8 Range 对象

8.1 引用Range

引用Range的主要方法：

Application.ActiveCell

Application.Range

Application.Selection

Worksheet.Cells

Worksheet.Columns

Worksheet.Range

Worksheet.Rows

Worksheet.UsedRange

CurrentRegion, NamedRange

代码清单8.1：使用Application对象引用Range

Sub ReferringToRangesI()
    Dim rg As Range 

    'ActiveCell is a range representing the
    'active cell. there can be one and
    'only one active cell.
    Debug.Print Application.ActiveCell.Address 

    'selection refers to a range representing
    'all of the selected cells. there can be
    'one or more cells in the range.
    Debug.Print Application.Selection.Address 

    'application.Range works on the active
    'worksheet
    ThisWorkbook.Worksheets().Activate
    Set rg = Application.Range("D5")
    Debug.Print "worksheets 1 is active"
    Debug.Print rg.Address
    Debug.Print rg.Parent.Name 

    ThisWorkbook.Worksheets().Activate
    Set rg = Application.Range("D5")
    Debug.Print "worksheets 2 is active"
    Debug.Print rg.Address
    Debug.Print rg.Parent.Name

    Set rg = Nothing
End Sub

Range中地址的表示法：

Application.Range("D5")
Application.Range("A1:C5")
Application.Range("A:A")
Application.Range("3:3")
Application.Range("A1:D5","D6:F10") 

8.1.1 WorkSheet对象的Cells属性和Range属性

代码清单8.2：使用Cells属性指定单个的单元格

Sub UsingCells()
    Dim rg As Range
    Dim nRow As Integer
    Dim nColumn As Integer
    Dim ws As Worksheet 

    Set ws = ThisWorkbook.Sheets() 

    For nRow =  To
        For nColumn =  To
            Set rg = ws.Cells(nRow, nColumn)
            rg.Value = rg.Address
        Next
    Next 

    Set rg = Nothing
    Set ws = Nothing
End Sub

代码清单8.3：使用Range属性指向单元格组

Sub UsingRange()
    Dim ws As Worksheet
    Dim rg As Range 

    Set ws = ThisWorkbook.Worksheets()
    'specifying a range using Cells
    'this range is equivalent to A1:J10
    Set rg = ws.Range(ws.Cells(, ), ws.Cells(, ))
    'sets the value of each cell in the range to 1
    rg.Value =  

    Set rg = ws.Range("D4", "E5")
    rg.Font.Bold = True
    ws.Range("A1:B2").HorizontalAlignment = xlLeft 

    Set rg = Nothing
    Set ws = Nothing
End Sub

考虑清单8.3中的语句：

Set rg = ws.Range(ws.Cells(, ), ws.Cells(, ))

此语句依靠四个整数确定Range引用的范围，这4个整数是两个对角单元格所在的行和列位置。所以特别适合动态确定范围。

8.1.2 指向命名范围可能是棘手的

有两种范围的名称，工作薄范围和工作表范围。工作薄名称范围必须是唯一的，而工作表范围只需要在它们创建的工作表中是唯一的。

代码清单8.4：使用Names对象列出所有的命名范围

'Test the ListWorkbookNmaes procedure
'outputs to cell A2 on the 2nd worksheet in the workbook
Sub TestListNames()
    ListWorkbookNames ThisWorkbook, ThisWorkbook.Worksheets().Range("A2")
End Sub 

Sub ListWorkbookNames(wb As Workbook, rgListStart As Range)
    Dim nm As Name
    For Each nm In wb.Names
        'print out the name of the range
        rgListStart.Value = nm.Name 

        'print out what the range refers to
        'the ' is required so that excel doesn't consider it as a formula
        rgListStart.Offset(, ).Value = "'" & nm.RefersTo
        rgListStart.Offset(, ).Value = "'" & nm.Value
        rgListStart.Offset(, ).Value = nm.RefersToRange 

        'set rgListStart to refer to the cell the next row down.
        Set rgListStart = rgListStart.Offset(, )
    Next
End Sub 

如果在工作表Sheet2中有一个名为Testing的名称，则可以使用下面的语句引用这个范围：

ThisWorkbook.Worksheets("Sheet2").Range("Testing")

但是，我们不能从Sheet1中引用这个单元格：

'这是非法的
ThisWorkbook.Worksheets("Sheet1").Range("Testing")
'这不是非法的
ThisWorkbook.Worksheets("Sheet2").Range("Testing")

