blocks|key|574897|text|考虑到这些约束(.NET+2.0)，您几乎达到了目标。IEnumerable<Rec_A>加上yield+return是一个更好的选择，国际海事组织：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|574898|public+IEnumerable<Rec_A>+getModifiedItems()
{
++foreach+(Rec_A+rec+in+this.Values)
++{
+++++if+(rec.modified)
++++++++yield+return+rec;
++}
}|code-block|syntax|javascript|574899|entityMap^0|R|I|1B|C|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

Given the constraints (.NET 2.0), you are almost on target. <code>IEnumerable&lt;Rec_A&gt;</code> plus <code>yield return</code> is a better alternative, IMO:

<pre><code>public IEnumerable&lt;Rec_A&gt; getModifiedItems()
{
 foreach (Rec_A rec in this.Values)
 {
 if (rec.modified)
 yield return rec;
 }
}
</code></pre>

blocks|key|2112208|text|是的，字典只有一个键的快速查找。如果要在值中查找任何内容，则必须遍历整个集合。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2112209|如果你经常这样做，你可以在你的集合中放一个列表，只跟踪修改过的项目。当修改集合时会有更多的开销，因为列表也必须更新，但只获取修改后的项将非常快。|2112210|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

Yes, a dictionary only has a fast lookup for the key. If you want to look for anything in the value, you have to loop through the entire collection.

If you do this a lot, you could put a list in your collection that keeps track of only the modified items. It will be a little more overhead when modifying the collection as the list has to be updated also, but getting just the modified items will be very fast.

blocks|key|2112275|text|搜索整个字典肯定是最简单的方法，尽管foreach循环会更干净：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2112276|foreach+(KeyValuePair<int,+Rec_A>+kvp+in+d)
{
++++//+Check+kvp.Value
}|code-block|syntax|javascript|2112277|如果您希望查找速度更快，可以在修改对象时将其添加到单独的列表中。这会减慢修改的速度，所以这里涉及到一个权衡。|2112278|entityMap^0|I|7|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

Searching through the entire dictionary is certainly the simplest way of doing it, though a <code>foreach</code> loop would be cleaner:

<pre><code>foreach (KeyValuePair&lt;int, Rec_A&gt; kvp in d)
{
 // Check kvp.Value
}
</code></pre>

If you want lookups to be faster you could add your modified objects in a separate list at the time you modify them. This will slow down modifications though, so there is a trade-off involved here.

