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Improved DragSource 

the drag source now gets the preferred drag effect and handles keyboard
inputs too
pull/1417/head
boombuler 9 years ago
parent
74163ff668
commit
97f581af49
1 changed files with 81 additions and 48 deletions
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  1. 129
      src/Avalonia.Controls/DragDrop/DragSource.cs

129
src/Avalonia.Controls/DragDrop/DragSource.cs
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@ -19,13 +19,14 @@ namespace Avalonia.Controls.DragDrop
private const InputModifiers MOUSE_INPUTMODIFIERS = InputModifiers.LeftMouseButton|InputModifiers.MiddleMouseButton|InputModifiers.RightMouseButton;
private readonly IDragDropDevice _dragDrop;
private readonly IInputManager _inputManager;
private readonly Subject<DragDropEffects> _result = new Subject<DragDropEffects>();
private DragDropEffects _allowedEffects;
private IDataObject _draggedData;
private IInputElement _lastRoot;
private InputModifiers? _initialInputModifiers;
private Point _lastPosition;
private object _lastCursor;
private InputModifiers? _initialInputModifiers;
public DragSource()
{
@ -40,35 +41,58 @@ namespace Avalonia.Controls.DragDrop
{
_draggedData = data;
_lastRoot = null;
_lastPosition = default(Point);
_allowedEffects = allowedEffects;
using (_inputManager.PreProcess.OfType<RawMouseEventArgs>().Subscribe(e => ProcessMouseEvents(e, allowedEffects)))
using (_inputManager.PreProcess.OfType<RawMouseEventArgs>().Subscribe(ProcessMouseEvents))
{
var effect = await _result.FirstAsync();
return effect;
using (_inputManager.PreProcess.OfType<RawKeyEventArgs>().Subscribe(ProcessKeyEvents))
{
var effect = await _result.FirstAsync();
return effect;
}
}
}
return DragDropEffects.None;
}
private DragDropEffects RaiseDragEvent(RawDragEventType type, IInputElement root, Point pt, DragDropEffects allowedEffects)
private DragDropEffects RaiseEventAndUpdateCursor(RawDragEventType type, IInputElement root, Point pt, InputModifiers modifiers)
{
RawDragEvent rawEvent = new RawDragEvent(_dragDrop, type, root, pt, _draggedData, allowedEffects);
_lastPosition = pt;
RawDragEvent rawEvent = new RawDragEvent(_dragDrop, type, root, pt, _draggedData, _allowedEffects);
var tl = root.GetSelfAndVisualAncestors().OfType<TopLevel>().FirstOrDefault();
tl.PlatformImpl.Input(rawEvent);
SetCursor(root, rawEvent.Effects);
return rawEvent.Effects;
var effect = GetPreferredEffect(rawEvent.Effects & _allowedEffects, modifiers);
UpdateCursor(root, effect);
return effect;
}
private DragDropEffects GetPreferredEffect(DragDropEffects effect, InputModifiers modifiers)
{
if (effect == DragDropEffects.Copy || effect == DragDropEffects.Move || effect == DragDropEffects.Link || effect == DragDropEffects.None)
return effect; // No need to check for the modifiers.
if (effect.HasFlag(DragDropEffects.Link) && modifiers.HasFlag(InputModifiers.Alt))
return DragDropEffects.Link;
if (effect.HasFlag(DragDropEffects.Copy) && modifiers.HasFlag(InputModifiers.Control))
return DragDropEffects.Copy;
return DragDropEffects.Move;
}
private Cursor GetCursorForDropEffect(DragDropEffects effects)
{
// Todo. Needs to choose cursor by effect.
if (effects == DragDropEffects.None)
return new Cursor(StandardCursorType.No);
return new Cursor(StandardCursorType.Hand);
if (effects.HasFlag(DragDropEffects.Copy))
return new Cursor(StandardCursorType.DragCopy);
if (effects.HasFlag(DragDropEffects.Move))
return new Cursor(StandardCursorType.DragMove);
if (effects.HasFlag(DragDropEffects.Link))
return new Cursor(StandardCursorType.DragLink);
return new Cursor(StandardCursorType.No);
}
private void SetCursor(IInputElement root, DragDropEffects effect)
private void UpdateCursor(IInputElement root, DragDropEffects effect)
{
if (_lastRoot != root)
{
@ -96,25 +120,45 @@ namespace Avalonia.Controls.DragDrop
if (root is InputElement ie)
