DataSet i dinamicko kreiranje komponenti

Code:

if Assigned(compo) then
  FreeAndNil(compo)

Code:
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DBXpress, StdCtrls, DB, SqlExpr, DBClient, SimpleDS, Grids,
  DBGrids, ExtCtrls;

type
  TForm1 = class(TForm)
    Panel2: TPanel;
    DataSource1: TDataSource;
    DBGrid1: TDBGrid;
    SimpleDataSet1: TSimpleDataSet;
    SQLConnection1: TSQLConnection;
    ComboBox1: TComboBox;
    pnlFilter: TPanel;
    procedure FormCreate(Sender: TObject);
    procedure ComboBox1Change(Sender: TObject);
    procedure SimpleDataSet1BeforeOpen(DataSet: TDataSet);
  private
    { Private declarations }
  public
   procedure cReateFilter(Text:String;pnl:TPanel);
   procedure DeleteFilters(pnl:TPanel);
   procedure OpenDataSet;
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{ TForm1 }

procedure TForm1.CreateFilter(Text:String;pnl:TPanel);
var
   i:Integer;
   ed:TEdit;
   lbl:TLabel;
   Compom:TComponent;
begin
   for i := 0 to SimpleDataSet1.FieldCount - 1 do
      begin

      Compom := pnl.FindComponent('lb;'+SimpleDataSet1.Fields[i].DisplayName);
      if Compom <> nil then
            Compom.Free;

      lbl := TLabel.Create(pnl);
         with lbl do
            begin
               Parent := pnl;
               Left := 10;
               Top := 5;
               if i>0 then
               begin
                  Compom := pnl.FindComponent('ed'+SimpleDataSet1.Fields[i-1].DisplayName);
                  if Compom<>nil then
                     Top := ed.Top + ed.Height  + Height;
               end;
               Caption := SimpleDataSet1.Fields[i].DisplayLabel;
               Name := 'lbl' + SimpleDataSet1.Fields[i].DisplayName;
            end;

      Compom := pnl.FindComponent('ed'+SimpleDataSet1.Fields[i].DisplayName);

      if Compom <> nil then
         Compom.Free;

      ed := TEdit.Create(pnl);
         with ed do
            begin
               Parent := pnl;
               Left := 10;
               Height := 20;
               Top := lbl.Top+lbl.Height + Height  + 5;
               Name :='ed' + SimpleDataSet1.Fields[i].DisplayName;
               Text := '';
            end;

      end;


end;

procedure TForm1.FormCreate(Sender: TObject);
begin
   SQLConnection1.GetTableNames(ComboBox1.Items);
end;

procedure TForm1.OpenDataSet;
var
   TD:TTransactionDesc;
   SqlText,ObjName:String;
begin
   TD.TransactionID := 1;
   TD.IsolationLevel := xilREADCOMMITTED;

   SqlText := 'select * from $ObjName$';
   ObjName := ComboBox1.Text;
   SqlText := StringReplace(SqlText,'$ObjName$',ObjName,[]);

   SimpleDataSet1.Close;
   SimpleDataSet1.DataSet.CommandText := SqlText;

   SQLConnection1.StartTransaction(TD);
   SimpleDataSet1.Open;
   SQLConnection1.Commit(TD);

   cReateFilter(SqlText,pnlFilter);
end;

procedure TForm1.ComboBox1Change(Sender: TObject);
begin
   OpenDataSet;
end;

procedure TForm1.SimpleDataSet1BeforeOpen(DataSet: TDataSet);
begin
   DeleteFilters(pnlFilter);
end;

procedure TForm1.DeleteFilters(pnl: TPanel);
var
   i,c:integer;
begin
   if pnl.ComponentCount>0 then
   for i := 0 to pnl.ComponentCount-1  do
   begin
      c:=i;//kad je i = pnl.ComponentCount - 2 pukne posle sledece linije 
      pnl.Components[i].Free;
      c := pnl.ComponentCount;
   end;
end;

end.

Code:

   if pnl.ComponentCount>0 then
   for i := 0 to pnl.ComponentCount-1  do
   begin
      if (pnl.Components[i] is TEdit) then
         (pnl.Components[i] as TEdit).Free;
      if (pnl.Components[i] is TLabel) then
         (pnl.Components[i] as TLabel).Free;
   end;

Code:

   if pnl.ComponentCount>0 then
   for i := 0 to pnl.ComponentCount-1  do
   begin
      if (pnl.Components[i] is TEdit) then
         (pnl.Components[i] as TEdit).Free;
      if (pnl.Components[i] is TLabel) then
         (pnl.Components[i] as TLabel).Free;
   end;