如果基本方法在VB中调用重写的方法会怎样? [英] What happens if a base method calls an overridden method in VB?
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问题描述
请考虑以下示例:
Public Class ParentClass
Public Sub GenerateReport
Dim Col As Collection
Col = GetItemCollection()
End Sub
Public Overridable Function GetItemCollection() As Collection
GetItemCollection = New Collection
GetItemCollection.Add("1")
GetItemCollection.Add("2")
GetItemCollection.Add("3")
End Function
End Class
Public Class ExtendedClass
Inherits ParentClass
Public Overrides Function GetItemCollection() As Collection
GetItemCollection = New Collection
GetItemCollection.Add("A")
GetItemCollection.Add("B")
GetItemCollection.Add("C")
End Function
End Class
Public Sub Main()
Dim cls As New ExtendedClass
cls.GenerateReport()
End Sub
当Main()
调用cls.GenerateReport()
时,变量Col
是数字还是字母的集合?我希望它能够识别cls
是ExtendedClass
的实例,并调用重写的方法并返回字母.
When Main()
calls cls.GenerateReport()
, is the variable Col
going to be a collection of numbers or letters? I'm hoping that it will recognize that cls
is an instance of ExtendedClass
and call the overridden method and return the letters.
推荐答案
它将覆盖字母,因为您确实覆盖了该方法.但是,您在哪里声明了GetItemCollection
?您仍然需要一个实例变量.
It will be a collection of letters as you did override the method. However, where did you declare the GetItemCollection
? You still need an instance variable.
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