ie.Cursor = GetCursorForDropEffect(effect);
}
private void ProcessMouseEvents(RawMouseEventArgs e, DragDropEffects allowedEffects)
private void CancelDragging()
{
if (!_initialInputModifiers.HasValue)
_initialInputModifiers = e.InputModifiers & MOUSE_INPUTMODIFIERS;
if (_lastRoot != null)
RaiseEventAndUpdateCursor(RawDragEventType.DragLeave, _lastRoot, _lastPosition, InputModifiers.None);
UpdateCursor(null, DragDropEffects.None);
_result.OnNext(DragDropEffects.None);
}
void CancelDragging()
private void ProcessKeyEvents(RawKeyEventArgs e)
{
if (e.Type == RawKeyEventType.KeyDown && e.Key == Key.Escape)
{
if (_lastRoot != null)
RaiseDragEvent(RawDragEventType.DragLeave, _lastRoot, _lastRoot.PointToClient(e.Root.PointToScreen(e.Position)), allowedEffects);
SetCursor(null, DragDropEffects.None);
RaiseEventAndUpdateCursor(RawDragEventType.DragLeave, _lastRoot, _lastPosition, e.Modifiers);
UpdateCursor(null, DragDropEffects.None);
_result.OnNext(DragDropEffects.None);
e.Handled = true;
}
void AcceptDragging()
else if (e.Key == Key.LeftCtrl || e.Key == Key.RightCtrl || e.Key == Key.LeftAlt || e.Key == Key.RightAlt)
RaiseEventAndUpdateCursor(RawDragEventType.DragOver, _lastRoot, _lastPosition, e.Modifiers);
}
private void ProcessMouseEvents(RawMouseEventArgs e)
{
if (!_initialInputModifiers.HasValue)
_initialInputModifiers = e.InputModifiers & MOUSE_INPUTMODIFIERS;
void CheckDraggingAccepted(InputModifiers changedMouseButton)
{
var result = RaiseDragEvent(RawDragEventType.Drop, e.Root, e.Position, allowedEffects) & allowedEffects;
SetCursor(null, DragDropEffects.None);
_result.OnNext(result);
if (_initialInputModifiers.Value.HasFlag(changedMouseButton))
{
var result = RaiseEventAndUpdateCursor(RawDragEventType.Drop, e.Root, e.Position, e.InputModifiers);
UpdateCursor(null, DragDropEffects.None);
_result.OnNext(result);
}
else
CancelDragging();
e.Handled = true;
}
@ -125,45 +169,34 @@ namespace Avalonia.Controls.DragDrop
case RawMouseEventType.MiddleButtonDown:
case RawMouseEventType.NonClientLeftButtonDown:
CancelDragging();
e.Handled = true;
return;
case RawMouseEventType.LeaveWindow:
RaiseDragEvent(RawDragEventType.DragLeave, e.Root, e.Position, allowedEffects);
break;
RaiseEventAndUpdateCursor(RawDragEventType.DragLeave, e.Root, e.Position, e.InputModifiers); break;
case RawMouseEventType.LeftButtonUp:
if (_initialInputModifiers.Value.HasFlag(InputModifiers.LeftMouseButton))
AcceptDragging();
else
CancelDragging();
return;
CheckDraggingAccepted(InputModifiers.LeftMouseButton); break;
case RawMouseEventType.MiddleButtonUp:
if (_initialInputModifiers.Value.HasFlag(InputModifiers.MiddleMouseButton))
AcceptDragging();
else
CancelDragging();
return;
CheckDraggingAccepted(InputModifiers.MiddleMouseButton); break;
case RawMouseEventType.RightButtonUp:
if (_initialInputModifiers.Value.HasFlag(InputModifiers.RightMouseButton))
AcceptDragging();
else
CancelDragging();
return;
CheckDraggingAccepted(InputModifiers.RightMouseButton); break;
case RawMouseEventType.Move:
var mods = e.InputModifiers & MOUSE_INPUTMODIFIERS;
if (_initialInputModifiers.Value != mods)
{
CancelDragging();
e.Handled = true;
return;
}
if (e.Root != _lastRoot)
{
if (_lastRoot != null)
RaiseDragEvent(RawDragEventType.DragLeave, _lastRoot, _lastRoot.PointToClient(e.Root.PointToScreen(e.Position)), allowedEffects);
RaiseDragEvent(RawDragEventType.DragEnter, e.Root, e.Position, allowedEffects);
RaiseEventAndUpdateCursor(RawDragEventType.DragLeave, _lastRoot, _lastRoot.PointToClient(e.Root.PointToScreen(e.Position)), e.InputModifiers);
RaiseEventAndUpdateCursor(RawDragEventType.DragEnter, e.Root, e.Position, e.InputModifiers);
}
else
RaiseDragEvent(RawDragEventType.DragOver, e.Root, e.Position, allowedEffects);
return;
RaiseEventAndUpdateCursor(RawDragEventType.DragOver, e.Root, e.Position, e.InputModifiers);
break;
}
}
}

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