blocks|key|181820|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|181821|table1.GroupBy(x+=>+x.Text).Select(x+=>+x.FirstOrDefault());|code-block|syntax|javascript|181822|这将按Text对表进行分组，并使用每个组中的第一行，从而得到Text为distinct的行。|offset|length|style|CODE|181823|entityMap^0|0|0|3|4|U|4|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]|$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|N|$]]

Try this:

<pre><code>table1.GroupBy(x =&gt; x.Text).Select(x =&gt; x.FirstOrDefault());
</code></pre>

This will group the table by <code>Text</code> and use the first row from each groups resulting in rows where <code>Text</code> is distinct.

blocks|key|399836|text|MoreLinq有一个您可以使用的DistinctBy方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|399837|它将允许您执行以下操作：|399838|var+results+=+table1.DistictBy(row+=>+row.Text);|code-block|syntax|javascript|399839|该方法的实现(简称参数验证)如下所示：|399840|private+static+IEnumerable<TSource>+DistinctByImpl<TSource,+TKey>(IEnumerable<TSource>+source,
++++Func<TSource,+TKey>+keySelector,+IEqualityComparer<TKey>+comparer)
{
++++HashSet<TKey>+knownKeys+=+new+HashSet<TKey>(comparer);
++++foreach+(TSource+element+in+source)
++++{
++++++++if+(knownKeys.Add(keySelector(element)))
++++++++{
++++++++++++yield+return+element;
++++++++}
++++}
}|399841|entityMap|0|LINK|mutability|MUTABLE|url|http://code.google.com/p/morelinq/source/browse/MoreLinq/DistinctBy.cs?r=f4c39a771d712a568467eaa31840cc22e07a5ed0^0|H|A|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|6|7|10|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|11|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|12|8|@]|9|@]|C|$]]|$1|M|3|N|5|H|7|13|8|@]|9|@]|C|$I|J]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]]]

MoreLinq has a <a href="http://code.google.com/p/morelinq/source/browse/MoreLinq/DistinctBy.cs?r=f4c39a771d712a568467eaa31840cc22e07a5ed0" rel="nofollow noreferrer">DistinctBy</a> method that you can use:
It will allow you to do:
<pre><code>var results = table1.DistictBy(row =&gt; row.Text);
</code></pre>
The implementation of the method (short of argument validation) is as follows:
<pre><code>private static IEnumerable&lt;TSource&gt; DistinctByImpl&lt;TSource, TKey&gt;(IEnumerable&lt;TSource&gt; source,
 Func&lt;TSource, TKey&gt; keySelector, IEqualityComparer&lt;TKey&gt; comparer)
{
 HashSet&lt;TKey&gt; knownKeys = new HashSet&lt;TKey&gt;(comparer);
 foreach (TSource element in source)
 {
 if (knownKeys.Add(keySelector(element)))
 {
 yield return element;
 }
 }
}
</code></pre>

blocks|key|181868|text|围绕这个话题有很多讨论。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|181869|你可以找到其中的一个here：|offset|length|181870|最受欢迎的建议之一是@Servy指出的将lambda表达式作为参数的独特方法。|181871|C#的首席架构师Anders+Hejlsberg提出了解决方案here。还解释了为什么框架设计团队决定不添加采用lambda的Distinct方法的重载。|181872|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/1300088/distinct-with-lambda|1|http://social.msdn.microsoft.com/Forums/en-US/linqprojectgeneral/thread/6834054e-e1c1-49db-970c-370a9012c675^0|0|A|4|0|0|0|V|4|1|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|U|8|@]|9|@$D|V|E|W|1|X]]|A|$]]|$1|F|3|G|5|6|7|Y|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|Z|8|@]|9|@$D|10|E|11|1|12]]|A|$]]|$1|J|3|-4|5|6|7|13|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q]]|R|$5|M|N|O|A|$P|S]]]]

There are lots of discussions around this topic.

You can find one of them <a href="https://stackoverflow.com/questions/1300088/distinct-with-lambda">here</a>: 

One of the most popular suggestions have been the Distinct method taking a lambda expression as a parameter as @Servy has pointed out.

The chief architect of C#, Anders Hejlsberg has suggested the solution <a href="http://social.msdn.microsoft.com/Forums/en-US/linqprojectgeneral/thread/6834054e-e1c1-49db-970c-370a9012c675" rel="nofollow noreferrer">here</a>. Also explaining why the framework design team decided not to add an overload of Distinct method which takes a lambda.

blocks|key|181874|text|你可以试试这个：table1.GroupBy(t+=>+t.Text).Select(shape+=>+shape.r)).Distinct();|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|181875|entityMap^0|8|1T|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

You can try this:<code>table1.GroupBy(t =&gt; t.Text).Select(shape =&gt; shape.r)).Distinct();</code>

blocks|key|181899|text|据我所知，你的问题大体上是正确的。只需将"select+r“更改为"select+r.Text”即可解决问题。这就是MSDN记录它应该如何工作的方式。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|181900|例如：|181901|++++var+query+=+(from+r+in+table1+orderby+r.Text+select+r.Text).distinct();|code-block|syntax|javascript|181902|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

From what I have found, your query is mostly correct. Just change "select r" to "select r.Text" is all and that should solve the problem. This is how MSDN documented how it should work.

Ex:

<pre><code> var query = (from r in table1 orderby r.Text select r.Text).distinct();
</code></pre>

blocks|key|181909|text|data.Select(x=>x.Name).Distinct().Select(x+=>+new+SelectListItem+{+Text+=+x+});|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|181910|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>data.Select(x=&gt;x.Name).Distinct().Select(x =&gt; new SelectListItem { Text = x });
</code></pre>

blocks|key|399928|text|尝试以下代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|399929|table1.GroupBy(x+=>+x.Text).Select(x+=>+x.FirstOrDefault());|code-block|syntax|javascript|399930|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 this code :

<pre><code>table1.GroupBy(x =&gt; x.Text).Select(x =&gt; x.FirstOrDefault());
</code></pre>

I am trying to use .distinct in Linq to get result based on one field of the table (so do not require a whole duplicated records from table).

I know writing basic query using distinct as followed:

<pre><code>var query = (from r in table1
orderby r.Text
select r).distinct();
</code></pre>

but I need results where <code>r.text</code> is not duplicated.

Distinct in Linq based on only one field of the table

我尝试在Linq中使用.distinct根据表中的一个字段来获得结果(所以不需要从表中获得整个重复的记录)。我知道使用distinct编写基本查询如下：var query = (from r in table1orderby r.Textselect r).distinct();但我需要不复制r.text的结果。

问Linq中的Distinct仅基于表的一个字段
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