Powershell-由函数变量定义的新变量“ -name”

Question

I want to have a function in which the result is stored in a variable where the function defines the variable name - essentially this:

function testfunction ($varname,$text){
    $readhost = read-host -prompt "$text"
    new-variable -name $varname -value $readhost
}

though when entering:

testfunction outputvar sampletext

get-variable -name outputvar

I just get an error that the variable "outputvar" doesnt exist. what am I missing here? Tried a number of other stuff but nothing seemed to work - what i want in the end is a variable that is named "outputvar" that contains the prompt input, just to clarify.

Answer 1

Your issue is due to scoping. The variable created via New-Variable is (by default) scoped so that it is only accessible within your function. You can override the scope via the -Scope parameter:

function testfunction ($varname,$text){
    $readhost = read-host -prompt "$text"
    new-variable -name $varname -value $readhost -scope Script
}

This changes the scope to Script and so the variable is now accessible outside of your function. Defining non-standard scopes for your variables isn't very good practice however. You should instead just be doing this:

function testfunction ($text){
    read-host -prompt "$text"
}

$outputvar = testfunction sampletext

Answer 2

Use the -OutVariable common parameter. To have your function support common parameters, add the CmdletBinding attribute decorator to the param block:

function Test-Function {
  [CmdletBinding()]
  param($text)

  return Read-Host -Prompt $text
}

Test-Function -OutVariable sampletext |Out-Null
$sampletext