Public Class Form1
    Dim FoundFiles As List(Of String) = New List(Of String)
    Private WithEvents bgw As New BackgroundWorker With _
      {.WorkerSupportsCancellation = True, .WorkerReportsProgress = True}
    Dim Abort As Boolean = False
 
 
    Private Sub Form1_FormClosing(sender As Object, e As _
      System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
        bgw.Dispose()
    End Sub
 
    Private Sub cmdGetFiles_Click(sender As System.Object, e As _
      System.EventArgs) Handles cmdGetFiles.Click
        Abort = False
        bgw.RunWorkerAsync()
    End Sub
 
    Private Sub cmdCancel_Click(sender As System.Object, e As System.EventArgs) _
      Handles cmdCancel.Click
        If bgw.WorkerSupportsCancellation = True Then
            bgw.CancelAsync()
        End If
        Abort = True
    End Sub
 
    Private Sub bgw_DoWork(sender As Object, e As _
      System.ComponentModel.DoWorkEventArgs) Handles bgw.DoWork
        SearchFiles("f:\", "bm*.hdc", True)
    End Sub
 
    Private Sub bgw_ProgressChanged(sender As Object, e As _
      System.ComponentModel.ProgressChangedEventArgs) Handles _
      bgw.ProgressChanged
    End Sub
 
    Private Sub bgw_RunWorkerCompleted(sender As Object, e As _
      System.ComponentModel.RunWorkerCompletedEventArgs) Handles _
      bgw.RunWorkerCompleted
        For Each f In FoundFiles
            Debug.Print(f)
        Next
    End Sub
 
 
    Private Sub SearchFiles(ByVal SearchFolder As String, ByVal SearchPattern _
      As String, Optional ByVal RecurseSubDirectories As Boolean = True)
        Dim FilesList As New List(Of String)
        Dim FoldersList As New List(Of String)
        Dim TmpLst As New List(Of String)
 
        Dim sDir As New IO.DirectoryInfo(SearchFolder)
        If Not sDir.Exists Then
            Exit Sub
        End If
 
        Try
            If Abort Then Return
            FilesList.AddRange(Directory.GetFiles(SearchFolder, SearchPattern))
            FoldersList.AddRange(Directory.GetDirectories(SearchFolder))
        Catch ex As UnauthorizedAccessException
            Debug.Print(ex.Message)
        End Try
 
        If Not RecurseSubDirectories Then
            FoundFiles = FilesList
        Else
            For Each Folder As String In FoldersList
                Try
                    If Abort Then Return
 
                    TmpLst.AddRange(Directory.GetFiles(Folder, SearchPattern))
                    If TmpLst IsNot Nothing Then FilesList.AddRange(TmpLst)
                Catch ex As UnauthorizedAccessException
                    Debug.Print(ex.Message)
                End Try
            Next
 
            FoundFiles = FilesList
        End If
    End Sub
End Class