หลังจากโหลดข้อมูลด้วย adobe PDF ready แต่ fucus ไม่ยอมเปลี่ยน

 Private Sub GridFiles_CellClick(sender As Object, e As DataGridViewCellEventArgs) Handles GridFiles.CellClick
        Try
            If GridFiles.RowCount = 0 Then Exit Sub
            Dim _File As String = GridFiles.Rows(GridFiles.CurrentCell.RowIndex).Cells(0).Value.ToString
            iRowSelect = GridFiles.CurrentCell.RowIndex
            PDFViewer.setShowToolbar(False)
            If File.Exists(_File) = True Then
                If ShowPDF(_File) = True Then
                    GridFiles.CurrentCell = GridFiles.Rows(iRowSelect).Cells(1)
                    GridFiles.Focus()
                End If
                StatusBar.Text = _File
            Else
                _File = Nothing
                PDFViewer.LoadFile(Nothing)
                StatusBar.Text = ""
                iRowSelect = Nothing
            End If

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub

    Function ShowPDF(ByVal PDFFile As String) As Boolean
        Dim Result As Boolean = False
        Try
            PDFViewer.LoadFile(PDFFile)
            PDFViewer.setZoomScroll(70, 0, 0)
            PDFViewer.Refresh()
            PDFViewer.setShowToolbar(False)
            Result = True
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
        Return Result
    End Function