0)
{
foreach (var selItem in new ArrayList(treeView.SelectedItems))
{
var e2 = new PreviewSelectionChangedEventArgs(false, selItem);
OnPreviewSelectionChanged(e2);
if (e2.CancelAll)
{
FocusHelper.Focus(item);
return(false);
}
if (!e2.CancelThis)
{
treeView.SelectedItems.Remove(selItem);
}
}
}
var e = new PreviewSelectionChangedEventArgs(true, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
FocusHelper.Focus(item, true);
return(false);
}
treeView.SelectedItems.Add(item.DataContext);
FocusHelper.Focus(item, true);
return(true);
}
internal bool DeselectRecursive(MultiSelectTreeViewItem item, bool includeSelf)
{
List <MultiSelectTreeViewItem> selectedChildren = new List <MultiSelectTreeViewItem>();
if (includeSelf)
{
if (item.IsSelected)
{
var e = new PreviewSelectionChangedEventArgs(false, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
return(false);
}
selectedChildren.Add(item);
}
}
if (!CollectDeselectRecursive(item, selectedChildren))
{
return(false);
}
foreach (var child in selectedChildren)
{
child.IsSelected = false;
}
return(true);
}
private bool CollectDeselectRecursive(MultiSelectTreeViewItem item, List <MultiSelectTreeViewItem> selectedChildren)
{
foreach (var child in item.Items)
{
MultiSelectTreeViewItem tvi = item.ItemContainerGenerator.ContainerFromItem(child) as MultiSelectTreeViewItem;
if (tvi != null)
{
if (tvi.IsSelected)
{
var e = new PreviewSelectionChangedEventArgs(false, child);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
return(false);
}
selectedChildren.Add(tvi);
}
if (!CollectDeselectRecursive(tvi, selectedChildren))
{
return(false);
}
}
}
return(true);
}
protected void OnPreviewSelectionChanged(PreviewSelectionChangedEventArgs e)
{
var handler = PreviewSelectionChanged;
if (handler != null)
{
handler(this, e);
}
}
internal bool ClearSelectionByRectangle()
{
foreach (var item in new ArrayList(SelectedItems))
{
var e = new PreviewSelectionChangedEventArgs(false, item);
OnPreviewSelectionChanged(e);
if (e.CancelAny) return false;
}
SelectedItems.Clear();
return true;
}
public bool Deselect(MultiSelectTreeViewItem item, bool bringIntoView = false)
{
var e = new PreviewSelectionChangedEventArgs(false, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
return(false);
}
treeView.SelectedItems.Remove(item.DataContext);
FocusHelper.Focus(item, bringIntoView);
return(true);
}
public bool Deselect(MultiSelectTreeViewItem item, bool bringIntoView = false)
{
var e = new PreviewSelectionChangedEventArgs(false, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny) return false;
treeView.SelectedItems.Remove(item.DataContext);
if (item.DataContext == lastShiftRoot)
{
lastShiftRoot = null;
}
FocusHelper.Focus(item, bringIntoView);
return true;
}
internal bool SelectByRectangle(MultiSelectTreeViewItem item)
{
var e = new PreviewSelectionChangedEventArgs(true, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
lastShiftRoot = item.DataContext;
return(false);
}
if (!treeView.SelectedItems.Contains(item.DataContext))
{
treeView.SelectedItems.Add(item.DataContext);
}
lastShiftRoot = item.DataContext;
return(true);
}
internal bool DeselectByRectangle(MultiSelectTreeViewItem item)
{
var e = new PreviewSelectionChangedEventArgs(false, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
lastShiftRoot = item.DataContext;
return(false);
}
treeView.SelectedItems.Remove(item.DataContext);
if (item.DataContext == lastShiftRoot)
{
lastShiftRoot = null;
}
return(true);
}
public bool ClearSelection()
{
if (SelectedItems.Count > 0)
{
foreach (var selItem in SelectedItems)
{
var e = new PreviewSelectionChangedEventArgs(false, selItem);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
return false;
}
}
SelectedItems.Clear();
}
return true;
}
public bool ClearSelection()
{
if (SelectedItems.Count > 0)
{
// Make a copy of the list and ignore changes to the selection while raising events
foreach (var selItem in new ArrayList(SelectedItems))
{
var e = new PreviewSelectionChangedEventArgs(false, selItem);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
return(false);
}
}
SelectedItems.Clear();
}
return(true);
}
public bool SelectAllFromKey()
{
var items = MultiSelectTreeView.RecursiveTreeViewItemEnumerable(treeView, false, false).ToList();
// Add new selected items
foreach (var item in items.Where(i => !treeView.SelectedItems.Contains(i.DataContext)))
{
var e = new PreviewSelectionChangedEventArgs(true, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAll)
{
return(false);
}
if (!e.CancelThis)
{
treeView.SelectedItems.Add(item.DataContext);
}
}
return(true);
}
public bool SelectCurrentBySpace()
{
var item = GetFocusedItem();
var e = new PreviewSelectionChangedEventArgs(true, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
FocusHelper.Focus(item, true);
return(false);
}
item.IsSelected = true;
if (!treeView.SelectedItems.Contains(item.DataContext))
{
treeView.SelectedItems.Add(item.DataContext);
}
FocusHelper.Focus(item, true);
return(true);
}
public bool SelectCurrentBySpace()
{
// Another item was focused by Ctrl+Arrow key
var item = GetFocusedItem();
if (treeView.SelectedItems.Contains(item.DataContext))
{
// With Ctrl key, toggle this item selection (deselect now).
