blocks|key|4441439|text|请尝试以下操作|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4441440|++List<string>+TheListParameter+=+new+List<string>{"string1",+"string2",+"string3"};

++var+TheOutput+=+(from+t+in+MyDC.SomeTable
+++++++++++++++++++where+TheListParameter.Any(e+=>+e+==+t.SomeColumn)
+++++++++++++++++++select+t.SomeColumn).ToList();|code-block|syntax|javascript|4441441|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 following 

<pre><code> List&lt;string&gt; TheListParameter = new List&lt;string&gt;{"string1", "string2", "string3"};

 var TheOutput = (from t in MyDC.SomeTable
 where TheListParameter.Any(e =&gt; e == t.SomeColumn)
 select t.SomeColumn).ToList();
</code></pre>

blocks|key|4441653|text|根据Contain的Documentation，Contains的参数可能是string，而不是一个字符串列表，所以应该是这样的：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4441654|List<string>+TheListParameter+=+new+List<string>+{"string1",+"string2",+"string3"};

var+TheOutput+=+(from+t+in+MyDC.SomeTable
+++++++++++++++++where+TheListParameter.Contains(t.SomeColumn.ToString())
+++++++++++++++++select+t.SomeColumn).ToList();|code-block|syntax|javascript|4441655|或者，如果您想返回一个布尔结果，如果MyDC.SomeTable.SomeColumn包含TheListParameter的一个字符串，您可以尝试如下所示：|4441656|bool+hasSameElements+=+MyDC.SomeTable.ToList()
++++++++++++++++++++++.Select(c+=>+c.SomeColumn)
++++++++++++++++++++++.Intersect(TheListParameter).Any();+//True+or+False|4441657|entityMap|0|LINK|mutability|MUTABLE|url|https://msdn.microsoft.com/library/bb352880(v=vs.100).aspx^0|2|7|O|8|12|6|A|D|0|0|0|I|P|19|G|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]]|D|@$9|13|A|14|1|15]]|E|$]]|$1|F|3|G|5|H|7|16|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|17|8|@$9|18|A|19|B|C]|$9|1A|A|1B|B|C]]|D|@]|E|$]]|$1|M|3|N|5|H|7|1C|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|1D|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

Based on <code>Contain</code>'s <a href="https://msdn.microsoft.com/library/bb352880(v=vs.100).aspx" rel="nofollow">Documentation</a> the parameter for <code>Contains</code> could be <code>string</code> not a list of string. So it should be like this:

<pre><code>List&lt;string&gt; TheListParameter = new List&lt;string&gt; {"string1", "string2", "string3"};

var TheOutput = (from t in MyDC.SomeTable
 where TheListParameter.Contains(t.SomeColumn.ToString())
 select t.SomeColumn).ToList();
</code></pre>

Or if you want to return a boolean result if <code>MyDC.SomeTable.SomeColumn</code> contains one of the <code>TheListParameter</code>'s strings you can try something like this:

<pre><code>bool hasSameElements = MyDC.SomeTable.ToList()
 .Select(c =&gt; c.SomeColumn)
 .Intersect(TheListParameter).Any(); //True or False
</code></pre>

blocks|key|4441480|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4441481|List<string>+TheListParameter+=+new+List<string>{"string1",+"string2",+"string3"};
var+result+=+MyDC.SomeTable.ToList().Select(l+=>+l.SomeColumn)
+++++++++++++++++++++++++++.Where(l+=>TheListParameter.Contains(l.SomeColumn)).ToList();|code-block|syntax|javascript|4441482|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:

<pre><code>List&lt;string&gt; TheListParameter = new List&lt;string&gt;{"string1", "string2", "string3"};
var result = MyDC.SomeTable.ToList().Select(l =&gt; l.SomeColumn)
 .Where(l =&gt;TheListParameter.Contains(l.SomeColumn)).ToList();
</code></pre>

blocks|key|4441531|text|LINQ+Oneliner|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4441532|List<string>+TheListParameter+=+new+List<string>{"string1",+"string2",+"string3"};

var+foundElements+=+MyDC.SomeTable.Where(a=>+TheListParameter.Contains(a.SomeColumn)).Select(a=>+a.SomeColumn);|code-block|syntax|javascript|4441533|为什么每个人都把ToList()扔到我身边。这完全取决于您是否需要实现所有数据。|offset|length|style|CODE|4441534|以这个例子为例。|4441535|using(dbCtx+myDc+=+new+dbCtx()){
++++var+unrealizedList+=+myDc.someEntity;
++++var+realizedList+=+myDc.someEntity.ToList();

