public ListCursor(ListCursor <T> Cursor)
{
this.List = Cursor.List;
this.Position = Cursor.Position;
this.Index = Cursor.Index;
this.StayAtFlag = Cursor.StayAtFlag;
}
public ListCursor <T> Next( )
{
int nxIndex = -1;
// 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;
nxIndex = this.Index;
}
else
{
switch (this.Position)
{
case RelativePosition.Begin:
nxIndex = 0;
break;
case RelativePosition.Before:
nxIndex = this.Index;
break;
case RelativePosition.At:
nxIndex = this.Index + 1;
break;
case RelativePosition.After:
nxIndex = this.Index + 1;
break;
case RelativePosition.End:
nxIndex = -1;
break;
default:
throw new ApplicationException("Next failed. Relative position is not set");
}
}
if ((nxIndex == -1) || (nxIndex >= this.List.Count))
{
return(null);
}
else
{
var csr = new ListCursor <T>(this.List, nxIndex, RelativePosition.At);
return(csr);
}
}
public ListCursor <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 ListCursor <T>(this.List, this.Index, RelativePosition.Before);
return(csr);
}
}
