I'm trying to add a SharePoint group to a specific list that exists on all the sites in a collection. I would think this would be easier but I'm having difficulties. Inheritance is already broken on the list.

Below is my code and then the error I'm getting.

$siteNumbers = "2210"
$listsOnSite = "QWERTY"

Foreach($wnl in $siteNumbers)
    $rootWeb = (Get-SPWeb ("http://url/to/site/" + $wnl))

    Foreach($lst in $listsOnSite)

    $list = $rootWeb.Lists[$lst]
    $group = $rootWeb.Groups["Global Read-Only QWERTY"]
    $role = $rootWeb.RoleDefinitions["Read"]

    $roleAssignment = New-Object Microsoft.SharePoint.SPRoleAssignment($group)

New-Object : Constructor not found. Cannot find an appropriate constructor for type Microsoft.SharePoint.SPRoleAssignment. At line:9 char:33 + $roleAssignment = New-Object <<<< Microsoft.SharePoint.SPRoleAssignment( $group) + CategoryInfo : ObjectNotFound: (:) [New-Object], PSArgumentExce ption + FullyQualifiedErrorId : CannotFindAppropriateCtor,Microsoft.PowerShell.C

Exception calling "Add" with "1" argument(s): "The permission level specified i s already added to the collection." At line:10 char:47 + $RoleAssignment.RoleDefinitionBindings.Add <<<< ($role) + CategoryInfo : NotSpecified: (:) [], MethodInvocationException + FullyQualifiedErrorId : DotNetMethodException

You cannot call a method on a null-valued expression. At line:12 char:30 + $list.RoleAssignments.Add <<<< ($roleAssignment) + CategoryInfo : InvalidOperation: (Add:String) [], RuntimeExcept ion + FullyQualifiedErrorId : InvokeMethodOnNull

You cannot call a method on a null-valued expression. At line:13 char:17 + $list.Update <<<< () + CategoryInfo : InvalidOperation: (Update:String) [], RuntimeExc eption + FullyQualifiedErrorId : InvokeMethodOnNull

  • I was able to reproduce the "Constructor not found" exception by setting $group to null. Are you sure the "Global Read-Only QWERTY" group exists? Commented Oct 24, 2017 at 16:24
  • I'm positive. I ran a script to verify. 2210 contains the following groups ======================== Global Read-Only QWERTY Main Members Main Owners Main Visitors
    – NMJohns
    Commented Oct 24, 2017 at 17:03
  • 2
    Check this sharepoint.stackexchange.com/questions/147617/… Commented Oct 24, 2017 at 17:07

1 Answer 1


Use this

$roleAssignment = new-object Microsoft.SharePoint.SPRoleAssignment([Microsoft.SharePoint.SPPrincipal]$group) 

Instead of

$roleAssignment = New-Object Microsoft.SharePoint.SPRoleAssignment($group)

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