Only allow one entry per User in a List - ListReceiver “Feature” for a List?

Question

I wonder if there is a way to create a Custom List in Sharepoint, but specify that each user may only create one item in the list.

I am thinking of two approaches:

• Develop a ListReceiver that checks if the user already created an item. Problem: I did not see a way to enable a Feature on a specific list (the idea is that non-developers can just create a custom list and "switch on" the Feature if they want
• Create a Custom List Type, so when people click the "Create" Button, they see "Custom Unique List" under "Custom Lists" as an additional type.

Before I do the second option, does anyone know if the first option is possible? Or even if it can already be done without custom development (and without a custom workflow in SPDesigner)

Answer 1

Without custom code you are out of luck. You can easily add a receiver to a single list using code, just add the receiver to the SPListItem.EventReceivers collection as such:

list.EventReceivers.Add(SPEventReceiverType.ItemAdded, "YOUR STRONG NAME", "YOUR CLASS NAME");

There is no way directly through a feature elements file, however.

If you want an option to enable or disable the feature on a particular list you can also add a CustomAction and bind it to that specific list template for instance so that an extra Action menu item allows Enable or Disable Unique Posts.

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