blocks|key|804623|text|虽然阅读和理解Josh的答案很好，但使用微软为此提供的类可能会更开心：System.Collections.BitArray它在所有版本的.NET框架中都可用。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|804624|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/system.collections.bitarray.aspx^0|Z|R|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

While it's good to read and understand Josh's answer, you'll probably be happier using the class Microsoft provided for this purpose: <a href="http://msdn.microsoft.com/en-us/library/system.collections.bitarray.aspx" rel="noreferrer">System.Collections.BitArray</a> It's available in all versions of .NET Framework.

blocks|key|804569|text|这|type|unstyled|depth|inlineStyleRanges|entityRanges|data|804570|public+static+bool+GetBit(this+byte+b,+int+bitNumber)+{
+++return+(b+&+(1+<<+bitNumber))+!=+0;
}|code-block|syntax|javascript|804571|我觉得应该这么做。|804572|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|$]]

This

<pre><code>public static bool GetBit(this byte b, int bitNumber) {
 return (b &amp; (1 &lt;&lt; bitNumber)) != 0;
}
</code></pre>

should do it, I think.

blocks|key|804790|text|这比0.1毫秒快。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|804791|return+(b+>>+bitNumber)+&+1;|code-block|syntax|javascript|804792|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 is works faster than 0.1 milliseconds. 

<pre><code>return (b &gt;&gt; bitNumber) &amp; 1;
</code></pre>

blocks|key|1019312|text|另一种方式:)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1019313|return+((b+>>+bitNumber)+&+1)+!=+0;|code-block|syntax|javascript|1019314|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|$]]

another way of doing it :)

<pre><code>return ((b &gt;&gt; bitNumber) &amp; 1) != 0;
</code></pre>

blocks|key|804753|text|按照OP的建议，使用BitArray类并创建一个扩展方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|804754|public+static+bool+GetBit(this+byte+b,+int+bitNumber)
{
++++System.Collections.BitArray+ba+=+new+BitArray(new+byte[]{b});
++++return+ba.Get(bitNumber);
}|code-block|syntax|javascript|804755|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/x3we7ff2.aspx^0|A|8|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

Using <a href="http://msdn.microsoft.com/en-us/library/x3we7ff2.aspx" rel="noreferrer">BitArray</a> class and making an extension method as OP suggests:

<pre><code>public static bool GetBit(this byte b, int bitNumber)
{
 System.Collections.BitArray ba = new BitArray(new byte[]{b});
 return ba.Get(bitNumber);
}
</code></pre>

blocks|key|1019192|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1019193|return+(b+&+(1+<<+bitNumber))>0;|code-block|syntax|javascript|1019194|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>return (b &amp; (1 &lt;&lt; bitNumber))&gt;0;
</code></pre>

blocks|key|1019297|text|该方法是使用另一个字节以及按位AND来掩码目标位。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1019298|我在这里使用了我的类中的约定，其中"0“是最重要的位，"7”是最不重要的位。|1019299|public+static+class+ByteExtensions
{
++++//+Assume+0+is+the+MSB+andd+7+is+the+LSB.
++++public+static+bool+GetBit(this+byte+byt,+int+index)
++++{
++++++++if+(index+<+0+%7C%7C+index+>+7)
++++++++++++throw+new+ArgumentOutOfRangeException();

++++++++int+shift+=+7+-+index;

++++++++//+Get+a+single+bit+in+the+proper+position.
++++++++byte+bitMask+=+(byte)(1+<<+shift);

++++++++//+Mask+out+the+appropriate+bit.
++++++++byte+masked+=+(byte)(byt+&+bitMask);

++++++++//+If+masked+!=+0,+then+the+masked+out+bit+is+1.
++++++++//+Otherwise,+masked+will+be+0.
++++++++return+masked+!=+0;
++++}
}|code-block|syntax|javascript|1019300|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|$]]

The method is to use another byte along with a bitwise AND to mask out the target bit.

I used convention from my classes here where "0" is the most significant bit and "7" is the least.

