PS exclusive parameter set switches - better error message for missing parameter?

Question

I've writen a short function to retrive info/status on an installed vpn client - it has 4 switches to specify what information is returned:

Function Get-ConnectInfo() {
    [CmdletBinding()]
    Param(
        [Parameter(ParameterSetName='Binaries')][switch]$BinaryPaths,
        [Parameter(ParameterSetName='Status')][switch]$ConnectionStatus,
        [Parameter(ParameterSetName='Profiles')][switch]$Profiles,
        [Parameter(ParameterSetName='Version')][switch]$Version
    )
#
    Begin {
    # Some code here
    }
    #
    Process {
        Switch ($PSBoundParameters.Keys) {
            BinaryPaths {
                Write-Host "BinaryDetail"
            }
            Version {
                Write-Host "VersionInfo"
            }
            Profiles {
                Write-Host "Profile Info"
            }
            ConnectionStatus {
                Write-Host "Connection Status"
            }
        }
    }
}

Thing is, if you don't pass any parameters, this is the error message:

Get-ConnectInfo : Parameter set cannot be resolved using the specified named parameters.
At line:1 char:1
+ Get-ConnectInfo
+ ~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [Get-ConnectInfo], ParameterBindingException
    + FullyQualifiedErrorId : AmbiguousParameterSet,Get-ConnectInfo

Is there an elegant way to change this error to something more informative like "Parameter not specified"?

Apparently, PowerShell Core 6 supports custom error messages with their Validate* attributes. I don't really see any official documentation on that though. I am sure that won't meet the subjective elegant requirement. — AdminOfThings
– AdminOfThings, Commented Nov 19, 2019 at 16:31

Mathias R. Jessen · Accepted Answer · 2019-11-19 16:56:16Z

You could:

Set a default parameter set
Throw a custom error and return if it's set inside the function:

function Get-ConnectInfo() {
    [CmdletBinding(DefaultParameterSetName='noOptions')]
    Param(
        [Parameter(ParameterSetName='Binaries')][switch]$BinaryPaths,
        [Parameter(ParameterSetName='Status')][switch]$ConnectionStatus,
        [Parameter(ParameterSetName='Profiles')][switch]$Profiles,
        [Parameter(ParameterSetName='Version')][switch]$Version
    )
#
    Begin {
        if($PSCmdlet.ParameterSetName -eq 'noOptions'){
            throw 'Please pass a switch argument of either "-Version", "-Profiles", "-ConnectionStatus", or "-BinaryPaths"'
            return
        }
    }
    #
    Process {
        Switch ($PSBoundParameters.Keys) {
            BinaryPaths {
                Write-Host "BinaryDetail"
            }
            Version {
                Write-Host "VersionInfo"
            }
            Profiles {
                Write-Host "Profile Info"
            }
            ConnectionStatus {
                Write-Host "Connection Status"
            }
        }
    }
}

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