private void MovePopupAndRaiseEvents(double horizontalChange, double verticalChange)
{
#if !(BRIDGE && MIGRATION)
if (_popup != null)
{
//popup moving with the pointer
_popup.HorizontalOffset += horizontalChange;
_popup.VerticalOffset += verticalChange;
}
// Prepare the "DragEventArgs" to pass to the raised events:
Selection selection = new Selection(_sourceItemContainer);
SelectionCollection selectionCollection = SelectionCollection.ToSelectionCollection(selection);
DataObject dataObject = new DataObject();
dataObject.SetData("ItemDragEventArgs", new ItemDragEventArgs(selectionCollection));
MS.DragEventArgs dragOverEventArgs = new MS.DragEventArgs(dataObject);
// Get the DragDropTarget element that is under the pointer, if any:
TItemContainerType targetItemContainer;
DragDropTarget <TItemsControlType, TItemContainerType> dragDropTargetUnderPointer = GetDragDropTargetUnderPointer(_pointerX, _pointerY, out targetItemContainer);
// Check if the element under the pointer has changed since the last PointerMoved:
if (_previousdragDropTargetUnderPointer != dragDropTargetUnderPointer)
{
//---------------------------------
// IF WHAT IS UNDER THE POINTER HAS CHANGED
//---------------------------------
// Raise the DragLeave event of the element that was under the pointer before:
if (_previousdragDropTargetUnderPointer != null && _previousdragDropTargetUnderPointer.DragLeave != null)
{
_previousdragDropTargetUnderPointer.DragLeave(_previousdragDropTargetUnderPointer, new MS.DragEventArgs(dataObject));
// Reset the value of "_isDragCancelled" when leaving a control. This variable lets the user prevent a Drop on an element when the user sets e.Handled=true in the "DragOver" event of that element.
_isDragCancelled = false;
}
// Remember the element that is under the pointer:
_previousdragDropTargetUnderPointer = dragDropTargetUnderPointer;
// Raise the DragEnter event of the new element that is under the pointer:
if (dragDropTargetUnderPointer != null && dragDropTargetUnderPointer.DragEnter != null)
{
dragDropTargetUnderPointer.DragEnter(dragDropTargetUnderPointer, new MS.DragEventArgs(dataObject));
}
}
if (dragDropTargetUnderPointer != null)
{
//---------------------------------
// IF UNDER THE POINTER THERE IS A DRAGDROPPANEL
//---------------------------------
// Raise the DragOver:
dragDropTargetUnderPointer.OnDragOver(dragOverEventArgs);
// Cancel the drag drop operation if the user has marked the DragOver event as "handled":
if (dragOverEventArgs.Handled && dragOverEventArgs.Effects == DragDropEffects.None)
{
_isDragCancelled = true;
}
}
// Show the appropriate icon depending on whether it is possible to drop or not:
if (dragDropTargetUnderPointer != null && dragDropTargetUnderPointer.AllowDrop && !_isDragCancelled)
{
//---------------------------------
// SHOW ICON "DRAG ALLOWED"
//---------------------------------
_iconArrow.Visibility = Visibility.Visible;
_iconStop.Visibility = Visibility.Collapsed;
}
else
{
//---------------------------------
// SHOW ICON "DRAG FORBIDDEN"
//---------------------------------
_iconArrow.Visibility = Visibility.Collapsed;
_iconStop.Visibility = Visibility.Visible;
}
#endif
}
void OnDropped(PointerRoutedEventArgs e)
#endif
{
_popup.IsOpen = false;
//We no longer have use for the popup
_popup.Child = null;
_popup = null;
// Prepare the event arguments:
Selection selection = new Selection(_sourceItemContainer);
SelectionCollection selectionCollection = SelectionCollection.ToSelectionCollection(selection);
// Get the DragDropTarget element that is under the pointer, if any:
TItemContainerType targetItemContainer;
DragDropTarget <TItemsControlType, TItemContainerType> dragDropTargetUnderPointer = GetDragDropTargetUnderPointer(_pointerX, _pointerY, out targetItemContainer);
if (dragDropTargetUnderPointer != null)
{
//---------------------------------
// IF A DROP TARGET IS FOUND
//---------------------------------
// Check if drop is allowed:
if (dragDropTargetUnderPointer.AllowDrop && !_isDragCancelled)
{
TItemsControlType targetContainer = (TItemsControlType)dragDropTargetUnderPointer.Content; // Note: a "container" is for example a Panel in case of PanekDragDropTarget.
