Unable to serialize List<SelectListItem>

Question

I'm moving an existing MVC3 app from InProc to ASP.Net Session State service. One of the model objects has this property:

public List<System.Web.Mvc.SelectListItem> StateCodes { get; set; }

and it's throwing this error

Unable to serialize the session state. In 'StateServer' and 'SQLServer' mode, ASP.NET will serialize the session state objects, and as a result non-serializable objects or MarshalByRef objects are not permitted. The same restriction applies if similar serialization is done by the custom session state store in 'Custom' mode.

Is there a way to get List<SelectListItem> to serialize?

Answer 1

Try to create the select list items in the Razor code instead by with a SelectList. Let the model instead have a property for the underlying data that the SelectList is based on. You may also try to place the SelectList in the ViewBag or ViewData, that could also solve problem.

Storing SelectList's in the view model is regarded as bad practice.