c# 串口调试

public bool IsCommPortValid(int port)

{
    try
    {
    SerialPort sp = new SerialPort("COM"+port.ToString());
    sp.Close();
    }
    catch
    {
        return false;
    }
}

                string port = null;
                port = Console.ReadLine();
                SerialPort sp = new SerialPort("COM" + port);
                try
                {
                    sp.Open();
                    Thread.Sleep(1000);
                    sp.Close();
                        Console.WriteLine("端口尚未打开");
                }
                catch (InvalidOperationException e)
                {
                    Console.WriteLine("端口已打开");
                }
                catch(Exception ee)
                {
                    Console.WriteLine( new Exception(ee.Message));
                }

string port = null;
port = Console.ReadLine();
SerialPort sp1 = new SerialPort("COM1");
sp1.Open();
SerialPort sp = new SerialPort("COM" + port);
try
{
    sp.Open();
    sp.Close();
    Console.WriteLine("端口尚未打开");
}
catch (InvalidOperationException e)
{
    Console.WriteLine("端口已打开");
}
catch(Exception ee)
{
    Console.WriteLine( new Exception(ee.Message));
}