display the item in tdbmemo from combobox

Question

i have combobox that have value category1 and category2...the category1 have items like pencil,food,magazine,newspaper... when i choose category1, i want to retrieve the items in tdbmemo.then the same items in tdbmemo i want to display in checklistbox...i dont know how to do...i use clcat.items.add to display the item but the items is not display

procedure TfrmSysConfig.FillInCheckListClCat;  
var  
  sTable  : string;  
  sqlCat  : TIBOQuery;  
  iIndex :integer;  
  lstCat : TStringList;  
begin  
  if tblMain.FieldByName('POS_ReceiptCatBreakDown').AsString <> '' then begin  
     sqlCat := TIBOQuery.Create(nil);  
     sqlCat.IB_Connection := dmMain.db;  
     lstCat := TStringList.Create;  
     try  
       sqlCat.SQL.Text := 'SELECT code FROM ' + cboCategory.Value;  
       sqlCat.Open;  
       while not sqlCat.Eof do begin  
         clCat.Items.Add( sqlCat.FieldByName( 'Code' ).AsString );  
         sqlCat.Next;  
       end;  
     finally  
       lstCat.Free;  
       sqlCat.Free;  
     end;  
  end;  
end;  

Answer 1

sqlCat.SQL.Text := 'SELECT code FROM ' + cboCategory.Value; - i believe this wouldn't work...a select clause is something like "select * from table where condition".

i've worked a while ago with IBObjects, and there are some useful properties on those components.

use IB_ComboBox for the list(category1 and category2,etc) and link it to a IB_Memo (i'm not sure 100% this is the name, but you'll figure out) and with a IBTable you can set an filter over it. also they have on the site a very useful documentation.

best regards,

Answer 2

heres how i did it... first drop three components on form combobox,dbmemo and check listbox(as you already have).

then add a string list variable in the units ''var' section i am naming it strs

strs : tstringlist;

next in the formcreate event initialize tstringlist items,clear combo box and add 'category1' and 'category2' items..... heres how to do it

procedure TForm2.FormCreate(Sender: TObject);
begin
    strs := TStringList.create;
    strs.Add('food');
    strs.Add('magazine');
     strs.Add('pencil');
    strs.Add('newspaper');
    Combobox1.Items.clear;
    ComboBox1.Items.add('category1');
    ComboBox1.Items.add('category2');

end;

next we write event handler for combobox change and write code for updating checklistbox and dbmemo :

procedure TForm2.ComboBox1Change(Sender: TObject);
begin
     if ComboBox1.ItemIndex = 0 then
     DBMemo1.lines.AddStrings(strs);
     CheckListBox1.Items.addstrings(strs);
end;

heres the complete code:

 unit project1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, DBCtrls, CheckLst;

type
  TForm2 = class(TForm)
    ComboBox1: TComboBox;
    DBMemo1: TDBMemo;
    CheckListBox1: TCheckListBox;
    procedure FormCreate(Sender: TObject);
    procedure ComboBox1Change(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form2: TForm2;
  strs : tstringlist;

implementation

{$R *.dfm}

procedure TForm2.ComboBox1Change(Sender: TObject);
begin
     if ComboBox1.ItemIndex = 0 then
     DBMemo1.lines.AddStrings(strs);
     CheckListBox1.Items.addstrings(strs);
end;

procedure TForm2.FormCreate(Sender: TObject);
begin
    strs := TStringList.create;
    strs.Add('food');
    strs.add('magazine');
     strs.Add('pencil');
    strs.add('newspaper');
    combobox1.Items.clear;
    ComboBox1.items.add('category1');
    ComboBox1.items.add('category2');

end;


end.

i hope this help ,please ask if something is unclear to you or you dont understand something, ill try to explain in more details.