Styjun

I am writing a script and I want to specify the parameters to do the following:

Parameter 1 is action (either check or kill)
Parameter 2 is computername.

If neither parameter is specified I want my Usage information displayed
Parameter 2 should ONLY be prompted if Parameter 1 is specified.

Param(
 [Parameter(Mandatory=$True,
 HelpMessage="Please Enter an Action. (C)heck, (K)ill, or (?) for usage")]
 [String]$Action,

 [Parameter(Mandatory = $false,
 Helpmessage="Please Enter One or More Hostnames. seperate multiple hostnames with an , EXAMPLE: Hostname1,Hostname2")]
 [ValidateNotNullorEmpty()]
 [String]$Computers 
 )

Why force users to guess at what input is expected?
Just tell them up front what is expected.

For example:

Function Test-DescriptiveUserPrompt

 [CmdletBinding()]

 Param
 (
 [ValidateSet('C','K')]
 [string]$Action = $(
 Write-Host '
 Please Enter an Action. (C)heck, (K)ill: ' -ForegroundColor Yellow -NoNewLine
 Read-Host 
 ),

 [ValidateNotNullorEmpty()]
 [string[]]$Computers = $(
 Write-Host '
 Please Enter One or More Hostnames. separate multiple hostnames with a comma. 
 EXAMPLE: Hostname1,Hostname2: ' -ForegroundColor Yellow -NoNewLine
 Read-Host 
 )
 )

 Process
 
 "You choose $Action"
 "You enter the list $Computers"
 



# Results

Test-DescriptiveUserPrompt

 Please Enter an Action. (C)heck, (K)ill: c

 Please Enter One or More Hostnames. seperate multiple hostnames with a comma. 
 EXAMPLE: Hostname1,Hostname2: localhost,remotehost
c
localhost,remotehost


Test-DescriptiveUserPrompt -Action C -Computers localhost,remotehost

C
localhost
remotehost

The quick and dirty and simpler way of doing things is to use Parameter Sets. In this case, it will default to displaying the Usage information if things aren't correct.

Function Test 
 [CmdletBinding()]
Param(
 [Parameter(Mandatory=$true, ParameterSetName = "Action",
 HelpMessage="Please Enter an Action. (C)heck, (K)ill, or (?) for usage")]
 [ValidateSet("C","K","?")]
 [Parameter(Mandatory=$false, ParameterSetName = "Usage")]
 [String]$Action,

 [Parameter(Mandatory = $true, ParameterSetName = "Action",
 Helpmessage="Please Enter One or More Hostnames. seperate multiple hostnames with an , EXAMPLE: Hostname1,Hostname2")]
 [ValidateNotNullorEmpty()]
 [String]$Computers 
 )
Process

 if($PSCmdlet.ParameterSetName -eq "Usage" -or $Action -eq "?")
 
 Write-Host "Usage"
 
 else
 
 Write-Host "Action"
 Write-Host $Action
 Write-Host $Computers