How do you support PowerShell's -WhatIf & -Confirm parameters in a Cmdlet that calls other Cmdlets?

Question

I have a PowerShell script cmdlet that supports the -WhatIf & -Confirm parameters.

It does this by calling the $PSCmdlet.Should

Answer 1

Here is a complete solution based on @Rynant and @Shay Levy's answers:

function Stop-CompanyXyzServices
{
    [CmdletBinding(SupportsShouldProcess=$true,ConfirmImpact='Medium')]

    Param(
        [Parameter(
            Position=0,
            ValueFromPipeline=$true,
            ValueFromPipelineByPropertyName=$true
        )]      
        [string]$Name
    )

    process
    {
        if($PSCmdlet.ShouldProcess($env:COMPUTERNAME,"Stop XYZ services '$Name'")){  
            ActualCmdletProcess
        }
        if([bool]$WhatIfPreference.IsPresent){
            ActualCmdletProcess
        }
    }
}

function ActualCmdletProcess{
# add here the actual logic of your cmdlet, and any call to other cmdlets
Stop-Service $name -WhatIf:([bool]$WhatIfPreference.IsPresent) -Confirm:("Low","Medium" -contains $ConfirmPreference)
}

We have to see if -WhatIf is passed separately as well so that the whatif can be passed on to the individual cmdlets. ActualCmdletProcess is basically a refactoring so that you don't call the same set of commands again just for the WhatIf. Hope this helps someone.