++++var+a1+=+unrealizedList.First()+//Works+
++++var+b1+=+realizedList.First()+//Works+
}
var+a2+=+unrealizedList.First()+//Fails+as+unrealizedList+is+empty+(not+loaded+and+context+is+gone)
var+b2+=+realizedList.First()+//Works+because+the+realizedList+was+loaded+completely+by+the+ToList()|4441536|现在，如果你有一个全局的或本地的(不是使用的)+Ctx，那么你可能永远不需要ToList()，尽管使用using是一种很好的、干净的方式来控制你的上下文，当你有多个上下文在彼此上工作时，这可能是一个问题。|4441537|ToList()+mid查询上的一个小指针。|4441538|var+a+=+myDc.someEntity.Where(a=>+a.someDate.DayOfYear+==+123);+
//+Fails+as+DayOfYear+cannot+be+translated+to++SQL+expression|4441539|在这里，您需要在过滤数据之前对其进行投影，遗憾的是，需要加载所有数据才能完成此操作|4441540|var+a+=+myDc.someEntity.ToList().Where(a=>+a.someDate.DayOfYear+==+123);+
//+Works+as+the+data+no+longer+is+filtered+in+SQL+(the+SQL+is+"Select+*+from+someEntity")|4441541|因此，如果可以，请在ToList()之前执行筛选，以限制从数据库中提取的数据量。|4441542|相反，如果使用ToList()，您也可以使用其他列表，如ToArray()|4441543|entityMap^0|0|0|8|8|0|0|0|12|8|1F|5|0|0|8|0|0|0|0|A|8|0|7|8|S|9|0^^$0|@$1|2|3|4|5|6|7|16|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|17|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|18|8|@$I|19|J|1A|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|1B|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|1C|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|1D|8|@$I|1E|J|1F|K|L]|$I|1G|J|1H|K|L]]|9|@]|A|$]]|$1|S|3|T|5|6|7|1I|8|@$I|1J|J|1K|K|L]]|9|@]|A|$]]|$1|U|3|V|5|D|7|1L|8|@]|9|@]|A|$E|F]]|$1|W|3|X|5|6|7|1M|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|D|7|1N|8|@]|9|@]|A|$E|F]]|$1|10|3|11|5|6|7|1O|8|@$I|1P|J|1Q|K|L]]|9|@]|A|$]]|$1|12|3|13|5|6|7|1R|8|@$I|1S|J|1T|K|L]|$I|1U|J|1V|K|L]]|9|@]|A|$]]|$1|14|3|-4|5|6|7|1W|8|@]|9|@]|A|$]]]|15|$]]

LINQ Oneliner

<pre><code>List&lt;string&gt; TheListParameter = new List&lt;string&gt;{"string1", "string2", "string3"};

var foundElements = MyDC.SomeTable.Where(a=&gt; TheListParameter.Contains(a.SomeColumn)).Select(a=&gt; a.SomeColumn);
</code></pre>

Why everyone throws on the <code>ToList()</code> is beside me. It all depends on if you need all the data realized or not. 

Take this example. 

<pre><code>using(dbCtx myDc = new dbCtx()){
 var unrealizedList = myDc.someEntity;
 var realizedList = myDc.someEntity.ToList();

 var a1 = unrealizedList.First() //Works 
 var b1 = realizedList.First() //Works 
}
var a2 = unrealizedList.First() //Fails as unrealizedList is empty (not loaded and context is gone)
var b2 = realizedList.First() //Works because the realizedList was loaded completely by the ToList()
</code></pre>

Now if you have a global or local (not a using) Ctx then you might never need <code>ToList()</code> albeit using <code>using</code> is a nice and clean way of gaining control over your context which can be a problem when you have several contexts working on eachother. 

A tiny pointer on <code>ToList()</code> mid query.

<pre><code>var a = myDc.someEntity.Where(a=&gt; a.someDate.DayOfYear == 123); 
// Fails as DayOfYear cannot be translated to SQL expression
</code></pre>

Here you need to project the data before you filter it, and sadly all the data needs to be loaded to do so

<pre><code>var a = myDc.someEntity.ToList().Where(a=&gt; a.someDate.DayOfYear == 123); 
// Works as the data no longer is filtered in SQL (the SQL is "Select * from someEntity")
</code></pre>

So if you can, perform your filtering before the <code>ToList()</code> to limit the amount of data pulled from the DB.

Instead if <code>ToList()</code> you can use other lists aswell like <code>ToArray()</code>

I have a parameter list of strings and I want to write a query that returns a list of strings that contain values of the parameter list that are present in the table. I have the following query but I can't get the where clause:

<pre><code>List&lt;string&gt; TheListParameter = new List&lt;string&gt;{"string1", "string2", "string3"};

var TheOutput = (from t in MyDC.SomeTable 
 where t.SomeColumn.Contains(TheListParameter) 
 select t.SomeColumn).ToList();
</code></pre>

How do I write the <code>where</code> clause for this search query?

Checking if a table contains values in a list

数据库

我有一个字符串的参数列表，并且我想编写一个查询，该查询返回一个字符串列表，其中包含表中存在的参数列表的值。我有以下查询，但我无法获取where子句：List<string> TheListParameter = new List<string>{"string1", "string2", "string3"};var ...

问检查表是否包含列表中的值
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