blocks|key|2158109|text|人们普遍认为你不能在powershell中做到这一点。不幸的是，经过几次谷歌搜索和Stack+Overflow的搜索，我正要放弃。但是后来我在gist上发现了this+post，事实证明你可以！|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2158110|考虑到发现它对我来说有多难，我想为其他人提供一个清晰且格式良好的示例(当我立即忘记如何做到这一点时，还有我未来的自己)|2158111|感谢JFFail将this发布到Github|2158112|你需要在适当的时候重载它们，它们应该是不言而喻的，但如果有什么不是，请随时询问|2158113|SetValue([int]$newValue)
GetValue()
[boolean]+Equals($otherNumber)
[string]+ToString()+#+you+can+get+more+advanced+by+overloading+"IConvertible.ToType"+but+that's+a+whole+can+of+worms+all+it's+own
static+[MyClass]+op_Addition+++([MyClass]$first,+[MyClass]$second)
static+[MyClass]+op_Subtraction([MyClass]$first,+[MyClass]$second)
static+[MyClass]+op_Multiply+++([MyClass]$first,+[MyClass]$second)
static+[MyClass]+op_Division+++([MyClass]$first,+[MyClass]$second)|code-block|syntax|javascript|2158114|对于-gt和-lt，您需要使用以下代码。注意:虽然它确实支持-eq，但您可以使用上面看到的Equals(object)本身获得它，这不需要从IComparable继承|style|CODE|2158115|class+MyClass+:+System.IComparable+
#+requires+inheritance+from+System.IComparable

[int]+CompareTo($otherNumber)
#+CANNOT+declare+type+in+parameter+declaration,+you'd+have+to+check+it+later.
#+1+is+greater+than
#+0+is+equal
#+-1+is+less+than
#+$null+can+be+returned+to+indicate+invalid+comparison|2158116|下面是一个有效的示例|2158117|#+If+you+don't+need+-lt+or+-gt+then+you+don't+have+to+inherit+from+System.IComparable
class+Number+:+System.IComparable
{
++++[int]+$value+=+0

++++Number()+{}+#+empty+constructor

++++Number+([int]$somethingElse)
++++++++{$this.value+=+$somethingElse}

++++[void]+SetValue+([int]$newValue)
++++++++{$this.value+=+$newValue}

++++[int]+GetValue()
++++++++{return+$this.value}

++++[boolean]+Equals($otherNumber)
++++{
++++++++if+($this.value+-eq+$otherNumber.GetValue())
++++++++++++{return+$true}
++++++++else
++++++++++++{return+$false}
++++}

++++[int]+CompareTo($otherNumber)
++++{
++++++++if+($this.value+-gt+$otherNumber.GetValue())+{return+1}
++++++++if+($this.value+-eq+$otherNumber.GetValue())+{return+0}
++++++++if+($this.value+-lt+$otherNumber.GetValue())+{return+-1}
++++++++return+$null
++++}

++++[string]+ToString()
++++++++{return+$this.value.ToString()}

++++static+[Number]+op_Addition+([Number]$first,+[Number]$second)
++++++++{return+[Number]::new($first.GetValue()+%2B+$second.GetValue())}

++++static+[Number]+op_Subtraction([Number]$first,+[Number]$second)
++++++++{return+[Number]::new($first.GetValue()+-+$second.GetValue())}

++++static+[Number]+op_Multiply([Number]$first,+[Number]$second)
++++++++{return+[Number]::new($first.GetValue()+*+$second.GetValue())}

++++static+[Number]+op_Division([Number]$first,+[Number]$second)
++++++++{return+[Number]::new($first.GetValue()+/+$second.GetValue())}
}

#+Very+Basic+Unit+Tests
$firstNumber+=+[Number]::new(8)
$secondNumber+=+[Number]::new(12)
$thirdNumber+=+[Number]::new(8)

if+($firstNumber+-eq+$secondNumber)
++++{Write-Output+("{0}+==+{1}"+-F+$firstNumber,+$secondNumber)}
else
++++{Write-Output+("{0}+<>+{1}"+-F+$firstNumber,+$secondNumber)}

if+($firstNumber+-eq+$thirdNumber)
++++{Write-Output+("{0}+==+{1}"+-F+$firstNumber,+$thirdNumber)}
else
++++{Write-Output+("{0}+<>+{1}"+-F+$firstNumber,+$thirdNumber)}

switch+($true)
{
++++($firstNumber+-gt+$secondNumber)+{Write-Output+("{0}+>+{1}"+-F+$firstNumber,+$secondNumber)}
++++($firstNumber+-eq+$secondNumber)+{Write-Output+("{0}+==+{1}"+-F+$firstNumber,+$secondNumber)}
++++($firstNumber+-lt+$secondNumber)+{Write-Output+("{0}+<+{1}"+-F+$firstNumber,+$secondNumber)}
}

