如何向模型添加模型集合?(ASP。NET MVC3具有实体框架)

I'm building an ASP.NET MVC 3 site using the code-first Entity Framework 4 approach. I have one object in my model, Problem, that contains a child collection of another model object, ProblemRating. Currently I have the Problem model set up as follows:I'm building an ASP.NET MVC 3 site using the co