combobox1.items.addobject()中的对象需要释放吗？

[westuser]

开发环境：delphi2007
测试代码：

procedure TForm1.FormCreate(Sender: TObject);
var
  i:integer;
  myClass: TMyClass;
begin
  for i :=0 to 9 do
  begin
    myClass := TMyClass.Create;
    myClass.id := 1;
    myClass.context := 'cccdddeee';
    ComboBox1.Items.AddObject(myClass.context,myClass);
  end;
end;

前提：myClass就定义成局部变量，类成员变量或全局变量不用讨论

myClass实际上是引用，这个时候不能释放。而定义的又是局部变量，Form1.Close的时候肯定是找不着了。

问题：最后还用释放他们吗？如何释放？是否通过循环：(ComboBox1.Items[i] as myClass).Free;

[starluck]

这里载入下指针,如果其它地方没有释放,这个就需要

[bdmh]

最好手动释放

[haitao]

需要人为释放

不过，如果包含这些items的对象如果能提供一个OnDeleteItem的事件就好了，可以在事件里释放，而事件是会在适当时机被触发

[ZyxIp]

不管是局部还是全局的，自己创建的自己释放。

[mjp1234airen4385]

需要。

[westuser]

如何释放？还是我这样写已经没办法释放了？

[火龙岛主]

不一定，只要有释放的地方就可以了。
但楼主的情况需要释放：

  for i :=ComboBox1.Items.count - 1 downto 0 do
  begin
    TMyClass(ComboBox1.Items.Objects[i]).Free;
    //或者FreeAndNil(TMyClass(ComboBox1.Items.Objects[i]));
  end;

[Hexpate]

需要释放 呵呵,抢不到sf

[xingyunmm]

unit Unit1;

interface

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

type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
ComboBoxStr: TComboBox;
Button3: TButton;
Button4: TButton;
Button5: TButton;
ComboBoxInt: TComboBox;
Button6: TButton;
procedure Button1Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
procedure Button6Click(Sender: TObject);
procedure Button5Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

const
MemSize=1024;

procedure TForm1.Button1Click(Sender: TObject);
procedure AddItem(str:string);
var
p:Pointer; //无类型指针
begin
GetMem(P,MemSize);
string(p^):='ptr: '+str;
ComboBoxStr.Items.AddObject(str,p);
// 第二个参数实际上就是一个指针
// 指针没指向任何地方或没显式分配内存时时就是nil
// string(Pointer(Items.Objects[itemIndex])^) 这样取指针里的内容就会报错误
end;
begin
AddItem('aaa');
AddItem('bbb');
AddItem('ccc');
end;

procedure TForm1.Button2Click(Sender: TObject);
var
I:Integer;
begin
with ComboBoxStr do
for I := Items.Count -1 downto 0 do
begin
FreeMem(Pointer(Items.Objects[I]),MemSize);
items.Delete(I);
//delete只是删除指针本身,所以指针指向的地方的内存要你自己负责Free
end;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
with ComboBoxStr do
if ItemIndex > -1 then
ShowMessage(string(Pointer(Items.Objects[itemIndex])^));
end;

procedure TForm1.Button4Click(Sender: TObject);
procedure AddItem(str:string);
begin
ComboBoxInt.Items.AddObject(str,TObject(StrToInt(str)));
//这里为什么没申请内存??因为指针本身就是用一个integer来表示的
end;
begin
AddItem('111');
AddItem('222');
AddItem('333');
end;


procedure TForm1.Button5Click(Sender: TObject);
var
I:Integer;
begin
with ComboBoxInt do
for I := Items.Count -1 downto 0 do
items.Delete(I);
end;

procedure TForm1.Button6Click(Sender: TObject);
begin
with ComboBoxInt do
if ItemIndex > -1 then
ShowMessageFmt('%d',[Integer(Items.Objects[itemIndex])]);
end;

end.



---------------------------------------------------------------------


object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 161
ClientWidth = 505
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
OldCreateOrder = False
Position = poDesktopCenter
PixelsPerInch = 96
TextHeight = 13
object Button1: TButton
Left = 232
Top = 40
Width = 75
Height = 25
Caption = #24314#31435
TabOrder = 0
OnClick = Button1Click
end
object Button2: TButton
Left = 394
Top = 40
Width = 75
Height = 25
Caption = #28165#38500
TabOrder = 1
OnClick = Button2Click
end
object ComboBoxStr: TComboBox
Left = 48
Top = 42
Width = 145
Height = 21
ItemHeight = 13
TabOrder = 2
Text = #27979#35797#23383#31526#20018
end
object Button3: TButton
Left = 313
Top = 40
Width = 75
Height = 25
Caption = #26597#30475
TabOrder = 3
OnClick = Button3Click
end
object Button4: TButton
Left = 232
Top = 88
Width = 75
Height = 25
Caption = #24314#31435
TabOrder = 4
OnClick = Button4Click
end
object Button5: TButton
Left = 394
Top = 88
Width = 75
Height = 25
Caption = #28165#38500
TabOrder = 5
OnClick = Button5Click
end
object ComboBoxInt: TComboBox
Left = 48
Top = 90
Width = 145
Height = 21
ItemHeight = 13
TabOrder = 6
Text = #27979#35797#25968#23383
end
object Button6: TButton
Left = 313
Top = 88
Width = 75
Height = 25
Caption = #26597#30475
TabOrder = 7
OnClick = Button6Click
end
end

[xingyunmm]

//上面代码有错,不应该用string,要指定长度string[100]这样

type
TMyStr=string[50];


procedure TForm1.Button1Click(Sender: TObject);
procedure AddItem(str:TMyStr);
var
p:Pointer; //无类型指针
begin
GetMem(P,Length(str));
TMyStr(p^):=str;
ComboBoxStr.Items.AddObject(str,p);
// 第二个参数实际上就是一个指针
// 指针没指向任何地方或没显式分配内存时时就是nil
// Pointer(Items.Objects[itemIndex])^ 这样取指针里的内容就会报错误
end;
begin
AddItem('aaa');
AddItem('bbb');
AddItem('ccc');
end;

[xingyunmm]

procedure TForm1.Button1Click(Sender: TObject);
procedure AddItem(str:TMyStr);
var
p:Pointer; //无类型指针
begin
GetMem(P,SizeOf(str)); //固定长度
//Length(str)),实际长度;
TMyStr(p^):=str;
ComboBoxStr.Items.AddObject(str,p);
// 第二个参数实际上就是一个指针
// 指针没指向任何地方或没显式分配内存时时就是nil
// Pointer(Items.Objects[itemIndex])^ 这样取指针里的内容就会报错误
end;
begin
AddItem('aaa');
AddItem('bbb');
AddItem('ccc');
end;