$fourthNumber+=+$firstNumber+%2B+$secondNumber
Write-Output+("{0}+=+{1}+%2B+{2}"+-F+$fourthNumber,+$firstNumber,+$secondNumber)

$fifthNumber+=+$secondNumber+-+$thirdNumber
Write-Output+("{0}+=+{1}+-+{2}"+-F+$fifthNumber,+$secondNumber,+$thirdNumber)

$sixthNumber+=+$firstNumber+*+$secondNumber
Write-Output+("{0}+=+{1}+*+{2}"+-F+$sixthNumber,+$firstNumber,+$secondNumber)

$seventhNumber+=+$sixthNumber+/+$firstNumber
Write-Output+("{0}+=+{1}+/+{2}"+-F+$seventhNumber,+$sixthNumber,+$firstNumber)|2158118|这是输出|2158119|>+8+<>+12
>+8+==+8
>+8+<+12
>+20+=+8+%2B+12
>+4+=+12+-+8
>+96+=+8+*+12
>+12+=+96+/+8|2158120|entityMap|0|LINK|mutability|MUTABLE|url|https://gist.github.com/JFFail/c629e8a667bed62f3eb980e902491841|1^0|27|9|0|0|0|9|4|1|0|0|0|2|3|6|3|U|3|19|E|1Y|B|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1B|8|@]|9|@$A|1C|B|1D|1|1E]]|C|$]]|$1|D|3|E|5|6|7|1F|8|@]|9|@]|C|$]]|$1|F|3|G|5|6|7|1G|8|@]|9|@$A|1H|B|1I|1|1J]]|C|$]]|$1|H|3|I|5|6|7|1K|8|@]|9|@]|C|$]]|$1|J|3|K|5|L|7|1L|8|@]|9|@]|C|$M|N]]|$1|O|3|P|5|6|7|1M|8|@$A|1N|B|1O|Q|R]|$A|1P|B|1Q|Q|R]|$A|1R|B|1S|Q|R]|$A|1T|B|1U|Q|R]|$A|1V|B|1W|Q|R]]|9|@]|C|$]]|$1|S|3|T|5|L|7|1X|8|@]|9|@]|C|$M|N]]|$1|U|3|V|5|6|7|1Y|8|@]|9|@]|C|$]]|$1|W|3|X|5|L|7|1Z|8|@]|9|@]|C|$M|N]]|$1|Y|3|Z|5|6|7|20|8|@]|9|@]|C|$]]|$1|10|3|11|5|L|7|21|8|@]|9|@]|C|$M|N]]|$1|12|3|-4|5|6|7|22|8|@]|9|@]|C|$]]]|13|$14|$5|15|16|17|C|$18|19]]|1A|$5|15|16|17|C|$18|19]]]]

It's commonly believed you can't do this in powershell. And unfortunately after several google searches and searching on Stack Overflow I was about to give up. But then I discovered <a href="https://gist.github.com/JFFail/c629e8a667bed62f3eb980e902491841" rel="nofollow noreferrer">this post</a> on gist and it turns out you can!

Given how hard it was for me to discover, I wanted to provide a clear and well formatted example for others (and my future self when I promptly forget how to do this)

Thanks to JFFail for posting <a href="https://gist.github.com/JFFail/c629e8a667bed62f3eb980e902491841" rel="nofollow noreferrer">this</a> to Github

You will need to overload these as appropriate, they should be self explanatory but feel free to ask if something isn't

<pre><code>SetValue([int]$newValue)
GetValue()
[boolean] Equals($otherNumber)
[string] ToString() # you can get more advanced by overloading "IConvertible.ToType" but that's a whole can of worms all it's own
static [MyClass] op_Addition ([MyClass]$first, [MyClass]$second)
static [MyClass] op_Subtraction([MyClass]$first, [MyClass]$second)
static [MyClass] op_Multiply ([MyClass]$first, [MyClass]$second)
static [MyClass] op_Division ([MyClass]$first, [MyClass]$second)
</code></pre>

For <code>-gt</code> and <code>-lt</code> you need to use the following. Note while this does support <code>-eq</code>, you can get that by itself using <code>Equals(object)</code> as seen above, and that doesn't require the inheritance from <code>IComparable</code>

<pre><code>class MyClass : System.IComparable 
# requires inheritance from System.IComparable

[int] CompareTo($otherNumber)
# CANNOT declare type in parameter declaration, you'd have to check it later.
# 1 is greater than
# 0 is equal
# -1 is less than
# $null can be returned to indicate invalid comparison
</code></pre>

