我正在编写一个宏，其中有一个中央输入表-让我们将此表称为-“主输入表”，用户在其中输入相关变量。在“主要输入表”中有一些输入说 - “还有输入表吗？” - 当“是”时，将显示与输入相对应的工作表（它以前被隐藏） - 我们称之为“关联输入表”。现在，我想确保用户在运行宏之前更新“关联输入表”。有没有办法可以做到这一点 - 使用 VBA 提供的事件处理程序或使用任何其他方式？
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Worksheet_Change 事件过程可能是要走的路，除非您在工作表的其他地方发生了其他事情，从而进行了大量更改。
那时，您的问题可以改写为：“自从我上次检查以来，我的范围有变化吗？”
抓取范围的副本并将其存储在某处，并逐个单元格地检查缓存副本的当前范围是一种蛮力方法：如果你只做一次也没关系，但如果你正在做它反复存储哈希更有效 - 由某种校验和函数生成的短代码或数字。
校验和算法各不相同。Adler32 简单快速，但性能很差——你会得到“哈希冲突”或无法为不同的数据输入返回不同的哈希值——比较（比如）一对 6-10 个字母的单词。但是，当被要求检测对 24 个 8 字母单词的列或数千个日期和数字的表的更改时，它确实表现得非常好。
查找其他哈希 - 并保持最新状态：您的 PC 将拥有多个带有 MD5 和 sha1 等哈希的库，它们的性能应该比 VBA 中的手动哈希更好。
这是一些使用 Adler-32 校验和的演示代码。阅读代码注释，您需要了解其中的一些内容才能使其适应您的项目：
Public Function RangeHasChanged() As Boolean
' Demonstration function for use of the Checksum() function below.
' For more advanced users, I have a 'Watched Range' class on the website:
' http://excellerando.blogspot.com
' Author: Nigel Heffernan, May 2006 http://excellerando.blogspot.com
' Please note that this code is in the public domain. Mark it clearly, with
' the author's name, and segregate it from any proprietary code if you need
' to assert ownership & commercial confidentiality on that proprietary code
' Coding Notes:
' It is expected that this function will be saved in the host worksheet's
' module and renamed to indicate the range or table being monitored. It's a
' good idea to use a named range rather than a hardcoded address.
' You might also choose to edit the '1 To 255' to the width of your range.
' Initialising the static values so that the first check in your VBA session
' does not automatically register a 'change' is left as an exercise for the
' reader: but calling the function on opening the workbook works well enough
' This is intended for use in VBA, not for use on the worksheet. Use the
' setting 'Option Private Module' to hide this from the function wizard.
Dim rngData As Excel.Range
Dim arrData As Variant
Dim lngChecksum As Long
Static lngExisting As Long
' Note that we capture the entire range in an Array, then work on the array:
' this is a single 'hit' to the sheet (the slow operation in any interaction
' with worksheet data) with all subsequent processing in VBA.
' BS 10/11/2021: Modified to look at the current selection if the hard-coded worksheet does not exist.
If Evaluate("ISREF('DataEntryMain'!A1)") Then
Set rngData = ThisWorkbook.Names("DataEntryMain").RefersToRange
Else
Set rngData = Intersect(Selection, Selection.parent.UsedRange) ' Reduce the range so it is never bigger than the UsedRange.
End If
arrData = rngData.Value2
RangeHasChanged = False
lngChecksum = CheckSum(arrData)
If rngData.count > 1 Then
' The passed range is more than one cell. Release the dynamic-array storage space.
Erase arrData
End If
' lngExisting is zero when the file opens, and whenever the
' VBA project is reinitialised, clearing all the variables.
' Neither of these events should be reported as a 'change'.
If lngExisting <> lngChecksum And lngExisting <> 0 Then
RangeHasChanged = True
End If
lngExisting = lngChecksum
Debug.Print RangeHasChanged, "The Adler-32 for " & rngData.Address & " is " & lngChecksum, Hex(lngChecksum)
End Function
' I could've sworn I posted this here, years ago, but here's an implementation of Adler-32 in
' 32-bit VBA.
'
' There 's a horrible hack in it: Adler-32 returns a 32-bit integer, and the VBA Long is a signed
' integer with a range ± (2^31) -1, so I've implemented a 'wrap around' of the overflow at +2^31,
' restarting at -2^31 +1. And done something I really, really shouldn't have done with a
' floating-point variable. Eventually everyone, everywhere, will have 64-bit Office and this'll
' be kind of quaint and unnecessary... Right?
'
' Of course, the real question is: why bother?
'
' It boils down to the common question of checking for changes: if you don't want to use the 'on
' change' event, or you're dealing with data directly in VBA before it hits the sheet, large data
' sets need something better than an item-by-item brute force approach. At least, if you're doing
' it more than once: the cost of rolling each item into your hash is always more than the cost of
' the one-by-one comparison...
'
' ...And that's still true if you're importing a fast hashing algorithm from MySQL or one of the
' web API libraries (try MDA5, if you can get at an exposed function), unless you can find
' something that reads VBA variant arrays directly and relieve your VBA thread of the task of
' enumerating the list values into the imported function.
