A Powershell Class with Mandatory Properties by Default

MandatoryProperties.ps1

using namespace System.Collections
using namespace System.Management.Automation
using namespace System.ComponentModel.DataAnnotations
using namespace System.Runtime.Serialization
class MandatoryProperties {
	MandatoryProperties([IDictionary]$properties) {
		$this.GetType().GetProperties([System.Reflection.BindingFlags]'Instance,Public') | ForEach-Object {
			$propertyName = $PSItem.Name
			[bool]$isOptional = $PSItem.GetCustomAttributes([OptionalFieldAttribute], $true).count -gt 0
			if (
				-not $properties.Contains($propertyName) -and
				-not $isOptional
			) {
				throw [ArgumentNullException]::new($propertyName, 'A Mandatory property was not specified')
			}
			$this.$propertyName = $properties[$propertyName]
		}
	}
}

zExample.ps1

# A group that includes all users in the org with a particular title
class GlobalGroup : MandatoryProperties {
	# The name of the list. Additional information may be added based on this name
	[string]$Name
	# Which user titles should be included in the group
	[string[]]$JobTitle
	# An additional description of the group, maybe including the full address
	[OptionalField()][string]$Description

	GlobalGroup([IDictionary]$properties) : base($properties) {}
}

#This will fail
[GlobalGroup]@{}

#This will fail and warn you jobtitle is mandatory
[GlobalGroup]@{Name='test'}

#This is fine because description is flagged as optional
[GlobalGroup]@{Name='test',JobTitle='manager'}