利用线程，和计时器，Function GetFolderSize从网上借鉴的，IO类只支持不同分区移动，所以移动目录只能在相同分区，设计界面如图，

如： d:/a  d:/b(空目录)

代码如下

Imports System.IO
Imports System.Threading

Public Class Form2
    Dim SourceDir, DestDir As String
    Dim SourceLen As Integer

    '返回文件夹大小
    Private Function GetFolderSize(ByVal DirPath As String, Optional ByVal IncludeSubFolders As Boolean = True) As Long
        Dim lngDirSize As Long
        Dim objFileInfo As FileInfo
        Dim objDir As DirectoryInfo = New DirectoryInfo(DirPath)
        Dim objSubFolder As DirectoryInfo
        Try
            For Each objFileInfo In objDir.GetFiles()
                lngDirSize += objFileInfo.Length
            Next
            If IncludeSubFolders Then
                For Each objSubFolder In objDir.GetDirectories()
                    lngDirSize += GetFolderSize(objSubFolder.FullName)
                Next
            End If
        Catch
        End Try
        Return lngDirSize
    End Function

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim T As New Thread(AddressOf DirMove)

        CheckForIllegalCrossThreadCalls = False

        SourceDir = TextBox1.Text
        DestDir = TextBox2.Text

        SourceLen = GetFolderSize(SourceDir)

        ProgressBar1.Value = 0
        Timer1.Interval = 100
        Timer1.Start()
        T.Start()
    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        If Directory.Exists(DestDir) = False Then Exit Sub
        If SourceLen <> 0 Then
            ProgressBar1.Value = Math.Round(GetFolderSize(DestDir) / SourceLen, 2) * 100
        End If

    End Sub

    Private Sub DirMove()
        Me.Text = "正在移动..."
        Directory.Move(SourceDir, DestDir)
        Me.Text = "移动完成！"
        ProgressBar1.Value = 100
        RichTextBox1.Text += DestDir & Environment.NewLine
    End Sub

    Private Sub DirCopy()
        My.Computer.FileSystem.CopyDirectory(SourceDir, DestDir, True, FileIO.UICancelOption.DoNothing)
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim T As New Thread(AddressOf DirCopy)

        CheckForIllegalCrossThreadCalls = False

        SourceDir = TextBox1.Text
        DestDir = TextBox2.Text

        SourceLen = GetFolderSize(SourceDir)

        ProgressBar1.Value = 0
        Timer1.Interval = 100
        Timer1.Start()
        T.Start()
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Dim a As New ArrayList
        a.Add(".MP3")
        Dim b As New ArrayList
        Dim c As New Hashtable

        clsUtil.findDirectory("D:/a", a, b, c)
    End Sub
End Class