Sharepoint 2010 - make Title, Description and Keyword fields as required fields in Picture Library using server-object-model - sharepoint

Question

I'm creating a Sharepoint feature, this feature has an event receiver associated to it. In the event receiver, I'm creating a Document Library and Picture Library using server-side object model. I'm also adding new custom columns (around 80) to these newly created document and picture library. Now I want to modify the properties of the Description, Keywords and Title fields that are by default created along with the picture library. I want to make these fields as Required fields. How do I do this? I tried to set SPList.AllowContentTypes = true and try to change the attributes of these fields, but it doesn't work (neither gives an error nor makes these required fields). I also tried to access the content types and try to change the attributes using SPContentType.FieldsLinks["Column_name"].Required and SPContentType.Fields["Column_name"].Required but it gives me an error. Does anyone have any other suggestions?

Answer 1

Here is the answer....
SPContentType ct = mypiclib.ContentTypes["Picture"];
SPFieldLinks titleLink = ct.FieldLinks["Title"];
SPFieldLinks descLink = ct.FieldLinks["comments"]; //internal name of Description
SPFieldLinks keywords = ct.FieldLinks["keywords"];
titlelink.Required = true;
descLink.Required = true;
keywords.Required = true;
ct.Update();

Answer 2

can you tell us the error you got when trying to use the fieldlinks? Because this should work... I have done it like this:
SPContentType ct = web.Lists["*ListName*"].ContentTypes["*ContentTypeName*"];
SPFieldLinkCollection flinks = ct.FieldLinks;
flinks["*ColumnName*"].Required = true;
ct.update();

Answer 3

This should do the trick:
SPWeb yourWeb = ... //assign your web
SPList yourPictureLibrary = ... //assign your picture library
web.AllowUnsafeUpdates = true;
yourPictureLibrary.Fields[SPBuiltInFieldId.Title].Required = true;
yourPictureLibrary.Fields[SPBuiltInFieldId.Description].Required = true;
yourPictureLibrary.Fields[SPBuiltInFieldId.Keywords].Required = true;
yourPictureLibrary.Update();

Answer 4

SPAllowContentTypes isn't settable. You might try setting ContentTypesEnabled instead.
I don't have a 2010 box to test against, but if SPAllowContentTypes returns false I think you're looking at modifying the definition of your picture library in the 14 hive (TEMPLATE\FEATURES\PictureLibrary\PicLib) to get what you're after. Tread lightly there.