// Without Ctrl key, always select it (is already selected).
if (IsControlKeyDown)
{
if (!Deselect(item, true))
{
return(false);
}
item.IsSelected = false;
}
}
else
{
var e = new PreviewSelectionChangedEventArgs(true, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
FocusHelper.Focus(item, true);
return(false);
}
item.IsSelected = true;
if (!treeView.SelectedItems.Contains(item.DataContext))
{
treeView.SelectedItems.Add(item.DataContext);
}
}
FocusHelper.Focus(item, true);
return(true);
}
public bool Select(MultiSelectTreeViewItem item)
{
if (IsControlKeyDown)
{
if (treeView.SelectedItems.Contains(item.DataContext))
{
return(Deselect(item, true));
}
else
{
var e = new PreviewSelectionChangedEventArgs(true, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
FocusHelper.Focus(item, true);
return(false);
}
return(SelectCore(item));
}
}
else
{
if (treeView.SelectedItems.Count == 1 &&
treeView.SelectedItems[0] == item.DataContext)
{
// Requested to select the single already-selected item. Don't change the selection.
FocusHelper.Focus(item, true);
lastShiftRoot = item.DataContext;
return(true);
}
else
{
return(SelectCore(item));
}
}
}
public bool Select(MultiSelectTreeViewItem item)
{
if (IsControlKeyDown)
{
if (treeView.SelectedItems.Contains(item.DataContext))
{
return Deselect(item, true);
}
else
{
var e = new PreviewSelectionChangedEventArgs(true, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
FocusHelper.Focus(item, true);
return false;
}
return SelectCore(item);
}
}
else
{
if (treeView.SelectedItems.Count == 1 &&
treeView.SelectedItems[0] == item.DataContext)
{
// Requested to select the single already-selected item. Don't change the selection.
FocusHelper.Focus(item, true);
lastShiftRoot = item.DataContext;
return true;
}
else
{
return SelectCore(item);
}
}
}
internal bool DeselectRecursive(MultiSelectTreeViewItem item, bool includeSelf)
{
List<MultiSelectTreeViewItem> selectedChildren = new List<MultiSelectTreeViewItem>();
if (includeSelf)
{
if (item.IsSelected)
{
var e = new PreviewSelectionChangedEventArgs(false, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
return false;
}
selectedChildren.Add(item);
}
}
if (!CollectDeselectRecursive(item, selectedChildren))
{
return false;
}
foreach (var child in selectedChildren)
{
child.IsSelected = false;
}
return true;
}
public bool SelectCore(MultiSelectTreeViewItem item)
{
if (IsControlKeyDown)
{
if (!treeView.SelectedItems.Contains(item.DataContext))
{
treeView.SelectedItems.Add(item.DataContext);
}
lastShiftRoot = item.DataContext;
}
else if (IsShiftKeyDown && treeView.SelectedItems.Count > 0)
{
object firstSelectedItem = lastShiftRoot ?? treeView.SelectedItems.First();
MultiSelectTreeViewItem shiftRootItem = treeView.GetTreeViewItemsFor(new List <object> {
firstSelectedItem
}).First();
var newSelection = treeView.GetNodesToSelectBetween(shiftRootItem, item).Select(n => n.DataContext).ToList();
// Make a copy of the list because we're modifying it while enumerating it
