blocks|key|1041625|text|不，这看起来很合理。有一个List.AddRange()方法基本上就是这样做的，但是要求您的集合是一个具体的List<T>。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1041626|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/z883w3dc.aspx^0|D|F|1I|7|D|F|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]]|D|@$9|S|A|T|1|U]]|E|$]]|$1|F|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

No, this seems perfectly reasonable. There is a <a href="http://msdn.microsoft.com/en-us/library/z883w3dc.aspx" rel="noreferrer"><code>List&lt;T&gt;.AddRange()</code></a> method that basically does just this, but requires your collection to be a concrete <code>List&lt;T&gt;</code>.

blocks|key|1042705|text|C5通用馆藏库类都支持AddRange方法。C5有一个更加健壮的接口，它实际上公开了其底层实现的所有功能，并且与System.Collections.Generic+ICollection和IList接口兼容，这意味着C5的集合可以很容易地替换为底层实现。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1042706|entityMap|0|LINK|mutability|MUTABLE|url|http://www.itu.dk/research/c5^0|B|8|1K|Q|2B|B|2N|5|31|2|0|7|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|C]|$9|U|A|V|B|C]|$9|W|A|X|B|C]]|D|@$9|Y|A|Z|1|10]]|E|$]]|$1|F|3|-4|5|6|7|11|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

The <a href="http://www.itu.dk/research/c5" rel="nofollow noreferrer">C5 Generic Collections Library</a> classes all support the <code>AddRange</code> method. C5 has a much more robust interface that actually exposes all of the features of its underlying implementations and is interface-compatible with the <code>System.Collections.Generic</code> <code>ICollection</code> and <code>IList</code> interfaces, meaning that <code>C5</code>'s collections can be easily substituted as the underlying implementation.

blocks|key|1022163|text|请记住，每个Add将检查集合的容量，并在必要时调整其大小(慢速)。使用AddRange，集合将被设置容量，然后添加项(更快)。这种扩展方法将非常缓慢，但会起作用。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1022164|entityMap^0|6|3|Z|8|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

Remember that each <code>Add</code> will check the capacity of the collection and resize it whenever necessary (slower). With <code>AddRange</code>, the collection will be set the capacity and then added the items (faster). This extension method will be extremely slow, but will work.

blocks|key|2548390|text|您可以将IEnumerable范围添加到列表中，然后将ICollection+=设置为列表。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2548391|++++++++IEnumerable<T>+source;

++++++++List<item>+list+=+new+List<item>();
++++++++list.AddRange(source);

++++++++ICollection<item>+destination+=+list;|code-block|syntax|javascript|2548392|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You could add your IEnumerable range to a list then set the ICollection = to the list.

<pre><code> IEnumerable&lt;T&gt; source;

 List&lt;item&gt; list = new List&lt;item&gt;();
 list.AddRange(source);

 ICollection&lt;item&gt; destination = list;
</code></pre>

blocks|key|1022226|text|在运行循环之前，尝试转换到扩展方法中的列表。这样，您就可以利用List.AddRange的性能。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1022227|public+static+void+AddRange<T>(this+ICollection<T>+destination,
+++++++++++++++++++++++++++++++IEnumerable<T>+source)
{
++++List<T>+list+=+destination+as+List<T>;

++++if+(list+!=+null)
++++{
++++++++list.AddRange(source);
++++}
++++else
++++{
++++++++foreach+(T+item+in+source)
++++++++{
++++++++++++destination.Add(item);
++++++++}
++++}
}|code-block|syntax|javascript|1022228|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try casting to List in the extension method before running the loop. That way you can take advantage of the performance of List.AddRange.

<pre><code>public static void AddRange&lt;T&gt;(this ICollection&lt;T&gt; destination,
 IEnumerable&lt;T&gt; source)
{
 List&lt;T&gt; list = destination as List&lt;T&gt;;

 if (list != null)
 {
 list.AddRange(source);
 }
 else
 {
 foreach (T item in source)
 {
 destination.Add(item);
 }
 }
}
</code></pre>

blocks|key|2548466|text|从.NET4.5开始，如果你想要一条线，你ForEach。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2548467|source.ForEach(o+=>+destination.Add(o));|code-block|syntax|javascript|2548468|或者更短的|2548469|source.ForEach(destination.Add);|2548470|就性能而言，它与每个循环(语法糖)相同。|2548471|另外，不要尝试分配它，如|BOLD|2548472|var+x+=+source.ForEach(destination.Add)+|2548473|因为ForEach是无效的。|2548474|编辑：复制自评论，利珀特对ForEach的看法。|2548475|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/bwabdf9z(v=vs.110).aspx|1|https://learn.microsoft.com/en-us/archive/blogs/ericlippert/foreach-vs-foreach^0|1|7|L|8|0|0|0|0|0|0|3|2|0|0|2|7|0|0|3|9|E|1|0^^$0|@$1|2|3|4|5|6|7|19|8|@$9|1A|A|1B|B|C]]|D|@$9|1C|A|1D|1|1E]]|E|$]]|$1|F|3|G|5|H|7|1F|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|1G|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|1H|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1I|8|@]|D|@]|E|$]]|$1|Q|3|R|5|6|7|1J|8|@$9|1K|A|1L|B|S]]|D|@]|E|$]]|$1|T|3|U|5|H|7|1M|8|@]|D|@]|E|$I|J]]|$1|V|3|W|5|6|7|1N|8|@$9|1O|A|1P|B|C]]|D|@]|E|$]]|$1|X|3|Y|5|6|7|1Q|8|@$9|1R|A|1S|B|S]]|D|@$9|1T|A|1U|1|1V]]|E|$]]|$1|Z|3|-4|5|6|7|1W|8|@]|D|@]|E|$]]]|10|$11|$5|12|13|14|E|$15|16]]|17|$5|12|13|14|E|$15|18]]]]

