.net 在运行时强制转换对象

请参阅下面的代码：

  Public Class Student
    Public Shared Function Factory(ByVal somecriteria As String) As Student
        'Return either a PostGraduate or UnderGraduate based on some criteria
    End Function
End Class

Public Class PostGraduate
    Inherits Student

End Class

Public Class UnderGraduate
    Inherits Student

End Class

假设我在应用程序中有如下代码：

Dim s as Student = Student.Factory(somecriteria)

---

根据Student.StudentFactory返回的内容，我如何在运行时将s变量强制转换为研究生或本科生？

很难理解您在这里想要实现什么，但要回答您的问题，您可以使用CType转换为具体类，使用GetType确定它是哪种类型的类首先：

Dim s As Student = Student.Factory("")
If s.GetType Is GetType(PostGraduate) Then
    Dim p As PostGraduate = CType(s, PostGraduate)
Else
    Dim u As UnderGraduate = CType(s, UnderGraduate)
End If

---

你不需要把他们转换成不同类型的学生。也许您应该改用接口？根据不同之处，基类上的StudentType属性也可能有所帮助。