Task.Factory.StartNew(Sub()
                                  Me.Invoke(Sub() Me.Cursor = Cursors.WaitCursor)
 
                                  For Each vUnidad As String In Directory.GetLogicalDrives()
 
 
                                      ListBox1.Invoke(DirectCast(Sub() ListBox1.Items.Add(vUnidad), MethodInvoker))
                                  Next vUnidad
 
                                  ''Recorrer las unidades detectadas 
                                  Dim Pdisco As String
                                  For i As Integer = 0 To Me.ListBox1.Items.Count - 1
                                      Pdisco = CStr(ListBox1.Items(i))
 
                                      'Obtener los ficheros de las unidades 
                                      Try
                                          Dim DirInfo As New DirectoryInfo(Pdisco)
                                          For Each Files As System.IO.FileInfo In DirInfo.GetFiles("*", SearchOption.TopDirectoryOnly)
                                              ListBox2.Invoke(DirectCast(Sub() ListBox2.Items.Add(Pdisco & Files.ToString), MethodInvoker))
                                          Next
                                      Catch ex As Exception
                                      End Try
                                  Next
                              End Sub).ContinueWith(Sub()
                                                        Me.Invoke(Sub() Me.Cursor = Cursors.Arrow)
                                                    End Sub)
 

        Dim strDirPath As String = "C:\"
 
        Dim astrSubDirectories As String() = Directory.GetDirectories(strDirPath)
        Dim strSubDirectory As String
        For Each strSubDirectory In astrSubDirectories
            Dim direct As String = strSubDirectory.Remove(0, strSubDirectory.LastIndexOf("\") + 1)
 
            Try
                Dim astrFiles As String() = Directory.GetFiles(strDirPath & direct)
                ListBox1.Items.Add(strSubDirectory)
                For Each strFileName In astrFiles
                    ListBox1.Items.Add(strFileName)
                Next
 
            Catch exc As Exception
 
            End Try
        Next
 
        Try
            Dim DirInfo As New DirectoryInfo(strDirPath)
            For Each Files As System.IO.FileInfo In DirInfo.GetFiles("*", SearchOption.TopDirectoryOnly)
                ListBox1.Items.Add(strDirPath & Files.ToString)
            Next
        Catch ex As Exception
        End Try

       Dim allDrives() As DriveInfo = DriveInfo.GetDrives()
        For Each [Drive] In allDrives
            Try
                Dim astrSubDirectories As String() = Directory.GetDirectories([Drive].ToString)
                Dim strSubDirectory As String
                For Each strSubDirectory In astrSubDirectories
                    Dim direct As String = strSubDirectory.Remove(0, strSubDirectory.LastIndexOf("\") + 1)
 
                    Try
                        Dim astrFiles As String() = Directory.GetFiles([Drive].ToString & direct)
                        ListBox1.Items.Add(strSubDirectory)
                        For Each strFileName In astrFiles
                            ListBox1.Items.Add(strFileName)
                        Next
 
                    Catch exc As Exception
 
                    End Try
                Next
 
                Try
                    Dim DirInfo As New DirectoryInfo([Drive].ToString)
                    For Each Files As System.IO.FileInfo In DirInfo.GetFiles("*", SearchOption.TopDirectoryOnly)
                        ListBox1.Items.Add([Drive].ToString & Files.ToString)
                    Next
                Catch ex As Exception
               'MessageBox.Show(ex.Message)
                End Try
            Catch ex As Exception
              'MessageBox.Show(ex.Message)
            End Try
 
        Next

"*", SearchOption.AllDirectories

Dim astrFiles As String() = Directory.GetFiles("C:\" & direct, "*", SearchOption.AllDirectories)

