display files and directories in Listview

Below is the C# code which displays all files and directories in listview control with their file size and creation date. If it is file then it also displays the extension of the file e.g. .txt, .jpg etc

Below is the design view of the project:

Listview to display files and directories with size and date created

Below is the source code of the project:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;

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

        private void button1_Click(object sender, EventArgs e)
        {
            listView1.Items.Clear();
            DirectoryInfo FileNm = new DirectoryInfo(textBox1.Text);
            var filename = FileNm.GetFiles();
            foreach (FileInfo f in filename)
            {
                ListViewItem a= listView1.Items.Add(f.Name);
                a.SubItems.Add("File size: "+f.Length+" File type is: "+f.Extension);
                a.SubItems.Add(""+f.LastAccessTime);
            }

            var dirname = FileNm.GetDirectories();
            foreach (DirectoryInfo f1 in dirname)
            {
                ListViewItem a = listView1.Items.Add("["+f1.Name+"]");
                a.SubItems.Add("[" + f1.Attributes + "]");
                a.SubItems.Add("[" + f1.LastAccessTime + "]");
            }
        }
    }
}