小白本人没学过c#，如果发现低级错误，各位大侠勿嘲笑...
说正题，winform做个设备管理界面，在学习论坛各位大神的帖子中也算是基本完成了开发，但在使用中发现问题，流程是登陆后获取到本机网卡，点击 button发送搜索数据包，等待所有设备回应，将所有设备信息显示到listview中，我在存储设备信息时用的是二维string[,], 将 string[,]再绘制到listview中，问题出在string[,]经常赋值不上，导致绘制listview时报错“未将对象引用设置到对象的实 例”。具体请看代码注释<重点问题>，里边还有两个关于socket的<附加问题>，也请大家帮忙看看，多谢！
private string[,] scanList = new string[,] { };
private int scanIndex;
private static System.Timers.Timer procTimer;
static Socket mySocket;
private static IPEndPoint dstPoint;
private void ToolStripButton5_Click(object sender, EventArgs e)
{
DeviceScanPublicValue.searchPort = int.Parse(ToolStripTextBox1.Text);
DeviceScanPublicValue.devManagePort = 1208;
/*附加问题1：因为后边有1s的搜索窗口，为防止再次点击按钮触发socket套接字错误，把按钮去使能了，定时器里再使能
*这里也想请教大家，怎么在发生socket套接字错误时恢复，我现在是一旦发生这种错误就死掉了，只能重新打开应用
*/
ToolStripButton5.Text = "搜索中...";
ToolStripButton5.Enabled = false;
scanList = new string[511, 11];//最多511个设备
scanIndex = 0;
ListView2.Items.Clear();
byte[] sendData = { 0x44, 0x55, 0x44, 0x55, 0xff, 0xff, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20 };
//Socket处理
mySocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
mySocket.Bind(new IPEndPoint(IPAddress.Parse(DeviceScanPublicValue.localIP), DeviceScanPublicValue.searchPort));
Thread recvThread = new Thread(ReciveMessage)
{
IsBackground = true
};
recvThread.Start();
dstPoint = new IPEndPoint(IPAddress.Broadcast, DeviceScanPublicValue.devManagePort);
string hostName = Dns.GetHostName();
mySocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1);
Thread sendThread = new Thread(SendMessage);
sendThread.Start(sendData);
//创建一个1000ms定时的定时器，因为不知道有多少设备，给个1s的搜索窗口,定时器结束绘制listview
procTimer = new System.Timers.Timer(1000);
procTimer.Elapsed += OnTimedEvent;
procTimer.AutoReset = false;
procTimer.Enabled = true;
procTimer.Start();
}
private void SendMessage(object obj)
{
byte[] message = (byte[])obj;
mySocket.SendTo(message, dstPoint);
}
private void ReciveMessage()
{
EndPoint point = new IPEndPoint(IPAddress.Any, DeviceScanPublicValue.devManagePort);
Thread.Sleep(50);
/*附加问题2：搜索时，电脑网卡确实收到4个设备回应的报文，但有时就会出现socket接收不全的情况，比如只解析三个设备
*/
while (true)
{
try
{
Thread.Sleep(50);
byte[] buffer = new byte[100];
int length = mySocket.ReceiveFrom(buffer, ref point); //接收数据报
SearchMessageProc(buffer);
}
catch (Exception)
{
}
finally
{
}
}
}
struct DeviceList
{
public string type;
public string name;
public string location;
public string logicId;
public string ip;
public string mac;
public string port;
public string model;
public string timeModel;
public string timeIn;
public string status;
public string topology;
};
private void SearchMessageProc(object obj)
{
DeviceList devInfo;
byte[] message = (byte[])obj;
if (message[0] == 0x44 && message[1] == 0x55 && message[4] == 0x21)
{
/*
解析报文，得到devInfo，不贴代码了，太长了
*/
//整合搜索设备信息
string[] deviceScanInfo = { devInfo.name , devInfo.location , devInfo.logicId , devInfo.ip , devInfo.mac ,
devInfo.port , devInfo.model , devInfo.timeModel , devInfo.timeIn , devInfo.status , devInfo.topology };
for (int i = 0; i < 11; i++)
{
/*
重点问题：就在这，我测试用四个设备，scanList偶尔就会出现其中一个设备信息为null，但deviceScanInfo是正确的，
scanIndex也能加到4，这样就导致后边绘制listview时有null报错,百思不得其解
*/
scanList[scanIndex9000, i] = deviceScanInfo[i];
scanIndex++;
}
}
}
private ListViewItem scanDevList;
private void OnTimedEvent(object sender, ElapsedEventArgs e)
{
ListView2.BeginUpdate();
for (int i = 0; i < scanIndex; i++)
{
scanDevList = new ListViewItem
{
