Фильтрация через Combobox

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 337
  ClientWidth = 635
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object DBLookupComboBox1: TDBLookupComboBox
    Left = 482
    Top = 13
    Width = 145
    Height = 21
    KeyField = 'EmpNo'
    ListField = 'FirstName'
    ListSource = DataSource1
    TabOrder = 0
  end
  object DBGrid1: TDBGrid
    Left = 8
    Top = 40
    Width = 619
    Height = 289
    DataSource = DataSource2
    TabOrder = 1
    TitleFont.Charset = DEFAULT_CHARSET
    TitleFont.Color = clWindowText
    TitleFont.Height = -11
    TitleFont.Name = 'Tahoma'
    TitleFont.Style = []
  end
  object ADOConnection1: TADOConnection
    Connected = True
    ConnectionString = 
      'Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\dbdemos.mdb;Pers' +
      'ist Security Info=False'
    LoginPrompt = False
    Mode = cmShareDenyNone
    Provider = 'Microsoft.Jet.OLEDB.4.0'
    Left = 48
    Top = 16
  end
  object ADOQuery1: TADOQuery
    Active = True
    Connection = ADOConnection1
    CursorType = ctStatic
    Parameters = <>
    SQL.Strings = (
      'select * from Employee')
    Left = 136
    Top = 16
  end
  object DataSource1: TDataSource
    DataSet = ADOQuery1
    Left = 136
    Top = 64
  end
  object ADOQuery2: TADOQuery
    Active = True
    Connection = ADOConnection1
    CursorType = ctStatic
    DataSource = DataSource1
    Parameters = <
      item
        Name = 'EmpNo'
        Attributes = [paNullable]
        DataType = ftInteger
        NumericScale = 255
        Precision = 255
        Value = 2
      end>
    SQL.Strings = (
      'select * from Orders where EmpNo=:EmpNo')
    Left = 216
    Top = 16
  end
  object DataSource2: TDataSource
    DataSet = ADOQuery2
    Left = 216
    Top = 64
  end
end

unit Unit1;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, ADODB, Grids, DBGrids, DBCtrls;
 
type
  TForm1 = class(TForm)
    ADOConnection1: TADOConnection;
    ADOQuery1: TADOQuery;
    DataSource1: TDataSource;
    DBLookupComboBox1: TDBLookupComboBox;
    DBGrid1: TDBGrid;
    ADOQuery2: TADOQuery;
    DataSource2: TDataSource;
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
end.

form1.ComboBox1.itesm.itemindex:=1

form1.ComboBox1.text:='Бухгалтер'

procedure TForm1.FormActivate(Sender: TObject);
begin
 DBLookupComboBox1.KeyValue := DBLookupComboBox1.ListSource.DataSet.Fields[0].AsInteger
end;