Powershell Splatting Object Attribute (Typeof System.Collections.Hashtable)

Question

Going to give an example to make it clearer what I want to do

$AzLogin = @{

 Subscription = [string] 'SubscriptionID';
 Tenant = [string] 'tenantID';
 Credential = [System.Management.Automation.PSCredential] $credsServicePrincipal;
 ServicePrincipal = $true;

}

try{
 Connect-Azaccount @$AzLogin -errorAction Stop
}catch{
 Write-Host "Error: $($_.exception)" -foregroundcolor red
}

This works correctly.

The one I want to do is pass splatted arguments stored in property 'CommonArgs' of object 'CSObject', something like this:

$CSObject =@ {
 [PScustomObject]@{CommonArgs=$AzLogin;}
}

try{
 Connect-Azaccount @CSObject.commonArgs -errorAction Stop
}catch{
 Write-Host "Error: $($_.exception)" -foregroundcolor red
}

Answer 1

• You can only splat a variable as a whole, not an expression that returns a property value - as of PowerShell 7.1

  • However, there's an approved RFC that would allow for expression-based splatting; there is no specific time frame for its implementation, though; community members are welcome to contribute.

• A variable used for splatting may only contain a hashtable (containing parameter-name-and-argument pairs, as in your question) or an array (containing positional arguments), not a [pscustomobject] - see about_Splatting.

Something like the following should work:

# Note: It is $CSObject as a whole that is a [pscustomobject] instance,
#       whereas the value of its .CommonArgs property is assumed to be
#       a *hashtable* (the one to use for splatting).
$CSObject = [pscustomobject] @{
  CommonArgs = $AzLogin  # assumes that $AzLogin is a *hashtable*
}

# Need a separate variable containing just the hashtable
# in order to be able to use it for splatting.
$varForSplatting = $CSObject.CommonArgs

Connect-Azaccount @varForSplatting -errorAction Stop