子/函数数组参数改变

问题描述

我有一个带有字符串数组作为参数的 Sub:

I have a Sub with an array of strings as parameter:

Private Sub des(ByVal array() As String)

    Dim i As Integer

    For i = 0 To UBound(array)
        array(i) = "hy"
    Next

End Sub

当我在主函数中调用该函数时，即使将数组传递给函数 ByVal，str 的值也会发生变化:

When I call the function inside my main function, the value of str changes even if the array is passed to the function ByVal:

Dim str() As String

str = {"11111", "22222", "33333", "44444", "5555", "66666"}

des(str)

我尝试在 Sub 中复制数组，但它仍然在主函数中发生变化.

I tried making a copy of the array in the Sub, but it still changes in the main function.

Private Sub des(ByVal array() As String)

    Dim i As Integer

    Dim array2() As String
    array2 = array

    For i = 0 To UBound(array)
        array(i) = "hy"
    Next

End Sub

我在一个网站上读到你不能通过数组 ByVal.这是真的?如果是这样，我应该如何进行?

I read on a site that you cannot pass arrays ByVal. Is this true? If so, how should I proceed?

推荐答案

不，这不是真的.

.NET 框架中的数组是引用类型.创建数组时，将创建一个System.Array 对象，并将其引用分配给引用变量.

An array in the .NET framework is a reference type. When you create an array, an object of System.Array will be created and its reference is assigned to the reference variable.

当你调用一个 des 方法时，会传递数组对象的引用.在des方法中，ByVal参数是一个System.Array类型的引用参数变量，它接收一个数组对象的引用副本.

When you call a des method, the reference of the array object will be passed. In des method, ByVal parameter is a reference parameter variable of type System.Array, and it receive a copy of reference of an array object.

MSDN 文章 - 按值和按引用传递参数(可视化基本)

MSDN article - Passing Arguments by Value and by Reference (Visual Basic)

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