var selectedItems = new object[treeView.SelectedItems.Count];
treeView.SelectedItems.CopyTo(selectedItems, 0);
// Remove all items no longer selected
foreach (var selItem in selectedItems.Where(i => !newSelection.Contains(i)))
{
var e = new PreviewSelectionChangedEventArgs(false, selItem);
OnPreviewSelectionChanged(e);
if (e.CancelAll)
{
FocusHelper.Focus(item);
return(false);
}
if (!e.CancelThis)
{
treeView.SelectedItems.Remove(selItem);
}
}
// Add new selected items
foreach (var newItem in newSelection.Where(i => !selectedItems.Contains(i)))
{
var e = new PreviewSelectionChangedEventArgs(true, newItem);
OnPreviewSelectionChanged(e);
if (e.CancelAll)
{
FocusHelper.Focus(item, true);
return(false);
}
if (!e.CancelThis)
{
treeView.SelectedItems.Add(newItem);
}
}
}
else
{
if (treeView.SelectedItems.Count > 0)
{
foreach (var selItem in new ArrayList(treeView.SelectedItems))
{
var e2 = new PreviewSelectionChangedEventArgs(false, selItem);
OnPreviewSelectionChanged(e2);
if (e2.CancelAll)
{
FocusHelper.Focus(item);
lastShiftRoot = item.DataContext;
return(false);
}
if (!e2.CancelThis)
{
treeView.SelectedItems.Remove(selItem);
}
}
}
var e = new PreviewSelectionChangedEventArgs(true, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
FocusHelper.Focus(item, true);
lastShiftRoot = item.DataContext;
return(false);
}
treeView.SelectedItems.Add(item.DataContext);
lastShiftRoot = item.DataContext;
}
FocusHelper.Focus(item, true);
return(true);
}
protected void OnPreviewSelectionChanged(PreviewSelectionChangedEventArgs e)
{
var handler = PreviewSelectionChanged;
handler?.Invoke(this, e);
}
protected virtual void OnPreviewSelectionChanged(PreviewSelectionChangedEventArgs e)
{
e.RoutedEvent = PreviewSelectionChangedEvent;
RaiseEvent(e);
}
protected void OnPreviewSelectionChanged(PreviewSelectionChangedEventArgs e)
{
var handler = PreviewSelectionChanged;
if (handler != null)
{
handler(this, e);
LastCancelAll = e.CancelAll;
}
}
internal bool SelectByRectangle(MultiSelectTreeViewItem item)
{
var e = new PreviewSelectionChangedEventArgs(true, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
lastShiftRoot = item.DataContext;
return false;
}
if (!treeView.SelectedItems.Contains(item.DataContext))
{
treeView.SelectedItems.Add(item.DataContext);
}
lastShiftRoot = item.DataContext;
return true;
}
internal bool DeselectByRectangle(MultiSelectTreeViewItem item)
{
var e = new PreviewSelectionChangedEventArgs(false, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
lastShiftRoot = item.DataContext;
return false;
}
treeView.SelectedItems.Remove(item.DataContext);
if (item.DataContext == lastShiftRoot)
{
lastShiftRoot = null;
}
return true;
}
public bool SelectCurrentBySpace()
{
// Another item was focused by Ctrl+Arrow key
var item = GetFocusedItem();
if (treeView.SelectedItems.Contains(item.DataContext))
{
// With Ctrl key, toggle this item selection (deselect now).
// Without Ctrl key, always select it (is already selected).
