程序代码：

 
private void button1_Click(object sender, EventArgs e)
{
            serialPort1.PortName = "COM1"; 
            serialPort1.BaudRate = 9600;     
            serialPort1.Open();    
            byte[] data = Encoding.Unicode.GetBytes(textBox1.Text);    
            string str = Convert.ToBase64String(data);                 
            serialPort1.WriteLine(str);
            MessageBox.Show("数据发送成功！", "系统提示");
       
           byte[] data = Convert.FromBase64String(serialPort1.ReadLine());
           textBox2.Text = Encoding.Unicode.GetString(data); 
           serialPort1.Close();                             
           MessageBox.Show("数据接收成功！", "系统提示");      

 }