blocks|key|2112328|text|你的问题的基本答案是肯定的，你必须遍历这些值来找到修改过的值。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2112329|现在，这个答案的其余部分将读起来像是代码审查。当我读到你的代码时，我的脑海中响起了许多警告的铃声，我觉得有必要这么做。|2112330|1)首先，你的代码可以正常工作。这是因为您将Dictionary中的键视为List或Array中的索引。您的for循环从0开始i，并将其递增到Count+(顺便说一下，这是KeyValuePair的数量)。但是，如果我在Dictionary中没有键等于0的值，该怎么办？基本上，对于这样的事情，你会得到一个异常：|offset|length|style|CODE|2112331|RecA_Dic+myD+=+new+RecA_Dic();
myD.Add(10,new+Rec_A());
myD.getModifiedItems();+//throws+KeyNotFoundException|code-block|syntax|javascript|2112332|现在，如果您使用从零开始的索引将值添加到Dictionary中，那么这就回避了一个问题:当List可以使用时，为什么还要使用Dictionary呢？|2112333|2)你不需要在this[i]上进行强制转换。因为您告诉Dictionary它将包含Rec_A值，所以它将以Rec_A的形式返回值。这就是泛型的美妙之处。|2112334|3)您不需要在if语句中比较modified和true。在使用bool变量时，通常认为不要将它们与true或false进行比较是一种良好的礼仪。另外，您可能需要考虑将modified重命名为IsModified。这更好地遵循了许多标准命名约定，并使代码更具可读性。|2112335|4)尽可能使用foreach而不是for。在这种情况下，foreach实际上可以解决我在1中提到的问题。|2112336|5)正如Humberto提到的，你可能想要考虑返回IEnumerable并使用yield+return。这为您提供了延迟执行的好处。|2112337|6)最后，你为什么还要继承Dictionary？根据您的代码，我猜您可以只创建一个Dictionary，将您的getModified方法设置为static，并使其接受Dictionary+(或者List，如果这是您真正需要的全部)作为参数。|2112338|我希望我的一些建议能帮助你解决问题。|2112339|entityMap^0|0|0|M|A|11|4|16|5|1I|3|1R|1|1Z|5|2E|C|32|A|0|0|K|A|19|4|1Q|A|0|7|7|R|A|15|5|1H|5|0|7|2|E|8|N|4|V|4|1D|4|1I|5|2B|8|2N|A|0|7|7|H|3|S|7|0|P|B|13|C|0|D|A|15|A|1J|B|1Z|6|2B|A|2P|4|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|15|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|16|8|@$F|17|G|18|H|I]|$F|19|G|1A|H|I]|$F|1B|G|1C|H|I]|$F|1D|G|1E|H|I]|$F|1F|G|1G|H|I]|$F|1H|G|1I|H|I]|$F|1J|G|1K|H|I]|$F|1L|G|1M|H|I]]|9|@]|A|$]]|$1|J|3|K|5|L|7|1N|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|1O|8|@$F|1P|G|1Q|H|I]|$F|1R|G|1S|H|I]|$F|1T|G|1U|H|I]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1V|8|@$F|1W|G|1X|H|I]|$F|1Y|G|1Z|H|I]|$F|20|G|21|H|I]|$F|22|G|23|H|I]]|9|@]|A|$]]|$1|S|3|T|5|6|7|24|8|@$F|25|G|26|H|I]|$F|27|G|28|H|I]|$F|29|G|2A|H|I]|$F|2B|G|2C|H|I]|$F|2D|G|2E|H|I]|$F|2F|G|2G|H|I]|$F|2H|G|2I|H|I]|$F|2J|G|2K|H|I]]|9|@]|A|$]]|$1|U|3|V|5|6|7|2L|8|@$F|2M|G|2N|H|I]|$F|2O|G|2P|H|I]|$F|2Q|G|2R|H|I]]|9|@]|A|$]]|$1|W|3|X|5|6|7|2S|8|@$F|2T|G|2U|H|I]|$F|2V|G|2W|H|I]]|9|@]|A|$]]|$1|Y|3|Z|5|6|7|2X|8|@$F|2Y|G|2Z|H|I]|$F|30|G|31|H|I]|$F|32|G|33|H|I]|$F|34|G|35|H|I]|$F|36|G|37|H|I]|$F|38|G|39|H|I]]|9|@]|A|$]]|$1|10|3|11|5|6|7|3A|8|@]|9|@]|A|$]]|$1|12|3|-4|5|6|7|3B|8|@]|9|@]|A|$]]]|13|$]]

The basic answer to your question is yes, you have to iterate through the values to find the modified ones.

Now the rest of this answer is going to read like a code review. So many warning bells went off in my head when I read your code that I felt compelled to do so.

1) First off your code will on even work. That's because you are treating the keys into the <code>Dictionary</code> like indexes into a <code>List</code> or <code>Array</code>. Your <code>for</code> loop starts <code>i</code> at 0 and increments it to the <code>Count</code> (which is the number of <code>KeyValuePair</code>s by the way). But what if I don't have a value in the <code>Dictionary</code> with a key equal to 0? Basically you'll get an exception for something like this:

<pre><code>RecA_Dic myD = new RecA_Dic();
myD.Add(10,new Rec_A());
myD.getModifiedItems(); //throws KeyNotFoundException
</code></pre>

Now if you are adding values into the <code>Dictionary</code> with a zero based index then that begs the question of why use a <code>Dictionary</code> when a <code>List</code> would do?

