using Microsoft.Data.SqlClient;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Configuration;
using System.Data;
using System.Diagnostics;
using System.Diagnostics.Tracing;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp4
{
    // it the ability to create events.
    public class SqlClientListener : EventListener
    {
        public SqlClientListener()
        {
            using (StreamWriter wr = new StreamWriter("log.txt", true))
            {
                wr.WriteLine("-----");
            }
        }

        protected override void OnEventSourceCreated(EventSource eventSource)
        {
            // Only enable events from SqlClientEventSource.
            if (eventSource.Name.StartsWith("Microsoft.Data.SqlClient"))
            {
                // Use EventKeyWord 2 to capture basic application flow events.
                // See the above table for all available keywords.
                EnableEvents(eventSource, EventLevel.Verbose, (EventKeywords)2);
            }
        }

        // This callback runs whenever an event is written by SqlClientEventSource.
        // Event data is accessed through the EventWrittenEventArgs parameter.
        protected override void OnEventWritten(EventWrittenEventArgs eventData)
        {
            // Print event data.
            Debug.WriteLine(eventData.Payload[0]);
            using (StreamWriter wr = new StreamWriter("log.txt", true))
            {
                wr.WriteLine(eventData.Payload[0]);
            }
        }
    }

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            using (new SqlClientListener())
            using (var con = new SqlConnection(ConfigurationManager.ConnectionStrings["Azure_DB"].ConnectionString))
            {
                txtResult.Text = "Connecting...";
                //con.OpenAsync().Wait();
                con.Open();

                using (var cmd = con.CreateCommand())
                {
                    cmd.CommandText = @"SELECT SUSER_SNAME() AS CurrentLogin";

                    using (var reader = cmd.ExecuteReader())
                    {
                        while (reader.Read())
                        {
                            string login = Convert.ToString(reader["CurrentLogin"]);
                            txtResult.Text += Environment.NewLine + "You have successfully logged on as: " + login;
                        }
                    }
                }
                con.Close();

                txtResult.Text += Environment.NewLine + "Connection closed";
            }
        }
    }
}