雙鏈表 C#。如何刪除雙鏈表中的所有節點

Question

我試圖刪除我的雙向鏈表中的所有節點，但遇到了麻煩。 調試時我的變量 this.Start 是 null，這導致我的代碼無法工作。 我想不出解決辦法。 是否有替代方法來刪除我的節點或修復我當前的代碼。 請幫忙 謝謝:D

public partial class Form2 : Form
    {
    
    SeatManager _seatManager = new SeatManager();
    DoubleLinkedList seatList = new DoubleLinkedList();
    Seat _seat = new Seat();
    public Form2()
    {
        InitializeComponent();
    }

   
    
    private void buttonCreateAndDisplay_Click(object sender, EventArgs e)
    {
        
        
                Label labelSeat = new Label();
                
                        
                        labelSeat.Click+=new EventHandler(HandleLabelClick);
                        Seat seat = _seatManager.InsertOneSeat(y, x);
                        labelSeat.Tag=seat;
                        labelSeat.Text=seat.ComputeSeatLabel();
                        

                    }
                }
            }
        }
        

    }
    private void HandleLabelClick(object sender, EventArgs e)
    {
        string labelName = "";
        Label labelSeat = (Label)sender;
        Seat seat = (Seat)labelSeat.Tag;
        labelMessage.Text=labelSeat.Name;
        
            if (seat.BookStatus==false)
            {
                seat=_seatManager.FindOneSeatToBook(seat.Row, seat.Column);
            }
            else
            {
                seat=_seatManager.FindOneSeatToUnbook(seat.Row, seat.Column);
            }
            if (seat.BookStatus==false)
            {
                labelSeat.BackColor=Color.LightGray;
            }
            else
            {
                labelSeat.BackColor=Color.LightGoldenrodYellow;
            }
        }
       
      
    }

   


    private void buttonReset_Click(object sender, EventArgs e)
    {
        seatList.ClearNodes(maxRow,maxColumn);  
        seatList.deleteAllNodes();
        _resetbuttonclicked=true;
        panelSeats.Controls.Clear();
        buttonCreateAndDisplay_Click(sender, e);

    }

   

雙鏈表

class DoubleLinkedList
    {
    public Node Start { get; set; }
    
    public DoubleLinkedList()
    {
        this.Start=null;
    }
    
    public void InsertAtEnd(Seat seatData)
    {
        Node newNode = new Node(seatData);
        if (this.Start==null)
        {
            this.Start=newNode;
            return;
        }
        Node p = this.Start;
        while (p.next!=null)
        {
            p=p.next;
            
        }
        p.next=newNode;
        newNode.prev=p;

    }

    
    public Seat SearchByRowAndColumn(int pRow, int pColumn)
    {
        Node p = this.Start;
        while (p!=null)
        {
            if ((p.seat.Column == pColumn) && (p.seat.Row == pRow))
            {   
                break;
            }
            p=p.next;
        }
        if (p==null)
        {
            return null;
        }
        else
        {
            return p.seat;
        }
    }

    public Seat ClearNodes(int pRow,int pColumn)
    {
        Node p = this.Start;
        while (p != null)
        {
            p=p.prev;
            p.next=null;
        }
        return null;

    }

    public void deleteAllNodes()
    {
        Node seat = new Node();
        while (this.Start != null)
        {
           seat = this.Start;
           this.Start = this.Start.next;
           seat = null;
        }
        this.Start=null;
    }

座位管理器

 class SeatManager
        {
        DoubleLinkedList _seats;
        public SeatManager()
        {
            _seats= new DoubleLinkedList();
        }
        public Seat InsertOneSeat(int row, int column)
        {
            Seat newSeat = new Seat();
            newSeat.Row = row;
            newSeat.Column = column;
            newSeat.CanBook = true;
            newSeat.Bookedby = "";
            _seats.InsertAtEnd(newSeat);
            return newSeat;
        }
        
    public Seat FindOneSeatToBook(int row, int column)
    {
        Seat seat = _seats.SearchByRowAndColumn(row, column);
        seat.BookStatus=true;
        return seat;
    }
    public Seat FindOneSeatToUnbook(int row, int column)
    {
        Seat seat = _seats.SearchByRowAndColumn(row, column);
        seat.BookStatus = false;
        return seat;
    }
    

Answer 1

你不能只寫

public void deleteAllNodes()
{
    this.Start = null;
}

讓垃圾收集器收拾殘局。