FileInfo c# find 2 files in folder

public partial class Form1 : Form
{
    int maxwidth = 0;
    public Form1()
    {
        InitializeComponent();
    }

    private void SearchAndDisplay()
    {
        Control ctrl = null; ;
        int relative = 10;
        DirectoryInfo di = new DirectoryInfo(@"C:\Users\kuthupar\Documents");
        // An empty list of FileInfo objects
        List<FileInfo> lFi = new List<FileInfo>();

        //Add the files of the directory to the list
        lFi.AddRange(di.GetFiles("BET*"));

        //Find the files on the list using a delegate
        lFi = lFi.FindAll(delegate(FileInfo f) { return f.Extension.ToLower() == ".ppt" || f.Extension.ToLower() == ".pptx" || f.Extension.ToLower() == ".ppt"; });
        int i = 1;
        //Iterate over each filtered file
        foreach (FileInfo fi in lFi)
        {
            TextBox txtbx = new TextBox();
            txtbx.Name = "TextBox " + i.ToString();
            try
            {
                Control[] ctrlArray = this.Controls.Find("TextBox " + (this.Controls.OfType<TextBox>().Count()).ToString(), false);
                ctrl = ctrlArray[0];
            }
            catch { }
            if (ctrl != null)
            {
                relative = ctrl.Bottom + ctrl.Height / 2;
            }
            txtbx.Top = relative;
            txtbx.Text = fi.Name + ":" + fi.LastWriteTime.ToString();
            maxwidth = maxwidth < txtbx.Text.Length * 6 + 10? txtbx.Text.Length*6+10: maxwidth;
            txtbx.Width = maxwidth;
            this.SuspendLayout();
            this.Controls.Add(txtbx);
            this.ResumeLayout();
            i++;
        }

    }

    private void AlignWidth()
    {
        foreach(Control ctrl in this.Controls.OfType<TextBox>())
        {
            ctrl.Width = maxwidth;
        }
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        SearchAndDisplay();
        AlignWidth();
    }


}