blocks|key|372945|text|由于这是公认的答案，我将尝试涵盖这个问题的每一个可能的含义：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|372946|var+dict+=+new+Dictionary<string,+int>+{+{+"b",+3+},+{+"a",+4+}+};

//+greatest+key
var+maxKey+=+dict.Keys.Max();+//+"b"

//+greatest+value
var+maxValue+=+dict.Values.Max();+//+4

//+key+of+the+greatest+value
//+4+is+the+greatest+value,+and+its+key+is+"a",+so+"a"+is+the+answer.
var+keyOfMaxValue+=+dict.Aggregate((x,+y)+=>+x.Value+>+y.Value+?+x+:+y).Key;+//+"a"|code-block|syntax|javascript|372947|注意:该问题的密钥类型为System.Guid。问“什么是最好的GUID”可能没有意义，因为它们只是想成为唯一的值，而不是代表任何可排序的概念。尽管如此，上面的代码可以与任何支持>运算符的类型一起工作，为了简洁起见，这里选择string和int。|offset|length|style|CODE|372948|entityMap^0|0|0|C|B|2H|1|34|6|3B|3|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]|$I|V|J|W|K|L]|$I|X|J|Y|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|N|$]]

Since this was the accepted answer, I'll try to cover every possible meaning of the question:

<pre><code>var dict = new Dictionary&lt;string, int&gt; { { "b", 3 }, { "a", 4 } };

// greatest key
var maxKey = dict.Keys.Max(); // "b"

// greatest value
var maxValue = dict.Values.Max(); // 4

// key of the greatest value
// 4 is the greatest value, and its key is "a", so "a" is the answer.
var keyOfMaxValue = dict.Aggregate((x, y) =&gt; x.Value &gt; y.Value ? x : y).Key; // "a"
</code></pre>

Note: the question has <code>System.Guid</code> as the key type. It might not make sense to ask "what is the greatest GUID", since they are simply intended to be unique values, rather than represent any orderable concept. Nonetheless, the above code will work with any type that supports the <code>&gt;</code> operator, <code>string</code> and <code>int</code> being chosen here for conciseness.

blocks|key|372972|text|Guid实现了IComparable，因此：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|372973|d.Keys.Max()|code-block|syntax|javascript|372974|也不清楚为什么要这样做……|372975|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|$]]

Guid implements IComparable, so:

<pre><code>d.Keys.Max()
</code></pre>

Also it is not clear why one would want to do so...

blocks|key|372985|text|++++++++++++var+maxGuid+=+Guid.Empty;
++++++++++++var+maxDateTime+=+DateTime.MinValue;
++++++++++++foreach+(var+kvp+in+d)
++++++++++++{
++++++++++++++++if+(kvp.Value+>+maxDateTime)
++++++++++++++++{
++++++++++++++++++++maxGuid+=+kvp.Key;
++++++++++++++++++++maxDateTime+=+kvp.Value;
++++++++++++++++}
++++++++++++}
++++++++++++Console.WriteLine("Guid+of+max+date+is:+"+%2B+maxGuid.ToString());|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|372986|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> var maxGuid = Guid.Empty;
 var maxDateTime = DateTime.MinValue;
 foreach (var kvp in d)
 {
 if (kvp.Value &gt; maxDateTime)
 {
 maxGuid = kvp.Key;
 maxDateTime = kvp.Value;
 }
 }
 Console.WriteLine("Guid of max date is: " + maxGuid.ToString());
</code></pre>

blocks|key|373024|text|这很好用。它将返回最大日期的GUID。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|373025|Dictionary<Guid,+DateTime>+d+=+new+Dictionary<Guid,+DateTime>();+
var+guidForMaxDate+=+d.FirstOrDefault(x+=>+x.Value+==+d.Values.Max()).Key;|code-block|syntax|javascript|373026|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|$]]

This works great. It will return the GUID for the MAX date.

<pre><code>Dictionary&lt;Guid, DateTime&gt; d = new Dictionary&lt;Guid, DateTime&gt;(); 
var guidForMaxDate = d.FirstOrDefault(x =&gt; x.Value == d.Values.Max()).Key;
</code></pre>

blocks|key|373086|text|首先对数据进行排序可能是一种解决方案。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|373087|var+maxGuid+=+d.OrderByDescending(x+=>+x.Value).FirstOrDefault().Key;|code-block|syntax|javascript|373088|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|$]]

Ordering your data in the first place could be one solution.

<pre><code>var maxGuid = d.OrderByDescending(x =&gt; x.Value).FirstOrDefault().Key;
</code></pre>

blocks|key|373116|text|被接受的答案对我不起作用。下面的代码(使用MoreLinq)完成了这项工作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|373117|var+fooDict+=+new+Dictionary<string,+int>();
var+keyForBiggest+=+fooDict.MaxBy(kvp+=>+kvp.Value).Key;
var+biggestInt+=+fooDict[keyForBiggest];|code-block|syntax|javascript|373118|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|$]]

The accepted answer didn't work for me. The following code (using MoreLinq) did the job though:

<pre><code>var fooDict = new Dictionary&lt;string, int&gt;();
var keyForBiggest = fooDict.MaxBy(kvp =&gt; kvp.Value).Key;
var biggestInt = fooDict[keyForBiggest];
</code></pre>

blocks|key|373153|text|通过在字典上使用LINQ。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|373154|var+MaximumValue+=+dict.FirstOrDefault(x+=>+x.Value.Equals(dict.Values.Max()));|code-block|syntax|javascript|373155|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|$]]

By using LINQ on dictionary.

<pre><code>var MaximumValue = dict.FirstOrDefault(x =&gt; x.Value.Equals(dict.Values.Max()));
</code></pre>

I have 

<pre><code>Dictionary&lt;Guid, DateTime&gt; d = new Dictionary&lt;Guid, DateTime&gt;();
</code></pre>

How I can get an <code>Guid</code> which has <code>MAX</code> value?

How to get MAX value from Dictionary?

我有过Dictionary<Guid, DateTime> d = new Dictionary<Guid, DateTime>();如何获取具有MAX值的Guid？

问如何从字典中获取最大值？
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