Site columns created programmatically don't show up anywhere

Question

I need to create a site column programmatically during feature activation (requirements - supose I can't change that).

My code is fairly straight forward:

string internalName = web.Fields.AddLookup("foo", someList.ID, false);
// *field name*, *ID of the list to point* and *required*, respectively.

SPFieldLookup foo = (SPFieldLookup)web.Fields.GetField("foo");
foo.Group = "bar";
foo.update();
web.update();

The field is created, alright - but when I navigate to the site where it was created, it does not show up in the "site columns" page, in the site administration.

I can't add it again because it's already in the site. I can't associate it to any content type because it doesn't show up in any page at all. I can't delete it programatically, either:

• With C# it tells me there is some list or content type using the field (which is not true at all)
• and with Powershell I either get no errors, or get a "wrong parameters" error when running Delete in any form below. But even after the commands run without errors the column is not truly deleted (I can still fetch it via C# and Powershell):

 

$site = Get-SPSite(siteUrl)
$web = $site.rootweb
$web.Fields["foo"].delete()
$foo = $web.Fields["foo"]
$foo.delete()
$web.Fields.Delete($foo)
etc...

(The only web in the site colletion is the root one.)

I have tried the brute force solution, that is, deleting the site collection and recreating it again (I'm just fiddling with a dev environment for now), thinking my site might have gone corrupt. It just doesn't solve the problem. When I create it again in a whole new site, the column stays there, and I can neither use it nor delete it.

Help?

Answer 1

Your code looks like it will only create a Field Link, linking an existing Field to for example a list.

You should use this method instead: http://msdn.microsoft.com/en-us/library/ms472869.aspx

Like web.Fields.Add("foo", SPFieldType.Text, false) before creating a field link.

This will create a new SiteColumn of type Text. Here you can find the available field types.

Answer 2

I found out what the problem was. I totally forgot to set the LookupField property of my new field.

FML.

While it was somewhat stupid of me to expect a lookup to work without pointing to a field in the target list... I think one would expect an inconsistent field like that to not work at all. Sorry for the rant, but if it was me designing Sharepoint, I would make sure you can't save a lookup until all the things it needs to work are set. I would sure force the target field to be informed in the AddLookup method, for example.

So there. I set that property and my site column is no longer haunting my site collection.