<pre><code>public static class ByteExtensions
{
 // Assume 0 is the MSB andd 7 is the LSB.
 public static bool GetBit(this byte byt, int index)
 {
 if (index &lt; 0 || index &gt; 7)
 throw new ArgumentOutOfRangeException();

 int shift = 7 - index;

 // Get a single bit in the proper position.
 byte bitMask = (byte)(1 &lt;&lt; shift);

 // Mask out the appropriate bit.
 byte masked = (byte)(byt &amp; bitMask);

 // If masked != 0, then the masked out bit is 1.
 // Otherwise, masked will be 0.
 return masked != 0;
 }
}
</code></pre>

blocks|key|804713|text|尝试下面的代码。与其他帖子的不同之处在于，您可以使用掩码(field)设置/获取多个位。例如，第4位的掩码可以是1<<3或0x10。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|804714|++++public+int+SetBits(this+int+target,+int+field,+bool+value)
++++{
++++++++if+(value)+//set+value
++++++++{
++++++++++++return+target+%7C+field;
++++++++}
++++++++else+//clear+value
++++++++{
++++++++++++return+target+&+(~field);
++++++++}
++++}

++++public+bool+GetBits(this+int+target,+int+field)
++++{
++++++++return+(target+&+field)+>+0;
++++}|code-block|syntax|javascript|804715|**示例**|804716|++++++++bool+is_ok+=+0x01AF.GetBits(0x10);+//false
++++++++int+res+=+0x01AF.SetBits(0x10,+true);
++++++++is_ok+=+res.GetBits(0x10);++//+true|804717|entityMap^0|T|5|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

Try the code below. The difference with other posts is that you can set/get multiple bits using a mask (<code>field</code>). The mask for the 4th bit can be 1&lt;&lt;3, or 0x10, for example.

<pre><code> public int SetBits(this int target, int field, bool value)
 {
 if (value) //set value
 {
 return target | field;
 }
 else //clear value
 {
 return target &amp; (~field);
 }
 }

 public bool GetBits(this int target, int field)
 {
 return (target &amp; field) &gt; 0;
 }
</code></pre>

** Example **

<pre><code> bool is_ok = 0x01AF.GetBits(0x10); //false
 int res = 0x01AF.SetBits(0x10, true);
 is_ok = res.GetBits(0x10); // true
</code></pre>

blocks|key|804801|text|[Flags]
enum+Relays+:+byte
{
++++relay0+=+1+<<+0,
++++relay1+=+1+<<+1,
++++relay2+=+1+<<+2,
++++relay3+=+1+<<+3,
++++relay4+=+1+<<+4,
++++relay5+=+1+<<+5,
++++relay6+=+1+<<+6,
++++relay7+=+1+<<+7
}

public+static+bool+GetRelay(byte+b,+Relays+relay)
{
++++return+(Relays)b.HasFlag(relay);
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|804802|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>[Flags]
enum Relays : byte
{
 relay0 = 1 &lt;&lt; 0,
 relay1 = 1 &lt;&lt; 1,
 relay2 = 1 &lt;&lt; 2,
 relay3 = 1 &lt;&lt; 3,
 relay4 = 1 &lt;&lt; 4,
 relay5 = 1 &lt;&lt; 5,
 relay6 = 1 &lt;&lt; 6,
 relay7 = 1 &lt;&lt; 7
}

public static bool GetRelay(byte b, Relays relay)
{
 return (Relays)b.HasFlag(relay);
}
</code></pre>

I have a byte, specifically one byte from a byte array which came in via UDP sent from another device. This byte stores the on/off state of 8 relays in the device.

How do I get the value of a specific bit in said byte? Ideally an extension method would look the most elegant and returning a bool would make the most sense to me.

<pre><code>public static bool GetBit(this byte b, int bitNumber)
{
 //black magic goes here
}
</code></pre>

Get a specific bit from byte

我有一个字节，特别是字节数组中的一个字节，它通过从另一个设备发送的UDP传入。该字节存储器件中8个继电器的接通/断开状态。如何获取所述字节中特定位的值？理想情况下，扩展方法看起来最优雅，返回布尔值对我来说最有意义。public static bool GetBit(this byte b, int bitNumber){    //black magic goes here}

问从字节中获取特定的位
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