SharePoint SE. Adding Document Library to Wiki Page (classic view) via script not showing as it did in 2016.

function AddHomePageWebPart($web, $libraryTitle){
    $homePageUrl = $web.RootFolder.WelcomePage # "/SitePages/Home.aspx";
    $wpmgr = $web.GetLimitedWebPartManager($homePageUrl, [system.web.ui.webcontrols.webparts.personalizationscope]::Shared);
    RemoveExistingWebParts $wpmgr $libraryTitle
    
    $webpart = $wpmgr.WebParts | ? { $_.Title -eq $libraryTitle };
    if($webpart -eq $null)
    {
		Write-Host "adding"   
        $library = $web.Lists.TryGetList($libraryTitle);
        if($library -ne $null)
        {
            $page = $web.GetFile($homePageUrl);
            $pwpmgr = $page.GetLimitedWebPartManager([System.Web.UI.WebControls.WebParts.PersonalizationScope]::Shared);
            $storageKey = [System.Guid]::NewGuid();
            $wpId = [System.String]::Format("{0}", $storageKey.ToString());
            $pagecontent = [System.String]::Format("placeholder div", $wpId)
            $webpart = New-Object microsoft.sharepoint.webpartpages.xsltlistviewwebpart;
            $webpart.Title = $libraryTitle;
            $webpart.ListName = $library.ID.ToString("B").ToUpper();
            $webpart.ListUrl = $libraryTitle;
            $webpart.ViewGuid = $library.DefaultView.ID.ToString("B").ToUpper();
            $webpart.ChromeType = [System.Web.UI.WebControls.WebParts.PartChromeType]::TitleOnly;
            $webpart.ID = $wpId;
            $page.CheckOut();
            $pageItem = $page.Item;
            $pageItem[[Microsoft.SharePoint.SPBuiltInFieldId]::WikiField] = $pagecontent;
            $pageItem.Update();
            $page.Update();
            $page.CheckIn("Add Project Documents Web Part", [Microsoft.SharePoint.SPCheckInType]::MajorCheckIn);
            $pwpmgr.AddWebPart($webpart, "wpz", 0);
            $pwpmgr.SaveChanges($webpart);
        }
    }
}

As you can see in code, ViewGuid is set.

Hi Greg Ogle

Thanks for replying

Based on my research, as stated in this document, it seems like the root cause is on classic wiki pages, a list (XsltListViewWebPart) doesn’t render unless two conditions are met:

• The page’s WikiField contains the required placeholder markup with a <div> whose id follows the pattern div_<GUID in D format>
• The web part itself is added to the special wiki zone named wpz and uses a web part ID in the form g_<GUID with underscores>.

In 2016 your script likely wrote correct placeholder HTML or the page already had it; in SE your current string "placeholder div" does not create the required <div id="div_...">, and your web part ID is not in the g_... format. As a result, the web part is present but has nowhere to render until a manual addition inserts proper wiki markup explaining why both parts show after you add one by hand.

Therefore, you can try the approach methods below to see if it can resolve your problem:

1. Insert correct placeholder markup in WikiField

Ensure the page’s WikiField contains the required <div> placeholder with id="div_<GUID>" and vid_<GUID> tags.

Without this markup, the web part has nowhere to render.

For example:

<div class='ms-rtestate-read ms-rte-wpbox' contentEditable='false'>
  <div class='ms-rtestate-read {GUID}' id='div_{GUID}'></div>
  <div style='display:none' id='vid_{GUID}'></div>
</div>

2. Use correct Web Part ID pattern and zone

Generate the web part ID in the format g_<GUID_with_underscores> and add it to the wpz zone.

$wpId = "g_" + $storageKey.ToString().Replace("-", "_")
$pwpmgr.AddWebPart($webpart, "wpz", 0)

Link instruction: https://sharepoint.stackexchange.com/questions/223257/adding-webparts-on-a-wiki-page-in-sharepoint-online-through-csom-and-powershell

Note: Microsoft is providing this information as a convenience to you. These sites are not controlled by Microsoft, and Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. Please ensure that you fully understand the risks before using any suggestions from the above link.

3. Use the correct ID patterns and zone

Generate a storage GUID and set the web part ID to g_<guid_with_underscores>; add it to zone wpz.

Example:

$storageKey = [Guid]::NewGuid()
$wpId = "g_" + $storageKey.ToString().Replace("-", "_")
$pwpmgr.AddWebPart($webpart, "wpz", 0)
$pwpmgr.SaveChanges($webpart)

Link reference: https://dori-uw-1.kuma-moon.com/en-us/previous-versions/office/developer/sharepoint-2010/ff806162%28v=office.14%29

Please take some time to test on this, after 2 days I will check on this again unless you come back to me at earlier time.
Feel free to let me know if you have any further questions.

Best regards.

Excellent. The format of GUID's was the key. I had the marker text (excluded from example due to issue posting), but it used the underscores in GUID which was incorrect.