void tb_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
SelItem = sender as TopicDragItem;
if (SelItem == null)
{
return;
}
SelItem.ReleaseMouseCapture();
// int index = LeftText.FindIndex(new Predicate<TopicDragItem>(FindItem));
object o = InputHitTest(e.GetPosition(this));
TopicDragItem tb2 = GetMouseSelItem((DependencyObject)InputHitTest(e.GetPosition(this))) as TopicDragItem;
if (tb2 != null)
{
SelItem.UserAnswer = tb2.Id;
tb2.LinePoint = currentPoint;
}
else
{
SelItem.LinePoint = new Point(0, 0);
currentPoint = new Point(0, 0);
SelItem.UserAnswer = -1;
}
DrawLine();
}
void tb_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
SelItem = sender as TopicDragItem;
if (SelItem == null)
{
return;
}
SelItem.UserAnswer = -1;
SelItem.LinePoint = new Point(e.GetPosition(null).X - e.GetPosition(SelItem).X + SelItem.ActualWidth, e.GetPosition(null).Y - e.GetPosition(SelItem).Y + SelItem.ActualHeight / 2);
}
bool FindItem(TopicDragItem p)// 比较器（这里的p为Plans中的元素，即p.PlanID与给定的PlanID比较）
{
if (SelItem.Id == p.Id)
{
return(true);
}
else
{
return(false);
}
}
void tb_PreviewMouseMove(object sender, MouseEventArgs e)
{
if (e.LeftButton != MouseButtonState.Pressed)
{
return;
}
SelItem = sender as TopicDragItem;
if (SelItem == null)
{
return;
}
// int index = LeftText.FindIndex(new Predicate<TopicDragItem>(FindItem));
if (e.GetPosition(null).X > currentPoint.X)
{
currentPoint.X = e.GetPosition(null).X - 1;
}
else
{
currentPoint.X = e.GetPosition(null).X + 1;
}
if (e.GetPosition(null).Y > currentPoint.Y)
{
currentPoint.Y = e.GetPosition(null).Y - 1;
}
else
{
currentPoint.Y = e.GetPosition(null).Y + 1;
}
if (SelItem.CaptureMouse())
{
DrawLine();
}
}