Text = (i + 1).ToString()
};
for (int j = 0; j < 11; j++)
{
scanDevList.SubItems.Add(scanList[i, j].ToString());
}
ListView2.Items.Add(scanDevList);
ListView2.Items[i].BackColor = Color.Lavender;
}
ListView2.EndUpdate();
ToolStripButton5.Text = "搜索设备";
ToolStripButton5.Enabled = true;
mySocket.Shutdown(SocketShutdown.Both);
mySocket.Close();
procTimer.Stop();
}
那你可以這樣改呀，
for (int i = 0; i < 11; i++)
{
/*
重点问题：就在这，我测试用四个设备，scanList偶尔就会出现其中一个设备信息为null，但deviceScanInfo是正确的，
scanIndex也能加到4，这样就导致后边绘制listview时有null报错,百思不得其解
*/
if( deviceScanInfo[i]!=null)//當不是null
{
scanList[scanIndex9000, i] = deviceScanInfo[i];
scanIndex++;
}
else
{
//導出日誌，列出設備的詳細信息，然後用調試工具測試這些信息能不能聯通到這台設備
}
}
感谢！这样是可以规避掉问题，我现在也是判断是否为空再做后续处理，起码可以不让程序死掉。但毕竟还是丢掉了相应的设备信息，目前只能靠重复搜索来保证搜全设备。。。
之前的代码有些地方贴错了，可能误导大家，重贴一下，并且突然想到能否用while语句来执行string[,]赋值，改完小蜜蜂论坛发帖机后效果确实好了很多,listview绘制时也加了些判断。就是不知道while会不会有风险
private string[,] ne9000List = new string[,] { };
private int scanIndex9000;
private static System.Timers.Timer procTimer;
static Socket mySocket;
static Thread recvThread;
static Thread sendThread;
private static IPEndPoint dstPoint;
struct DeviceList
{
public string type;
public string name;
public string location;
public string logicId;
public string ip;
public string mac;
public string port;
public string model;
public string timeModel;
public string timeIn;
public string status;
public string topology;
};
private void SearchMessageProc(object obj)
{
DeviceList devInfo;
byte[] message = (byte[])obj;
if (message[0] == 0x4E && message[1] == 0x53 && message[4] == 0x21)
{
/*devInfo处理
*/
string[] deviceScanInfo = { devInfo.name , devInfo.location , devInfo.logicId , devInfo.ip , devInfo.mac ,
devInfo.port , devInfo.model , devInfo.timeModel , devInfo.timeIn , devInfo.status , devInfo.topology };
bool scanErr = false;
for (int i = 0; i < 11; i++)
{
if (deviceScanInfo[i] == null)
scanErr = true;
}
if (scanErr == false)
{
while (ne9000List[scanIndex9000, 0] == null || ne9000List[scanIndex9000, 1] == null || ne9000List[scanIndex9000, 2] == null || ne9000List[scanIndex9000, 3] == null ||
ne9000List[scanIndex9000, 4] == null || ne9000List[scanIndex9000, 5] == null || ne9000List[scanIndex9000, 6] == null || ne9000List[scanIndex9000, 7] == null ||
ne9000List[scanIndex9000, 8] == null || ne9000List[scanIndex9000, 9] == null || ne9000List[scanIndex9000, 10] == null )
{
for (int i = 0; i < 11; i++)
{
ne9000List[scanIndex9000, i] = deviceScanInfo[i];
}
}
scanIndex9000++;
}
}
}
private ListViewItem scanDevList;
private void OnTimedEvent(object sender, ElapsedEventArgs e)
{
ListView2.BeginUpdate();
int validNum9000 = 0;
for (int i = 0; i < scanIndex9000; i++)
{
if (ne9000List[i, 0] != null && ne9000List[i, 1] != null && ne9000List[i, 2] != null && ne9000List[i, 3] != null &&
ne9000List[i, 4] != null && ne9000List[i, 5] != null && ne9000List[i, 6] != null && ne9000List[i, 7] != null &&
ne9000List[i, 8] != null && ne9000List[i, 9] != null && ne9000List[i, 10] != null)
{
scanDevList = new ListViewItem
{
Text = (validNum9000 + 1).ToString()
};
for (int j = 0; j < 11; j++)
{
scanDevList.SubItems.Add(ne9000List[i, j].ToString());
}
ListView2.Items.Add(scanDevList);
ListView2.Items[validNum9000].BackColor = Color.Lavender;
validNum9000++;
}
}
ListView2.EndUpdate();
ToolStripButton5.Text = "网络设备搜索";
ToolStripButton5.Enabled = true;
mySocket.Shutdown(SocketShutdown.Both);
mySocket.Close();
procTimer.Stop();
}