'
' Meanwhile, here's a hash algorithm that's within reach of VBA: Adler32. The details are in
' Wikipedia’s article on Adler32: http://en.wikipedia.org/wiki/Adler-32 and an hour's testing
' will teach you some lessons about hashing:
'
' 'Hash collisions' (differing data sets returning the same hash code) are more common than you
' expected, especially with data containing repeated patterns (like dates);>
' Choice of hashing algorithm is important;
' ...And that choice is more of an art than a science;
' Admitting that you really shouldn't have bothered and resorting to brute force is often the
' better part of valour.
'
' Adler-32 is actually more useful as a tool to teach those lessons, than as a workaday checksum.
' It's great for detecting changes in lists of more than 100 distinct items; it's tolerable, on a
' list of 24 randomly-generated 8-letter words (hash collisions at 1 in 1800 attempts) and it
' starts giving you single-digit percentage occurrences of the hash collision error in a list of
' 50 not-so-distinct option maturities, where the differences are mostly in the last 10 chars and
' those ten chars are recurring 3-month maturity dates.
'
' By the time you're comparing pairs of 6-letter strings, more than 10% of your changes will be
' missed by the checksum in a non-random data set. And then you realise that might as well be
' using string comparison for that kind of trivial computation anyway.
'
' So the answer is always: test it.
'
' Meanwhile, here 's the algorithm, horrible hacks and all:
Public Function CheckSum(ByRef ColArray As Variant) As Long
Application.Volatile False
' Returns an Adler32 checksum of all the numeric and text values in a column
' Capture data from cells as myRange.Value2 and use a 32-bit checksum to see
' if any value in the range subsequently changes. You can run this on multi-
' column ranges, but it's MUCH faster to run this separately for each column
'
' Note that the VBA Long Integer data type is not a 32-bit integer, it's a
' signed integer with a range of ± (2^31) -1. So our return value is signed
' and return values exceeding +2^31 -1 'wraparound' and restart at -2^31 +1.
' Coding Notes:
' This is intended for use in VBA, and not for use on the worksheet. Use the
' setting 'Option Private Module' to hide CheckSum from the function wizard
' Author: Nigel Heffernan, May 2006 http://excellerando.blogspot.com
' Acknowledgements and thanks to Paul Crowley, who recommended Adler-32
' Please note that this code is in the public domain. Mark it clearly, with
' the author's name, and segregate it from any proprietary code if you need
' to assert ownership & commercial confidentiality on your proprietary code
Const LONG_LIMIT As Long = (2 ^ 31) - 1
Const MOD_ADLER As Long = 65521
Dim a As Long
Dim b As Long
Dim i As Long
Dim j As Long
Dim k As Long
Dim arrByte() As Byte
Dim dblOverflow As Double
If TypeName(ColArray) = "Range" Then
ColArray = ColArray.Value2
End If
If IsEmpty(ColArray) Then
CheckSum = 0
Exit Function
End If
If (VarType(ColArray) And vbArray) = 0 Then
' single-cell range, or a scalar data type
ReDim arrData(0 To 0, 0 To 0)
arrData(0, 0) = CStr(ColArray)
Else
arrData = ColArray
End If
a = 1
b = 0
For j = LBound(arrData, 2) To UBound(arrData, 2)
For i = LBound(arrData, 1) To UBound(arrData, 1)
' VBA Strings are byte arrays: arrByte(n) is faster than Mid$(s, n)
arrByte = CStr(arrData(i, j)) ' Is this type conversion efficient?
For k = LBound(arrByte) To UBound(arrByte)
a = (a + arrByte(k)) Mod MOD_ADLER
b = (b + a) Mod MOD_ADLER
Next k
' Terminating each item with a 'vTab' char constructs a better hash
' than vbNullString which, being equal to zero, adds no information
' to the hash and therefore permits the clash ABCD+EFGH = ABC+DEFGH
' However, we wish to avoid inefficient string concatenation, so we
' roll the terminating character's bytecode directly into the hash:
a = (a + 11) Mod MOD_ADLER ' vbVerticalTab = Chr(11)
b = (b + a) Mod MOD_ADLER
Next i
' Roll the column into the hash with a terminating horizontal tab char:
a = (a + 9) Mod MOD_ADLER ' Horizontal Tab = Chr(9)
b = (b + a) Mod MOD_ADLER
Next j
' Using a float in an integer calculation? We can get away with it, because
' the float error for a VBA double is < ±0.5 with numbers smaller than 2^32
dblOverflow = (1# * b * MOD_ADLER) + a
If dblOverflow > LONG_LIMIT Then ' wraparound 2^31 to 1-(2^31)
Do Until dblOverflow < LONG_LIMIT
dblOverflow = dblOverflow - LONG_LIMIT
Loop
CheckSum = 1 + dblOverflow - LONG_LIMIT
Else
CheckSum = b * MOD_ADLER + a
End If
End Function
于 2012-05-15T11:08:11.860 回答
1
有一个 Worksheet_change 事件可能会做你想做的事：
Private Sub Worksheet_Change(ByVal Target As Range)
End Sub
将其放在“主要信息表”的代码中，每次更改工作表时都会运行。
但是，如果您不希望每次更新工作表时都运行电子表格，而只想检查它是否已更新......您可以做的是创建一个这样的全局变量（必须放置声明在标准模块中：
Global MainSheetHasChanged as Boolean
然后，您只需将这行代码放在 worksheet_changed 宏中：
Private Sub Worksheet_Change(ByVal Target As Range)
MainSheetHasChanged = True
End Sub
只需确保在运行其他宏后始终将变量设置回 false。这是你要找的吗？
于 2012-05-14T12:36:25.053 回答