             Dim strDrive As String = "D:\" '[Drive].ToString
        Dim DriveSubDirectories As String() = Directory.GetDirectories(strDrive)
        For Each strSubDirectory As String In DriveSubDirectories
            Dim strFolder As String = strSubDirectory.Remove(0, strSubDirectory.LastIndexOf("\") + 1)
            ListBox1.Items.Add(strSubDirectory) '<---Carpeta
            Try
                Dim strFiles As String() = Directory.GetFiles(strDrive & strFolder, "*", SearchOption.AllDirectories)
                For Each strFileName In strFiles
                    ListBox1.Items.Add(strFileName) '<--Archivo con ruta completa
                Next
            Catch ex As Exception
                '   MessageBox.Show(ex.Message)
            End Try 'strFiles
        Next   'strSubDirectory
        Try
            Dim DirInfo As New DirectoryInfo(strDrive)
            For Each Files As System.IO.FileInfo In DirInfo.GetFiles("*", SearchOption.TopDirectoryOnly)
                ListBox1.Items.Add(strDrive & Files.ToString)
            Next
        Catch ex As Exception
        End Try 'DirInfo

 
           Dim allDrives() As DriveInfo = DriveInfo.GetDrives()
        For Each [Drive] In allDrives
            Try
                Dim strDrive As String = [Drive].ToString
                Dim DriveSubDirectories As String() = Directory.GetDirectories(strDrive)
                For Each strSubDirectory As String In DriveSubDirectories
                    Dim strFolder As String = strSubDirectory.Remove(0, strSubDirectory.LastIndexOf("\") + 1)
                    ListBox1.Items.Add(strSubDirectory) '<---Carpeta
                    Try
                        Dim strFiles As String() = Directory.GetFiles(strDrive &
                                                                      strFolder,
                                                                      "*",
                                                                      SearchOption.AllDirectories)
                        For Each strFileName In strFiles
                            ListBox1.Items.Add(strFileName) '<--Archivo con ruta completa
                        Next 'strFileName
                    Catch ex As Exception
                        '   MessageBox.Show(ex.Message)
                    End Try 'strFiles
                Next  'strSubDirectory
 
                Try
                    Dim DirInfo As New DirectoryInfo(strDrive)
                    For Each Files As System.IO.FileInfo In DirInfo.GetFiles("*", SearchOption.TopDirectoryOnly)
                        ListBox1.Items.Add(strDrive & Files.ToString)
                    Next 'Files
                Catch ex As Exception
                    '   MessageBox.Show(ex.Message)
                End Try 'DirInfo
 
            Catch ex As Exception
                MessageBox.Show(ex.Message)
            End Try 'Drives
        Next '[Drive]
 

 
 Private Sub FormA_FormClosed(sender As Object, e As FormClosedEventArgs) Handles Me.FormClosed
        '  FormA.Visible = True
        FormA.Show()
    End Sub
 

Public NotInheritable Class FormA : Inherits Form
 
    Friend ButtonShowFormB As Button
 
    Public Sub New()
        MyClass.InitializeComponent()
        Me.Text = "FormA"
    End Sub
 
    Private Sub FormA_VisibleChanged(sender As Object, e As EventArgs) Handles Me.VisibleChanged
 
        If DirectCast(sender, Form).Visible Then
            Me.ButtonShowFormB = New Button With
       {
         .Text = "Show FormB",
.Location = New Point(10, 10)
       }
            Me.Controls.Add(Me.ButtonShowFormB)
            AddHandler Me.ButtonShowFormB.Click, AddressOf ButtonShowFormB_Click
 
        End If
    End Sub
 
 
    Private Sub FormMain_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
        Me.Controls.Add(Me.ButtonShowFormB)
    End Sub
 
    Private Sub ButtonShowFormB_Click(ByVal sender As Object, ByVal e As EventArgs)
        RemoveHandler Me.ButtonShowFormB.Click, AddressOf ButtonShowFormB_Click
        Me.ButtonShowFormB.Dispose()
        Me.ButtonShowFormB = Nothing
        Me.Hide()
        FormB.Show()
    End Sub
 
