是将这个ArrayList的一个泛型列表高效？ [英] Is converting this ArrayList to a Generic List efficient?

问题描述

在code我写收到来自非托管code一个ArrayList，并且此ArrayList总是包含类型Grid_Heading_Blk的一个或多个对象。我考虑过改变此ArrayList到一个通用的列表，但我不能确定是否转换操作会如此昂贵，以抵消与泛型列表的工作所带来的好处。目前，我只是运行一个的foreach（Grid_Heading_Blk在myArrayList）操作传递的ArrayList的类，将使用后的ArrayList的内容合作。

The code I'm writing receives an ArrayList from unmanaged code, and this ArrayList will always contain one or more objects of type Grid_Heading_Blk. I've considered changing this ArrayList to a generic List, but I'm unsure if the conversion operation will be so expensive as to nullify the benefits of working with the generic list. Currently, I'm just running a foreach (Grid_Heading_Blk in myArrayList) operation to work with the ArrayList contents after passing the ArrayList to the class that will use it.

我应该ArrayList的转换为一个通用的类型化列表？如果是的话，什么是这样做的最有效的方法是什么？

Should I convert the ArrayList to a generic typed list? And if so, what is the most efficient way of doing so?

推荐答案

下面是一个刺在高性能的方式来创建一个ArrayList泛型列表。

Here's a stab at a performant way to create a generic list from an ArrayList.

List<Grid_Heading_Blk> myList = new List<Grid_Heading_Blk>(source.Count);
myList.AddRange(source.OfType<Grid_Heading_Blk>());

通过调用的的构造函数，它接受一个int 的，后备存储分配一次。

By calling the constructor that accepts an int, the backing storage is allocated only once.

与往常一样，你应该使用什么工具，你通常使用衡​​量性能。

As always, you should measure the performance using whatever tools you normally use.

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