Better way to validate when not using a function ValidateSet - powershell

Question

I'm looking for a better way to validate a "response" from a user for my script. I know you can use a function to validate this but I want it to be more interactive.
$DPString = #"
Enter users department.
Valid choices are;
"Accounts","Claims","Broker Services","Underwriting","Compliance","HR","IT","Developmet","Legal" and "Legal Underwriting"
"#
$Department = Read-Host "$DPString"
do
{
Switch ($Department)
{
Accounts { $DepBool = $true }
Claims { $DepBool = $true }
"Broker Services" { $DepBool = $true }
Underwriting { $DepBool = $true }
Compliance { $DepBool = $true }
"Legal Underwriting" { $DepBool = $true }
Legal { $DepBool = $true }
HR { $DepBool = $true }
IT { $DepBool = $true }
Development { $DepBool = $true }
Default { $DepBool = $false }
}
if ($DepBool -eq $true)
{
$DepLoop = $false
}
else {
$Department = Read-Host "Please enter a valid Department"
$DepLoop = $true
}
}
while ($DepLoop)

Answer 1

It's not clear in what context the user is being prompted for input, but I would favour a list of valid parameters being passed in on the command line. I would make them mutually exclusive using Parameter Sets.
However, if this is a part of a larger script which prompts for input part way through, then it might be appropriate to prompt for input using the windows API for displaying an input box. Here's a link which describes this approach in more detail Creating a Custom Input Box.
Although it feels wrong to display UI from powershell, I understand that there are times when this is desirable, using the link above here's an implementation of a ListBox, you simply pass it a string array and it returns the selected value:
<#
.SYNOPSIS
Displays a Windows List Control and returns the selected item
.EXAMPLE
Get-ListBoxChoice -Title "Select Environment" -Prompt "Choose an environment" -Options #("Option 1","Option 2")
This command displays a list box containing two options.
.NOTES
There are two command buttons OK and Cancel, selecting OK will return the selected option, whilst
Cancel will return nothing.
.RELATED LINKS
http://technet.microsoft.com/en-us/library/ff730941.aspx
#>
Function Get-ListBoxChoice
{
[cmdletbinding()]
param
(
[Parameter(Mandatory=$true)]
[string] $Title,
[Parameter(Mandatory=$true)]
[string] $Prompt,
[Parameter(Mandatory=$true)]
[string[]] $Options
)
Write-Verbose "Get-ListBoxChoice"
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms")
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Drawing")
$uiForm = New-Object System.Windows.Forms.Form
$uiForm.Text = $Title
$uiForm.FormBorderStyle = 'Fixed3D'
$uiForm.MaximizeBox = $false
$uiForm.Size = New-Object System.Drawing.Size(300,240)
$uiForm.StartPosition = "CenterScreen"
$uiForm.KeyPreview = $True
$uiForm.Add_KeyDown({if ($_.KeyCode -eq "Enter")
{$chosenValue=$objListBox.SelectedItem;$uiForm.Close()}})
$uiForm.Add_KeyDown({if ($_.KeyCode -eq "Escape")
{$uiForm.Close()}})
$OKButton = New-Object System.Windows.Forms.Button
$OKButton.Location = New-Object System.Drawing.Size(75,160)
$OKButton.Size = New-Object System.Drawing.Size(75,23)
$OKButton.Text = "OK"
$OKButton.Add_Click({$chosenValue=$objListBox.SelectedItem;$uiForm.Close()})
$uiForm.Controls.Add($OKButton)
$CancelButton = New-Object System.Windows.Forms.Button
$CancelButton.Location = New-Object System.Drawing.Size(150,160)
$CancelButton.Size = New-Object System.Drawing.Size(75,23)
$CancelButton.Text = "Cancel"
$CancelButton.Add_Click({$uiForm.Close()})
$uiForm.Controls.Add($CancelButton)
$uiLabel = New-Object System.Windows.Forms.Label
$uiLabel.Location = New-Object System.Drawing.Size(10,20)
$uiLabel.Size = New-Object System.Drawing.Size(280,20)
$uiLabel.Text = $Prompt
$uiForm.Controls.Add($uiLabel)
$objListBox = New-Object System.Windows.Forms.ListBox
$objListBox.Location = New-Object System.Drawing.Size(10,40)
$objListBox.Size = New-Object System.Drawing.Size(260,20)
$objListBox.Height = 120
$Options | % {
[void] $objListBox.Items.Add($_)
}
$uiForm.Controls.Add($objListBox)
$uiForm.Topmost = $True
$uiForm.Add_Shown({$uiForm.Activate()})
[void] $uiForm.ShowDialog()
$chosenValue
}

Answer 2

If they're running at least V3, you can use Out-Gridview:
$Departments = #(
[PSCustomObject]#{Name = 'Accounts';Description = 'Accounting Department'}
[PSCustomObject]#{Name = 'Claims';Description = 'Claims Department'}
[PSCustomObject]#{Name = 'Broker';Description = 'Broker Services'}
)
$GridParams = #{
Title = "Select a department, and press 'OK', or 'Cancel' to quit."
OutPutMode = 'Single'
}
$Department = $Departments | Out-Gridview #GridParams
If ($Department)
{ #Do stuff }