backgroundworderエラー - インデックスが配列の範囲外です。vb.net

Question

私はvb.netを使用してプログラムを終了しようとしていました。 "Stock.xlsx"というファイルをDataGridViewにインポートする際に、Backgroundworkderを使用するプログラム。しかし、私がスタートボタンをクリックすると、 "インデックスが配列の境界外にある"というエラーが発生します。誰かが私を助けてください。

プログラムとスナップショットエラー下記をご覧ください：

パブリック・クラスのForm1 strRow(3)またはstrRow(4)を行うときは、第四にアクセスしようとしている

Dim strRow As String()    'String array to read all fields in a row 
Dim dblAmount As Double    'Variable for total amount 
Dim blnReported As Boolean = True 'Flag to check progress report completed or not 

'Create TextFieldParser class to parse the stock.csv file in the current location 
Dim txtFile As FileIO.TextFieldParser 



Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load 

    'Allow background operation to be cancelled 
    bgWorker.WorkerSupportsCancellation = True 

    'Allow background operation to report progress 
    bgWorker.WorkerReportsProgress = True 

    'Disable Stop Button. It is enabled only after start 
    'button is pressed 
    btnStop.Enabled = False 

    'set status message 
    lblStatus.Text = "Press Start to import data from csv." 

    'Add columns to the grid 
    dgvCSVData.Columns.Add("colNo", "No") 
    dgvCSVData.Columns("colNo").Width = 30 
    dgvCSVData.Columns.Add("colDate", "Date") 
    dgvCSVData.Columns("colDate").Width = 60 
    dgvCSVData.Columns.Add("colItem", "Item") 
    dgvCSVData.Columns("colItem").Width = 120 
    dgvCSVData.Columns.Add("colQty", "Quantity") 
    dgvCSVData.Columns("colQty").Width = 50 
    dgvCSVData.Columns.Add("colUnit", "Unit") 
    dgvCSVData.Columns("colUnit").Width = 30 
    dgvCSVData.Columns.Add("colAmt", "Amt") 
    dgvCSVData.Columns("colAmt").Width = 60 


End Sub 
Private Sub btnStart_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnStart.Click 

    'Disable Start button and Enable Stop 
    btnStart.Enabled = False 
    btnStop.Enabled = True 

    'set status message 
    lblStatus.Text = "Importing data from CSV file." 

    'Start time-consuming operation in background 
    Call bgWorker.RunWorkerAsync() 

End Sub 

Private Sub btnStop_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnStop.Click 
    'Enable Start button and disable Stop 
    btnStart.Enabled = True 
    btnStop.Enabled = False 

    'Stop background operation 
    bgWorker.CancelAsync() 

    'set status message 
    lblStatus.Text = "Import cancelled. Press Start again." 
End Sub 


Private Sub bgWorker_DoWork(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bgWorker.DoWork 
    Dim intCount As Int16 = 0 

    txtFile = New FileIO.TextFieldParser("stock.xlsx") 

    'Specify structure of the file 
    txtFile.TextFieldType = FileIO.FieldType.Delimited 
    txtFile.SetDelimiters(",") 

    'Skip header row 
    txtFile.ReadFields() 

    'Start reading data from file 
    While Not txtFile.EndOfData 

     If bgWorker.CancellationPending Then 
      e.Cancel = True 
      Exit Sub 

     Else 

      'Wait for Progress Report to finish 
      While Not blnReported 
       Application.DoEvents() 
      End While 

      'Read all field in a row into a string array 
      strRow = txtFile.ReadFields() 

      'Do some calculations and assign value to data grid 
      dblAmount = CDbl(strRow(3)) * CDbl(strRow(4)) 

      'Add some sleep to simulate a long running operation 
      System.Threading.Thread.Sleep(500) 

      'Progress report pending 
      blnReported = False 

      'increment counter 
      intCount += 1 

      'Report the progress 
      bgWorker.ReportProgress(10, intCount) 

     End If 

    End While 

End Sub 

Private Sub bgWorker_ProgressChanged(ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) Handles bgWorker.ProgressChanged 
    'Copy values to data grid 
    dgvCSVData.Rows.Add(strRow) 
    dgvCSVData.Rows(dgvCSVData.CurrentRow.Index - 1).Cells("colAmt").Value = dblAmount 

    pgbCopyProgress.Value = e.UserState 
    'Progress report finished 
    blnReported = True 

End Sub 


Private Sub bgWorker_RunWorkerCompleted(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles bgWorker.RunWorkerCompleted 

    If e.Cancelled Or Not IsNothing(e.Error) Then 
     'Clear the data grid 
     dgvCSVData.Rows.Clear() 
    Else 
     'Progress completed 
     pgbCopyProgress.Value = 100 

     'Release txtfile 
     txtFile.Dispose() 
     btnStop.Enabled = False 
     btnStart.Enabled = True 

    End If 
End Sub 

エンドクラス

Answer 1

配列の5番目の要素。配列にはそれほど多くの要素がないようです。

また、要素にアクセスする前に配列の長さをチェックするのは良い習慣です。