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

namespace InternetConnectionState
{
    public delegate void ConnectionEvent(object sender, EventArgs e);

    public partial class InternetConnectionState : UserControl
    {
        public InternetConnectionState()
        {
            InitializeComponent();
            this.MaximumSize = new Size(170, 22);
            this.MinimumSize = new Size(170, 22);
        }

        [DllImport("wininet.dll")]
        private extern static bool InternetGetConnectedState(out int desc, int reserved);

        public enum ConnectionState
        {
            Disconnected,
            Connected
        }

        public ConnectionState InternetConnection
        {
            get
            {
                int desc;
                return (InternetGetConnectedState(out desc, 0)) ?
                            ConnectionState.Connected :
                            ConnectionState.Disconnected;
            }
        }

        [Description("Occurs while disconnected to the internet.")]
        public event ConnectionEvent WhileConnected;

        [Description("Occurs while connected to the internet.")]
        public event ConnectionEvent WhileDisconnected;

        public virtual void Connected(object sender, EventArgs e)
        {
            if (WhileConnected != null)
                WhileConnected(sender, e);
        }

        public virtual void Disconnected(object sender, EventArgs e)
        {
            if (WhileDisconnected != null)
                WhileDisconnected(sender, e);
        }

        private void InternetConnectionState_Load(object sender, EventArgs e)
        {
            timer1.Start();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            if (InternetConnection == ConnectionState.Connected)
            {
                label1.Text = "State: Connected";
                label1.ForeColor = Color.Green;
                ovalShape1.BorderColor = Color.Lime;
                ovalShape1.FillColor = Color.Lime;
                ovalShape1.FillGradientColor = Color.Green;
            }

            else
            {
                label1.Text = "State: Disconnected";
                label1.ForeColor = Color.Red;
                ovalShape1.BorderColor = Color.Red;
                ovalShape1.FillColor = Color.Red;
                ovalShape1.FillGradientColor = Color.Maroon;
            }
        }
    }
}