c# - 错误:NullReferenceException:对象引用未设置为对象的实例
问题描述
我正在尝试创建 TCP 客户端-服务器连接,客户端可以成功连接到服务器,但我无法接收从服务器发送的数据,并且出现此错误:
NullReferenceException:对象引用未设置为对象的实例 ClientHandlePackets.HandleDataPackets (System.Byte[] data) (at Assets/Client/Scripts/ClientHanlePackets.cs:89) ClientHandlePackets.HandleData (System.Byte[] data) (at Assets/Client/Scripts/ClientHanlePackets.cs:61) ClientTCP.Update () (在 Assets/Client/Scripts/ClientTCP.cs:31)
我该如何解决这个问题?
c#
using System.Collections.Generic;
using UnityEngine;
public enum ServerPackets
{
S_INFORMATION = 1,
S_EXECUTEMETHODONCLIENT,
}
public class ClientHandlePackets : MonoBehaviour
{
public static Bytebuffer playerbuffer;
public delegate void Packet_(byte[] data);
private static Dictionary<long, Packet_> packets;
private static long pLength;
private void Awake()
{
initalizePackets();
}
private static void initalizePackets()
{
packets = new Dictionary<long, Packet_>();
packets.Add((long)ServerPackets.S_INFORMATION, PacketInformation);
}
public static void HandleData(byte[] data)
{
byte[] Buffer;
Buffer = (byte[])data.Clone();
if (playerbuffer == null) { playerbuffer = new Bytebuffer(); };
playerbuffer.WriteBytes(Buffer);
if (playerbuffer.Count() == 0)
{
playerbuffer.Clear();
return;
}
if (playerbuffer.Length() >= 8)
{
pLength = playerbuffer.ReadLong(false);
if (pLength <= 0)
{
playerbuffer.Clear();
return;
}
}
while (pLength > 0 & pLength <= playerbuffer.Length() - 8)
{
if (pLength <= playerbuffer.Length() - 8)
{
playerbuffer.ReadLong(); //REads out the packet identifier
data = playerbuffer.Readbytes((int)pLength); // Gets the full package length
HandleDataPackets(data);
}
pLength = 0;
if (playerbuffer.Length() >= 8)
{
pLength = playerbuffer.ReadLong(false);
if (pLength < 0)
{
playerbuffer.Clear();
return;
}
}
}
}
private static void HandleDataPackets(byte[] data)
{
long packetIdentifier;
Bytebuffer Buffer;
Packet_ packet;
Buffer = new Bytebuffer();
Buffer.WriteBytes(data);
packetIdentifier = Buffer.ReadLong();
Buffer.Dispose();
if (packets.TryGetValue(packetIdentifier, out packet))
{
packet.Invoke(data);
}
}
private static void PacketInformation(byte[] data)
{
Bytebuffer buffer = new Bytebuffer();
buffer.WriteBytes(data);
long packetIdentifier = buffer.ReadLong();
string msg1 = buffer.Readstring();
string msg2 = buffer.Readstring();
int Level = buffer.ReadInteger();
Debug.Log(msg1);
Debug.Log(msg2);
Debug.Log(Level);
}
}
using System;
using System.Net.Sockets;
using UnityEngine;
using UnityEngine.UI;
public class ClientTCP: MonoBehaviour
{
public Text info;
public static ClientTCP instance;
public TcpClient client;
public NetworkStream mystream;
private byte[] AsynchBuffer;
public bool IsConnected;
public byte[] Receivebyte;
public bool handleData = false;
private string IP_Adress= "127.0.0.1";
private int port=5555;
private void Awake()
{
instance = this;
}
private void Update()
{
if (handleData == true)
{
ClientHandlePackets.HandleData(Receivebyte);
handleData = false;
}
}
public void Connect()
{
Debug.Log("Trying to connect to the sever...");
client = new TcpClient();
client.ReceiveBufferSize = 4096;
client.SendBufferSize = 4096;
AsynchBuffer = new byte[8192];
try
{
client.BeginConnect(IP_Adress, port, new AsyncCallback(ConnectCallback), client);
}
catch
{
Debug.Log("unable to connect to the server");
}
}
private void ConnectCallback(IAsyncResult result)
{
try
{
client.EndConnect(result);
if (client.Connected == false)
{
return;
}
else
{
mystream = client.GetStream();
mystream.BeginRead(AsynchBuffer,0,8192,OnRecieveData,null);
IsConnected = true;
Debug.Log("You are connected to the server successfully!");
}
}
catch (Exception)
{
IsConnected = false;
return;
}
}
private void OnRecieveData(IAsyncResult result)
{
try
{
int packetlength = mystream.EndRead(result);
Receivebyte = new byte[packetlength];
Buffer.BlockCopy(AsynchBuffer, 0, Receivebyte, 0, packetlength);
if (packetlength == 0)
{
Debug.Log("disconnected");
Application.Quit();
return;
}
handleData = true;
mystream.BeginRead(AsynchBuffer, 0, 8192, OnRecieveData, null);
}
catch (Exception)
{
Debug.Log("disconnected");
Application.Quit();
return;
}
}
}
解决方案
问题在这里:
if (packets.TryGetValue(packetIdentifier, out packet))
{
packet.Invoke(data);
}
为避免此错误,您可以使用
if (packets.TryGetValue(packetIdentifier, out packet))
{
packet?.Invoke(data);
}
但问题是我看不到你在哪里用代码中的数据填充数据包的字典。你能展示你的ByteBuffer
班级吗?
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