public LinkedListCursor(LinkedListCursor <T> Cursor)
: this()
{
this.Position = Cursor.Position;
this.Node = Cursor.Node;
this.StayAtFlag = Cursor.StayAtFlag;
}
public static LinkedListCursor <T> PositionBegin <T>(this LinkedList <T> List) where T : class
{
var firstNode = List.First;
LinkedListCursor <T> cursor = new LinkedListCursor <T>(firstNode, RelativePosition.Before);
return(cursor);
}
public LinkedListCursor <T> Next( )
{
LinkedListNode <T> nxNode = null;
// stay at the current location.
if (StayAtFlag == true)
{
if (this.Position != RelativePosition.At)
{
throw new ApplicationException("cursor not position at location to stay at");
}
StayAtFlag = false;
nxNode = this.Node;
}
else
{
switch (this.Position)
{
case RelativePosition.Begin:
throw new ApplicationException("begin position not supported.");
case RelativePosition.Before:
nxNode = this.Node;
break;
case RelativePosition.At:
nxNode = this.Node.Next;
break;
case RelativePosition.After:
nxNode = this.Node.Next;
break;
case RelativePosition.End:
nxNode = null;
break;
default:
throw new ApplicationException("Next failed. Relative position is not set");
}
}
if (nxNode == null)
{
return(null);
}
else
{
var csr = new LinkedListCursor <T>(nxNode, RelativePosition.At);
return(csr);
}
}
public LinkedListCursor <T> PositionBefore()
{
if (_Position == RelativePosition.Begin)
{
return(PositionBegin());
}
else if (_Position == RelativePosition.End)
{
return(PositionEnd());
}
else if (_Position == RelativePosition.None)
{
throw new ApplicationException("PositionBefore cursor is set to None");
}
else
{
var csr = new LinkedListCursor <T>(this.Node, RelativePosition.Before);
return(csr);
}
}
