blocks|key|347598|text|使用逗号运算符分隔case语句|type|unstyled|depth|inlineStyleRanges|entityRanges|data|347599|Select+Case+2
++++Case+0,1,2,3
++++++++Console.WriteLine("hit")
+End+Select|code-block|syntax|javascript|347600|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|$]]

Use the comma operator to delimit case statements

<pre><code>Select Case 2
 Case 0,1,2,3
 Console.WriteLine("hit")
 End Select
</code></pre>

blocks|key|3340987|text|正如Jared所说，您需要使用逗号操作符来分隔case语句。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3340988|你正在做的Or是一个位OR，结果是"3“。有趣的是，"2和3“可能适用于您的特定情况。|offset|length|style|CODE|3340989|entityMap^0|0|5|2|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

As Jared said, you need to use the comma operator to delimit case statements.

The <code>Or</code> you were doing is a bitwise OR, resulting in it being "3". Amusingly, "2 AND 3" would probably have worked for your specific case.

blocks|key|3340960|text|JaredPar是正确的，但是您也可以使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3340961|Select+Case+2
++++Case+0,1
++++Case+2+To+3
++++++++Console.WriteLine("Hit")
End+Select|code-block|syntax|javascript|3340962|这将是0或1什么也不做，2或3打印Hit...The构造是一个范围...|3340963|Here's+the+MSDN|offset|length|3340964|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/cy37t14y.aspx^0|0|0|0|0|F|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|W|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|X|8|@]|9|@$K|Y|L|Z|1|10]]|A|$]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

JaredPar has it right but you can also use the To construct

<pre><code>Select Case 2
 Case 0,1
 Case 2 To 3
 Console.WriteLine("Hit")
End Select
</code></pre>

This would be 0 or 1 do nothing, 2 or 3 print Hit...The To construct is a range...

<a href="http://msdn.microsoft.com/en-us/library/cy37t14y.aspx" rel="noreferrer">Here's the MSDN</a>

blocks|key|347585|text|编辑：似乎我假设VB.NET不允许Case+ORing是错误的。我在C#和IL中思考，似乎我错了。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|347586|然而，正如有人指出的那样，你的代码不能工作的原因是因为情况2或3将2或3计算为按位或，因此计算结果为情况3。|347587|需要澄清的是：|347588|+++++++2+binary+=+0000+0010
+++++++3+binary+=+0000+0011
++2+Or+3+binary+=+0000+0011+(=+3)|code-block|syntax|javascript|347589|++Select+Case+2
+++++Case+0++++++++++++'-->+no+match

+++++Case+1++++++++++++'-->+no+match

+++++Case+2+Or+3+++++++'(equivalent+to+Case+3++-->+no+match)
+++End+Select|347590|但是，我觉得我应该指出，为了性能的原因，不应该使用这样的构造。当编译器遇到Select语句(C#中的switch)时，它将尝试使用查找表和switch+MSIL指令编译它们，但在您有类似case+1,2,11,55的情况下，编译器将无法将其转换为查找表，而必须使用一系列比较(类似于使用If..否则)。|347591|重点是，为了真正利用Select语句，案例的设计应该考虑到这一点。否则，唯一的好处就是代码的可读性。|347592|设计良好的开关是O(1)运算，而设计不佳的开关(相当于一系列If..Then..Else语句)是O(n)运算。|347593|entityMap^0|0|3|0|0|0|0|0|1X|6|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|11|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|12|8|@]|D|@]|E|$]]|$1|J|3|K|5|L|7|13|8|@]|D|@]|E|$M|N]]|$1|O|3|P|5|L|7|14|8|@]|D|@]|E|$M|N]]|$1|Q|3|R|5|6|7|15|8|@$9|16|A|17|B|C]]|D|@]|E|$]]|$1|S|3|T|5|6|7|18|8|@]|D|@]|E|$]]|$1|U|3|V|5|6|7|19|8|@]|D|@]|E|$]]|$1|W|3|-4|5|6|7|1A|8|@]|D|@]|E|$]]]|X|$]]

Edit: It appears I was wrong in assuming that VB.NET doesn't allow Case ORing. I was thinking in C# and IL and it appears I was wrong.

However, as someone pointed out, the reason your code did not work was because Case 2 Or 3 was evaluating 2 Or 3 as a bitwise or and hence evaluating to Case 3.

