如何使用 VBA 在特定工作表的列中获取最小（最小值）和最大（最大值）值

Question

我的代码有问题，它无法在 A 列中显示最小值和最大值。我不知道缺少或错误的代码在哪里...

我的程序打开 txt 文件并将数据输入到 Excel 表中。例如A列的数据是：

0.23
0.19
0.19
0.13
0.15
0.18
0.19
0.25
0.25
0.22
0.13

然后我在 VBA 中输入我的代码：

Private Sub CommandButton1_Click()

Dim vMin, vMax
Dim mg As Range
Dim NOR, lastrow, currentrow As Long

filetoopen = Application.GetOpenFilename("Text File (*.txt),*.txt", , "Select", , False)

If VarType(filetoopen) = vbBoolean Then
    Exit Sub
End If

Workbooks.OpenText filetoopen, Origin _
    :=437, StartRow:=1, DataType:=xlDelimited, TextQualifier:=xlDoubleQuote _
    , ConsecutiveDelimiter:=False, Tab:=True, Semicolon:=False, Comma:= _
    False, Space:=False, other:=False, FieldInfo:=Array(Array(1, 1), Array(2, 1) _
    , Array(3, 1), Array(4, 1), Array(5, 1), Array(6, 1), Array(7, 1), Array(8, 1), Array(9, 1), _
    Array(10, 1), Array(11, 1), Array(12, 1), Array(13, 1), Array(14, 1), Array(15, 1)), _
    TrailingMinusNumbers:=True

'get number of rows (row with value inside)-------------
With ActiveSheet
   NOR = .Cells(Rows.Count, "A").End(xlUp).Row
End With

'GET SMALLEST & LARGEST VALUE FROM COLUMN A==========
With ActiveSheet
    lastrow = NOR

    For currentrow = 2 To lastrow
        Set mg = ThisWorkbook.Sheets(1).Rows(currentrow)

        'if row no data then no read------------------------
        If WorksheetFunction.CountA(mg) = 0 Then

        Else
            vMin = Application.WorksheetFunction.Min(Columns("A"))
            vMax = Application.WorksheetFunction.Max(Columns("A"))
        End If
    Next currentrow

End With

MsgBox "Minimum =  " & vMin & ", " & "Maximum =  " & vMax, vbInformation
MsgBox "last row A is = " & NOR

End Sub

如果我运行此代码，MessageBox 无法在 A 列中显示最小（最小）值和最大（最大）值。

希望你能帮我解决问题。

aaf

Answer 1

我已经尝试过你的代码......并且有两个想法：

1. 将函数应用于 `Columns("A")´ 意味着所有列 无需使用 for 进行迭代。

2. 在我的情况下，可能不是您的导入数字使用点小数分隔符，而我的系统使用逗号作为小数分隔符，因此导入 数字作为文本导入，“Max”和“Min”都不起作用 直到将点改为逗号。

所以工作代码可能是：

Private Sub CommandButton1_Click()

Dim vMin, vMax

Dim mg As Range

Dim NOR, lastrow, currentrow As Long

filetoopen = Application.GetOpenFilename("Text File (*.txt),*.txt", , "Select", , False)

        If VarType(filetoopen) = vbBoolean Then
        Exit Sub
        End If
        Workbooks.OpenText filetoopen, Origin _
        :=437, StartRow:=1, DataType:=xlDelimited, TextQualifier:=xlDoubleQuote _
        , ConsecutiveDelimiter:=False, Tab:=True, Semicolon:=False, Comma:= _
        False, Space:=False, Other:=False, FieldInfo:=Array(Array(1, 1), Array(2, 1) _
        , Array(3, 1), Array(4, 1), Array(5, 1), Array(6, 1), Array(7, 1), Array(8, 1), Array(9, 1), _
        Array(10, 1), Array(11, 1), Array(12, 1), Array(13, 1), Array(14, 1), Array(15, 1)), _
        TrailingMinusNumbers:=True

'get number of rows (row with value inside)-------------

   With ActiveSheet

   NOR = .Cells(Rows.Count, "A").End(xlUp).Row

   End With

'GET SMALLEST & LARGEST VALUE FROM COLUMN A==========

With ActiveSheet

  lastrow = NOR

    'For currentrow = 2 To lastrow

    'Set mg = ThisWorkbook.Sheets(1).Rows(currentrow)

    'if row no data then no read------------------------

    'If WorksheetFunction.CountA(mg) = 0 Then

    'Else

        vMin = Application.WorksheetFunction.Min(Columns("A"))

        vMax = Application.WorksheetFunction.Max(Columns("A"))

     'End If

    'Next currentrow

End With

MsgBox "Minimum =  " & vMin & ", " & "Maximum =  " & vMax, vbInformation

MsgBox "last row A is = " & NOR

End Sub

结果：

希望对你有帮助！

Answer 2

这是一种替代方法，它将使用 ADO 直接读取文件，而不必将其导入 Excel，这样应该会更快。该选项是更少的代码，并且应该运行非常快，即使对于大型数据集也是如此。

代码：

Public Sub ShowMinAndMax()
    Dim objConnection As Object: Set objConnection = CreateObject("ADODB.Connection")
    Dim objRecordset  As Object: Set objRecordset = CreateObject("ADODB.Recordset")
    Dim FolderPath    As String: FolderPath = "C:\SomeFolderHere\" ' The folderpath to the file you want to read

    objConnection.Open "Provider=Microsoft.Ace.OLEDB.12.0;" & _
                       "Data Source=" & FolderPath & ";" & _
                       "Extended Properties=""text;HDR=No;FMT=TabDelimited"""

    'Get the minimum and maximum value, you also need to
    'change the fileName, currently my File is Named Example.Txt. 
    'You need to update that in the SQL statement
    objRecordset.Open "SELECT Min(F1) as MinVal, Max(F1) as MaxVal FROM Example.txt", objConnection, 3

    MsgBox ("The minimum value is: " & objRecordset.Fields("MinVal") & vbCrLf & _
            "The maximum value is: " & objRecordset.Fields("MaxVal"))

    'Clean Up
    If objRecordset.State = 1 Then objRecordset.Close
    objConnection.Close
    Set objConnection = Nothing
    Set objRecordset = Nothing
End Sub