程序代码：

delegate void SetTextCallback(string text);
        private void SetText(string text)
        {
            try
            {
                if (this.richTextBox2.InvokeRequired)
                {
                    SetTextCallback d = new SetTextCallback(SetText);
                    this.Invoke(d, new object[] { text });//就是这个地方不理解，不知道如何将接收到的字符传给richtextbox2.text显示出来
                }
                else
                {
                    this.richTextBox2.Text += text;
                }
            }
            catch (Exception)
            {
            }
        }

        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)//串口是否收到字符，当收到字符时调用 SetText(string text);

        {
            char[] c;
            while (true)
            {
                try
                {
                    if (serialPort1.IsOpen)
                    {
                        c = new char[serialPort1.BytesToRead];
                        serialPort1.Read(c, 0, c.Length);
                        if (c.Length > 0)
                        {
                         
                            SetText(new string(c));//
                          
                        }
                    }
                }
                catch (Exception) { }
            }
        }