Question

I am attempting to make an image control be displayed after a port check is run.

namespace MonitorFlux
{
    public partial class Form1 : Form
    {

        PortChecks PortCheckObject = new PortChecks();

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        public static void CheckHTTP()
        {
            string hostname = "google.com";
            int portno = 80;

            IPAddress ipa = (IPAddress)Dns.GetHostAddresses(hostname)[0];

            Form1 formobject = new Form1();  // Create new class object, so can call other methods in the class
            try
            {
                System.Net.Sockets.Socket sock = new System.Net.Sockets.Socket(System.Net.Sockets.AddressFamily.InterNetwork, System.Net.Sockets.SocketType.Stream, System.Net.Sockets.ProtocolType.Tcp);
                sock.Connect(ipa, portno);
                if (sock.Connected == true) // Port is in use and connection is successful
                {

                    MessageBox.Show("Port is Open");
                    formobject.displayGreen();
                }
                sock.Close();

            }
            catch (System.Net.Sockets.SocketException ex)
            {
                if (ex.ErrorCode == 10061) // Port is unused and could not establish connection 
                {
                    formobject.displayRed();
                    MessageBox.Show("Port is Closed");
                }
                else
                {
                    MessageBox.Show(ex.Message);
                }
            }

        }

        public void displayGreen()
        {
            pictureBox2.Visible = false;
            pictureBox1.Visible = true;
        }

        private void displayRed()
        {
            pictureBox2.Visible = true;
            pictureBox1.Visible = false;
        }

        private void testCheck_Click(object sender, EventArgs e)
        {
            CheckHTTP();
            // MessageBox.Show(PortCheckObject.httpport);
        }


    }
}

It won’t let me call a method from within the try clause e.g. displayRed()

So I create an object of Form1 class to run the displayRed() method, although when the method runs it doesn’t hide the image controls as expected. I assume this is because I have create another instance of the class. (If I run the method normally – not using an object, the image controls are hidden correctly.)

So I guess my questions is how can I get around this issue?

Please let me know if I have not explained the situation very well and I’ll try my best to elaborate. Thanks

Answer 1

CheckHTTP is static and you can’t call instance methods from a static method unless, like you’ve shown, you create a new object in that method, in which case you are working with a different object so you likely won’t get the behavior you want.