Powershell: How do I pass variables to switch parameters when invoking powershell at the command line?

Question

Normally, if you want to defer the specification of a switch parameter to some variable, you can pass an expression to the switch parameter, as seen with the WhatIf parameter.

Answer 1

This behaviour has been filed as a bug on connect. This is a workaround:

powershell ./test.ps1 -source test.ps1 -dest test.copy.ps1 -test:$true

Answer 2

Use the IsPresent property of the switch. Example:

function test-switch{
param([switch]$test)
  function inner{
    param([switch]$inner_test)
    write-host $inner_test
  }
  inner -inner_test:$test.IsPresent
}
test-switch -test:$true
test-switch -test
test-switch -test:$false

True
True
False

BTW, I used functions rather than a script so it would be easier to test.