VB：如何创建嵌套类？ [英] VB: How do I create nested classes?

问题描述

我想在自己的现有类中编写一个嵌套类。但是我找不到方法，因为我不知道这是怎么称呼的。

I would like to write a nested class into an existing class of my own. But I can't find how because I have no idea how this is really called.

嵌套类是什么意思？使用 DataTable 类中的表 dt ，我可以编写 dt.Columns.add（ ）。 Columns 是主类的属性， add 是嵌套类的方法。

What do I mean by nested class? With a table dt from the DataTable class, I can write dt.Columns.add(). Columns would be property of the main class and add would be a method from a nested class.

有什么建议吗？

推荐答案

那不是嵌套类，它只是一个类。 Columns属性的类型为 DataColumnCollection ，它具有名为 Add 的公共方法。要以类似的方式构建自己的数据库，只需：

That is not a nested class, it's simply a class. The Columns property is of the type DataColumnCollection that has a public method called Add. To build your own in a similar fashion it would simply be:

Public Class MyFirstClass

    Public Sub New()

    End Sub

    Dim _second As New MySecondClass()
    Public Property Second() As MySecondClass
        Get
            Return _second
        End Get
        Set(ByVal Value As MySecondClass)
            _second = Value
        End Set
    End Property
End Class

Public Class MySecondClass
    Public Sub New()
    End Sub

    Public Sub MySecondClassMethod()
        'Do something
    End Sub
End Class

然后将在其他一些类或功能中调用它，例如：

This would then be called in some other class or functionality like:

Dim x as New MyFirstClass()
x.Second.MySecondClassMethod()

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