| public static GetDragDropCopyKeyState ( UIElement target ) : DragDropKeyStates | ||
| target | UIElement | |
| return | DragDropKeyStates | |
/// <summary>
/// Initializes a new instance of the DragInfo class.
/// </summary>
/// <param name="sender">The sender of the input event that initiated the drag operation.</param>
/// <param name="originalSource">The original source of the input event.</param>
/// <param name="mouseButton">The mouse button which was used for the drag operation.</param>
/// <param name="getPosition">A function of the input event which is used to get drag position points.</param>
public DragInfo(object sender, object originalSource, MouseButton mouseButton, Func <IInputElement, Point> getPosition)
{
this.MouseButton = mouseButton;
this.Effects = DragDropEffects.None;
this.VisualSource = sender as UIElement;
this.DragStartPosition = getPosition(this.VisualSource);
this.DragDropCopyKeyState = DragDrop.GetDragDropCopyKeyState(this.VisualSource);
var dataFormat = DragDrop.GetDataFormat(this.VisualSource);
if (dataFormat != null)
{
this.DataFormat = dataFormat;
}
var sourceElement = originalSource as UIElement;
// If we can't cast object as a UIElement it might be a FrameworkContentElement, if so try and use its parent.
if (sourceElement == null && originalSource is FrameworkContentElement frameworkContentElement)
{
sourceElement = frameworkContentElement.Parent as UIElement;
}
if (sender is ItemsControl itemsControl)
{
this.SourceGroup = itemsControl.FindGroup(this.DragStartPosition);
this.VisualSourceFlowDirection = itemsControl.GetItemsPanelFlowDirection();
UIElement item = null;
if (sourceElement != null)
{
item = itemsControl.GetItemContainer(sourceElement);
}
if (item == null)
{
var itemPosition = this.DragStartPosition;
if (DragDrop.GetDragDirectlySelectedOnly(this.VisualSource))
{
item = itemsControl.GetItemContainerAt(itemPosition);
}
else
{
item = itemsControl.GetItemContainerAt(itemPosition, itemsControl.GetItemsPanelOrientation());
if (item.IsDragSourceIgnored())
{
item = null;
}
}
}
if (item != null)
{
// Remember the relative position of the item being dragged
this.PositionInDraggedItem = getPosition(item);
var itemParent = ItemsControl.ItemsControlFromItemContainer(item);
if (itemParent != null)
{
this.SourceCollection = itemParent.ItemsSource ?? itemParent.Items;
if (itemParent != itemsControl)
{
if (item is TreeViewItem tvItem)
{
var tv = tvItem.GetVisualAncestor <TreeView>();
if (tv != null && tv != itemsControl && !tv.IsDragSource())
{
return;
}
}
else if (itemsControl.ItemContainerGenerator.IndexFromContainer(itemParent) < 0 && !itemParent.IsDragSource())
{
return;
}
}
this.SourceIndex = itemParent.ItemContainerGenerator.IndexFromContainer(item);
this.SourceItem = itemParent.ItemContainerGenerator.ItemFromContainer(item);
}
else
{
this.SourceIndex = -1;
}
var selectedItems = itemsControl.GetSelectedItems().OfType <object>().Where(i => i != CollectionView.NewItemPlaceholder).ToList();
this.SourceItems = selectedItems;
// Some controls (I'm looking at you TreeView!) haven't updated their
// SelectedItem by this point. Check to see if there 1 or less item in
// the SourceItems collection, and if so, override the control's SelectedItems with the clicked item.
