Mutual Exclusive Parameters

Sometimes, PowerShell functions have parameters that should be mutually exclusive: the user should only be able to use either one, not both.

To create mutually exclusive parameters, assign them to different parameter sets, and make sure you define a default parameter set name (which is used if PowerShell cannot automatically pick the right parameter set):

function Test-ParameterSet
{
  [CmdletBinding(DefaultParameterSetName='number')]
  param
  (
    [int]
    [Parameter(ParameterSetName='number', Position=0)]
    $id,

    [string]
    [Parameter(ParameterSetName='text', Position=0)]
    $name
  )

  $PSCmdlet.ParameterSetName
  $PSBoundParameters
} 

The function Test-ParameterSet has two parameters: -id and -name. The user can only specify one, not both at the same time. The sample also illustrates how you find out which one the user picked.

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