在VB.Net参考 [英] References in VB.Net

问题描述

有点不清楚我是引用（指针？），以班级在VB.Net。我要问的问题可以通过测试的一点点来回答，但我想知道如果任何人都可以发布一个体面的解释（或链接，太）。

Somewhat unclear to me are references (pointers?) to classes in VB.Net. The question I am about to ask can be answered by a little bit of testing, but I was wondering if anybody could post a decent explanation (or links, too).

如果你创建一个类：

Public Class ReferenceClass

    Private myBooleanValue As Boolean = False
    Public Property BooleanValue As Boolean
        Get
            Return myBooleanValue
        End Get
        Set(value As Boolean)
            myBooleanValue = value
        End Set
    End Property

End Class

和随后实际使用这个类作为一个属性类：

And then a class which actually uses this class as a property:

Public Class UsingClass

     Private myReference As ReferenceClass
     Public Property Reference As ReferenceClass
        Get
             return myReference
         End Get
         Set(value As ReferenceClass)
             myReference = value
         End Set
     End Property

     Public Sub New(ByVal Reference As ReferenceClass)
         myReference = Reference
     End Sub

End Class

，然后用它是这样的：

And then use it like this:

Public Class RuntimeOrSomething

     Public Shared myReference As ReferenceClass
     Public Shared ReadOnly Property Reference As ReferenceClass
         Get
             If myReference Is Nothing Then myReference = new ReferenceClass()
             return myReference
         End Get
     End Property

     Public Shared Function BooleanCheck() As Boolean
         Reference.BooleanValue = True
         Dim tempClass As New UsingClass(Reference)
         tempClass.Reference.BooleanValue = False

         Return (tempClass.Reference.BooleanValue = Reference.BooleanValue)
     End Sub

     Public Shared Sub DoNothing()
          Reference.BooleanValue = True
          Dim someBoolean As Boolean = BooleanCheck

          'now Reference.Booleanvalue is "False"
     End Sub

End Class

现在的功能 BooleanCheck 总是返回真，即使引用传递给新类 UsingClass 按价值，而不是参考。因此，类的副本不言，但 myReference 在 UsingClass 的局部变量仍然引用/指向性参考在 RuntimeOrSomething 。

Now the function BooleanCheck will always return true, even though the reference is passed to the new class UsingClass "by value", not by reference. So a copy of the class is not made, but the local variable myReference in UsingClass still references/points to the property Reference in RuntimeOrSomething.

这又如何解释优雅？任何反馈和关于这个话题的意见是值得欢迎的。

How can this be explained elegantly? Any feedback and comments about this topic are welcome.

推荐答案

一个参考点到对象的一个​​实例，它不是一个对象的一个​​实例。制作的方向副本的对象不创建另一个对象，它创建另一个引用也指向同一个对象。

A reference points to an instance of an object, it is not an instance of an object. Making a copy of the directions to the object does not create another object, it creates another reference that also points to the same object.

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