当命令行开关接受管道输入时,ByPropertyName和ByValue之间有什么区别？

Question

一些PowerShell命令行开关接受管道输入ByProperyName,一些做ByValue,其他人为它们做.这是什么意思？它如何影响我们的PowerShell脚本？

Answer 1

的ValueFromPipeline参数属性将映射的参数值的任何对象类型是从管道传递到.如果使用ValueFromPipelineByPropertyName参数属性,则将使用通过管道传递到命令+参数的对象使用特定属性.

ValueFromPipeline示例

Get-Process | Stop-Process; # Stop-Process expects to receive a Process object

<#
 -InputObject <Process[]>
    Stops the processes represented by the specified process objects. Enter a variable that contains the objects, or
    type a command or expression that gets the objects.

    Required?                    true
    Position?                    1
    Default value
    Accept pipeline input?       true (ByValue)
    Accept wildcard characters?  false
#>

ValueFromPipelineByPropertyName示例

# Get-Process looks for a ComputerName property on the incoming objects
[PSCustomObject]@{
    ComputerName = 'localhost';
    } | Get-Process;

<#
-ComputerName <String[]>
    Gets the processes running on the specified computers. The default is the local computer.

    Type the NetBIOS name, an IP address, or a fully qualified domain name of one or more computers. To specify the
    local computer, type the computer name, a dot (.), or "localhost".

    This parameter does not rely on Windows PowerShell remoting. You can use the ComputerName parameter of Get-Process
    even if your computer is not configured to run remote commands.

    Required?                    false
    Position?                    named
    Default value                Local computer
    Accept pipeline input?       True (ByPropertyName)
    Accept wildcard characters?  false
#>