public static void IsDragSelectingEnabledPropertyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
{
ListBox listBox = o as ListBox;
bool isDragSelectionEnabled = DragSelectionHelper.GetIsDragSelectionEnabled(listBox);
// if DragSelection is enabled
if (isDragSelectionEnabled)
{
// set the listbox's selection mode to multiple ( didn't work with extended )
listBox.SelectionMode = SelectionMode.Multiple;
// set the static listbox property
DragSelectionHelper.ListBox = listBox;
// and subscribe to the required events to handle the drag selection and the attached properties
listBox.PreviewMouseLeftButtonDown += new MouseButtonEventHandler(DragSelectionHelper.listBox_PreviewMouseLeftButtonDown);
listBox.PreviewMouseRightButtonDown += new MouseButtonEventHandler(listBox_PreviewMouseRightButtonDown);
listBox.MouseLeftButtonUp += new MouseButtonEventHandler(DragSelectionHelper.listBox_MouseLeftButtonUp);
}
else // is selection is disabled
{
// set selection mode to the default
listBox.SelectionMode = SelectionMode.Single;
// dereference the listbox
DragSelectionHelper.ListBox = null;
// unsuscribe from the events
listBox.PreviewMouseLeftButtonDown -= new MouseButtonEventHandler(DragSelectionHelper.listBox_PreviewMouseLeftButtonDown);
listBox.MouseLeftButtonUp -= new MouseButtonEventHandler(DragSelectionHelper.listBox_MouseLeftButtonUp);
listBox.MouseLeftButtonUp -= new MouseButtonEventHandler(DragSelectionHelper.listBox_MouseLeftButtonUp);
}
}
public static void IsDragClickStartedPropertyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
{
bool isDragClickStarted = DragSelectionHelper.GetIsDragClickStarted(DragSelectionHelper.ListBox);
// if click has been drag click has started, clear the current selected items and start drag selection operation again
if (isDragClickStarted)
{
DragSelectionHelper.ListBox.SelectedItems.Clear();
}
}
public static void IsDragSelectingPropertyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
{
StackPanel item = o as StackPanel;
bool clickInitiated = DragSelectionHelper.GetIsDragClickStarted(DragSelectionHelper.ListBox);
// this is where the item.Parent was null, it was supposed to be the ListBox, I guess it's null because items are not
// really StackPanels but are wells
if (clickInitiated)
{
bool isDragSelecting = DragSelectionHelper.GetIsDragSelecting(item);
if (isDragSelecting)
{
// using the ListBox static reference because could not get to it through the item.Parent property
DragSelectionHelper.ListBox.SelectedItems.Add(item);
}
}
}
private static void listBox_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
// notify the helper class that the list box has terminated the drag click
DragSelectionHelper.SetIsDragClickStarted(DragSelectionHelper.ListBox, false);
}
private static void listBox_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
// notify the helper class that the listbox has initiated the drag click
DragSelectionHelper.SetIsDragClickStarted(DragSelectionHelper.ListBox, true);
}