Trying to update a Document Library field in 150 SharePoint sites

Question

We have 150 customer portals in our SP site collection, all sites are a templated copy of each other - i.e. they all have an Internal Documents, Working Documents and Final Documents.

Inside each document library, there is a choice field called "Assessment Categories". I have been asked to add another choice called Declaration.

So I basically have 450 "Assessment Categories" Fields that need a new choice added: Declaration.

I have created a .csv file with two columns:

Name         URL
Client 1     http://sp-client1
Client 2     http://sp-client2
Client 3     http://sp-client3

And this is the code I have created so far:

# PowerShell script to add a new option to a choice field in each website.
# Websites are stored in a .csv file

$A = Import-Csv -Path "c:\AllSharePointSites.csv" -Header 'Name', 'URL'

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue

#Define URL and List name variables

$WebURL=$A.URL

$ListName1 ="Internal Documents"
$ListName2 ="Working Documents"
$ListName3 ="Final Documents"

# -->   Update Internal Documents

#Get the Web and Lists objects
$web = Get-SPWeb $WebURL
$List = $web.Lists[$ListName1]

#Add Choices to the field
$ChoiceField = $list.Fields.GetField("Assessment Category") #Get the field
$ChoiceField.Choices.Add("Declaration")

#Commit changes
$ChoiceField.update()


# -->   Update Working Documents

#Get the Web and Lists objects
$web = Get-SPWeb $WebURL
$List = $web.Lists[$ListName2]

#Add Choices to the field
$ChoiceField = $list.Fields.GetField("Assessment Category") #Get the field
$ChoiceField.Choices.Add("Declaration")

#Commit changes
$ChoiceField.update()


# -->   Update Final Documents

#Get the Web and Lists objects
$web = Get-SPWeb $WebURL
$List = $web.Lists[$ListName3]

#Add Choices to the field
$ChoiceField = $list.Fields.GetField("Assessment Category") #Get the field
$ChoiceField.Choices.Add("Declaration")

#Commit changes
$ChoiceField.update()

if anyone could help me with the correct code I would be most grateful.

Ok I tired to run this section of the code, and manually create the string $list and I received the following error:

$ListName1 ="Internal Documents"
$ListName2 ="Working Documents"
$ListName3 ="Final Documents"



# -->   Update Internal Documents

#Get the Web and Lists objects
$web = "http://sp-prod/WorkArea/74643"
Fieldname = "Assesment Category"
$List = "http://sp-prod/WorkArea/74643.lists[Internal Documents].fields.getfield($fieldname)"

write-host $list

#Add Choices to the field
$ChoiceField = $list
$ChoiceField.Choices.Add("Declaration")

#Commit changes
$ChoiceField.update()

Exit

And it produces the following error:

http://sp-prod/WorkArea/74643.lists[Internal Documents].fields.getfield() You cannot call a method on a null-valued expression. At C:\SPS\UpdateChoiceFieldInSites - AddNewChoice1.ps1:31 char:25 + $ChoiceField.Choices.Add <<<< ("Declaration") + CategoryInfo : InvalidOperation: (Add:String) [], RuntimeException + FullyQualifiedErrorId : InvokeMethodOnNull

Method invocation failed because [System.String] doesn't contain a method named 'update'. At C:\SPS\UpdateChoiceFieldInSites - AddNewChoice1.ps1:34 char:20 + $ChoiceField.update <<<< () + CategoryInfo : InvalidOperation: (update:String) [], RuntimeException + FullyQualifiedErrorId : MethodNotFound

Can anyone advise why I am getting this?

Thanks, G.