C#

BobJanova wrote:

TCP operates a timeout if no packets are sent for some time, because this is
usually a sign that the connection has been lost.

BobJanova wrote:

you want to maintain a connection despite no user interaction, you need to send
'keep-alive' packets or 'pings' every few seconds (one every 20s should be
enough) to keep the connection open

BobJanova wrote:

However, remember that if you do this, idle connections will never time
out and you can run out of server sockets if too many people leave your app
open, so you then should have some client code that logs out and closes the
socket after a longer inactive time (30 mins or so).

TCP does not do that.

BobJanova wrote:

I thought I'd read that, but if it is not TCP, then it is the operating system,
because if you open a TCP connection to your own server and send nothing in
either direction, at some point it will get closed.

SimpleData wrote:

I've used Control.CheckForIllegalCrossThreadCalls = false when the form is
loaded

SimpleData wrote:

Control.CheckForIllegalCrossThreadCalls = false

using (FileStream fs = new FileStream(last_save_location, FileMode.Append, FileAccess.Write))
{
    fs.Write(message, 8, bytesRead - 8);
    fs.Close();
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form2 form2;
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (form2 == null)
            {
                form2 = new Form2(this);
                form2.Show();
            }
            else
            {
                form2.Show();
            }
            this.Hide();
            button2.BackColor = Color.Green;
        }
    }
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form2 : Form
    {
        public Form form1;
        public Form2(Form form1)
        {
            InitializeComponent();
            this.form1 = form1;
        }

        private void Form2_Load(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (form1 == null)
            {
                form1 = new Form();
                form1.Show();
                
            }
            else
            {
                form1.Show();
            }
            this.Hide();
        }
    }
}