Background worker repeat process

Private Sub btn_send_Click(sender As System.Object, e As System.EventArgs) Handles btn_send.Click
        Try
            Dim checkedItems As ListView.CheckedListViewItemCollection = lvKiosk.CheckedItems
            Dim item As ListViewItem
            arr_sendkiosk = New ArrayList
            For Each item In checkedItems
                arr_sendkiosk.Add(item.SubItems(1).Text)
            Next
            If IsNothing(BackgroundWorker1) Then
                BackgroundWorker1 = New BackgroundWorker
            End If
            If BackgroundWorker1.IsBusy <> True Then
                ' Start the asynchronous operation.
                BackgroundWorker1.WorkerSupportsCancellation = True
                BackgroundWorker1.WorkerReportsProgress = True
                BackgroundWorker1.RunWorkerAsync()
            End If
        Catch ex As Exception
            AppendNegative("Error send file.")
        End Try
End Sub

Private Sub BackgroundWorker1_DoWork1(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
    Try
        If (BackgroundWorker1.CancellationPending = True) Then
            BackgroundWorker1.CancelAsync()
            Exit Sub
        End If
        If cbx_images.Checked = True Then
            For i = 0 To (arr_sendkiosk.Count - 1)
                If StartSendingImages(i) Then
                    AppendPositive("Sending." & vbCrLf & vbCrLf)
                Else
                    AppendNegative("Failed." & vbCrLf & vbCrLf)
                End If
            Next
        End If
    Catch ex As Exception
        AppendNegative("Task not completed. Ex-" & ex.Message)
    End Try
End Sub

Private Sub BackgroundWorker1_RunWorkerCompleted1(sender As Object, e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
        If e.Cancelled = True Then
            AppendNormal("Task cancelled.")
        ElseIf e.Error IsNot Nothing Then
            AppendNegative("Error: " & e.Error.Message)
        End If
        lbl_progress.Text = "Background Process Complete.."
        BackgroundWorker1.Dispose()
End Sub

Private Delegate Sub AddToMessageBoxDelegate(ByVal msg As String)
Public Sub AppendPositive(ByVal msg As String)
        If Me.InvokeRequired Then
            Dim d As New AddToMessageBoxDelegate(AddressOf Me.AppendPositive)
            Me.BeginInvoke(d, New Object() {msg})
        Else
            Try
                WritePositive(msg & vbCrLf)
            Catch ex As Exception
            End Try
        End If
    End Sub
    Public Sub AppendNegative(ByVal msg As String)
        If Me.InvokeRequired Then
            Dim d As New AddToMessageBoxDelegate(AddressOf Me.AppendNegative)
            Me.BeginInvoke(d, New Object() {msg})
        Else
            Try
                WriteNegative(msg & vbCrLf)
            Catch ex As Exception
            End Try
        End If
    End Sub
Private Sub WritePositive(ByVal str As String)
    Dim length As Integer = rtb_evt.TextLength ' at end of text
    rtb_evt.AppendText(str)
    rtb_evt.SelectionStart = length
    rtb_evt.SelectionLength = str.Length
    rtb_evt.SelectionColor = Color.Green
    rtb_evt.Lines.Last()
End Sub
Private Sub WriteNegative(ByVal str As String)
    Dim length As Integer = rtb_evt.TextLength ' at end of text
    rtb_evt.AppendText(str)
    rtb_evt.SelectionStart = length
    rtb_evt.SelectionLength = str.Length
    rtb_evt.SelectionColor = Color.Red
    rtb_evt.Lines.Last()
End Sub