/// <summary>
/// Is called if the user begins a drag operation on the canvas and there is no other
/// mouse handler (eg, AssociationMouseHandler) currently activated.
///
/// Otherwise, the OnShapeDragBegin method of the other mouse handler is executed and
/// this method is completely ignorred for the current drag operation.
/// </summary>
/// <param name="position"></param>
/// <param name="shape"></param>
void ICanvasViewMouseHandler.OnShapeDragBegin(Point position, ShapeViewModelBase shape)
{
if (shape != null)
{
// Activate shape selection if user starts to drag a shape
if (shape.IsSelected == false)
{
((ICanvasViewMouseHandler)this).OnShapeClick(this.mDragShape);
}
}
else // user starts a drag operation on the canvas so we setup a rubber band adorner command
{ // to implement multi object selection via rubber band
if (this.mCurrentMouseHandler == this)
{
// Clear current selection if no control key is pressed on the keyboard (which would allow adding selected items)
if ((Keyboard.IsKeyDown(Key.LeftCtrl) == false &&
Keyboard.IsKeyDown(Key.RightCtrl) == false))
{
CanvasViewModel.SelectedItem.SelectShape(null);
}
RubberBandViewModel vm = this.GetRubberBand(position);
// Create a new mouse handler command, attach event on completion, and hook it into the system
CreateRubberBandMouseHandler handler = new CreateRubberBandMouseHandler(vm, this.CanvasViewModel);
handler.RubberBandSelection += handler_RubberBandSelection;
// Hook up into frame work system
this.CanvasViewModel.BeginCanvasViewMouseHandler(handler);
this.BeginMouseOperation();
//this.mCurrentMouseHandler = this.CanvasViewModel.CanvasViewMouseHandler;
}
}
}
private void handler_RubberBandSelection(object sender, RubberBandSelectionEventArgs e)
{
if (this.mCurrentMouseHandler is CreateRubberBandMouseHandler)
{
CreateRubberBandMouseHandler handler = this.mCurrentMouseHandler as CreateRubberBandMouseHandler;
handler.RubberBandSelection -= this.handler_RubberBandSelection;
}
this.CanvasViewModel.Handle_RubberBandSelection(e);
this.EndMouseOperation();
this.DestroyRubberband();
}
/// <summary>
/// This method is called when the association drawing mode is cancelled
/// (either via explicit command [click on Select Mode button] or
/// because the source or target may be in-appropriate).
/// </summary>
public void CancelCanvasViewMouseHandler()
{
var handler = this.CanvasViewMouseHandler;
this.CanvasViewMouseHandler = null;
try
{
handler.OnCancelMouseHandler();
CreateRubberBandMouseHandler rbh = handler as CreateRubberBandMouseHandler;
// Make sure event completion handler is detached when mouse command handler is finished
//// if (rbh != null)
//// rbh.RubberBandSelection -= this.handle_RubberBandSelection;
}
finally
{
DocumentViewModel.dm_DocumentDataModel.EndOperation("CanvasViewMouseHandler session");
}
}
