评估（）在VBA [英] Evaluate() in VBA

问题描述

您好，欢迎来到评估（））神秘

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MSDN Office开发者参考（2013）文档说：

使用方括号（例如，[A1：C5]）与使用字符串参数的Evaluate方法调用
相同。

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所以，我运行了一个非常简单的代码来查看 Microsoft的Evaluate（）方法的文档。

毫不奇怪，我得到了一个奇怪的，虽然一致的结果。

注意： 执行每个立即窗口中的4个命令 CTRL + G 。查看每个电话的区别。请注意，内置的 错误 ，其中 显示每个MsgBox两次 。只要记住这一点，不要困惑...

将此代码粘贴到模块中

  Private Sub SleepESub（）
 Application.Wait Now + TimeValue（0:00:20）
 MsgBoxw8'd
 End Sub 
  

然后在立即窗口中执行这4个命令（每次1个）



？评估（SleepESub（））

？ [SleepESub（）]

？ [SleepESub]

？ SleepESub

第一个2立即执行代码;对我来说，他们已经评估了代码。第三个（根据文档）应该是 评估 ，但它的行为方式不同>在模块的主体中​​。立即窗口提供错误2023 但是，从模块的正文中执行相同的调用，就像您正在调用子程序一样。它等待 20秒 喜欢，如果它是一个普通的调用SleepESub（）这是4号呼叫。



任何人都可以解释我在这里缺少什么？行号3不适合评估通话？或者是否评估对子本身的调用（如果有意义）

更新：

我认为有些人误会了我在这里评估 - 不要担心这是一个高级话题，我不是书作家，你不介意读者。 （原谅我... ）


要想得到一个更好的主意，您可以比较直接窗口与模块的正文的结果。尝试以下代码：

 '在模块的正文中分别运行每个调用
' 
'来自立即窗口的以前的调用
 Sub ModuleBody（）
 Evaluate（SleepESub（））
'[SleepESub（）] 
'[ SleepESub] 
'SleepESub 
 End Sub 
  

解决方案

在我看来，执行代码的不同方式有什么不同之处在于它运行的线程 - UI线程或后台线程以及解析器。 评估执行函数的处理方式与显式定义的函数不同，从立即窗口调用的函数也会略有不同。

In：

  Sub ModuleBody（）
 Evaluate（SleepESub（））
 [SleepESub（）] 
 [SleepESub] 
 SleepESub 
 End Sub 
  

评估（SleepESub（））和 [SleepESub（）] 似乎在期待一个公式，

根据解析器如何处理该过程，每个命令可以在单个线程中依次执行，导致从 Application.Wait 或 Application.Wait 可能被认为仅在UI线程上有效，并且在后台线程上运行时跳过。

这可以由以下代码确认，由？[SleepESub（ ）] 或？在立即窗口中评估（SleepESub（））

 私有声明PtrSafe Sub sapiSleep Libkernel32别名睡眠（ByVal dwMilliseconds As Long）
 Private Sub SleepESub（）
'Application.Wait Now + TimeValue （0:00:05）
 sapiSleep 5000 
 MsgBoxw8'd
 End Sub 
  

当使用 sapiSleep 5000 API调用时，等待发生（两次！ - 所提到的错误），但是当使用 Application.Wait Now + TimeValue（0:00:05）时，不会发生延迟。

Hi and welcome to the Evaluate() mystery

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The MSDN Office Developer Reference (2013) Documentation says:

Using square brackets (for example, "[A1:C5]") is identical to calling the Evaluate method with a string argument.

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So, I have ran a very simple code to see how accurate the Microsoft's Documentation of the Evaluate() method is.
Not surprisingly, I am getting a strange albeit consistent result.
note: execute each of the 4 commands in the Immediate Window CTRL+G. See the difference in each of the calls. Notice the built-in bug which shows each MsgBox twice. Just keep that in mind and do not get confused...
Stick this code in a module

Private Sub SleepESub()
    Application.Wait Now + TimeValue("0:00:20")
    MsgBox "w8'd "
End Sub

then execute these 4 commands ( 1 at a time ) in the Immediate Window

? Evaluate ("SleepESub()")
? [SleepESub()]
? [SleepESub]
? SleepESub

The first 2 execute the code right away; means to me they have evaluated the code. The third one (according to the documentation) should be Evaluating but it doesn't act the same way as it does in a module's body. The Immediate Window is giving an Error 2023 however the same call from within a module's body executes it as if you were calling a sub.It waits the 20 seconds like if it was a normal Call SleepESub() which is the number 4 call.

Can anyone explain what I am missing here? Is the line number 3 not a proper Evaluation call? or does it evaluate the call to sub itself (if that makes sense)

Update:
I think some people are misunderstanding what I am evaluating here - don't worry it is an advanced topic and I am not a book writer and you are not mind readers. (forgive me...)
To get a better idea you can compare results from the immediate window vs. module's body. Try this code:

' Run each of the calls separately
' in a module's body and compare it with 
' the previous calls from the Immediate Window
    Sub ModuleBody()
        Evaluate ("SleepESub()")
        '[SleepESub()]
        '[SleepESub]
        'SleepESub
    End Sub

解决方案

It would appear to me that what differs in the different ways of executing the code would be the thread that it runs on - the UI thread or a background thread, and the parser. Evaluate executed functions would be handled differently to explicitly defined functions, and functions called from the Immediate window would be handled slightly differently also.

In:

Sub ModuleBody()
    Evaluate ("SleepESub()")
    [SleepESub()]
    [SleepESub]
    SleepESub
End Sub

Evaluate ("SleepESub()") and [SleepESub()] appear to be expecting a formula, and Private Sub SleepESub() is not being executed at all.

Depending on how the parser handles the procedure, each command may be executed in sequence in a single thread, resulting in the delay from the Application.Wait, or the Application.Wait may be considered to be valid only on the UI thread, and skipped when run on a background thread.

This can be confirmed by the following code, executed by ?[SleepESub()] or ?Evaluate("SleepESub()") in the Immediate window:

Private Declare PtrSafe Sub sapiSleep Lib "kernel32" Alias "Sleep" (ByVal dwMilliseconds As Long)
Private Sub SleepESub()
    'Application.Wait Now + TimeValue("0:00:05")
    sapiSleep 5000
    MsgBox "w8'd "
End Sub

When using the sapiSleep 5000 API call, the wait occurs (twice! - that bug that was mentioned), but when using Application.Wait Now + TimeValue("0:00:05"), no delay occurs.

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