Bellow is the code for loop throught all files in a folder.

// How much deep to scan. (of course you can also pass it to the method)
const int HowDeepToScan=4;

public static void ProcessDir(string sourceDir, int recursionLvl) 
{
  if (recursionLvl<=HowDeepToScan)
  {
    // Process the list of files found in the directory.
    string [] fileEntries = Directory.GetFiles(sourceDir);
    foreach(string fileName in fileEntries)
    {
       // do something with fileName
       Console.WriteLine(fileName);
    }

    // Recurse into subdirectories of this directory.
    string [] subdirEntries = Directory.GetDirectories(sourceDir);
    foreach(string subdir in subdirEntries)
       // Do not iterate through reparse points
       if ((File.GetAttributes(subdir) &
            FileAttributes.ReparsePoint) !=
                FileAttributes.ReparsePoint)

            ProcessDir(subdir,recursionLvl+1);
  }
}

To create directory on web server with ASP.NET server side code, you can use this code:

[ C# ]

using System;
using System.Data;
using System.Configuration;
// We need this namespace to create directory
using System.IO;
 
public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string NewDir = Server.MapPath("New Folder");
        // Call function for creating a directory
        MakeDirectoryIfExists(NewDir);
    }
 
    private void MakeDirectoryIfExists(string NewDirectory)
    {
        try
        {
            // Check if directory exists
            if (!Directory.Exists(NewDirectory))
            {
                // Create the directory.
                Directory.CreateDirectory(NewDirectory);
            }
        }
        catch (IOException _ex)
        {
            Response.Write(_ex.Message);
        }
    }
}

[ VB.NET ]

' We need this namespace to make a directory
Imports System.IO
 
Partial Class _Default
    Inherits System.Web.UI.Page
 
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim NewDir As String = Server.MapPath("New Folder")
        ' Call function for creating a directory
        MakeDirectoryIfExists(NewDir)
    End Sub
 
    Private Sub MakeDirectoryIfExists(ByVal NewDirectory As String)
        Try
            ' Check if directory exists
            If Not Directory.Exists(NewDirectory) Then
                ' Create the directory.
                Directory.CreateDirectory(NewDirectory)
            End If
        Catch _ex As IOException
            Response.Write(_ex.Message)
        End Try
    End Sub