Since <code>.NET4.5</code> if you want one-liner you <a href="http://msdn.microsoft.com/en-us/library/bwabdf9z(v=vs.110).aspx" rel="noreferrer">can use <code>System.Collections.Generic</code> ForEach.</a>
<pre><code>source.ForEach(o =&gt; destination.Add(o));
</code></pre>
or even shorter as
<pre><code>source.ForEach(destination.Add);
</code></pre>
Performance-wise it's the same as for each loop (syntactic sugar).
Also don't try assigning it like
<pre><code>var x = source.ForEach(destination.Add) 
</code></pre>
cause <code>ForEach</code> is void.
Edit: Copied from comments, <a href="https://learn.microsoft.com/en-us/archive/blogs/ericlippert/foreach-vs-foreach" rel="noreferrer">Lippert's opinion on ForEach</a>.

blocks|key|2548559|text|或者您可以这样做一个ICollection扩展：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2548560|+public+static+ICollection<T>+AddRange<T>(this+ICollection<T>+@this,+IEnumerable<T>+items)
++++{
++++++++foreach(var+item+in+items)
++++++++{
++++++++++++@this.Add(item);
++++++++}

++++++++return+@this;
++++}|code-block|syntax|javascript|2548561|使用它就像在列表中使用它一样：|2548562|collectionA.AddRange(IEnumerable<object>+items);|2548563|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Or you can just make an ICollection extension like this:

<pre><code> public static ICollection&lt;T&gt; AddRange&lt;T&gt;(this ICollection&lt;T&gt; @this, IEnumerable&lt;T&gt; items)
 {
 foreach(var item in items)
 {
 @this.Add(item);
 }

 return @this;
 }
</code></pre>

Using it would be just like using it on a list: 

<pre><code>collectionA.AddRange(IEnumerable&lt;object&gt; items);
</code></pre>

blocks|key|1042837|text|这里有一个更高级的/可生产的版本：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1042838|++++public+static+class+CollectionExtensions
++++{
++++++++public+static+TCol+AddRange<TCol,+TItem>(this+TCol+destination,+IEnumerable<TItem>+source)
++++++++++++where+TCol+:+ICollection<TItem>
++++++++{
++++++++++++if(destination+==+null)+throw+new+ArgumentNullException(nameof(destination));
++++++++++++if(source+==+null)+throw+new+ArgumentNullException(nameof(source));

++++++++++++//+don't+cast+to+IList+to+prevent+recursion
++++++++++++if+(destination+is+List<TItem>+list)
++++++++++++{
++++++++++++++++list.AddRange(source);
++++++++++++++++return+destination;
++++++++++++}

++++++++++++foreach+(var+item+in+source)
++++++++++++{
++++++++++++++++destination.Add(item);
++++++++++++}

++++++++++++return+destination;
++++++++}
++++}|code-block|syntax|javascript|1042839|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here is a bit more advanced/production-ready version: 

<pre class="lang-cs prettyprint-override"><code> public static class CollectionExtensions
 {
 public static TCol AddRange&lt;TCol, TItem&gt;(this TCol destination, IEnumerable&lt;TItem&gt; source)
 where TCol : ICollection&lt;TItem&gt;
 {
 if(destination == null) throw new ArgumentNullException(nameof(destination));
 if(source == null) throw new ArgumentNullException(nameof(source));

 // don't cast to IList to prevent recursion
 if (destination is List&lt;TItem&gt; list)
 {
 list.AddRange(source);
 return destination;
 }

 foreach (var item in source)
 {
 destination.Add(item);
 }

 return destination;
 }
 }
</code></pre>

blocks|key|1022396|text|同意上面的一些人和Lipert的观点。在我的例子中，经常这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1022397|ICollection<int>+A;
var+B+=+new+List<int>+{1,2,3,4,5};
B.ForEach(A.Add);|code-block|syntax|javascript|1022398|在我看来，这类操作的扩展方法有点多余。|1022399|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Agree with some guys above and Lipert's opinion.
In my case, it's quite often to do like this:
<pre><code>ICollection&lt;int&gt; A;
var B = new List&lt;int&gt; {1,2,3,4,5};
B.ForEach(A.Add);
</code></pre>
To have an extension method for such operation a bit redundant in my view.

A coworker asked me today how to add a range to a collection. He has a class that inherits from <code>Collection&lt;T&gt;</code>. There's a get-only property of that type that already contains some items. He wants to add the items in another collection to the property collection. How can he do so in a C#3-friendly fashion? (Note the constraint about the get-only property, which prevents solutions like doing Union and reassigning.)

Sure, a foreach with Property. Add will work. But a <code>List&lt;T&gt;</code>-style AddRange would be far more elegant.

It's easy enough to write an extension method:

<pre><code>public static class CollectionHelpers
{
 public static void AddRange&lt;T&gt;(this ICollection&lt;T&gt; destination,
 IEnumerable&lt;T&gt; source)
 {
 foreach (T item in source)
 {
 destination.Add(item);
 }
 }
}
</code></pre>

But I have the feeling I'm reinventing the wheel. I didn't find anything similar in <code>System.Linq</code> or <a href="http://code.google.com/p/morelinq/" rel="noreferrer">morelinq</a>.

Bad design? Just Call Add? Missing the obvious?

AddRange to a Collection

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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一位同事今天问我如何在一个集合中添加一个范围。他有一个继承自Collection<T>的类。有一个已包含某些项的那种类型的get-only属性。他希望将另一个集合中的项添加到属性集合中。他怎么能以C#3友好的方式这么做呢？(请注意有关get-only属性的约束，它阻止执行Union和重新分配之类的解决方案。)当然，有财...

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