The type arguments for method cannot be inferred from the usage

means you need to be specific in the method call

.getBlahs<Collection<Blah>>()

The type must be a reference type in order to use it as parameter 'T' in the generic type or method

usually just means you need to add where T : class

Generic properties for non generic classes

are illegal

    class Test

    {

        public T  y<T> { get; set; }

    }

instead you need the following

    class Test <T>

    {

        public T  y { get; set; }

    }