Create Lookup Site Column from Subsite using PowerShell
Creating a lookup field as a site column was explained in my other post: Create a Cross-Site Lookup Site Column in SharePoint 2013. Now got a requirement to create a lookup site column from the subsite’s list! Unfortunately, there is no UI to create a site column from subsite list values. Lookup site columns can be created only from the lists of the same site.
PowerShell comes to the rescue! We can create a lookup site column referencing any site of the site collection using PowerShell! Here is the PowerShell script to create a lookup column from the list on another site.
PowerShell to create lookup site column from subsite’s (or different site) list:
Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue
#Where the Source List for Lookup Exists
$ParentWebURL="https://portal.crescent.com/sales/"
$ParentListName="Regions"
$ParentLookupColumnName="Region"
#Where the Lookup Site column Going to get created
$ChildWebURL="https://portal.crescent.com"
$ChildLookupColumnName="Sales Region"
#Get the Parent and Child Webs and List
$ParentWeb = Get-SPWeb $ParentWebURL
$ParentList = $ParentWeb.Lists[$ParentListName]
$ChildWeb = Get-SPWeb $ChildWebURL
#Check if Field exists already
if(!$ChildWeb.Fields.ContainsField($ChildLookupColumnName))
{
#Add Lookup Field
$ChildLookupColumn = $ChildWeb.Fields.AddLookup($ChildLookupColumnName,$ParentList.id,$False)
$ChildLookupColumn = $ChildWeb.Fields[$ChildLookupColumnName]
#Setup lookup Field property
$ChildLookupColumn.LookupWebId = $ParentWeb.ID
$ChildLookupColumn.LookupField = $ParentList.Fields[$ParentLookupColumnName].InternalName
#$ChildLookupColumn.AllowMultipleValues=$true
$ChildLookupColumn.update()
write-host "Lookup field added successfully!" -f green
}
else
{
write-host "Field Exists already!" -f red
}
This PowerShell script creates a SharePoint lookup column from the list on another site! By the way, Site columns must be created on the Root web to be consumed by any subsite underneath.
