// Отбор по одной колнке
 class otbor
        {
            public string columnname { get; set; } // название колонки
            public bool active { get; set; } // включён отбор
            public object value { get; set; } // значение отбор
            public object value1 { get; set; } // значение отбор
        }

ListOtbor.Clear();
            ListOtbor.Add(new otbor { columnname = "CustomerID", active = ch_CustomerID.Checked, value = textBox_CustomerID.Text });
            ListOtbor.Add(new otbor { columnname = "OrderDate", active = ch_OrderDate.Checked, value = OrderDate_dateTimePicker.Value.Date });
            ListOtbor.Add(new otbor { columnname = "ShipName", active = ch_ShipName.Checked, value = textBox_ShipName.Text });

  var result = from c in db.Orders
                         select c; 
            foreach (otbor item in ListOtbor)
            {              
                if (item.active)
                {
                    if (item.columnname == "OrderDate")
                        result = (from c in query
                                  where c.OrderDate == (DateTime)item.value
                                  select c).AsQueryable<Order>();
                    else if (item.columnname == "CustomerID")
                        result = (from c in query
                                  where c.CustomerID == item.value.ToString()
                                  select c).AsQueryable<Order>();
                    else if (item.columnname == "ShipName")
                        result = (from c in query
                                  where c.CustomerID == item.value.ToString()
                                  select c).AsQueryable<Order>();
                }
            }

exec sp_executesql N'SELECT [t0].[OrderID], [t0].[CustomerID], [t0].[EmployeeID], [t0].[OrderDate], [t0].[RequiredDate], [t0].[ShippedDate], 
[t0].[ShipVia], [t0].[Freight], [t0].[ShipName], [t0].[ShipAddress], [t0].[ShipCity], [t0].[ShipRegion], [t0].[ShipPostalCode], [t0].[ShipCountry]
FROM [dbo].[Orders] AS [t0]
WHERE [t0].[CustomerID] = @p0',N'@p0 nvarchar(5)',@p0=N''

 if (ListOtbor[ 0 ].active)   
                  result = (from c in query
                                  where c.CustomerID == ListOtbor[ 0 ].value.ToString()
                                  select c).AsQueryable<Order>();
            if (ListOtbor[ 1 ].active)  
                        result = (from c in query
                                  where c.OrderDate == (DateTime)ListOtbor[ 1 ].value
                                  select c).AsQueryable<Order>();
            if (ListOtbor[ 2 ].active)  
                        result = (from c in query
                                  where c.CustomerID == ListOtbor[ 2 ].value.ToString()
                                  select c).AsQueryable<Order>();
             bindingSource2.DataSource = result;

var result = (from c in query
                                  where c.CustomerID == ListOtbor[ 0 ].value.ToString()
                                  select c)
var q = (
                     from c in result 
                     select c.Country
                    ).Union(
                     from e in db.Employees
                     select e.Country
                    );

            var query = from c in db.Dogovors
                        join mo in db.MyOrgs on c.dg_mo_id equals mo.mo_id                        
                        select new Dogovor
                        {
                            dg_id = c.dg_id,
                            dg_num = c.dg_num,
                            dg_descr = c.dg_descr,
                        };
            bindingSource1.DataSource = query;

            var query = from c in db.Dogovors
                        join mo in db.MyOrgs on c.dg_mo_id equals mo.mo_id                        
                        select new Dogovor
                        {
                            dg_id = c.dg_id,
                            dg_num = c.dg_num,
                            dg_descr = c.dg_descr,
                        };
            bindingSource1.RaiseListChangedEvents = false; // ДОБАВЛЕНО 
            bindingSource1.DataSource = query;
            bindingSource1.RaiseListChangedEvents = true; // ДОБАВЛЕНО
            bindingSource1.ResetBindings(false); // ДОБАВЛЕНО

             
            bindingSource1.RaiseListChangedEvents = false; // ДОБАВЛЕНО 
            bindingSource1.DataSource = query;
            bindingSource1.RaiseListChangedEvents = true; // ДОБАВЛЕНО
            bindingSource1.ResetBindings(false); // ДОБАВЛЕНО

masterbindingsource.onCurrebtChange 

MasterbindingSource.RaiseListChangedEvents = false;
Adapter.Fill(MasterTable)
MasterbindingSource.RaiseListChangedEvents = true; 
MasterbindingSource.ResetBindings(false);