C# 从 Collection 到 List<T> 的最快转换
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Fastest Convert from Collection to List<T>
提问by t3rse
What I'd like to avoid:
我想避免什么：
ManagementClass m = new ManagementClass("Win32_LogicalDisk");
ManagementObjectCollection managementObjects = m.GetInstances();
List<ManagementObject> managementList = new List<ManagementObject>();
foreach(ManagementObject m in managementObjects){
managementList.Add(m);
}
Isn't there a way to get that collection into a List that looks something like:
有没有办法将该集合放入一个类似于以下内容的列表中：
List<ManagementObject> managementList = new List<ManagementObjec>(collection_array);
采纳答案by Marc Gravell
What version of the framework? With 3.5 you could presumably use:
什么版本的框架？使用 3.5，您大概可以使用：
List<ManagementObject> managementList = managementObjects.Cast<ManagementObject>().ToList();
(edited to remove simpler version; I checked and ManagementObjectCollectiononly implements the non-generic IEnumerableform)
（编辑以删除更简单的版本；我检查并ManagementObjectCollection仅实现了非通用IEnumerable形式）
回答by steffenj
You could try:
你可以试试：
List<ManagementObject> managementList = new List<ManagementObject>(managementObjects.ToArray());
Not sure if .ToArray() is available for the collection. If you do use the code you posted, make sure you initialize the List with the number of existing elements:
不确定 .ToArray() 是否可用于集合。如果您确实使用了您发布的代码，请确保使用现有元素的数量初始化 List：
List<ManagementObject> managementList = new List<ManagementObject>(managementObjects.Count); // or .Length
回答by MagicKat
As long as ManagementObjectCollection implements IEnumerable<ManagementObject> you can do:
只要 ManagementObjectCollection 实现 IEnumerable<ManagementObject> 你就可以做到：
List<ManagementObject> managementList = new List<ManagementObjec>(managementObjects);
If it doesn't, then you are stuck doing it the way that you are doing it.
如果没有，那么您就只能按照自己的方式去做。
回答by mancaus
managementObjects.Cast<ManagementBaseObject>().ToList();is a good choice.
managementObjects.Cast<ManagementBaseObject>().ToList();是个不错的选择。
You could improve performance by pre-initialising the list capacity:
您可以通过预先初始化列表容量来提高性能：
public static class Helpers
{
public static List<T> CollectionToList<T>(this System.Collections.ICollection other)
{
var output = new List<T>(other.Count);
output.AddRange(other.Cast<T>());
return output;
}
}
回答by mancaus
you can convert like below code snippet
您可以像下面的代码片段一样进行转换
Collection<A> obj=new Collection<return ListRetunAPI()>
回答by stoto
Since 3.5, anything inherited from System.Collection.IEnumerable has the convenient extension method OfType available.
从 3.5 开始，从 System.Collection.IEnumerable 继承的任何东西都有方便的扩展方法 OfType 可用。
If your collection is from ICollection or IEnumerable, you can just do this:
如果您的集合来自 ICollection 或 IEnumerable，您可以这样做：
List<ManagementObject> managementList = ManagementObjectCollection.OfType<ManagementObject>().ToList();
Can't find any way simpler. : )
找不到任何更简单的方法。:)
回答by jacobsgriffith
You could use
你可以用
using System.Linq;
That will give you a ToList<> extension method for ICollection<>
这将为您提供 ICollection<> 的 ToList<> 扩展方法
