// for ControlCollection
public static bool Swap(this Control.ControlCollection source, int fromIndex, int toIndex)
{
Action <int, object> insertAtCallback = (index, item) => {
source.Add((Control)item);
source.SetChildIndex((Control)item, index);
};
return(source.Swap(fromIndex, toIndex, insertAtCallback));
}
public static void Shift <T>(this Control.ControlCollection source, int fromIndex, int toIndex, Func <T, bool> isItemMovable, Action <int, int> fromIndex_ToIndexCallback = null, Action <T, T> from_ToCallback = null) where T : Control
{
if (isItemMovable((T)source[fromIndex]) && isItemMovable((T)source[toIndex]))
{
var ascend = fromIndex < toIndex;
for (; ;)
{
if (ascend && fromIndex < toIndex || !ascend && fromIndex > toIndex)
{
var _toIndex = fromIndex;
next:
var _fromIndex = fromIndex + (ascend ? 1 : -1);
Action next = () => fromIndex = ascend ? fromIndex + 1 : fromIndex - 1;
if (_fromIndex == toIndex || _fromIndex != toIndex && isItemMovable((T)source[_fromIndex]))
{
source.Swap(_fromIndex, _toIndex);
fromIndex_ToIndexCallback?.Invoke(_fromIndex, _toIndex);
from_ToCallback?.Invoke((T)source[_fromIndex], (T)source[_toIndex]);
next();
}
else
{
next();
goto next;
}
}
else
{
break;
}
}
}
}