C# file and directory operations

So, I was facing the task for displaying the directory and file contents for each directory and could not find any good help... anyways, here are the functions as I came up with them

Displaying all the directory names along with date last modified

    private string displayDirectories( DirectoryInfo parentDirectory )
    {
        DirectoryInfo[] diArrGE = parentDirectory.GetDirectories();
        // Response.Write(parentDirectory.Name + "

---

");
        String link = "
";
        foreach (DirectoryInfo dri in diArrGE)
            {
            Int32 index = dri.Name.IndexOf('_');
            String dirName = dri.Name.Substring(index).Replace("_", " ");
            link += string.Format("
", category, dri.Name, dirName, dri.LastWriteTime.ToLongDateString());
            }
        link += "

{2} (Last updated: {3})

";
     
        return link;
        }



Displaying all the files in a directory sorted by date modified... 



    private string displayFiles( DirectoryInfo di )
        {
        string link = string.Empty;
         StringBuilder test = new StringBuilder();
//I just need html files in the directory
        FileInfo[] rgFiles = di.GetFiles("*.html");


        try
            {
            string category = "";
            if (di.FullName.Contains("Agenda"))
                {
                category = "Agenda";

                }
            else if (di.FullName.Contains("Minutes"))
                {
                category = "Minutes";
                }
            else
            {
                category = "Panel";
            }

            // Now read the creation time for each file
            DateTime[] creationTimes = new DateTime[rgFiles.Length];
            for (int i = 0; i < rgFiles.Length; i++)
                creationTimes[i] = rgFiles[i].LastWriteTime;
         //   Response.Write(creationTimes.Length);
            // sort it
            Array.Sort(creationTimes, rgFiles);

            foreach (FileInfo fi in rgFiles)
                {

           
                string[] result = fi.Name.Split(new Char[] { '.' });


                string[] fileName = result[0].Split('_');

                string fileNameDisplay = string.Format("{0} {1},{2}", fileName[1], fileName[0], fileName[2]);

                //  Response.Write(fileNameDisplay);


                link = "" + fileNameDisplay + "   {Last Update: " +
                               fi.LastWriteTime.ToString("D") + "}";

                test.Insert(0, link);
                }
            //link = "";
                test.Insert(0, "
");
            test.Append("
");
            }
        catch (Exception e)
            {

            Response.Write("Error in file " + e);
            }
        return test.ToString();
        }

I really liked the sorting function

       // Now read the creation time for each file
            DateTime[] creationTimes = new DateTime[rgFiles.Length];
            for (int i = 0; i < rgFiles.Length; i++)
                creationTimes[i] = rgFiles[i].LastWriteTime;
         //   Response.Write(creationTimes.Length);
            // sort it
            Array.Sort(creationTimes, rgFiles);


WOO WOO for that