Создать компонент любого класса

unit InfoForm;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
  StdCtrls, ExtCtrls, Buttons, Clipbrd, Comctrls, Db, Dbcgrids,
  Dbctrls, Dbgrids, Dblookup, Dbtables, Ddeman, Dialogs,
  Filectrl, Grids, Mask, Menus, Mplayer, Oleconst, Olectnrs,
  Olectrls, Outline, Tabnotbk, Tabs, ExtDlgs, CheckLst, ToolWin;

type
  TForm1 = class(TForm)
    Panel1: TPanel;
    ComboBox1: TComboBox;
    Label1: TLabel;
    Label2: TLabel;
    ComboBox2: TComboBox;
    procedure FormCreate(Sender: TObject);
    procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
  private
    function GetNextName (MyClass: TComponentClass): string;
    procedure UpdateList;
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

type
  TClassArray = array [1..133] of TPersistentClass;
// definition temporary used to check the data types
// TClassArray = array [1..133] of TComponentClass;
const
  ClassArray: TClassArray = (
TApplication,
TBatchMove,
TColorDialog,
TFindDialog,
TReplaceDialog,
TFontDialog,
TOpenDialog ,
TOpenPictureDialog,
TSavePictureDialog,
TSaveDialog,
TPrintDialog,
TPrinterSetupDialog,
TBevel,
TCustomLabel,
TDBText,
TLabel,
TImage,
TPaintBox,
TShape,
TSpeedButton,
TSplitter,
TToolButton,
TAnimate,
TButton,
TBitBtn,
TCheckBox,
TDBCheckBox,
TRadioButton,
TComboBox,
TDBComboBox,
TDriveComboBox,
TFilterComboBox,
TCustomDBGrid,
TDBGrid,
TDBLookupList,
TPopupGrid,
TOutline,
TDrawGrid,
TStringGrid,
TDBRadioGroup,
TRadioGroup,
TGroupBox,
TDBNavigator,
TPanel,
TDBImage,
TDBLookupControl,
TDBLookupComboBox,
TDBLookupListBox,
TPopupDataList,
THeader,
THintWindow,
TMediaPlayer,
TNotebook,
TOleContainer,
TPage,
TScroller,
TTabSet,
TDBEdit,
TInplaceEdit,
TMaskEdit,
TCustomRichEdit,
TDBRichEdit,
TRichEdit,
TDBMemo,
TMemo,
TDBLookupCombo,
TEdit,
THotKey,
TCheckListBox,
TDBListBox,
TDirectoryListBox,
TFileListBox,
TListBox,
TListView,
TStaticText,
TPageControl,
TTabbedNotebook,
TTabControl,
TTreeView,
TUpDown,
TDateTimePicker,
TDBCtrlGrid,
TDBCtrlPanel,
THeaderControl,
TOleControl,
TProgressBar,
TScrollBar,
TScrollBox,
TStatusBar,
TTabPage,
TTabSheet,
TToolWindow,
TCoolBar,
TToolBar,
TTrackBar,
TImageList,
TDatabase,
TDataModule,
TQuery,
TStoredProc,
TTable,
TUpdateSQL,
TDataSource,
TDdeClientConv,
TDdeClientItem,
TDdeMgr,
TDdeServerConv,
TDdeServerItem,
TBinaryField,
TBytesField,
TVarBytesField,
TBlobField,
TGraphicField,
TMemoField,
TBooleanField,
TDateTimeField,
TDateField,
TTimeField,
TNumericField,
TBCDField,
TFloatField,
TCurrencyField,
TIntegerField,
TAutoIncField,
TSmallintField,
TWordField,
TStringField,
TMainMenu,
TPopupMenu,
TMenuItem,
TScreen,
TSession,
TTimer
);

procedure TForm1.FormCreate(Sender: TObject);
var
  I: Integer;
begin
  // register all of the classes
  RegisterClasses (ClassArray);
  // copy class names to the listbox
  for I := Low (ClassArray) to High (ClassArray) do
    ComboBox1.Items.Add (ClassArray [I].ClassName);
  UpdateList;
end;

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
var
  MyClass: TComponentClass;
  MyComp: TComponent;
begin
  MyClass := TComponentClass (GetClass (ComboBox1.Text));
  if MyClass = nil then
    Beep
  else
  begin
    MyComp := MyClass.Create (self);
    MyComp.Name := GetNextName (MyClass);
    if MyClass.InheritsFrom (TControl) then
    // if MyComp is TControl then  // alternative version
    begin
      TControl (MyComp).Left := X;
      TControl (MyComp).Top := Y;
      TControl (MyComp).Parent := self;
    end;
  end;
  UpdateList;
end;

function TForm1.GetNextName (MyClass: TComponentClass): string;
var
  I, nTot: Integer;
begin
  nTot := 0;
  for I := 0 to ComponentCount - 1 do
    if Components [I].ClassType = MyClass then
      Inc (nTot);
  Result := Copy (MyClass.ClassName, 2, Length (MyClass.ClassName) - 1) +
    IntToStr (nTot);
end;

procedure TForm1.UpdateList;
var
  I: Integer;
begin
  Combobox2.Items.Clear;
  for I := 0 to ComponentCount - 1 do
    ComboBox2.Items.Add (Components [I].Name);
end;

end.