 
End Class
 
Public NotInheritable Class FormB : Inherits Form
    Friend ButtonShowFormB As Button
    Public Sub New()
        Me.Text = "FormB"
        Me.ButtonShowFormB = New Button With
            {
              .Text = "Show FormA",
              .Location = New Point(10, 10)
            }
        AddHandler Me.ButtonShowFormB.Click, AddressOf ButtonShowFormB_Click
    End Sub
 
    Private Sub FormA_FormClosed(sender As Object, e As FormClosedEventArgs) Handles Me.FormClosed
        '  FormA.Visible = True
        FormA.Show()
    End Sub
 
    Private Sub FormMain_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
        Me.Controls.Add(Me.ButtonShowFormB)
    End Sub
 
    Private Sub ButtonShowFormB_Click(ByVal sender As Object, ByVal e As EventArgs)
        Me.Close()
    End Sub
End Class

 
Dim frmMain As New FormA
        frmMain.Show()
 

Public NotInheritable Class FormA : Inherits Form
 
    Friend ButtonShowFormB As Button
 
    Public Sub New()
        MyClass.InitializeComponent()
        Me.Text = "FormA"
        Me.ButtonShowFormB = New Button With
            {
              .Text = "Show FormB",
              .Location = New Point(10, 10)
            }
        AddHandler Me.ButtonShowFormB.Click, AddressOf ButtonShowFormB_Click
    End Sub
 
    Private Sub FormMain_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
        Me.Controls.Add(Me.ButtonShowFormB)
    End Sub
 
    Private Sub ButtonShowFormB_Click(ByVal sender As Object, ByVal e As EventArgs)
        'Libera los controles
        ButtonShowFormB.Dispose()
        RemoveHandler Me.ButtonShowFormB.Click, AddressOf ButtonShowFormB_Click
 
        'Oculta el form
        Me.Hide()
 
        'Muestra el Form2
        FormB.Show()
    End Sub
 
End Class

Public NotInheritable Class FormB : Inherits Form
 
    Friend WithEvents ButtonShowFormA As Button
 
    Public Sub New()
 
        MyClass.InitializeComponent()
 
        With Me
            .Text = "FormFB"
            .FormBorderStyle = FormBorderStyle.FixedDialog
            .Owner = My.MyProject.Forms.FormA
            .StartPosition = FormStartPosition.CenterParent
        End With
 
        Me.ButtonShowFormA = New Button With
            {
              .Text = "Show FormA",
              .Location = New Point(10, 10)
            }
 
    End Sub
 
    Private Sub FormB_FormClosing(sender As Object, e As FormClosingEventArgs) Handles Me.FormClosing
        Dim frm As New FormA
        frm.Show()
    End Sub
 
    Private Sub FormDlg_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
        Me.Controls.Add(Me.ButtonShowFormA)
    End Sub
 
    Private Sub ButtonShowFormA_Click(ByVal sender As Object, ByVal e As EventArgs) Handles ButtonShowFormA.Click
        Me.Close()
    End Sub
 
End Class

   Private Sub FormB_FormClosing(sender As Object, e As FormClosingEventArgs) Handles Me.FormClosing
        Dim frm As New FormA
        frm.Show()
    End Sub

    Private Sub ButtonShowFormB_Click(ByVal sender As Object, ByVal e As EventArgs)
        'Libera los controles
        '  ButtonShowFormB.Dispose()
        'RemoveHandler Me.ButtonShowFormB.Click, AddressOf ButtonShowFormB_Click
        MyBase.Dispose(disposing:=True) 'o  Me.Dispose()
 
        'Oculta el form
        Me.Hide()
 
        'Muestra el Form2
        FormB.Show()
    End Sub

Public NotInheritable Class frmMain
    Inherits Form
    Friend MyButton1 As Button
 
    Public Sub New()
 
