Проблема в пгинации

---

Всем Привет,
Я столкнулся с проблемой говорит - В позиции 0 нет строки." .. Я получил этот код с этого сайта Пагинация
На самом деле это так полезно , и с некоторыми небольшими изменениями я избавился от некоторых проблем, таких как "нет строки в позиции 0". но она появляется случайным образом ....
Мне придется показать весь свой код, чтобы облегчить зрение

Public Function GetData() As DataView
        
        Dim SelectQry = "SELECT BillInfo.InvoiceNo as [رقم الايصال],
                                    ProductSold.SoldDate as [تاريخ البيع],                                    
                                    BillInfo.CustomerName as [اسم العميل],
                                    ProductSold.ProductCode as [كود الصنف], 
                                    ProductSold.ProductName as [اسم الصنف],
                                    ProductSold.Price as [سعر التكلفة],
                                    ProductSold.Category as [اسم الباكية], 
                                    ProductSold.AVP as [الكمية المتاحة عند البيع], 
                                    ProductSold.SellPrice as [سعر البيع],
                                    ProductSold.SoldPackets as [الكمية المباعة], 
                                    ProductSold.TotalAmount as [الاجمالى المبيعات من الصنف],
                                    ProductSold.NewAVP as [الكمية المتاحة الجديدة]
                                    FROM BillInfo INNER JOIN ProductSold ON BillInfo.InvoiceNo = ProductSold.InvoiceNo 
                                    WHERE SoldDate >= @D1 AND SoldDate <= @D2
                                    ORDER BY SoldDate DESC"
        Dim ds As New DataSet
        Dim dv As DataView
        Try
            conn = New OleDbConnection(cs)
            Dim cmd As New OleDbCommand()
            Dim da = New OleDbDataAdapter()
            cmd.CommandText = SelectQry
            cmd.Connection = conn
            cmd.Parameters.Add("@D1", OleDbType.DBDate).Value = dtpInvoiceDateFrom.Value
            cmd.Parameters.Add("@D2", OleDbType.DBDate).Value = dtpInvoiceDateTo.Value

            da.SelectCommand = cmd
            da.Fill(ds)
            dv = ds.Tables(0).DefaultView
        Catch ex As Exception
            Throw ex
            MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
        Return dv
    End Function

    Private Sub loadDGV(Statement As String, TableName As String)

        Using conn As New OleDbConnection(cs)
            conn.Open()
            Using cmd As New OleDbCommand(Statement, conn)
                'cmd.Parameters.Add("@ID", SqlDbType.Int).Value = CInt(Val(txt))

                'Set the DataAdapter's query.
                da = New OleDbDataAdapter(cmd)
                ds = New DataSet()

                ' Fill the DataSet.
                da.Fill(ds, TableName)
                'da.Fill(ds, TableName1)

                ' Set the source table.
                dtSource = ds.Tables(TableName)
                'dtSource = ds.Tables(TableName1)
                'dt = ds1.Tables(TableName1)
            End Using
        End Using
    End Sub

    Private Sub LoadPage()
        Dim i As Integer
        Dim startRec As Integer
        Dim endRec As Integer
        Dim dtTemp As DataTable
       
       
        Select Case True
            Case DataGridView1.RowCount = Nothing
                Exit Sub
        End Select
        'Duplicate or clone the source table to create the temporary table.
        dtTemp = dtSource.Clone
       

        If currentPage = PageCount Then
            endRec = maxRec
        Else
            endRec = pageSize * currentPage
        End If

        startRec = recNo

        'Copy the rows from the source table to fill the temporary table.
        For i = startRec To endRec - 1
            dtTemp.ImportRow(dtSource.Rows(i))
            recNo = recNo + 1
        Next

        DataGridView1.DataSource = dtTemp
        
        DisplayPageInfo()

    End Sub

    Private Function CheckFillButton() As Boolean

        'Check if the user clicks the "Fill Grid" button.
        If pageSize = 0 Then
            MessageBox.Show("Set the Page Size, and then click the button!", "Hint")
            CheckFillButton = False
        Else
            CheckFillButton = True
        End If
    End Function

    Private Sub DisplayPageInfo()
        txtDisplayPageNo.Text = "Page " & currentPage.ToString & "/ " & PageCount.ToString
    End Sub

    Private Sub btnLast_Click(sender As Object, e As EventArgs) Handles btnLast.Click
        If Not CheckFillButton() Then Return

        btnLast.Enabled = False
        btnPrevious.Enabled = True
        btnNext.Enabled = False
        btnFirst.Enabled = True

        ' Check if you are already at the last page.
        If recNo = maxRec Then
            MessageBox.Show("You are at the Last Page!", "Hint")
            
            Return
        End If

        currentPage = PageCount

        recNo = pageSize * (currentPage - 1)

        LoadPage()
    End Sub

    Private Sub btnPrevious_Click(sender As Object, e As EventArgs) Handles btnPrevious.Click
        If Not CheckFillButton() Then Return
       
        btnNext.Enabled = True
        btnLast.Enabled = True

        If currentPage = PageCount Then
            recNo = pageSize * (currentPage - 2)
        End If

        currentPage = currentPage - 1

        'Check if you are already at the first page.
        If currentPage < 1 Then
            MessageBox.Show("You are at the First Page!")
            btnPrevious.Enabled = False
            
            btnFirst.Enabled = False
          
            currentPage = 1
            Return
        Else
            recNo = pageSize * (currentPage - 1)
        End If