8.1.2.1 安全第一：在使用命名范围之前确认他们有效

代码清单8.5：使用过程RangeNameExists确认名称有效

'checks for the existence of a named range on a worksheet
Function RangeNameExists(ws As Worksheet, sName As String) As Boolean
    Dim s As String
    On Error GoTo ErrHandler 

    s = ws.Range(sName).Address
    RangeNameExists = True
    Exit Function
ErrHandler:
    RangeNameExists = False
End Function 

Sub ValidateNamedRangeExample()
    If RangeNameExists(ThisWorkbook.Worksheets(), "Test") Then
        MsgBox "The name exists, it refers to: " & ThisWorkbook.Names("Test").RefersTo, vbOKOnly
    Else
        MsgBox "the name does not exist", vbOKOnly
    End If
    If RangeNameExists(ThisWorkbook.Worksheets(), "djfs") Then
        MsgBox "The name exists, it refers to: " & ThisWorkbook.Worksheets().Names("djfs").RefersTo, vbOKOnly
    Else
        MsgBox "the name does not exist", vbOKOnly
    End If
End Sub 

8.2 找到我们的方法

8.2.1 Offset用于相对导航

可以使用Offset处理一个结构化的列表。设置列表的第一行和第一列的引用，然后循环遍历列表，继续引用下一行，当到达一个空行时终止循环。代码8.6使用这个技术对列表进行过滤。

代码清单8.6：使用Offset属性的列表处理方法

Sub ListExample()
    FilterYear
End Sub 

Sub Reset()
    With ThisWorkbook.Worksheets("List Example")
        .Rows.Hidden = False
        .Rows.Font.Bold = False
        .Rows().Font.Bold = True
    End With
End Sub 

Sub FilterYear(nYear As Integer)
    Dim rg As Range
    Dim nMileageOffset As Integer 

    '1st row is column header so start with 2nd row
    Set rg = ThisWorkbook.Worksheets("List Example").Range("A2")
    nMileageOffset =  

    'go until we bump into first empty cell
    Do Until IsEmpty(rg)
        If rg.Value < nYear Then
            rg.EntireRow.Hidden = True
        Else
            'check milage
            If rg.Offset(, nMileageOffset).Value <  Then
                rg.Offset(, nMileageOffset).Font.Bold = True
            Else
                rg.Offset(, nMileageOffset).Font.Bold = False
            End If
            rg.EntireRow.Hidden = False
        End If
        'move down to the next row
        Set rg = rg.Offset(, )
    Loop 

    Set rg = Nothing
End Sub

8.2.2 最后的但不是最不重要的—找到End

Ctrl+箭头操作是将活动单元格向箭头方向移动到下一个末端，这里的末端指的是连续非空区域开始或最后的单元格，算法：

如果当前单元格为空，跳到下一个非空单元格。如果不能发现非空单元格，则跳到工作表边界最近的单元格。

如果当前单元格非空，则查看下一个单元格是否为空。如果为空，则选择下一个非空单元格，如果不能发现非空单元格，则跳到工作表边界最近的单元格。如果非空，则选择连续非空单元格的最后一个单元格。

End属性返回指定单元格在指定方向上的下一个末端。

代码清单8.7：使用End属性在一个工作表中导航

Sub ExperimentWithEnd()
    Dim ws As Worksheet
    Dim rg As Range 

    Set ws = ThisWorkbook.Worksheets()
    Set rg = ws.Cells(, ) 

    ws.Cells(, ).Value = "rg.address = " & rg.Address
    ws.Cells(, ).Value = "rg.End(xlDown).Address = " & rg.End(xlDown).Address
    ws.Cells(, ).Value = "rg.End(xlDown).End(xlDown).Address = " & rg.End(xlDown).End(xlDown).Address
    ws.Cells(, ).Value = "rg.End(xlToRight).Address = " & rg.End(xlToRight).Address 

