LINQ in VB InvalidCastException

I run into this problem

System.InvalidCastException: Unable to cast object of type 'System.Data.Linq.DataQuery1[Student]' to type 'System.Collections.Generic.List1[Student]'

When I debug this function:

Public Shared Function SearchStudent(ByVal firstname As String) As List(Of Student)

    Dim db As New DemoDataContext()
    Dim query = From st In db.Students _
                Where (st.FirstName.StartsWith(firstname)) _
                Select st

    Return CType(query, List(Of S开发者_运维知识库tudent))


End Function

My project property setting: Option explicit ON and Option strict ON

I want to return a List of Student from the query. Can anyone help me? Thank you.

    Dim query = (From st In db.Students _
            Where (st.FirstName.StartsWith(firstname)) _
            Select st).ToList()