抱歉，我不是有意放弃这个问题的.发布的答案不是我想要的，但我在发布后不久就想出了一种方法，并且很长时间没有回到该网站.由于尚未发布解决方案，这就是我想出的.当我问这个问题时，这并不是我的想法，也不是太漂亮，但显然这是唯一的方法:

Sorry, I didn't mean to abandon this question. The answers that were posted weren't what I was driving at, but I figured out a way to do it shortly after posting, and didn't come back to the site for a long time. Since a solution hasn't been posted, here's what I came up with. It's not quite what I had in mind when I asked the question and it isn't too pretty, but apparently it's the only way to do it:

<statement> | <filter1> | foreach {if (<condition>) {$_ | <filter2>} else {$_} | <filter3> | <filter4> | <filter5>

因此，在示例中，该行

|where {$_.psiscontainer} `

将改为

|foreach {if (-not $files) {$_ | where {$_.psiscontainer}} else {$_}} `

和

|where {$_.isinherited -eq 'False'} `

将改为

|foreach {if (-not $inherited) {$_ | where {$_.isinherited -eq 'False'}} else {$_}} `

(是的，通常我会把它写成 |foreach {if ($files) {$_} else {$_ | where {$_.psiscontainer}}} 和 |foreach {if ($inherited) {$_} else {$_ | where {$_.isinherited -eq 'False'}}} 但为了清楚起见，我是这样做的.)

(Yes, normally I'd write that as |foreach {if ($files) {$_} else {$_ | where {$_.psiscontainer}}}, and |foreach {if ($inherited) {$_} else {$_ | where {$_.isinherited -eq 'False'}}} but I did it this way for clarity.)

我希望可能有更优雅的东西，它会评估过滤器前面的条件一次，以确定是执行还是跳过管道的一个阶段.像这样:

I was hoping there might be something more elegant, that would evaluate a condition in front of the filter once to determine whether to execute or skip a stage of the pipeline. Something like this:

<statement> | <filter1> | if (<condition>) {<filter2>} | <filter3>

(if 的特例，不是通常的意思；可以使用不同的关键字)，或者

(a special case of if, not the usual meaning; a different keyword could be used), or maybe

<statement> | <filter1> | (<condition>) ? <filter2> | <filter3>

$_ 在条件中无效，除非它是在当前管道之外定义的，例如如果管道包含在 switch 语句中，$ 中的 _ 将引用 switch 语句的 $_.

$_ would be invalid in the condition, unless it's defined outside the current pipeline, for example if the pipeline is contained within a switch statement, $_ in the <condition> would refer the switch statement's $_.

我想我会向 Microsoft 提出功能建议.这不仅会使代码更优雅，而且效率也会更高，因为如果它是一个内置特性， 可以被评估一次整个管道，而不是在每次迭代中测试相同的独立条件.

I think I'll make a feature suggestion to Microsoft. This would not only make the code more elegant, it would be more efficient as well, because if it's a built-in feature, <condition> could be evaluated once for the entire pipeline, rather then testing the same independent condition in each iteration.