How to display accessible files only and skip inaccessible file?

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Diagnostics;
using System.Reflection;
using System.Security.Permissions;


namespace MonitorDirectory
{
    public partial class Form1 : Form
    {   private Timer timer;
        private int count;
        DataTable dt = new DataTable();
        DataRow dr;
        String[] s1;
        public Form1()
        {
            InitializeComponent();
        }

 
        private void Form1_Load(object sender, EventArgs e)
        {

            count = 0;
            timer = new Timer();
            timer.Interval = 1000;
            timer.Tick += new EventHandler(timer1_Tick);
            timer.Start();
            
                    
            s1 = Directory.GetFiles(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location), "*.*", SearchOption.AllDirectories);
            for (int i = 0; i <= s1.Length - 1; i++)
            {
                if (i == 0)
                   {
                       dt.Columns.Add("File_Name");
                       dt.Columns.Add("File_Type");
                       dt.Columns.Add("File_Size");
                       dt.Columns.Add("Create_Date");
                   }

                try
                {
                   FileInfo info = new FileInfo(s1[i]);
                   FileSystemInfo sysInfo = new FileInfo(s1[i]);
                   dr = dt.NewRow();

                   dr["File_Name"] = sysInfo.Name;
                   dr["File_Type"] = sysInfo.Extension;
                   dr["File_Size"] = (info.Length / 1024).ToString();
                   dr["Create_Date"] = sysInfo.CreationTime.Date.ToString("dd/MM/yyyy");
                   dt.Rows.Add(dr);


                   if ((info.Length / 1024) > 1500000)
                   {
                      MessageBox.Show("" + sysInfo.Name + " had reach its size limit.");
                   }
                }

                catch (Exception ex)
                {
                  MessageBox.Show("Error : " + ex.Message);
                  continue;
                }
            }

            if (dt.Rows.Count > 0)
            {
               dataGridView1.DataSource = dt;
            }
       }


        private void timer1_Tick(object sender, EventArgs e)
        {
                count++;
                if (count == 60)
                {
                    count = 0;
                    timer.Stop();
                    Application.Restart();
                }
        }

        public string secondsToTime(int seconds)
        {
             int minutes = 0;
             int hours = 0;

             while (seconds >= 60)
             {
                minutes += 1;
                seconds -= 60;
             }
             while (minutes >= 60)
             {
                hours += 1;
                minutes -= 60;
             }

             string strHours = hours.ToString();
             string strMinutes = minutes.ToString();
             string strSeconds = seconds.ToString();

             if (strHours.Length < 2)
                 strHours = "0" + strHours;
             if (strMinutes.Length < 2)
                 strMinutes = "0" + strMinutes;
             if (strSeconds.Length < 2)
                 strSeconds = "0" + strSeconds;
             return strHours + ":" + strMinutes + ":" + strSeconds;
         }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            BindingSource bind = new BindingSource();
            bind.DataSource = dt;
            bind.Filter = string.Format("File_Name like '%{0}%'", textBox1.Text.Trim());
        }
         
   }
}