SupportsShouldProcess

Cmdlets whose execution changes the state of the system where some risk is involved should include risk mitigation parameters, which are the following:

• -WhatIf

• -Confirm

For an advanced function to use these parameters, the SupportsShouldProcess parameter of the CmdletBinding attribute should be given a value of $true. Portions of code that involve the risk should be guarded with the $PSCmdlet.ShouldProcess() method. This method returns $true unless the caller specified the –WhatIf switch or the –Confirm switch followed by a negative response:

function remove-something{
[CmdletBinding(SupportsShouldProcess=$true)]
Param($item)

    if ($PSCmdlet.ShouldProcess($item)){
       Write-Output "Removing $item"
    }

}

Here is some sample output from that advanced function showing the operation of the –Whatif and –Confirm switches:

Parameter name validation

One important consequence of writing advanced functions (that is, using CmdletBinding) is that named parameters that are...