问题
What does it mean? I used a list of list in ASP.NET MVC and sent them through ViewData of ActionResuls to retrieve it in views.
However, when I change it to list of list, it gives me an error of HttpWebException. When I check it inside the immediate window, it tells me that the error is:
Using the generic type 'System.Collections.Generic.List<T>' requires 1 type arguments
So, what does it mean and what did I do wrong using it?
回答1:
The List<T> class is a generic type.
In order to use it, you need to provide a type argument.
For example, if you want to have a list of integers, you need to declare it as List<int>, not List.
回答2:
I guess you wrote something like List<List>> ...
But there is no class named List.. - List has a generic type parameter.
For example - list of lists of integers should be
List<List<int>> listOfLists = .....
For better understanding of C# generics take a look here.
回答3:
I was able to just use using System.Collections.Generic; to get access to lists.
来源：https://stackoverflow.com/questions/3223102/using-the-generic-type-system-collections-generic-listt-requires-1-type-argu