Parameter attributes (Mandatory, ValidateSet) in PowerShell - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the Mandatory attribute do in a PowerShell parameter?

The Mandatory attribute makes a parameter required. PowerShell will ask the user to provide a value if it is not supplied when running the script or function.

beginner

What is the purpose of the ValidateSet attribute in PowerShell parameters?

The ValidateSet attribute restricts the parameter's input to a predefined list of allowed values. This helps prevent errors by limiting choices to valid options.

intermediate

How do you define a mandatory parameter named Color that only accepts 'Red', 'Green', or 'Blue'?

Use [Parameter(Mandatory=$true)][ValidateSet('Red','Green','Blue')]$Color in the parameter block to make it required and limit choices.

beginner

What happens if a user provides a value not in the ValidateSet list?

PowerShell throws an error and stops execution, telling the user the value is invalid and showing the allowed options.

beginner

Can you combine Mandatory and ValidateSet attributes on the same parameter?

Yes, combining them ensures the parameter is required and only accepts specific values from the set.

What does the Mandatory attribute do in a PowerShell parameter?

A Validates the parameter type

B Limits the parameter to specific values

C Makes the parameter optional

D Makes the parameter required to be provided

The Mandatory attribute forces the user to provide a value for the parameter.

Which attribute restricts a parameter's input to a fixed list of values?

A Mandatory

B ValidateRange

C ValidateSet

D Parameter

ValidateSet limits input to a predefined set of allowed values.

What will happen if a user omits a parameter marked as Mandatory?

A PowerShell will assign a default value

B PowerShell will prompt the user to enter a value

C PowerShell will ignore the parameter

D PowerShell will throw an error immediately

PowerShell prompts the user to enter a value for mandatory parameters if missing.

If a parameter has ValidateSet('Red','Green','Blue'), what happens if the user inputs 'Yellow'?

A PowerShell throws an error about invalid value

B PowerShell ignores the parameter

C PowerShell converts 'Yellow' to 'Red'

D The script runs normally

PowerShell throws an error because 'Yellow' is not in the allowed set.

How do you make a parameter both required and limited to specific values?

A Use both <code>[Parameter(Mandatory=$true)]</code> and <code>[ValidateSet()]</code>

B Use <code>[ValidateSet()]</code> only

C Use <code>[Parameter(Mandatory=$true)]</code> only

D Use <code>[MandatorySet()]</code>

Combining both attributes makes the parameter required and restricts its values.

Explain how the Mandatory and ValidateSet attributes work together in PowerShell parameters.

Think about forcing the user to choose from specific options.

Describe what happens when a user runs a script without providing a mandatory parameter that has a ValidateSet.

Consider the user experience when input is missing or wrong.