求吧里的大神指教，socket通信接受不到数据

//这是与服务器建立连接的函数~
private void btnClient_Click(object sender, EventArgs e)
{
//定义一个套字节监听 包含3个参数(IP4寻址协议,流式连接,TCP协议)
socketClient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//需要获取文本框中的IP地址
IPAddress ipaddress = IPAddress.Parse(txtIP.Text.Trim());
//将获取的ip地址和端口号绑定到网络节点endpoint上
IPEndPoint endpoint = new IPEndPoint(ipaddress, int.Parse(txtPort.Text.Trim()));
//这里客户端套接字连接到网络节点(服务端)用的方法是Connect 而不是Bind
socketClient.Connect(endpoint);
//创建一个线程 用于监听服务端发来的消息
threadClient = new Thread(RecMsg);
//将窗体线程设置为与后台同步
threadClient.IsBackground = true;
//启动线程
threadClient.Start();
rtbContent.AppendText("系统提示:成功与服务器建立起连接，现在可以开始通信！" + "\r\n");
}

//这是接受消息的函数~问题就在这里，我调试的时候在里面设置断点，结果服务器发来消息，根本没有进去这个函数里面，自然也就没有收到消息了~请问下如何解决~
private void RecMsg()
{
long fileLength = 0;
while (true)
{
int firstReceived = 0;
byte[] buffer = new byte[ReceiveBufferSize];
try
{
//获取接收的数据,并存入内存缓冲区 返回一个字节数组的长度
if (socketClient!= null)
firstReceived = socketClient.Receive(buffer);
if (firstReceived == 0)
{
rtbContent.AppendText("未接受到数据"+ "\r\n" );
}
if (firstReceived > 0) //接受到的长度大于0 说明有信息或文件传来
{
if (buffer[0] == 0) //0为文字信息
{
strSRecMsg = Encoding.UTF8.GetString(buffer, 1, firstReceived - 1);//真实有用的文本信息要比接收到的少1(标识符)
rtbContent.AppendText("对方 " + GetCurrentTime() + "\r\n" + strSRecMsg + "\r\n");
}
if (buffer[0] == 2)//2为文件名字和长度
{
string fileNameWithLength = Encoding.UTF8.GetString(buffer, 1, firstReceived - 1);
strSRecMsg = fileNameWithLength.Split('-').First(); //获取文件名
fileLength = Convert.ToInt64(fileNameWithLength.Split('-').Last());//获取文件长度
}
if (buffer[0] == 1)//1为文件
{
string fileNameSuffix = strSRecMsg.Substring(strSRecMsg.LastIndexOf('.')); //文件后缀
SaveFileDialog sfDialog = new SaveFileDialog()
{
Filter = "(*" + fileNameSuffix + ")|*" + fileNameSuffix + "", //文件类型
FileName = strSRecMsg
};
//如果点击了对话框中的保存文件按钮
if (sfDialog.ShowDialog(this) == DialogResult.OK)
{
string savePath = sfDialog.FileName; //获取文件的全路径
//保存文件
int received = 0;
long receivedTotalFilelength = 0;
bool firstWrite = true;
using (FileStream fs = new FileStream(savePath, FileMode.Create, FileAccess.Write))
{
while (receivedTotalFilelength < fileLength) //之后收到的文件字节数组
{
if (firstWrite)
{
fs.Write(buffer, 1, firstReceived - 1); //第一次收到的文件字节数组 需要移除标识符1 后写入文件
fs.Flush();
receivedTotalFilelength += firstReceived - 1;
firstWrite = false;
continue;
}
received = socketClient.Receive(buffer); //之后每次收到的文件字节数组 可以直接写入文件
fs.Write(buffer, 0, received);
fs.Flush();
receivedTotalFilelength += received;
}
fs.Close();
}
string fName = savePath.Substring(savePath.LastIndexOf("\\") + 1); //文件名 不带路径
string fPath = savePath.Substring(0, savePath.LastIndexOf("\\")); //文件路径 不带文件名
rtbContent.AppendText(strname + " " + GetCurrentTime() + "\r\n您成功接收了文件" + fName + "\r\n保存路径为:" + fPath + "\r\n");
}
}
}
}
catch (Exception ex)
{
rtbContent.AppendText("系统异常消息:" + ex.Message);
break;
}
}
}

先用CMD ping ，然后看看是不是端口通讯被占用，或者被防火墙干掉了