For clarification: 

<pre><code>
 2 binary = 0000 0010
 3 binary = 0000 0011
 2 Or 3 binary = 0000 0011 (= 3)
</code></pre>

<pre><code>
 Select Case 2
 Case 0 '--> no match

 Case 1 '--> no match

 Case 2 Or 3 '(equivalent to Case 3 --> no match)
 End Select
</code></pre>

However, I feel that I should point out that for the sake of performance, one should not use such constructs. When the compiler encounters Select statements (switch in C#) it will try to compile them using lookup tables and the switch MSIL instruction but in the case where you have something like Case 1,2,11,55 the compiler will not be able to convert that to a lookup table and it will have to use a series of compares (which is like using If.. Else).

The point is that in order to really take advantage of the Select statement, the cases should be designed with that in mind. Otherwise, the only benefit is code readability.

A well designed switch is an O(1) operation whereas an poorly designed one (which is equivalent to a series of If..Then..Else statements) is an O(n) operation.

blocks|key|3128019|text|这将允许您在0的情况下执行"something“，在1的情况下执行"something”，在2或3的情况下执行"hit“，或者在其他情况下执行"hit+else”。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3128020|Select+Case+2
++++Case+0
++++++++Console.WriteLine("something")
++++Case+1
++++++++Console.WriteLine("something+else")
++++Case+Is+2+To+3
++++++++Console.WriteLine("hit")
++++Else
++++++++Console.WriteLine("hit+else")
+End+Select|code-block|syntax|javascript|3128021|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 will allow you to perform "something" in the case of 0, "something else" in the case of 1, "hit" in the case of 2 or 3 or "hit else" otherwise. 

<pre><code>Select Case 2
 Case 0
 Console.WriteLine("something")
 Case 1
 Console.WriteLine("something else")
 Case Is 2 To 3
 Console.WriteLine("hit")
 Else
 Console.WriteLine("hit else")
 End Select
</code></pre>

blocks|key|3128199|text|大多数或所有这些答案都忽略了失败(或转到案例)的目的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3128200|无需重用代码或为同一Select+Case/If+Tree中的几个区域创建特殊函数，这样您就可以避免重用代码，如下面的Javascript。|offset|length|style|CODE|3128201|这些样本都是人为设计的。当然有很多方法可以简化这个场景，但是很多时候是没有的。|3128202|let+pay+=+100,+perks+=+'';
Switch+(EmpObj.type)+{
++Case+'Boss':
++++pay+=+pay+*+10;
++++perks+=+'11+month+vacation+per+year';
++Case+'Manager':
++++pay+=+pay+*+3;+//+This+will+make+Boss+pay+*+30
++Case+'Employee':
++++EmpObj.pay+=+pay;
++++EmpObj.perks+=+perks;
++++break;
++Case+'Intern':
++++EmpObj.sendMessage("Go+get+some+coffee.")
}+|code-block|syntax|javascript|3128203|在VB.net中，相同的代码应该是|3128204|dim+pay+=+100,+perks+=+"";
Switch+(EmpObj.type)+{
++Case+"Boss":
++++pay+=+pay+*+30
++++perks+=+"11+month+vacation+per+year"
++Case+"Manager":
++++pay+=+pay+*+3
++Case+"Employee":
++Case+'Intern':
++++pay+=+0
++++EmpObj.sendMessage("Go+get+some+coffee.")
End+Select

EmpObj.pay+=+pay;
EmpObj.perks+=+perks;|3128205|在简单的情况下，Case比一个比较的if分支更容易读写，但最好的部分是它的失效。|3128206|现在至少在Visual+Basic+2017中有一种方法可以工作。不过，这并不是最漂亮的。|3128207|GoTo+Case+"[label]"和Goto+[Case-label]仍然不起作用。|3128208|标签(此处为Number2)必须在Case之后。这是最令人失望的部分。|3128209|dim+Value+=+"1"
Select+Case+Value
++++Case+"0"
+++++++'+do+nothing,+example
++++Case+"1"
++++++++MsgBox("one")
++++++++GoTo+Number2
++++Case+"2"
Number2:
++++++++MsgBox("two")
++++Case+"boolean"
++++++++MsgBox("three")
++++++++'+just+to+show+it+won't+fall+through
End+Select|3128210|entityMap^0|0|A|B|M|7|0|0|0|0|0|0|0|0|J|K|H|0|6|7|H|4|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|15|8|@$D|16|E|17|F|G]|$D|18|E|19|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|1A|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|1B|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|1C|8|@]|9|@]|A|$]]|$1|Q|3|R|5|L|7|1D|8|@]|9|@]|A|$M|N]]|$1|S|3|T|5|6|7|1E|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1F|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1G|8|@$D|1H|E|1I|F|G]|$D|1J|E|1K|F|G]]|9|@]|A|$]]|$1|Y|3|Z|5|6|7|1L|8|@$D|1M|E|1N|F|G]|$D|1O|E|1P|F|G]]|9|@]|A|$]]|$1|10|3|11|5|L|7|1Q|8|@]|9|@]|A|$M|N]]|$1|12|3|-4|5|6|7|1R|8|@]|9|@]|A|$]]]|13|$]]