// Check if we are dropping on the source element itself (ie. from the source to the placeholder that we put in place of the source) (cf. "ItemDropOnSource" event):
if (ContainerFromIndex(targetContainer, _indexOfSourceContainerWithinItemsControl) == _sourcePlaceholder)
{
//---------------------------------
// IF WE ARE DROPPING THE SOURCE ON ITSELF
//---------------------------------
// Put the dragged element back to where it was:
PutSourceBackToOriginalPlace();
//Raise the "ItemDroppedOnSource" Event
if (dragDropTargetUnderPointer.ItemDroppedOnSource != null)
{
// Prepare the event args:
DataObject dataObject = new DataObject();
dataObject.SetData("ItemDragEventArgs", new ItemDragEventArgs(selectionCollection));
#if !(BRIDGE && MIGRATION)
dragDropTargetUnderPointer.ItemDroppedOnSource(dragDropTargetUnderPointer, new MS.DragEventArgs(dataObject, e));
#endif
}
}
//else we drop on another DragDropTarget
else
{
//---------------------------------
// IF WE ARE DROPPING ON ANOTHER DRAGDROPTARGET
//---------------------------------
// Remove the temporary placeholder (see the comment where the placeholder is defined):
this.RemoveItemAtIndex(_sourceItemsControl, _indexOfSourceContainerWithinItemsControl);
// Raise the Drop event:
if (dragDropTargetUnderPointer.Drop != null)
{
// Prepare the event args:
DataObject dataObject = new DataObject();
dataObject.SetData("ItemDragEventArgs", new ItemDragEventArgs(selectionCollection));
// Raise the Drop event:
#if !(BRIDGE && MIGRATION)
dragDropTargetUnderPointer.Drop(dragDropTargetUnderPointer, new MS.DragEventArgs(dataObject, e));
#endif
}
// Put the source into the target:
dragDropTargetUnderPointer.AddItem((TItemsControlType)dragDropTargetUnderPointer.Content, _sourceItemContainer);
}
}
//Can't drop so we put what was in the popup back in the content
else
{
// Put the dragged element back to where it was:
PutSourceBackToOriginalPlace();
}
}
//not a DragDropTarget under the pointer so we put what was in the popup back in the content
else
{
// Put the dragged element back to where it was:
PutSourceBackToOriginalPlace();
}
// Raise the "ItemDragCompleted" event:
if (ItemDragCompleted != null)
{
ItemDragCompleted(this, new ItemDragEventArgs(selectionCollection));
}
}
private void DragDropTarget_PointerPressed(object sender, PointerRoutedEventArgs e)
#endif
{
//----------------------------------
// DRAG OPERATION STARTS HERE
//----------------------------------
// Prevent the PointerPressed event from bubbling up so that if there are two nested DragDropTargets, only the inner one will be dragged:
e.Handled = true;
// We verify that drag operation is not taking place, which can lead a case if we missed the pointer released event due to a glitch such as moving the mouse outside the browser and releasing
if (!_isPointerCaptured)
{
// Reset some variables:
_isDragCancelled = false;
_previousdragDropTargetUnderPointer = null;
// Remember the current pointer position:
#if MIGRATION
_pointerX = e.GetPosition(null).X;
_pointerY = e.GetPosition(null).Y;
#else
_pointerX = e.GetCurrentPoint(null).Position.X;
_pointerY = e.GetCurrentPoint(null).Position.Y;
#endif
// Get the source DragDropTarget element that is under the pointer, if any:
DragDropTarget <TItemsControlType, TItemContainerType> sourceDragDropTarget = GetDragDropTargetUnderPointer(_pointerX, _pointerY, out _sourceItemContainer);
if (sourceDragDropTarget != this)
{
throw new Exception("The DragDropTarget is not supposed to support dragging an outer DragDropTarget in case of nested DragDropTargets.");
}
// We do something only if the source exists (ie. if an item was found under the pointer):
if (_sourceItemContainer != null)
{
// Get a reference to the ItemsControl:
_sourceItemsControl = (TItemsControlType)this.Content; // Note: there is no risk of InvalidCastException because the type has been tested before, and the derived class (PanelDragDropTarget) also verifies the type in the "OnContentChanged" method.
// Capture the pointer so that when dragged outside the DragDropPanel, we can still get its position:
#if MIGRATION
this.CaptureMouse();
#else
this.CapturePointer(e.Pointer);
#endif
// Remember that the pointer is currently captured:
_isPointerCaptured = true;
_capturedPointer = e.Pointer;
//Size of the content
double height;
double width;
if (_sourceItemContainer is FrameworkElement)
{
Size actualSize = (_sourceItemContainer as FrameworkElement).INTERNAL_GetActualWidthAndHeight();
height = actualSize.Height;
width = actualSize.Width;
}
else
{
height = double.NaN;
width = double.NaN;
}
// Prepare the arguments of the "ItemDragStarting" event:
Selection selection = new Selection(_sourceItemContainer);
SelectionCollection selectionCollection = SelectionCollection.ToSelectionCollection(selection);
ItemDragEventArgs itemDragStartingEventArgs = new ItemDragEventArgs(selectionCollection);
// Raise the "ItemDragStarting" event:
if (ItemDragStarting != null)
{
ItemDragStarting(this, itemDragStartingEventArgs);
}
// Show the popup, unless the user has cancelled the drag operation:
if (itemDragStartingEventArgs.Handled && itemDragStartingEventArgs.Cancel)
{
//----------------------------------
// CANCELLED BY USER
//----------------------------------
if (_isPointerCaptured)
{
// Stop capturing the pointer:
_isPointerCaptured = false;
#if MIGRATION
this.ReleaseMouseCapture();
#else
this.ReleasePointerCapture(_capturedPointer);
#endif
}
}
else
{
//----------------------------------
// SHOW POPUP
//----------------------------------
// Put a placeholder in place of the source that will occupy the same space. This is useful to: 1) let the user drop over the source itself (cf. "ItemDroppedOnSource" event), and 2) prevent the other elements from being displaced during the drag operation.
RemoveSourceAndPutTransparentPlaceholderInPlace(height, width);
// Put the source into a popup:
StackPanel stackPanelInPopUp = GeneratePopupContent(_sourceItemContainer, out _iconStop, out _iconArrow);
this._popup = new Popup()
{
Child = stackPanelInPopUp,
HorizontalAlignment = HorizontalAlignment.Left,
VerticalAlignment = VerticalAlignment.Top,
HorizontalContentAlignment = HorizontalAlignment.Left,
VerticalContentAlignment = VerticalAlignment.Top,
IsHitTestVisible = false
};
// Set the popup position:
this._popup.HorizontalOffset = this._pointerX;
this._popup.VerticalOffset = this._pointerY;
// Show the popup:
this._popup.IsOpen = true;
}
}
}
}
