I am building a PowerShell function that builds a hash table. I am looking for a way I can use a switch parameter to either be specified as absent, true or false. How can I determine this?
I can resolve this by using a [boolean] parameter, but I didn't find this an elegant solution. Alternatively I could also use two switch parameters.
function Invoke-API {
param(
[switch]$AddHash
)
$requestparams = @{'header'='yes'}
if ($AddHash) {
$requestparams.Code = $true
}
How would I get it to display false when false is specified and nothing when the switch parameter isn't specified?
To check whether a parameter was either passed in by the caller or not, inspect the $PSBoundParameters
automatic variable:
if($PSBoundParameters.ContainsKey('AddHash')) {
# switch parameter was explicitly passed by the caller
# grab its value
$requestparams.Code = $AddHash.IsPresent
}
else {
# parameter was absent from the invocation, don't add it to the request
}
If you have multiple switch parameters that you want to pass through, iterate over the entries in $PSBoundParameters
and test the type of each value:
param(
[switch]$AddHash,
[switch]$AddOtherStuff,
[switch]$Yolo
)
$requestParams = @{ header = 'value' }
$PSBoundParameters.GetEnumerator() |ForEach-Object {
$value = $_.Value
if($value -is [switch]){
$value = $value.IsPresent
}
$requestParams[$_.Key] = $value
}
If you have a parameter that can be $true
, $false
or unspecified, then you might not want the [Switch]
parameter type because it can only be $true
or $false
( $false
is the same as unspecified). As an alternative, you can use a nullable boolean parameter. Example:
function Test-Boolean {
param(
[Nullable[Boolean]] $Test
)
if ( $Test -ne $null ) {
if ( $Test ) {
"You specified -Test `$true"
}
else {
"You specified -Test `$false"
}
}
else {
"You did not specify -Test"
}
}
even simpler:
function test{
[CmdletBinding()]
param(
[Parameter(Mandatory=$False,Position=1)][switch]$set
)
write-host "commence normal operation"
if(-not $set){"switch is not set, i execute this"}
else{"switch is set"}
}
output enter image description here
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