Get the all Files with their name, size from a folder ASP.Net

You can get all the filename from any directory. We can also get their names, sizes, then we can operate any condition to add/remove files from the datatable, in which we store all the files. In the below example we show all the files in Gridview
 public void LoadUploadedFiles(ref GridView gv)
    {
         DataTable dtFiles =new DataTable();
         if (Session["dt"] != null)
         {
             dtFiles = (DataTable)Session["dt"];
             DataTable dtFiles1 = GetFilesInDirectory(HttpContext.Current.Server.MapPath(foldername));
         }
        gv.DataSource = dtFiles;
        gv.DataBind();
     
    }
 public DataTable GetFilesInDirectory(string sourcePath)
    {
        System.Data.DataTable dtFiles = new System.Data.DataTable();
        if ((Directory.Exists(sourcePath)))
        {
            dtFiles.Columns.Add(new System.Data.DataColumn("Name"));
            dtFiles.Columns.Add(new System.Data.DataColumn("Size"));
            dtFiles.Columns["Size"].DataType = typeof(double);
            dtFiles.Columns.Add(new System.Data.DataColumn("ConvertedSize"));
            DirectoryInfo dir = new DirectoryInfo(sourcePath);
            foreach (FileInfo files in dir.GetFiles("*.*"))
            {
                System.Data.DataRow drFile = dtFiles.NewRow();
                drFile["Name"] = files.Name;
                drFile["Size"] = files.Length;
                drFile["ConvertedSize"] = CalculateFileSize(files.Length);
                dtFiles.Rows.Add(drFile);
            }
        }
        return dtFiles;
    }

public string CalculateFileSize(double FileInBytes)
    {
        string strSize = "00";
        if (FileInBytes < 1024)
            strSize = FileInBytes + " B";//Byte
        else if (FileInBytes > 1024 & FileInBytes < 1048576)
            strSize = Math.Round((FileInBytes / 1024), 2) + " KB";//Kilobyte
        else if (FileInBytes > 1048576 & FileInBytes < 107341824)
            strSize = Math.Round((FileInBytes / 1024) / 1024, 2) + " MB";//Megabyte
        else if (FileInBytes > 107341824 & FileInBytes < 1099511627776)
            strSize = Math.Round(((FileInBytes / 1024) / 1024) / 1024, 2) + " GB";//Gigabyte
        else
            strSize = Math.Round((((FileInBytes / 1024) / 1024) / 1024) / 1024, 2) + " TB";//Terabyte
        return strSize;
    }