<h2 id="most-or-all-of-these-answers-are-ignoring-the-purpose-of-fall-through-or-goto-case-8qnx">Most or all of these answers are ignoring the purpose of fall-through (or Goto Case):</h2>
Not having to reuse code or create a special function just for a few areas in the same <code>Select Case</code>/<code>If Tree</code> so that you can avoid reusing code, like this Javascript.
These samples are pretty contrived. There are definitely ways to simplify this scenario, but a lot of times, there aren't.
<pre><code>let pay = 100, perks = '';
Switch (EmpObj.type) {
 Case 'Boss':
 pay = pay * 10;
 perks = '11 month vacation per year';
 Case 'Manager':
 pay = pay * 3; // This will make Boss pay * 30
 Case 'Employee':
 EmpObj.pay = pay;
 EmpObj.perks = perks;
 break;
 Case 'Intern':
 EmpObj.sendMessage(&quot;Go get some coffee.&quot;)
} 
</code></pre>
In VB.net, the same code would be
<pre><code>dim pay = 100, perks = &quot;&quot;;
Switch (EmpObj.type) {
 Case &quot;Boss&quot;:
 pay = pay * 30
 perks = &quot;11 month vacation per year&quot;
 Case &quot;Manager&quot;:
 pay = pay * 3
 Case &quot;Employee&quot;:
 Case 'Intern':
 pay = 0
 EmpObj.sendMessage(&quot;Go get some coffee.&quot;)
End Select

EmpObj.pay = pay;
EmpObj.perks = perks;
</code></pre>
Case, in simple situations, is easier to read and write than a comparative if-branch, but the fall-through is the best part.
<h2 id="theres-a-way-that-works-now-at-least-in-visual-basic-2017.its-not-the-prettiest-though-b38q">There's a way that works now at least in Visual Basic 2017. It's not the prettiest though.</h2>
<code>GoTo Case &quot;[label]&quot;</code> and <code>Goto [Case-label]</code> still do not work.
The label (<code>Number2</code> here) must be after the <code>Case</code>. That was the most disappointing part.
<pre><code>dim Value = &quot;1&quot;
Select Case Value
 Case &quot;0&quot;
 ' do nothing, example
 Case &quot;1&quot;
 MsgBox(&quot;one&quot;)
 GoTo Number2
 Case &quot;2&quot;
Number2:
 MsgBox(&quot;two&quot;)
 Case &quot;boolean&quot;
 MsgBox(&quot;three&quot;)
 ' just to show it won't fall through
End Select
</code></pre>

I'm using an <a href="https://msdn.microsoft.com/en-us/library/06s37a7f.aspx" rel="noreferrer">Or</a> statement in my case expression.

Even though I have a value within this range, it didn't find a match. Why not?

Example Code:

<pre><code>Select Case 2
 Case 0
 ' Some logic

 Case 1
 ' Some other logic

 Case 2 Or 3
 Console.WriteLine("hit")

 End Select
</code></pre>

With the above I would assume that <code>hit</code> would be printed, but that's not the case.

What is the VB.NET select case statement logic with case OR-ing?

编译器

我在case表达式中使用了语句。即使我有一个在这个范围内的值，它也没有找到匹配的值。为什么不行？示例代码Select Case 2    Case 0        ' Some logic    Case 1        ' Some other logic    Case 2 Or 3        Console.WriteLine("hit") End Select有了上面的内容，我会假

问使用case OR运算的VB.NET select case语句逻辑是什么？
EN

回答 6

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问使用case OR运算的VB.NET select case语句逻辑是什么？EN

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问使用case OR运算的VB.NET select case语句逻辑是什么？
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