Search Files on Server's Folder (Directory) and display details in ASP.Net

Please refer this code

HTML

File Name :
<asp:TextBox ID="txtFileName" runat="server"></asp:TextBox>
<asp:Button ID="btnSearch" Text="Search" OnClick="Search" runat="server" />
<br />
<asp:GridView ID="gvFile" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="FileName" HeaderText="FileName" />
        <asp:BoundField DataField="Directory" HeaderText="File Directory" />
    </Columns>
</asp:GridView>

Namespaces

using System.IO;
using System.Data;

C#

protected void Search(object sender, EventArgs e)
{
    bool isPresent = false;
    if (!string.IsNullOrEmpty(this.txtFileName.Text.Trim()))
    {
        DirectoryInfo dir = new DirectoryInfo(Server.MapPath("~/Files"));
        FileInfo[] listfiles = dir.GetFiles();
        if (listfiles.Length > 0)
        {
            SearchFile(listfiles);
        }
        else
        {
            DirectoryInfo[] subDirectory = dir.GetDirectories();
            foreach (DirectoryInfo directoryInfo in subDirectory)
            {
                FileInfo[] files = directoryInfo.GetFiles();
                if (files.Length > 0)
                {
                    isPresent = SearchFile(files);
                    if (isPresent)
                    {
                        break;
                    }
                }
            }
        }
    }
    if (!isPresent)
    {
        ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('File not found!')", true);
    }
}

private bool SearchFile(FileInfo[] files)
{
    bool isPresent = false;
    foreach (FileInfo file in files)
    {
        if (file.Name == this.txtFileName.Text.Trim())
        {
            if (file.Exists)
            {
                DataTable dt = new DataTable();
                dt.Columns.Add("FileName");
                dt.Columns.Add("Directory");
                dt.Rows.Add(file.Name, "~\\" + file.Directory.Parent.Name + "\\" + file.Directory.Name);
                this.gvFile.DataSource = dt;
                this.gvFile.DataBind();
                isPresent = true;
                break;
            }
        }
    }
    return isPresent;
}

Screenshot