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PowerShell - Using Parameter Sets

💡 What are parameter sets in PowerShell and how to use them

Have you ever wondered when you are writing a PowerShell function or commandlet how you can make only certain parameters be presented to the consumer of the function in certain scenarios? That's where parameter sets come in. 😄

We will look at the following test function: [Test-ParameterSets] on exactly how this functionality can be used.

The first step is to add a DefaultParameterSetName="Default". We can set that in our [CmdletBinding()] as follow:

// code/demo-function.ps1#L2-L2

[CmdletBinding(SupportsShouldProcess, DefaultParameterSetName="Default")]
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By declaring a default parameter set name on our [CmdletBinding()] will set all of our parameters defined under the Default set. What we will do next is define which parameters needs to be presented if the parameter switch $A is used. We do not want to present parameters from switch $B in this case. We will do this by defining a new parameter set name and grouping the parameters we want to be part of that particular set.

// code/demo-function.ps1#L8-L13

[Parameter(Mandatory=$false, ParameterSetName="A")]
[Parameter(Mandatory=$false, ParameterSetName="A")]
[Parameter(Mandatory=$false, ParameterSetName="A")]
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We will also give parameter switch $B and it's corresponding parameters, it's own parameter set name.

// code/demo-function.ps1#L14-L19

[Parameter(Mandatory=$false, ParameterSetName="B")]
[Parameter(Mandatory=$false, ParameterSetName="B")]
[Parameter(Mandatory=$false, ParameterSetName="B")]
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Now that we have defined our parameter sets and grouped the relevant parameters according to their sets our function/Cmdlet will now only present corresponding parameters based on which switch is used when calling the function/Cmdlet.


You can also find some very helpful documentation on parameter sets on Microsoft Docs.

I hope you have enjoyed this post and have learned something new. You can also find the code samples used in this blog post on my GitHub page. ❤️


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Top comments (2)

cbergmeister profile image
Chris Bergmeister • Edited

Two suggestions:

  • Mandatory property on parameters default to false, therefore you could make the code easier to read by just removing all the Mandatory=$false bits. As an aside: When adding the Mandatory attribute one doesn't even need to assign a value, one can do just [Parameter(Mandatory], which makes it nicer to read.
  • Use .IsPresent property on switch parameters so that the person reading the code knows it's a switch paramter
pwd9000 profile image

Those are awesome tips @cbergmeister Thank you!