Control.CheckForIllegalCrossThreadCalls

Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
        count_rows()
    End Sub

    Private Sub BackgroundWorker1_RunWorkerCompleted(sender As Object, e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
        MsgBox("Products imported successfully!", MsgBoxStyle.Information, "Import")
        Me.Close()
    End Sub
Public Sub count_rows()
        import_attendance_sheet(1054)
    End Sub
Private Sub import_attendance_sheet(ByVal id As Integer)
        ProgressBar1.Minimum = 0
        ProgressBar1.Maximum = id
        ProgressBar1.Value = 0
        Dim path As String = txtPath.Text
        Dim excel_connection As OleDbConnection
        Dim dt As DataTable
        Dim cmd As OleDbDataAdapter
        'Dim sql As String
        'Dim result As Boolean
        Dim emp_type_id As String = ""
        Dim branch_id As String = ""
        Dim bank_id As String = ""
        'Dim sheet_dates As New List(Of String)
        'excel_connection = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0; Data Source=" + path + ";Extended Properties=Excel 12.0 Xml; HDR=Yes;")
        excel_connection = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties='Excel 12.0 Xml;HDR=No;IMEX=1;';")
        cmd = New OleDbDataAdapter("SELECT * FROM [sheet$]", excel_connection)
        dt = New DataTable
        cmd.Fill(dt)
        'initialize symbol row
        Dim count As Integer = 6
        'Loop through dates(column/header)
        For Each column As DataColumn In dt.Columns
            Dim colum_name As String = dt.Rows(0)(column.ColumnName).ToString()
            'check if column cell is empty
            If colum_name = "" Then
                'Empty do nothing
            Else
                'increment symbol row by 1
                count = count + 1
                'MsgBox(count)
                'Loop through rows of a particular date/column/header
                For Each r As DataRow In dt.Rows
                    'check row(empNo) cell is not empty & does not have a string
                    If r(5).ToString() = "" Or r(5).ToString() = "COY #" Then
                        'Empty do nothing
                    Else
                        'show date | Emp No | Name | symbol index
                        'MsgBox(colum_name & " " & r(5).ToString() & " " & r(6).ToString() & " " & r(count).ToString())
                        'do the calculation
                        Dim employ_id As String = get_employee_id(r(5).ToString)
                        Dim basic_salary As Decimal = get_employee_basic_salary(r(5).ToString)
                        Dim staff_type_id As String = get_employee_type_id(r(5).ToString)
                        Dim days_per_month As Integer = get_employee_days_per_month(staff_type_id)
                        Dim hours_per_day As Double = get_employee_hours_per_day(staff_type_id)
                        Dim hourly_rate As Double = basic_salary / days_per_month / hours_per_day
                        Dim daily_rate As Double = basic_salary / days_per_month
                        Dim normal_working_hrs As String = get_normal_working_hrs()
                        Dim shift_duration As String = get_shift_duration()
                        'get symbol id and its rate
                        Dim symbol_id As String = get_attendance_symbol_id(r(count).ToString)
                        Dim symbol_rate As Double = get_attendance_symbol_rate(symbol_id)
                        Dim symbol_deduction_status As String = get_symbol_deduction_status(symbol_id)
                        Dim td_amount As Double = 0
                        If symbol_deduction_status = "DEDUCT" Then
                            td_amount = hourly_rate
                        Else
                            td_amount = 0
                        End If
                        Dim overtime As Double = shift_duration - normal_working_hrs
                        Dim ot_amount As Double = overtime * hourly_rate * symbol_rate
                        Dim chaka As String = Date.Now.ToString("yyyy")
                        Dim tsiku As String = Date.Now.ToString("dd")
                        Dim tsiku_mawu As String = Date.Now.ToString("dddd")
                        Dim mwezi As String = Date.Now.ToString("MMMM")
                        ' ''insert values into DB
                        sql = "INSERT INTO tbl_attendance (employee_id,time_in,time_out,total_hours_worked,overtime,ot_amount,td_amount,attendance_code_id,attendance_code,attendance_date,comment,year,date,day,month,hourly_rate,bsalary,ot_status) VALUES ('" & employ_id & "','" & 0 & "','" & 0 & "','" & shift_duration & "','" & overtime & "','" & ot_amount & "','" & td_amount & "','" & symbol_id & "','" & r(count).ToString & "','" & calc_attendance_date(colum_name) & "','import','" & chaka & "','" & tsiku & "','" & tsiku_mawu & "','" & mwezi & "','" & hourly_rate & "','" & basic_salary & "','" & symbol_rate & "')"
                        result = save_to_db(sql)
                        ProgressBar1.Value = ProgressBar1.Value + 1
                        'If result Then
                        '    Timer1.Start()
                        'End If
                    End If
                Next
            End If
        Next
    End Sub
'******* Function which shows the error ****************
Public Function calc_attendance_date(ByVal value As String)
        Dim at_date As String = ""
        Dim current_month As String = frmMain.cmbMonth.Text
        Dim current_year As String = frmMain.cmbYear.Text
        Dim mwezi As String
        Dim chaka As String
        Dim format_day As String = ""
        Dim format_month As String = ""
        'Date.Now.ToString("yyyy-MM-dd")
        '****  find previous month
        'when its january
        If current_month = "January" And value >= 22 And value <= 31 Then
            mwezi = "12"
            chaka = Convert.ToInt32(current_year) - 1
            at_date = chaka & "-" & mwezi & "-" & value
        ElseIf current_month <> "January" And value >= 22 And value <= 31 Then
            mwezi = IntMonth() - 1
            'day
            If value < 10 Then
                format_day = "0" & value
            ElseIf value >= 10 Then
                format_day = value
            End If
            'format mwezi
            If mwezi < 10 Then
                format_month = "0" & mwezi
            ElseIf mwezi >= 10 Then
                format_month = mwezi
            End If
            chaka = current_year
            at_date = chaka & "-" & format_month & "-" & format_day
        End If
        '****  find current month
        If current_month = "January" And value >= 1 And value <= 21 Then
            mwezi = IntMonth()
            chaka = current_year
            'day
            If value < 10 Then
                format_day = "0" & value
            ElseIf value >= 10 Then
                format_day = value
            End If
            'format mwezi
            If mwezi < 10 Then
                format_month = "0" & mwezi
            ElseIf mwezi >= 10 Then
                format_month = mwezi
            End If
            at_date = chaka & "-" & format_month & "-" & format_day
        ElseIf current_month <> "January" And value >= 1 And value <= 21 Then
            mwezi = IntMonth()
            chaka = current_year
            'day
            If value < 10 Then
                format_day = "0" & value
            ElseIf value >= 10 Then
                format_day = value
            End If
            'format mwezi
            If mwezi < 10 Then
                format_month = "0" & mwezi
            ElseIf mwezi >= 10 Then
                format_month = mwezi
            End If
            at_date = chaka & "-" & format_month & "-" & format_day
        End If
        Return at_date
    End Function