[英]Evaluate() in VBA
Hi and welcome to the Evaluate() mystery 嗨,欢迎来到Evaluate()之谜
Using square brackets (for example, "[A1:C5]") is identical to calling the Evaluate method with a string argument.
使用方括号(例如,“ [A1:C5]”)与使用字符串参数调用Evaluate方法相同。
So, I have ran a very simple code to see how accurate the Microsoft's Documentation of the Evaluate() method is. 因此,我运行了一个非常简单的代码,以查看Microsoft的Evaluate()方法的文档的准确性。
Not surprisingly, I am getting a strange albeit consistent result. 毫不奇怪,尽管得到了一致的结果,但我得到了一个奇怪的结果。
note: execute each of the 4 commands in the Immediate Window
CTRL + G . 注意: 在
Immediate Window
CTRL + G中执行这4条命令。 See the difference in each of the calls . 查看每个调用的区别 。 Notice the built-in bug which shows each MsgBox twice .
注意内置错误 ,该错误将每个MsgBox两次显示 。 Just keep that in mind and do not get confused...
请记住这一点,不要感到困惑...
Stick this code in a module 将此代码粘贴到模块中
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 然后在立即窗口中执行这4条命令(一次1条)
? Evaluate ("SleepESub()")
? [SleepESub()]
? [SleepESub]
? SleepESub
The first 2 execute the code right away; 前两个立即执行代码。 means to me they have evaluated the code.
对我来说意味着他们已经评估了代码。 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 . 第三篇文章(根据文档)应该是
Evaluating
但其作用方式与模块主体中的方式不同 。 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. 即时窗口显示
Error 2023
但是从模块主体内部执行的相同调用就像执行子调用一样执行,它等待20 seconds
就像它是普通的Call SleepESub()
即4号调用)一样。
Can anyone explain what I am missing here? 谁能解释我在这里缺少什么? Is the line number 3 not a proper
Evaluation
call? 3号线不是正确的
Evaluation
电话吗? or does it evaluate the call to sub itself (if that makes sense) 还是评估对sub本身的调用(如果有意义)
Update: 更新:
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. 我认为有些人误会了我在这里评估的内容-不用担心这是一个高级话题,我不是读书作家,而且您不是介意读者。 ( forgive me... )
( 原谅我... )
To get a better idea you can compare results from the immediate window vs. module's body. 为了获得更好的主意,您可以比较即时窗口与模块主体的结果。 Try this code:
试试这个代码:
' 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
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. 在我看来,执行代码的不同方式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。
Evaluate
executed functions would be handled differently to explicitly defined functions, and functions called from the Immediate window would be handled slightly differently also. Evaluate
执行的函数将与显式定义的函数进行不同的处理,并且从“即时”窗口调用的函数的处理也将稍有不同。
In: 在:
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. Evaluate ("SleepESub()")
和[SleepESub()]
似乎期望公式,并且完全不执行Private Sub SleepESub()
。
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. 根据解析器处理该过程的方式,每个命令可能会在单个线程中按顺序执行,从而导致
Application.Wait
或Application.Wait
的延迟仅在UI线程上才有效,因此被跳过在后台线程上运行时。
This can be confirmed by the following code, executed by ?[SleepESub()]
or ?Evaluate("SleepESub()")
in the Immediate window: 这可以通过以下代码来确认,该代码由
?Evaluate("SleepESub()")
立即”窗口中的?[SleepESub()]
或?Evaluate("SleepESub()")
执行:
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. 使用
sapiSleep 5000
API调用时,会发生等待(两次!-提到的那个错误),但是使用Application.Wait Now + TimeValue("0:00:05")
,不会发生延迟。
I think that it is wrong to state that the 3rd call is not evaluating : it does indeed evaluate the provided object, and return its value (as documented). 我认为声明第三个调用没有评估是错误的:它确实评估了提供的对象并返回其值(如文档所示)。
I have slightly modified the Sub to illustrate: 我稍微修改了Sub来说明:
Private Function SleepESub()
Debug.Print Application.Wait(Now + TimeValue("0:00:02"))
MsgBox "w8'd "
SleepESub = 42
End Function
Each of the 4 evaluation calls will indeed return 42 as expected. 4个评估调用中的每一个确实将按预期返回42。
What is different is: 不同的是:
Application.Wait
succeeds, in the other it fails - notice the debug output which returns either true or false) Application.Wait
的调用成功,而在另一种情况下,则失败-请注意调试输出,返回true或false) I have no explanation for either of these differences, though. 不过,我没有任何解释。
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