Here's a working example

<pre><code># If you don't need -lt or -gt then you don't have to inherit from System.IComparable
class Number : System.IComparable
{
 [int] $value = 0

 Number() {} # empty constructor

 Number ([int]$somethingElse)
 {$this.value = $somethingElse}

 [void] SetValue ([int]$newValue)
 {$this.value = $newValue}

 [int] GetValue()
 {return $this.value}

 [boolean] Equals($otherNumber)
 {
 if ($this.value -eq $otherNumber.GetValue())
 {return $true}
 else
 {return $false}
 }

 [int] CompareTo($otherNumber)
 {
 if ($this.value -gt $otherNumber.GetValue()) {return 1}
 if ($this.value -eq $otherNumber.GetValue()) {return 0}
 if ($this.value -lt $otherNumber.GetValue()) {return -1}
 return $null
 }

 [string] ToString()
 {return $this.value.ToString()}

 static [Number] op_Addition ([Number]$first, [Number]$second)
 {return [Number]::new($first.GetValue() + $second.GetValue())}

 static [Number] op_Subtraction([Number]$first, [Number]$second)
 {return [Number]::new($first.GetValue() - $second.GetValue())}

 static [Number] op_Multiply([Number]$first, [Number]$second)
 {return [Number]::new($first.GetValue() * $second.GetValue())}

 static [Number] op_Division([Number]$first, [Number]$second)
 {return [Number]::new($first.GetValue() / $second.GetValue())}
}

# Very Basic Unit Tests
$firstNumber = [Number]::new(8)
$secondNumber = [Number]::new(12)
$thirdNumber = [Number]::new(8)

if ($firstNumber -eq $secondNumber)
 {Write-Output ("{0} == {1}" -F $firstNumber, $secondNumber)}
else
 {Write-Output ("{0} &lt;&gt; {1}" -F $firstNumber, $secondNumber)}

if ($firstNumber -eq $thirdNumber)
 {Write-Output ("{0} == {1}" -F $firstNumber, $thirdNumber)}
else
 {Write-Output ("{0} &lt;&gt; {1}" -F $firstNumber, $thirdNumber)}

switch ($true)
{
 ($firstNumber -gt $secondNumber) {Write-Output ("{0} &gt; {1}" -F $firstNumber, $secondNumber)}
 ($firstNumber -eq $secondNumber) {Write-Output ("{0} == {1}" -F $firstNumber, $secondNumber)}
 ($firstNumber -lt $secondNumber) {Write-Output ("{0} &lt; {1}" -F $firstNumber, $secondNumber)}
}

$fourthNumber = $firstNumber + $secondNumber
Write-Output ("{0} = {1} + {2}" -F $fourthNumber, $firstNumber, $secondNumber)

$fifthNumber = $secondNumber - $thirdNumber
Write-Output ("{0} = {1} - {2}" -F $fifthNumber, $secondNumber, $thirdNumber)

$sixthNumber = $firstNumber * $secondNumber
Write-Output ("{0} = {1} * {2}" -F $sixthNumber, $firstNumber, $secondNumber)

$seventhNumber = $sixthNumber / $firstNumber
Write-Output ("{0} = {1} / {2}" -F $seventhNumber, $sixthNumber, $firstNumber)
</code></pre>

And here's the output

<pre><code>&gt; 8 &lt;&gt; 12
&gt; 8 == 8
&gt; 8 &lt; 12
&gt; 20 = 8 + 12
&gt; 4 = 12 - 8
&gt; 96 = 8 * 12
&gt; 12 = 96 / 8
</code></pre>

With Powershell 5 you can now implement custom classes. With this eventually comes a time when you want to start overloading the operators to do things like 

<pre><code>class Number
{
 [int] $value = 0

 Number() {} # empty constructor

 Number ([int]$somethingElse)
 {$this.value = $somethingElse}
}

$one = [number]::new(1)
$two = [number]::new(2)
$three = $one + $two
if ($three -eq ($one + $two))
 {"3 = 1 + 2"}
else
 {"3 &lt;&gt; 1 + 2 "}
</code></pre>

But this doesn't seem to be well documented and after searching on Stack Overflow I can't find how to do this

Powershell Overriding Assignment and Comparison operators

使用Powershell5，您现在可以实现自定义类。随之而来的是，您最终需要开始重载操作符，以便执行以下操作class Number{    [int] $value = 0    Number() {} # empty constructor    Number ([int]$somethingElse)      ...

问Powershell重写赋值和比较运算符
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问Powershell重写赋值和比较运算符EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问Powershell重写赋值和比较运算符
EN