Last week I had to “reproduce” a custom list having a rather complex structure from a root web site into a sub web site. I mean, I had to create another list having the same fields and views like the original one, but located in another web site.
I fulfilled the requirements via a PowerShell script by creating a temporary list template (without including content), creating a list based on the template, and finally deleting the list template (as the title of this post promises), since we didn’t want to allow others to create the same list in the webs they have write access to.
Note: There are several alternative ways to copy a list from one site to another, for example via the SharePoint Content Deployment and the Migration API (see samples here, here and here), or via the Export-SPWeb and Import-SPWeb PowerShell Cmdlets. as illustrated in this example. Of course, each of these solutions has its own pros and cons, and it really depends on the exact requirements (do you need to copy the content, or just the structure; do you need to copy security or not; do you need to copy the versions or not, etc.) which way we may or should choose. The comparison of these methods is beyond the scope of the current post, but it is useful to know these alternatives.
But back to the deletion of the list template. The solutions I found on the web after a quick search were IMHO a bit complicated as it should be (see this and this one for example), as they iterate through the list items in the List Template Gallery list to find the file / list item that corresponds to our template.
Based on my experience, we can find the template directly via the indexer of the SPListTemplateCollection by name. It results in solution that is so simple:
$listTemplates = $web.Site.GetCustomListTemplates($web)
$listTemplate = $listTemplates[$listName]
$listTemplateFile = $web.GetFile("_catalogs/lt/" + $listTemplate.InternalName)
$listTemplateFile.Delete()
If you need the full code we used to copy the list, it is here as well:
$url = "http://YourSharePointSite"
$targetWebUrl = "/SubSite"
$listName = "CustomListName"
$site = Get-SPSite $url
$sourceWeb = $site.RootWeb
$targetWeb = Get-SPWeb ($url + $targetWebUrl)
$list = $sourceWeb.Lists[$listName]
# create a temporary list template
# we copy the list without data, so the last param is 0
$list.SaveAsTemplate($listName, $listName, $listName, 0)
$listTemplates = $site.GetCustomListTemplates($sourceWeb)
$listTemplate = $listTemplates[$listName]
# create the list in the target web
# get the list description from the source list
$targetWeb.Lists.Add($listName, $list.Description, $listTemplate)
# delete the temporary list template, we don’t need it anymore
$listTemplateFile = $sourceWeb.GetFile("_catalogs/lt/" + $listTemplate.InternalName)
$listTemplateFile.Delete()
