[WebMethod] 
             public DirectoryInfo[] Dir(string dir) 
             {
                   DirectoryInfo di = new DirectoryInfo(dir); 

                   DirectoryInfo[] diList = di.GetDirectories("*.*"); 

                   return diList; 

             } 

<WebMethod()> Public Function Dir(ByVal dir As String) As DirectoryInfo() 

    Dim di As New DirectoryInfo(dir) 

        Dim diList as di.GetDirectories("*.*") 

    Return diList 
End Function 

using System; 
using System.Collections; 
using System.ComponentModel; 
using System.Data; 
using System.Diagnostics; 
using System.Web; 
using System.Web.Services; 
using System.Xml.Serialization; 
using System.IO; 

namespace DirectoryTools 
{
      /// <summary> 
      /// Summary description for Service1. 
      /// </summary> 
      public class Service1 : System.Web.Services.WebService 
      {
            public Service1() 
            {
                  //CODEGEN: This call is required by the ASP.NET Web 
Services Designer 
                  InitializeComponent(); 
            } 

            #region Component Designer generated code 
            /// <summary> 
            /// Required method for Designer support - do not modify 
            /// the contents of this method with the code editor. 
            /// </summary> 
            private void InitializeComponent() 
            {
            } 
            #endregion 

            /// <summary> 
            /// Clean up any resources being used. 
            /// </summary> 
            protected override void Dispose( bool disposing ) 
            {
            } 
            // WEB SERVICE EXAMPLE 
            // The HelloWorld() example service returns the string Hello World 
            // To build, uncomment the following lines and then save and build the project 
// To test this web service, press F5 

            [WebMethod] 
            public string HelloWorld() 
            {
                  return "Hello World"; 
            } 

            [WebMethod()] 
            [XmlInclude(typeof(DirObject))] 
            public DirObject Test( string sPath) 
            {
                  DirectoryInfo di = new DirectoryInfo(sPath); 
                  DirectoryInfo[] diList = di.GetDirectories("*.*"); 
                  DirObject temp = new DirObject(); 
                  int x = 0; 
                  foreach ( DirectoryInfo d in diList) 
                  {
                        temp[x] = d; 
                        x++; 
                  } 
                  return temp; 
            } 
      } 

      [XmlInclude(typeof(DirItem))] 
      public class DirObject 
      {
            [XmlElement("Item")] 

            public ArrayList Data 
            {
                  get { return data;} 
                  set { data = value;} 
            } 
            protected ArrayList data = new ArrayList(); 

            public object this [int idx] 
            {
                  get 
                  {
                         if (idx > -1 && idx < data.Count) 
                         {
                               return (data[idx]); 
                         } 
                         else 

                               return null; 
                         } 
                  } 

                  set 
                  {
                         if (idx > -1 && idx < data.Count) 
                         {
                               data[idx] = value; 
                         } 
                         else if (idx == data.Count) 
                         {
                               DirItem x = new DirItem(); 
                               DirectoryInfo temp = (DirectoryInfo)value; 
                               x.FileName = temp.FullName; 
                               data.Add(x); 

                         } 
                         else 
                         {
                               //Possibly throw an exception here. 
} 
                  } 
            } 

      } // MyClass 

      public class DirItem 
      {
            protected string filename; 

            public DirItem() 
            {
            } 

            [XmlAttribute("FileName")] 
            public string FileName 
            {
                  get { return filename;} 
                  set { filename = value;} 
            } 
      } 

} //Name space 

Imports System.Web.Services 
Imports System.IO 
Imports System.Xml 
Imports System.Xml.Serialization 

<WebService(Namespace:="http://microsoft.com/webservices/")> Public Class Service1 
    Inherits System.Web.Services.WebService 

#Region " Web Services Designer Generated Code " 

    Public Sub New() 
        MyBase.New() 

        'This call is required by the Web Services Designer. 
        InitializeComponent() 

        'Add your own initialization code after the InitializeComponent() call 

    End Sub 
    'Required by the Web Services Designer 
    Private components As System.ComponentModel.Container 

    'Do not modify it using the code editor. 
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent() 

        components = New System.ComponentModel.Container() 

    End Sub 

    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean) 
        'Do not modify it using the code editor. 
    End Sub 

#End Region 

    ' 
    <WebMethod()> Public Function Test(ByVal path As String) As DirObject 
        Dim di As DirectoryInfo = New DirectoryInfo(path) 
        Dim diList() As DirectoryInfo 
        Dim d As DirectoryInfo 
        Dim temp As DirObject = New DirObject() 
        Dim x As Integer = 0 

        diList = di.GetDirectories("*.*") 

        For Each d In diList 
            temp(x) = d 
            x = x + 1 
        Next 
        Return temp 
    End Function 


    <XmlInclude(GetType(DirItem)), XmlRoot("Root")> Public Class DirObject 
        Private pdata As ArrayList = New ArrayList() 

        <XmlElement("Item")> Public Property Data() As ArrayList 
        Get 
            Return pdata 
        End Get 

        Set(ByVal Value As ArrayList) 
            pdata = Value 
        End Set 
    End Property 

    Default Public Property base(ByVal idx As Integer) As Object 
        Get 
            If (idx > -1 And idx < Data.Count) Then 

                Return pdata(idx) 

            Else 

                Return Nothing 

            End If 

        End Get 

        Set(ByVal Value As Object) 
            If (idx > -1 And idx < pdata.Count) Then 
                pdata(idx) = Value 

            ElseIf (idx = pdata.Count) Then 
                Dim x As DirItem = New DirItem() 
                Dim temp As DirectoryInfo 

                temp = CType(Value, DirectoryInfo) 
                x.FileName = temp.FullName 
                x.LastAccessDate = temp.LastAccessTime 
                pdata.Add(x) 

            Else 
                'Possibly throw an exception here. 
            End If 

        End Set 

    End Property 
    End Class 

    Public Class DirItem 

        Private pfilename As String 
        Private pLastAccessDate As Date 

        Sub DirItem() 

        End Sub 

        <XmlElement("FileName")> Public Property FileName() As String 
            Get 
                Return pfilename 
            End Get 

            Set(ByVal Value As String) 
                pfilename = Value 
            End Set 

        End Property 

     <XmlElement("LastAccessDate")> Public Property LastAccessDate() As Date 
            Get 
                Return pLastAccessDate 
            End Get 

            Set(ByVal Value As Date) 
                pLastAccessDate = Value 
            End Set 

        End Property 

    End Class 

End Class