PowerShell function parameters syntax

问题

Why do the Write-Host outside of the function work different than inside of the function?

It seems like somehow the parameters variables are changing from what I declared it to be...

function a([string]$svr, [string]$usr) {
    $x = "$svr\$usr"
    Write-Host $x
}

$svr = 'abc'
$usr = 'def'
$x = "$svr\$usr"
Write-Host $x
a($svr, $usr)

Results…

abc\def

abc def\

回答1:

Don't call functions or cmdlets in PowerShell with parentheses and commas (only do this in method calls)!

When you call a($svr, $usr) you're passing an array with the two values as the single value of the first parameter. It's equivalent to calling it like a -svr $svr,$usr which means the $usr parameter is not specified at all. So now $x equals the string representation of the array (a join with spaces), followed by a backslash, followed by nothing.

Instead call it like this:

a $svr $usr
a -svr $svr -usr $usr

来源：https://stackoverflow.com/questions/26941644/powershell-function-parameters-syntax