asp.net mvc viewmodel获取getenumerator的错误公共定义

I can get my Products model to my view ok. but I need to pass it in a ViewModel so I can interact with data from several models. When I bind my view to ProductPageViewModel then I get the "no public definition for GetEnumerator" error. I have tried all manner of IEnumerable options and cannot find the right combination. I can get my Products model to my view ok. but