2) You don't need to do the casts on <code>this[i]</code>. Because you told the <code>Dictionary</code> that it will contain <code>Rec_A</code> values, it will return the values as <code>Rec_A</code>. That's the beauty of generics.

3) You don't need to compare <code>modified</code> to <code>true</code> in the <code>if</code> statement. When working with <code>bool</code> variables is is typically considered good etiquette to not compare them to <code>true</code> or <code>false</code>. On a side note you might want to consider renaming <code>modified</code> to <code>IsModified</code>. That better adheres to many standard naming conventions and makes the code more readable. 

4) Whenever possible try to use <code>foreach</code> instead of <code>for</code>. In this case a <code>foreach</code> would actually fix the problem I mentioned in 1.

5) As Humberto mentioned you might want to consider returning <code>IEnumerable</code> and using <code>yield return</code>. This gives you the benefit of delayed execution.

6) Finally why are you even inheriting from <code>Dictionary</code>? Based on your code I would guess you could just create a <code>Dictionary</code> and make your <code>getModified</code> method <code>static</code> and make it take the <code>Dictionary</code> (or <code>List</code> if that's all you really need) as a parameter.

I hope some of my suggestions will help you out.

blocks|key|1322263|text|是。要么必须检查每个值，要么必须跟踪另一个数据结构中的更改，例如已修改对象的列表。(您可以将其隐藏在专门的字典实现中。)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1322264|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Yes. Either you have to check every value, or you'll have to track changes in another data structure, such as a list of modified objects. (You could hide it within your specialized dictionary implementation.)

blocks|key|1318342|text|为了详细说明Mark+Byer的回应:例如，假设我们有一个名为Family的类，它包含一些值(无论有多少)，并且我们构建了一个字典来保存其数据。如果我们想要搜索这个列表，我们可以这样写：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1318343|foreach+(KeyValuePair<string,+Family>+kvPair+in+familyListDictionary)
++++++++{
++++++++++++if+(kvPair.Key+==+"4")
++++++++++++{
++++++++++++++++Console.WriteLine+(kvPair);
++++++++++++}
++++++++}|code-block|syntax|javascript|1318344|如果我们搜索关键字"4"...(在我的例子中，TKey是一个字符串)。|1318345|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|$]]

To elaborate Mark Byers response:
e.g. 
Lets say that we have a class named Family which holds some values (no matter how many) and we built a Dictionary to hold its data.
If we like to search through this list we write:

<pre><code>foreach (KeyValuePair&lt;string, Family&gt; kvPair in familyListDictionary)
 {
 if (kvPair.Key == "4")
 {
 Console.WriteLine (kvPair);
 }
 }
</code></pre>

And if we search for key "4"... (In my case TKey is a string).

what would be the best way to search for a value in a dictionary.
for instance I would like to search for modified objects, would going through the entire collection be the only way to do this?

c#, .net 2.0

<pre><code>class RecA
 { 
 public bool modified {get;set:}
 public string txt {get;set;}
 }

class RecA_Dic : Dictionary&lt;int,Rec_A&gt;
{

 public bool GetItemByKey(int key,out obj)
 {
 return this.TryGetValue(key, out obj);
 }

 public List&lt;Rec_A&gt; getModifiedItems()
 {
 List&lt;Rec_A&gt; li = new List&lt;Rec_A&gt;();
 for(int i=0;i&lt;this.count;i++)
 if (((Rec_A)this[i]).modified == true)
 li.Add((Rec_A)this[i]);
 return li;
 }

}
</code></pre>

How do I search for values in a dictionary

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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在字典中搜索值的最佳方式是什么？例如，我想搜索修改过的对象，遍历整个集合是唯一的方法吗？c#、.net 2.0class RecA { public bool modified {get;set:} public string txt {get;set;} }class RecA_Dic : Dictionary<int,Rec_A>{ public bool GetItemByKey(in

问如何在字典中搜索值
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