在控件离开当前方法之前，必须分配out参数

private void getDetails(out IPAddress ipAddress, out int port)
{
    IPAddress Ip;
    int Port;

    try
    {
        Ip = IPAddress.Parse(textboxIp.Text);
        Port = int.Parse(textboxPort.Text);
    }
    catch (Exception ex)
    {
        IPAddress Ip null;
        int Port = -1;
        MessageBox.Show(ex.Message);
    }
}
private void getDetails(out IPAddress ipAddress