/// <summary>
/// Gets invoked when drag helper first attempts to initiate a drag operation.
/// </summary>
/// <param name="e">Event data object</param>
/// <remarks>The event data contains DragData field which must be filled in with a valid data
/// object. The base implementation of this method fires an event giving any listener a chance
/// to provide the data object. Alternatively, a deriving class can provide it's own override
/// of this method and fill in data object there. Without the data object, drag operation will
/// not be started. It is advisable for derived class to make sure base implementation of this
/// method is called.</remarks>
protected virtual void OnQueryDragData(QueryDragDataEventArgs e)
{
if (QueryDragData != null)
{
QueryDragData(this, e);
}
}
/// <summary>
/// Gets invoked when drag helper detects that a drag source has been dragged far enough
/// for drag operation to initiate. If this method is overriden, deriving class must ensure
/// that base implementation is invoked.
/// </summary>
protected virtual void DoDragDrop()
{
var eventArgs = new QueryDragDataEventArgs(_clickPoint);
OnQueryDragData(eventArgs);
if (eventArgs.IsCancelled || eventArgs.DragData == null)
{
return;
}
OnDragStarted(eventArgs.DragData);
_adorner = new DragDropAdorner(_dragSource, _clickPoint);
DragDropEffects result = DragDrop.DoDragDrop(
_dragSource, eventArgs.DragData, DragDropEffects.Move | DragDropEffects.Link);
_adorner.RemoveAdorner();
_adorner = null;
OnDragComplete(eventArgs.DragData, result);
}
/// <inheritdoc/>
protected override void OnQueryDragData(QueryDragDataEventArgs e)
{
if (_dragFrozenCount > 0)
{
return;
}
base.OnQueryDragData(e);
if (e.DragData == null)
{
var data = new WidgetSiteDragDropData()
{
DraggableOffset = e.DraggableOffset,
Site = Parent,
Widget = (Data.WidgetData)Parent.Content
};
var dataObject = new DataObject(data);
e.DragData = dataObject;
}
}
/// <summary>
/// Gets invoked when drag helper first attempts to initiate a drag operation.
/// </summary>
/// <param name="e">Event data object</param>
/// <remarks>The event data contains DragData field which must be filled in with a valid data
/// object. The base implementation of this method fires an event giving any listener a chance
/// to provide the data object. Alternatively, a deriving class can provide it's own override
/// of this method and fill in data object there. Without the data object, drag operation will
/// not be started. It is advisable for derived class to make sure base implementation of this
/// method is called.</remarks>
protected virtual void OnQueryDragData( QueryDragDataEventArgs e )
{
if( QueryDragData != null )
{
QueryDragData( this, e );
}
}
/// <summary>
/// Gets invoked when drag helper detects that a drag source has been dragged far enough
/// for drag operation to initiate. If this method is overriden, deriving class must ensure
/// that base implementation is invoked.
/// </summary>
protected virtual void DoDragDrop()
{
var eventArgs = new QueryDragDataEventArgs( _clickPoint );
OnQueryDragData( eventArgs );
if( eventArgs.IsCancelled || eventArgs.DragData == null ) return;
OnDragStarted( eventArgs.DragData );
_adorner = new DragDropAdorner( _dragSource, _clickPoint );
DragDropEffects result = DragDrop.DoDragDrop(
_dragSource, eventArgs.DragData, DragDropEffects.Move | DragDropEffects.Link );
_adorner.RemoveAdorner();
_adorner = null;
OnDragComplete( eventArgs.DragData, result );
}
/// <inheritdoc/>
protected override void OnQueryDragData( QueryDragDataEventArgs e )
{
if( _dragFrozenCount > 0 ) return;
base.OnQueryDragData( e );
if( e.DragData == null )
{
var data = new WidgetSiteDragDropData() {
DraggableOffset = e.DraggableOffset,
Site = Parent,
Widget = (Data.WidgetData)Parent.Content
};
var dataObject = new DataObject( data );
e.DragData = dataObject;
}
}
