Powershell and Sharepoint - Update list - powershell

Question

I've been reading a ton of these articles that say to use Get-SPWeb, but I've never been able to get those functions working due to authentication errors. I have build my own little functions to do what I need but I'm struggling to figure out what I'm doing wrong for my update function. Below are the functions I've built, and all of them work:
If (!$cred) {$cred = get-credential -UserName "$ENV:Username#$ENV:UserDomain.com" -Message "Enter your office 365 login"}
function Get-AuthenticationCookie($context)
{
$sharePointUri = New-Object System.Uri($context.site.Url)
$authCookie = $context.Credentials.GetAuthenticationCookie($sharePointUri)
if ($? -eq $false) #https://ss64.com/ps/syntax-automatic-variables.html
{
return $null
}
$fedAuthString = $authCookie.TrimStart("SPOIDCRL=".ToCharArray())
$cookieContainer = New-Object System.Net.CookieContainer
$cookieContainer.Add($sharePointUri, (New-Object System.Net.Cookie("SPOIDCRL", $fedAuthString)))
return $cookieContainer
}
function Get-SharepointContext
{
Param(
[Parameter(Mandatory = $true)]
$siteUrl,
[Parameter(Mandatory = $false)]
$cred)
If (!$cred) {$cred = get-credential -UserName "$ENV:Username#$env:USERDNSDOMAIN" -Message "Login"}
[string]$username = $cred.UserName
$securePassword = $cred.Password
[Void][System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client")
[Void][System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client.ClientContext")
$ctx = New-Object Microsoft.SharePoint.Client.ClientContext($siteUrl)
$ctx.RequestTimeOut = 1000 * 60 * 10;
$ctx.AuthenticationMode = [Microsoft.SharePoint.Client.ClientAuthenticationMode]::Default
$credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($username, $securePassword)
$ctx.Credentials = $credentials
Return $ctx
}
function Add-SharepointListEntry
{
#example
#Add-SharepointListEntry -cred $cred -clientName $DestinationPages
Param(
[Parameter(Mandatory = $true)]
$cred,
[Parameter(Mandatory = $true)]
$sitename,
$siteUrl = "https://$env:Userdomain.sharepoint.com/$sitename",
[Parameter(Mandatory = $true)]
$ListName,
$SharepointData
)
[Void][System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client")
# Bind to site collection
$Context = Get-SharepointContext -siteUrl $siteUrl -cred $cred
# Get List
$List = $Context.Web.Lists.GetByTitle($ListName)
$Context.Load($List)
$Context.ExecuteQuery()
# Create Single List Item
$ListItemCreationInformation = New-Object Microsoft.SharePoint.Client.ListItemCreationInformation
$NewListItem = $List.AddItem($ListItemCreationInformation)
#construct the entry to insert
$NewListItem["Title"] = $SharepointData.Title #Client Name
$NewListItem["Description"] = $SharepointData.Title
#These objects should pass right through
$NewListItem["Client"] = $SharepointData.Client
$NewListItem["Author"] = $SharepointData.Author
$NewListItem["Initials"] = $SharepointData.Author
$NewListItem["Created"] = $SharepointData.Created
$NewListItem.Update()
$Context.ExecuteQuery()
}
Function Get-SharepointListData
{
#example
#Get-SharepointListData -cred $cred
Param(
[Parameter(Mandatory = $true)]
$cred,
[Parameter(Mandatory = $true)]
$sitename,
$siteUrl = "https://$env:Userdomain.sharepoint.com/$sitename",
[Parameter(Mandatory = $true)]
$ListName
)
[Void][System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client")
# Bind to site collection
$Context = Get-SharepointContext -siteUrl $siteUrl -cred $cred
#Retrive the List
$List = $Context.web.Lists.GetByTitle($ListName)
#Get All List Items
#reference https://gallery.technet.microsoft.com/office/How-to-do-a-CAML-Query-6f5260cf
$Query = New-Object Microsoft.SharePoint.Client.CamlQuery
$ListItems = $List.GetItems($Query)
$context.Load($ListItems)
$context.ExecuteQuery()
# Turn item into a catch array
$ListItemCollection = #()
ForEach ($item in $ListItems)
{
$propertiesValues = New-Object PSObject
$currentItem = $item
$item.FieldValues.Keys | Where {$_ -ne "MetaInfo"} | ForEach {Add-Member -InputObject $propertiesValues -MemberType NoteProperty -Name $_ -Value $currentItem[$_]}
$ListItemCollection += $propertiesValues
Remove-Variable propertiesValues
}
Return $ListItemCollection
}
Now I'm building a new function and trying to use one list (which is querying a sharepoint folder) to update a sharepoint list. I query the directory with the get-sharepointlistdata, then loop through the results to add new entries if something is missing. This whole process works without issue. I'm trying to add a step in to update for any changes, but the function keeps failing on $list.Items.GetByID($index) throwing the error "You cannot call a method on a null-valued expression.":
Function Set-SharepointListData
{
Param(
[Parameter(Mandatory = $true)]
$cred,
[Parameter(Mandatory = $true)]
$sitename,
$siteUrl = "https://$env:userdomain.sharepoint.com/$sitename",
[Parameter(Mandatory = $true)]
$ListName,
[Parameter(Mandatory = $true)]
[int]$Index,
[Parameter(Mandatory = $true)]
$Time
)
[Void][System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint.Client")
# Bind to site collection
$Context = Get-SharepointContext -siteUrl $siteUrl -cred $cred
# Get List
$List = $Context.Web.Lists.GetByTitle($ListName)
$Context.Load($List)
$Context.ExecuteQuery()
# Select Single List Item
$ListItem = $List.Items.GetById($index)
$ListItem["Created"] = $time
$ListItem.Update();
$Context.ExecuteQuery();
}
I'm certain I'm overlooking something obvious here... anyone have any ideas?

Answer 1

The $Context.Web.Lists.GetByTitle($ListName) doesn't return the Items of the list. You have to load the Items... normally done via caml query. See here - Although the sample is in C# it should get you started.
Actually I rather suggest you to use PnPPowershell, there are plenty of cmdlets to work with Sharepoint.