        ' Llamada necesaria para el diseñador.
        MyClass.InitializeComponent()
        Me.MyButton1 = New Button With {
            .Text = "Show Form2",
            .Location = New Point(10, 10)
        }
        ' Agregue cualquier inicialización después de la llamada a InitializeComponent().
        AddHandler MyButton1.Click, AddressOf MyButton1_Click
    End Sub
 
 
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.Controls.Add(MyButton1)
        Me.Text = "frmMain"
    End Sub
    Private Sub MyButton1_Click(sender As Object, e As EventArgs)
        DisposeControls()
        Me.Hide()
        frmDialog.Show()
    End Sub
 
    Sub DisposeControls()
        Me.MyButton1.Dispose()
        RemoveHandler MyButton1.Click, AddressOf MyButton1_Click
    End Sub
 
End Class
 

Public NotInheritable Class frmDialog
    Inherits Form
    Friend MyButton2 As Button
    Friend fmain As New frmMain
    Public Sub New()
        ' Llamada necesaria para el diseñador.
        MyClass.InitializeComponent()
        MyButton2 = New Button With
        {
            .Text = "Show Form1",
            .Location = New Point(10, 10)
        }
        ' Agregue cualquier inicialización después de la llamada a InitializeComponent().
        AddHandler MyButton2.Click, AddressOf MyButton2_Click
    End Sub
 
    Private Sub frmDialog_FormClosing(sender As Object, e As FormClosingEventArgs) Handles Me.FormClosing
        fmain.Show()
        ' fmain.Visible=tue
 
    End Sub
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.Controls.Add(MyButton2)
        Me.Text = "frmDialog"
    End Sub
    Private Sub MyButton2_Click(sender As Object, e As EventArgs)
        DisposeControls()
        Me.Close()
    End Sub
    Sub DisposeControls()
 
        RemoveHandler MyButton2.Click, AddressOf MyButton2_Click
        Me.MyButton2.Dispose()
    End Sub
End Class

Public NotInheritable Class frmMain
    Inherits Form
    Friend MyButton1 As Button
 
    Public Sub New()
 
        ' Llamada necesaria para el diseñador.
        MyClass.InitializeComponent()
        Me.MyButton1 = New Button With {
            .Text = "Show Form2",
            .Location = New Point(10, 10)
        }
        ' Agregue cualquier inicialización después de la llamada a InitializeComponent().
        AddHandler MyButton1.Click, AddressOf MyButton1_Click
    End Sub
 
 
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.Controls.Add(MyButton1)
        Me.Text = "frmMain"
    End Sub
    Private Sub MyButton1_Click(sender As Object, e As EventArgs)
        DisposeControls()
        Me.Hide()
        frmDialog.Show()
    End Sub
 
    Sub DisposeControls()
        Me.MyButton1.Dispose()
        RemoveHandler MyButton1.Click, AddressOf MyButton1_Click
    End Sub
 
End Class

Public NotInheritable Class frmDialog
    Inherits Form
    Friend MyButton2 As Button
    Public Sub New()
        ' Llamada necesaria para el diseñador.
        MyClass.InitializeComponent()
        MyButton2 = New Button With
        {
            .Text = "Show Form1",
            .Location = New Point(10, 10)
        }
        ' Agregue cualquier inicialización después de la llamada a InitializeComponent().
        AddHandler MyButton2.Click, AddressOf MyButton2_Click
    End Sub
 
    Private Sub frmDialog_FormClosing(sender As Object, e As FormClosingEventArgs) Handles Me.FormClosing
        '  fmain.Show()
        frmMain.Show()
 
    End Sub
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.Controls.Add(MyButton2)
        Me.Text = "frmDialog"
    End Sub
    Private Sub MyButton2_Click(sender As Object, e As EventArgs)
        'DisposeControls()
        Me.Close()
    End Sub
    Sub DisposeControls()
 
        RemoveHandler MyButton2.Click, AddressOf MyButton2_Click
        Me.MyButton2.Dispose()
    End Sub
End Class