Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        Form1.ShowDialog()
End Sub

Public Class Form1
    'Текст запроса с параметрами
    Dim GeneralStringCommand As String
    'Текст запроса со значениями параметрами
    Dim SelectProductGroup As String
    Const TotalByProductGroup As String = "Итого по Бренду"

    Private Sub GeneralForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Connector = New OleDbConnection
        Connector.ConnectionString = "Provider = Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\iivanov\Desktop\Базы данных\Access\Для калькулятора.accdb;Persist Security Info=False;"
        Connector.Open()

        Dim Command As New OleDbCommand("Select Наименование From Бренды", Connector)
        Dim dr As OleDbDataReader = Command.ExecuteReader
        'Заполняем ComboBox
        Try
            ComboBox_ProductGroup.Items.Clear()

            While dr.Read()
                ComboBox_ProductGroup.Items.Add(dr(0))
            End While
            dr.Close()
        Catch ex As Exception
            If dr.IsClosed = False Then
                dr.Close()
            End If
        End Try



        Dim Command2 As New OleDbCommand("SELECT ИмяЗапроса, ТекстЗапроса FROM Запросы", Connector)
        Dim dr2 As OleDbDataReader = Command2.ExecuteReader
        'Вытаскиваем запрос с параметром
        Try
            While dr2.Read()
                If dr2.Item("ИмяЗапроса") = "SQLQuery2" Then
                    GeneralStringCommand = dr2.Item("ТекстЗапроса")
                    Exit While
                End If
            End While
            dr2.Close()
        Catch ex As Exception
            If dr2.IsClosed = False Then
                dr2.Close()
            End If
        End Try      
    End Sub

    'Выбираем элемент ComboBox
    Private Sub ComboBox_ProductGroup_SelectedValueChanged(sender As Object, e As EventArgs) Handles ComboBox_ProductGroup.SelectedValueChanged
        RefreshGrig_Plan()
    End Sub

    Private Sub RefreshGrig_Plan()
        If ComboBox_ProductGroup.SelectedItem = Nothing Then
            Exit Sub
        End If

        SelectProductGroup = ComboBox_ProductGroup.SelectedItem.ToString()
        
        'Вставляем в параметр запроса значение
        Dim StringCommand
        StringCommand = Replace(GeneralStringCommand, "@Select_ProductGroup", SelectProductGroup)
        RefreshGrig(DataGridView, StringCommand, "План") ' Вызывает отдельную процедуру из модуля для обновления данных DataGridView
        GridFormat_Plan()
    End Sub


    'Закрашиваем ячейки в DataGridView
    Private Sub GridFormat_Plan()
        For Each CurrentRow In DataGridView.Rows
            If CurrentRow.cells(DataGridView.Columns("Город").Index).Value <> TotalByProductGroup Then ' итоговую строку не нужно закрашивать
               If CurrentRow.cells(DataGridView.Columns("Январь_Заморозка").Index).Value = True Then
                    CurrentRow.cells(DataGridView.Columns("Январь").Index).Style.BackColor = Color.Yellow
               End If   
      
               '.....

               If CurrentRow.cells(DataGridView.Columns("Декабрь_Заморозка").Index).Value = True Then
                    CurrentRow.cells(DataGridView.Columns("Декабрь").Index).Style.BackColor = Color.Yellow
               End If  
        Next CurrentRow
    End Sub
End Class