Using an "If" statement with the ValidateScript parameter validation attribute

PowerShell Help
1

I would like to use an “If” statement within a ValidateScript parameter validation attribute for an advanced function I am writing instead of having to use the $PSBoundParameters variable to check if more than one parameter is being used.

I would like to be able to use Method 1 rather than Method 2 if possible, but not sure if there is a way of doing this, because I keep getting the following error when using Method 1 below:

[blockquote]Check-Parameters : Cannot validate argument on parameter
‘Param2’. The “If ($Param1){ Write-Warning -Message “The Param1
parameter and the Param2 parameter cannot be used together!” }”
validation script for the argument with value “10” did not return a result of
True. Determine why the validation script failed, and then try the command
again.[/blockquote]

Method 1

Function Check-Parameters
{ 
  
  [cmdletbinding[]]

  Param
  (
        $ComputerName = $env:COMPUTERNAME,
        [Switch]$Param1,
        [ValidateScript[({If ($Param1){Write-Warning -Message "The Param1 parameter and the Param2 parameter cannot be used together!" }}]]
        [Int]$Param2
  )

Check-Parameters -Param1 -Param2 "10"
}

Method 2

Function Check-Parameters
{ 
  
  [cmdletbinding[]]

  Param
  (
        $ComputerName = $env:COMPUTERNAME,
        [Switch]$Param1,
        [Int]$Param2
  )

$ParamString = @(
                 
            $Params = @(    
                            Foreach ($Param in 'Param1', 'Param2')
                            { 
                                If ($PSBoundParameters[$Param])
                                {  
                                    $Param 
                                } 
                            } 
                        )
 
                Write-Output $Params)

     If (($ParamString -eq "Param1") -and ($ParamString -eq "Param2"))
     {
         Write-Warning -Message "The Param1 parameter and the Param2 parameter cannot be used     
         together!"
     }

     ElseIf (($ParamString -eq "Param1") -and ($ParamString -ne "Param2"))
     {
        "Param1 is being used!"
     }

     ElseIf (($ParamString -ne "Param1") -and ($ParamString -eq "Param2"))
     {
        "Param2 is being used!"
     }

     ElseIf (!($ParamString))
     {
        "No parameter is being used!"
     }
}

OR

Should I use Parameter Sets?

Thanks

2

Is there a reason I am not receiving a response?

3

The ValidateScript has to return $true for the validation to pass.

Here is a working example:

Function Check-Parameters
{ 
  [cmdletbinding()]
  Param
  (
    $ComputerName = $env:COMPUTERNAME,
    [Switch]$Param1,
    [ValidateScript({If ($Param1){Throw "The Param1 parameter and the Param2 parameter cannot be used together!" }else {$true}})]
    [Int]$Param2
  )
  'Running function with parameters: {0}' -f ($PSBoundParameters.Keys -join ', ')
}
Check-Parameters -Param1 -Param2 "10"
Check-Parameters -Param2 "10"
Check-Parameters -Param1