how to get SharePoint lookup field value using powershell

Question

Can anyone show me how can I get the lookup field value?

I used this line of code but it is throwing an error:

#$Lookup = new-object Microsoft.SharePoint.SPFieldLookupValue($listItem["Business_x0020_Unit"])

new-object : Cannot find type [Microsoft.SharePoint.SPFieldLookupValue]: make sure the assembly containing this type is loaded.

Below is my code.

 $loc = "C:\Scripts\ReadListUsingCSOM\dlls" # Location of DLL's
 $siteUrl = "https://collaborate.com/"

$listName = "Project"

Set-Location $loc

Add-Type -Path (Resolve-Path "Microsoft.SharePoint.Client.dll")
Add-Type -Path (Resolve-Path "Microsoft.SharePoint.Client.Runtime.dll")

#Write-Host "Please enter password for $($siteUrl):"
#$pwd = Read-Host -AsSecureString
$ctx = New-Object Microsoft.SharePoint.Client.ClientContext($siteUrl)
# Remove or replace line below to change authentication method
#$ctx.Credentials = New-Object System.Net.NetworkCredential($loginname, $pwd)

$web = $ctx.Web 
$ctx.Load($web) 
$ctx.ExecuteQuery()


$list = $ctx.Web.Lists.GetByTitle($listName)
$caml = new-object Microsoft.SharePoint.Client.CamlQuery
$caml.ViewXML = "<View />"

$listItems = $list.GetItems($caml)
$ctx.Load($listItems);
$ctx.ExecuteQuery();

Write-Host " Current web title is '$($web.Title)', $($web.Url)"
Write-Host $listItems.Count
foreach ($listItem in $listItems) 
{ 
    #We have all the list item data. For example, Title. 
$Lookup = new-object Microsoft.SharePoint.SPFieldLookupValue($listItem["Business_x0020_Unit"])
[Microsoft.SharePoint.SPFieldLookupValue]$listItem["Business_x0020_Unit"]; 
    Write-Host $listItem.ID $listItem["Project_x0020_Full_x0020_Number"] 
} 

Answer 1

You are using CSOM in your example but the SSOM Microsoft.SharePoint.SPFieldLookupValue type is specified for a Lookup Field.

The line:

$Lookup = new-object Microsoft.SharePoint.SPFieldLookupValue($listItem["Business_x0020_Unit"])

have to be replaced with this one:

$businessUnit = [Microsoft.SharePoint.Client.FieldLookupValue]$listItem["Business_x0020_Unit"]

P.S.

How to get the type of a Client Object:

$type = $item["Business_x0020_Unit"].GetType()

Answer 2

The class you are trying to use is not a client class (not originating from Microsoft.SharePoint.Client).

What you are looking for is Microsoft.SharePoint.Client.FieldLookupValue