        LoadPage()
    End Sub

    Private Sub btnNext_Click(sender As Object, e As EventArgs) Handles btnNext.Click
        'If the user did not click the "Fill Grid" button then Return
        If Not CheckFillButton() Then Return

        btnPrevious.Enabled = True
        btnFirst.Enabled = True
        
        'Check if the user clicked the "Fill Grid" button.
        If pageSize = 0 Then
            MessageBox.Show("Set the Page Size, and then click the button!")
            Return
        End If

        currentPage = currentPage + 1

        If currentPage > PageCount Then
            currentPage = PageCount

            'Check if you are already at the last page.
            If recNo = maxRec Then
                MessageBox.Show("You are at the Last Page!")
                btnNext.Enabled = False
              
                btnLast.Enabled = False
                Return
            End If
        End If

        LoadPage()
    End Sub

    Private Sub btnFirst_Click(sender As Object, e As EventArgs) Handles btnFirst.Click
        If Not CheckFillButton() Then Return
        
        btnFirst.Enabled = False
        btnPrevious.Enabled = False
        btnNext.Enabled = True
        btnLast.Enabled = True

        ' Check if you are already at the first page.
        If currentPage = 1 Then
            MessageBox.Show("You are at the First Page!")
         
            Return
        End If

        currentPage = 1
        recNo = 0

        LoadPage()
    End Sub

    Private Sub btnFill_Click(sender As Object, e As EventArgs) Handles btnFill.Click

        Using conn As New OleDbConnection(cs)
            conn.Open()
            Using cmd As New OleDbCommand("SELECT BillInfo.InvoiceNo as [رقم الايصال],
                                    ProductSold.SoldDate as [تاريخ البيع],                                    
                                    BillInfo.CustomerName as [اسم العميل],
                                    ProductSold.ProductCode as [كود الصنف], 
                                    ProductSold.ProductName as [اسم الصنف],
                                    ProductSold.Price as [سعر التكلفة],
                                    ProductSold.Category as [اسم الباكية], 
                                    ProductSold.AVP as [الكمية المتاحة عند البيع], 
                                    ProductSold.SellPrice as [سعر البيع],
                                    ProductSold.SoldPackets as [الكمية المباعة], 
                                    ProductSold.TotalAmount as [الاجمالى المبيعات من الصنف],
                                    ProductSold.NewAVP as [الكمية المتاحة الجديدة]
                                    FROM BillInfo INNER JOIN ProductSold ON BillInfo.InvoiceNo = ProductSold.InvoiceNo 
                                    WHERE SoldDate >= @D1 AND SoldDate <= @D2
                                    ORDER BY SoldDate DESC", conn)
                cmd.Parameters.Add("@D1", OleDbType.DBDate).Value = dtpInvoiceDateFrom.Value
                cmd.Parameters.Add("@D2", OleDbType.DBDate).Value = dtpInvoiceDateTo.Value

                'Set the DataAdapter's query.
                da = New OleDbDataAdapter(cmd)
                ds = New DataSet()

                ' Fill the DataSet.
                da.Fill(ds, "BillInfo")
                

                ' Set the source table.
                dtSource = ds.Tables("BillInfo")

            End Using
        End Using

        'Set the start and max records. 
        pageSize = CInt(Val(txtPageSize.Text))
        maxRec = dtSource.Rows.Count

        PageCount = maxRec \ pageSize

        ' Adjust the page number if the last page contains a partial page.
        If (maxRec Mod pageSize) > 0 Then
            PageCount = PageCount + 1
        End If

        'Initial seeings
        currentPage = 1
        recNo = 0

        ' Display the content of the current page.
        LoadPage()
    End Sub

    Private Sub txtPageSize_TextChanged(sender As Object, e As EventArgs) Handles txtPageSize.TextChanged
        If Val(txtPageSize.Text) > 100 Then
            Exit Sub
        End If
        Select Case True
            Case Val(txtPageSize.Text) = 0 Or txtPageSize.Text = ""
                
                Exit Sub
        End Select

        btnFill_Click(sender, e)
        btnFirst.Enabled = False
        btnPrevious.Enabled = False
        btnNext.Enabled = True
        btnLast.Enabled = True
    End Sub

Любое предложение .
Заранее спасибо.......................
С уважением от Амр Али

Что я уже пробовал:

Я попытался избежать исключения, сделав это

btnFirst.Enabled = False
      btnPrevious.Enabled = False
      btnNext.Enabled = True
      btnLast.Enabled = True

Как говорится в приведенном выше коде, но исключение появляется снова ..... И вот теперь во время написания моего вопроса мне пришла в голову мысль избежать исключения но бесполезно
делая select case в каждой кнопке, как это

Select Case True
        Case DataGridView1.RowCount = Nothing
            Exit Sub
        Case recNo = maxRec
            MessageBox.Show("You are at the Last Page!", "Hint")
            Exit Sub
    End Select
    LoadPage()

Потому что ошибка произошла в субстрате LoadPage
Это образ моего исключения .. С помощью кнопки "first" ошибка заключается в том, что "в позиции 0 нет строки".
а с кнопкой "Далее" ошибка заключается в том, что "в позиции -50 нет строки".

Извините я забыл сказать что ошибка всегда возникает в этой строке

dtTemp.ImportRow(dtSource.Rows(i))

---