Is it possible to force PowerShell script to throw if a required parameter is omitted?

Question

I would like the second function call in this script to throw an error:

function Deploy
{

param(

    [Parameter(Mandatory=$true)]
    [ValidateNotNullOrEmp         


        

Answer 1

@Emperor XLII has a nice comment in the question that I think can be a better answer for some use cases:

if you run powershell.exe with the -NonInteractive flag, missing mandatory parameters will cause an error and result in a non-zero exit code for the process.

The reasons to use this can be:

1. You have a lot of such Mandatory=$true parameters and the cost is high to convert all of them.
2. The script will be used both interactively and non-interactively, and when run interactively you do want to be prompted for missing parameters.

Answer 2

Once the parameter is marked as mandatory PowerShell will prompt for value. That said, if you remove the mandatory attribute then you can set a default value with a throw statement:

function Deploy
{
    param(
        [Parameter()]
        [ValidateNotNullOrEmpty()]
        [string]$BuildName=$(throw "BuildName is mandatory, please provide a value.")
    )

    Write-Host "Build name is: $BuildName"
}