Lookup field incorrect list id

Question

I have 2 lists a1 and a2

List a1 has lookup field which looks into a2

This was working fine

Then I wanted to add more fields to a2 list. I decided to delete a2 list and created list with same name which includes Content Type also

Now the lookup field in a1 list is not working

I think it's still referring to old list id

How can I fix this problem?

Thanks

Answer 1

Using PowerShell you can update the lookup list Id

$webURL = "http://server/sites/XY"
$listName = "MyList"
$columnName = "MyColumn"
$lookupListName = "Category"
$lookupWebURL = "http://server/sites/X"
RepairListLookupColumns -webURL $webURL -listName $listName -columnName $columnName -lookupListName $lookupListName -lookupWeb $lookupWebURL

Function RepairListLookupColumns($webURL, $listName, $columnName, $lookupListName, $lookupWebURL)
{
    #Get web, list and column object
    $web = Get-SPWeb $webURL
    $lookupWeb = Get-SPWeb $lookupWebURL
    $lookupWeb = Get-SPWeb $lookupWebURL
    $list = $web.Lists[$listName]
    $column = $list.Fields[$columnName]
    $lookupList = $lookupWeb.Lists[$lookupListName]
    $newLookupListID = "{"+.     $lookupList.ID.ToString()+"}"
    $newLookupWebID = "{"+$lookupWeb.ID.ToString()+"}"
    #Change schema XML on the lookup column
    $column.SchemaXml = $column.SchemaXml.Replace($column.LookupWebId.ToString(), $newLookupWebID)
    $column.SchemaXml = $column.SchemaXml.Replace($column.LookupList.ToString(), $newLookupListID)
    $column.Update()
    #Write confirmation to console and dispose of web object
   write-host "In Site" $web.Url "column " $column.Title "in Liste" $list.Title "is connected with"  $lookupList.Title "from" $lookupWeb.Url
    $web.Dispose()
    $lookupWeb.Dispose()
}

Source - http://www.ilikesharepoint.de/2013/12/sharepoint-repair-lookup-columns-which-are-not-connected-to-a-list/