如何生成用字符串指定类型的对象？(20分)

如何生成用字符串指定类型的对象？
例：str='TEdit'
要求生成TEdit型的对象

使用：类类性；
Teditclass=class of Tedit;
var i:Teditclass;
i.create;

fan2先生给出的例子是针对具体的类的，如果我有一个stringlist.其中每一项字符
串指定一个类名，现要生成该类型的对象，如何办？我的目的是根据给定的字符串
来判断应生成什么样的对象（即所写的函数或过程中应把该字符串作为参数)

INFOFORM.PAS
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 .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 .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 .Name);
end;

end.

谢谢delphi fan2