清除TList或TObjectList [英] Clear a TList or a TObjectList

问题描述

我对于将对象存储在列表中使用什么感到有些困惑. 到目前为止，我已经使用TList并在循环中释放了每个项目.然后，我发现TObjectList从Free自动执行此操作.然后我从TList.Clear的文档中看到了这一点:

I'm a bit puzzled of what to use for storing objects in a list. Until now I have used TList and freed each item in a loop. Then I discovered TObjectList that do this automatically from Free. Then I saw this from the doc of TList.Clear:

调用Clear清空Items数组并将Count设置为0. 释放用于存储Items数组的内存，并将Capacity设置为0.

Call Clear to empty the Items array and set the Count to 0. Clear also frees the memory used to store the Items array and sets the Capacity to 0.

所以基本上是一样的.所以

So it is basically the same. So

用于TList

mylist.Clear;
myList.Free;

与TObjectList相同吗?

myList.Free;

TObjectList只能作为类用于项目还是可以存储记录?

Can TObjectList only be used for items as classes or can I store records?

推荐答案

1. TList不会同时使用Clear或Free释放元素.

1. TList won't free the elements, with both Clear or Free.

aList.Clear;

aList.Clear;

只需设置aList.Count := 0而不释放aList.Items[]元素.因此，您将泄漏内存.您需要像这样的显式免费版本:

Will just set aList.Count := 0 without freeing the aList.Items[] elements. So you'll leak memory. You'll need an explicit free as such:

for i := 0 to aList.Count-1 do
  TObject(aList[i]).Free;

但这是TObjectList的工作...:)

But this is what TObjectList does... :)

关于TObjectList，值得一提的是TObjectList.Destroy正在呼叫Clear.

About TObjectList, it is worth saying that TObjectList.Destroy is calling Clear.

所以

aObjectList.Clear;
aObjectList.Free;

与

aObjectList.Free;

2.要存储记录列表，可以使用动态数组.

通过我们的

You'll get all TList methods (and more) with our dynamic array wrapper. That is, Add / Delete / Clear / Count / IndexOf / Find...

它具有内置的序列化功能(二进制或JSON)，自动排序和比较(使用RTTI)，而TList/TObjectList不存在.从Delphi 5及更高版本开始.

It has built-in serialization features (in binary or JSON), automated sorting and comparison (using RTTI) which are not existing with a TList/TObjectList. From Delphi 5 and later.

在Delphi的较新版本中，如果您不想使用第三方库，则可以使用泛型来处理动态数组.

With more modern version of Delp you may use generics to handle the dynamic array, if you do not want to use a third-party library.

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