如何在 VBA 过程中使用可选的数组参数? [英] How can I use an optional array argument in a VBA procedure?

问题描述

我在 MS Access 的 VBA 脚本中有一个私有过程:

I've got a private procedure in a VBA script for MS Access:

Private Sub drawLineDiagram(chartSpace As Variant, title As String, caption As String, x_val() As Variant, y_val() As Variant, Optional y_val2() As Variant = ????)

如您所见，我想为一组值设置一个可选的最后一个参数.

As you see, I want to have an optional last parameter for an array of values.

我必须分配什么样的默认参数?如果我用一个可选的整数值来做它并分配它，例如0 没事.

What kind of default parameter must I assign? If I do it with an optional integer value and assign it e.g. 0 it's all fine.

如果我使用如上所示的数组执行此操作并分配一个数组，则该行标记为红色 => 作为错误(并且不会编译).

If I do it with an array as shown above and assign an array, the line is marked red => as an error (and it won't compile).

推荐答案

如果您在 VBA 中需要一个可选数组，请将其声明为 Variant 而不使用数组说明符，但无论如何都可以将其作为数组访问.通过这种方式，您将获得一个 Variant(单个变量)，其中包含一个 Variant 数组，而不仅仅是 Variant 数组.不需要默认值:

If you need an optional array in VBA, declare it as Variant without array specificator, but access it as an array anyway. This way you get a Variant (single variable) that holds an array of Variants, as opposed to just array of Variants. No default value is required:

Private Sub drawLineDiagram(chartSpace As Variant, title As String, caption As String, x_val As Variant, y_val As Variant, Optional y_val2 As Variant)

为了一致性，另外两个参数也声明为普通的Variants.

For consistency, also declare as plain Variants the other two parameters.

如果您讨厌 IDE，请不要使用它.使用记事本.然后粘贴写好的代码.

If you hate the IDE, do not use it. Use notepad. Then paste written code.

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