if (IsControlKeyDown)
{
if (!Deselect(item, true)) return false;
item.IsSelected = false;
}
}
else
{
var e = new PreviewSelectionChangedEventArgs(true, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
FocusHelper.Focus(item, true);
return false;
}
item.IsSelected = true;
if (!treeView.SelectedItems.Contains(item.DataContext))
{
treeView.SelectedItems.Add(item.DataContext);
}
}
FocusHelper.Focus(item, true);
return true;
}
internal bool ClearSelectionByRectangle()
{
foreach (var item in new ArrayList(SelectedItems))
{
var e = new PreviewSelectionChangedEventArgs(false, item);
OnPreviewSelectionChanged(e);
if (e.CancelAny) return false;
}
SelectedItems.Clear();
return true;
}
private bool CollectDeselectRecursive(MultiSelectTreeViewItem item, List<MultiSelectTreeViewItem> selectedChildren)
{
foreach (var child in item.Items)
{
MultiSelectTreeViewItem tvi = item.ItemContainerGenerator.ContainerFromItem(child) as MultiSelectTreeViewItem;
if (tvi != null)
{
if (tvi.IsSelected)
{
var e = new PreviewSelectionChangedEventArgs(false, child);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
return false;
}
selectedChildren.Add(tvi);
}
if (!CollectDeselectRecursive(tvi, selectedChildren))
{
return false;
}
}
}
return true;
}
private void PreviewSelectionChangedHandler(object sender, PreviewSelectionChangedEventArgs e)
{
OnPreviewSelectionChanged(e);
}
public bool SelectCore(MultiSelectTreeViewItem item)
{
if (IsControlKeyDown)
{
if (!treeView.SelectedItems.Contains(item.DataContext))
{
treeView.SelectedItems.Add(item.DataContext);
}
lastShiftRoot = item.DataContext;
}
else if (IsShiftKeyDown && treeView.SelectedItems.Count > 0)
{
object firstSelectedItem = lastShiftRoot ?? treeView.SelectedItems.First();
MultiSelectTreeViewItem shiftRootItem = treeView.GetTreeViewItemsFor(new List<object> { firstSelectedItem }).First();
var newSelection = treeView.GetNodesToSelectBetween(shiftRootItem, item).Select(n => n.DataContext).ToList();
// Make a copy of the list because we're modifying it while enumerating it
var selectedItems = new object[treeView.SelectedItems.Count];
treeView.SelectedItems.CopyTo(selectedItems, 0);
// Remove all items no longer selected
foreach (var selItem in selectedItems.Where(i => !newSelection.Contains(i)))
{
var e = new PreviewSelectionChangedEventArgs(false, selItem);
OnPreviewSelectionChanged(e);
if (e.CancelAll)
{
FocusHelper.Focus(item);
return false;
}
if (!e.CancelThis)
{
treeView.SelectedItems.Remove(selItem);
}
}
// Add new selected items
foreach (var newItem in newSelection.Where(i => !selectedItems.Contains(i)))
{
var e = new PreviewSelectionChangedEventArgs(true, newItem);
OnPreviewSelectionChanged(e);
if (e.CancelAll)
{
FocusHelper.Focus(item, true);
return false;
}
if (!e.CancelThis)
{
treeView.SelectedItems.Add(newItem);
}
}
}
else
{
if (treeView.SelectedItems.Count > 0)
{
foreach (var selItem in new ArrayList(treeView.SelectedItems))
{
var e2 = new PreviewSelectionChangedEventArgs(false, selItem);
OnPreviewSelectionChanged(e2);
if (e2.CancelAll)
{
FocusHelper.Focus(item);
lastShiftRoot = item.DataContext;
return false;
}
if (!e2.CancelThis)
{
treeView.SelectedItems.Remove(selItem);
}
}
}
var e = new PreviewSelectionChangedEventArgs(true, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
FocusHelper.Focus(item, true);
lastShiftRoot = item.DataContext;
return false;
}
treeView.SelectedItems.Add(item.DataContext);
lastShiftRoot = item.DataContext;
}
FocusHelper.Focus(item, true);
return true;
}
public bool ClearSelection()
{
if (SelectedItems.Count > 0)
{
foreach (var selItem in SelectedItems)
{
var e = new PreviewSelectionChangedEventArgs(false, selItem);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
return false;
}
}
SelectedItems.Clear();
}
return true;
}
public bool SelectAllFromKey()
{
var items = MultiSelectTreeView.RecursiveTreeViewItemEnumerable(treeView, false, false).ToList();
// Add new selected items
foreach (var item in items.Where(i => !treeView.SelectedItems.Contains(i.DataContext)))
{
var e = new PreviewSelectionChangedEventArgs(true, item.DataContext);
OnPreviewSelectionChanged(e);
if (e.CancelAll)
{
return false;
}
if (!e.CancelThis)
{
treeView.SelectedItems.Add(item.DataContext);
}
}
return true;
}
public bool ClearSelection()
{
if (SelectedItems.Count > 0)
{
// Make a copy of the list and ignore changes to the selection while raising events
foreach (var selItem in new ArrayList(SelectedItems))
{
var e = new PreviewSelectionChangedEventArgs(false, selItem);
OnPreviewSelectionChanged(e);
if (e.CancelAny)
{
return false;
}
}
SelectedItems.Clear();
}
return true;
}