//
// The control has still the old selected items at the mouse down event, so we should check this and give only the real selected item to the user.
if (selectedItems.Count <= 1 || this.SourceItem != null && !selectedItems.Contains(this.SourceItem))
{
this.SourceItems = Enumerable.Repeat(this.SourceItem, 1);
}
this.VisualSourceItem = item;
}
else
{
this.SourceCollection = itemsControl.ItemsSource ?? itemsControl.Items;
}
}
else
{
this.SourceItem = (sender as FrameworkElement)?.DataContext;
if (this.SourceItem != null)
{
this.SourceItems = Enumerable.Repeat(this.SourceItem, 1);
}
this.VisualSourceItem = sourceElement;
this.PositionInDraggedItem = sourceElement != null?getPosition(sourceElement) : this.DragStartPosition;
}
this.SourceItems ??= Enumerable.Empty <object>();
}
/// <summary>
/// Initializes a new instance of the DragInfo class.
/// </summary>
///
/// <param name="sender">
/// The sender of the mouse event that initiated the drag.
/// </param>
///
/// <param name="e">
/// The mouse event that initiated the drag.
/// </param>
public DragInfo(object sender, MouseButtonEventArgs e)
{
this.DragStartPosition = e.GetPosition((IInputElement)sender);
this.Effects = DragDropEffects.None;
this.MouseButton = e.ChangedButton;
this.VisualSource = sender as UIElement;
this.DragDropCopyKeyState = DragDrop.GetDragDropCopyKeyState(this.VisualSource);
if (sender is ItemsControl)
{
var itemsControl = (ItemsControl)sender;
this.SourceGroup = itemsControl.FindGroup(this.DragStartPosition);
this.VisualSourceFlowDirection = itemsControl.GetItemsPanelFlowDirection();
var sourceItem = e.OriginalSource as UIElement; // If we can't cast object as a UIElement it might be a FrameworkContentElement, if so try and use its parent.
if (sourceItem == null && e.OriginalSource is FrameworkContentElement)
{
sourceItem = ((FrameworkContentElement)e.OriginalSource).Parent as UIElement;
}
UIElement item = null;
if (sourceItem != null)
{
item = itemsControl.GetItemContainer(sourceItem);
}
if (item == null)
{
if (DragDrop.GetDragDirectlySelectedOnly(VisualSource))
{
item = itemsControl.GetItemContainerAt(e.GetPosition(itemsControl));
}
else
{
item = itemsControl.GetItemContainerAt(e.GetPosition(itemsControl), itemsControl.GetItemsPanelOrientation());
}
}
if (item != null)
{
// Remember the relative position of the item being dragged
this.PositionInDraggedItem = e.GetPosition(item);
var itemParent = ItemsControl.ItemsControlFromItemContainer(item);
if (itemParent != null)
{
this.SourceCollection = itemParent.ItemsSource ?? itemParent.Items;
if (itemParent != itemsControl)
{
var tvItem = item as TreeViewItem;
if (tvItem != null)
{
var tv = tvItem.GetVisualAncestor <TreeView>();
if (tv != null && tv != itemsControl && !tv.IsDragSource())
{
return;
}
}
else if (itemsControl.ItemContainerGenerator.IndexFromContainer(itemParent) < 0 && !itemParent.IsDragSource())
{
return;
}
}
this.SourceIndex = itemParent.ItemContainerGenerator.IndexFromContainer(item);
this.SourceItem = itemParent.ItemContainerGenerator.ItemFromContainer(item);
}
else
{
this.SourceIndex = -1;
}
this.SourceItems = itemsControl.GetSelectedItems();
// Some controls (I'm looking at you TreeView!) haven't updated their
// SelectedItem by this point. Check to see if there 1 or less item in
// the SourceItems collection, and if so, override the control's
// SelectedItems with the clicked item.
if (this.SourceItems.Cast <object>().Count() <= 1)
{
this.SourceItems = Enumerable.Repeat(this.SourceItem, 1);
}
this.VisualSourceItem = item;
}
else
{
this.SourceCollection = itemsControl.ItemsSource ?? itemsControl.Items;
}
}
else
{
if (sender is UIElement)
{
this.PositionInDraggedItem = e.GetPosition((UIElement)sender);
}
}
if (this.SourceItems == null)
{
this.SourceItems = Enumerable.Empty <object>();
}
}