    Set rg = Nothing
    Set ws = Nothing
End Sub 

因为End属性返回一个Range对象，所以可以在同一个语句中多次使用它。

代码8.8首先找到工作表边界的最后单元格，然后向工作表开始方向应用End属性。

代码清单8.8：查找列或者行中最后使用的单元格

'returns a range object that represents the last
'non-empty cell in the same column
Function GetLastCellInColumn(rg As Range) As Range
    Dim lMaxRows As Long 

    lMaxRows = ThisWorkbook.Worksheets().Rows.Count 

    'make sure the last cell in the column is empty
    If IsEmpty(rg.Parent.Cells(lMaxRows, rg.Column)) Then
        Set GetLastCellInColumn = rg.Parent.Cells(lMaxRows, rg.Column).End(xlUp)
    Else
        Set GetLastCellInColumn = rg.Parent.Cells(lMaxRows, rg.Column)
    End If
End Function 

'returns a range object that represents the last
'non-empty cell in the same row
Function GetLastCellInRow(rg As Range) As Range
    Dim lMaxColumns As Long 

    lMaxColumns = ThisWorkbook.Worksheets().Columns.Count 

    'make sure the last cell in the row is empty
    If IsEmpty(rg.Parent.Cells(rg.Row, lMaxColumns)) Then
        Set GetLastCellInRow = rg.Parent.Cells(rg.Row, lMaxColumns).End(xlToLeft)
    Else
        Set GetLastCellInRow = rg.Parent.Cells(rg.Row, lMaxColumns)
    End If
End Function

函数中的lMaxRows和lMaxColumns分别是工作表的最大行数和最大列数，这两个值对于每个工作表都是相同的，在Excel 2013中测试分别是1048576和16384。

然后，测试这个单元格是否为空，如果为空，向开始方向应用一次End属性找到最后单元格。否则非空，这个单元格就是最后的单元格。

代码8.9与代码8.8基本一样，不同的是代码8.8返回单元格本身，而代码8.9返回的是Long类型的单元格的位置。

代码清单8.9：使用工作表可调用函数，返回列或者行中最后使用的单元格

'returns a number that represents the last
'nonempty cell in the same column
'callable from a worksheet
Function GetLastUsedRow(rg As Range) As Long
    Dim lMaxRows As Long 

    lMaxRows = ThisWorkbook.Worksheets().Rows.Count
    'make sure the last cell in the column is empty
    If IsEmpty(rg.Parent.Cells(lMaxRows, rg.Column)) Then
        GetLastUsedRow = rg.Parent.Cells(lMaxRows, rg.Column).End(xlUp).Row
    Else
        GetLastUsedRow = rg.Parent.Cells(lMaxRows, rg.Column).Row
    End If 

End Function 

'returns a number that represents the last
'nonempty cell in the same row
'callable from a worksheet
Function GetLastUsedColumn(rg As Range) As Long
    Dim lMaxColumns As Long 

    lMaxColumns = ThisWorkbook.Worksheets().Columns.Count
    If IsEmpty(rg.Parent.Cells(rg.Row, lMaxColumns)) Then
        GetLastUsedColumn = rg.Parent.Cells(rg.Row, lMaxColumns).End(xlToLeft).Column
    Else
        GetLastUsedColumn = rg.Parent.Cells(rg.Row, lMaxColumns).Column
    End If
End Function

8.3 轻松输入；轻松输出

8.3.1 输出策略

代码清单8.10是一个僵化程序的反面教材。

代码清单8.10：提防包含了许多说明性文字范围的过程

'this is procedures are generally error prone
'and unnecessarily difficult to maintain/modify
Sub RigidFormattingProcedure()
    'Activate Test Report worksheet
    ThisWorkbook.Worksheets("Test Report").Activate
    'make text in first column bold
    ActiveSheet.Range("A:A").Font.Bold = True
    'widen first column to display text
    ActiveSheet.Range("A:A").EntireColumn.AutoFit
    'format date on report
    ActiveSheet.Range("A2").NumberFormat = "mmm-yy"
    'Make column headings bold
    ActiveSheet.Range("6:6").Font.Bold = True 

    'add & format totals
    ActiveSheet.Range("N7:N15").Formula = "=sum(rc[-12]:rc[-1])"
    ActiveSheet.Range("N7:N15").Font.Bold = True 

    ActiveSheet.Range("B16:N16").Formula = "=sum(r[-9]c:r[-1]c)"
    ActiveSheet.Range("B16:N16").Font.Bold = True 

    'format data range
    ActiveSheet.Range("B7:N16").NumberFormat = "#,##0"
End Sub 

使用命名范围的好处是，如果插入或删除行或列，命名范围受到更少的影响。因为命名范围会自动调整它的RefersTo。

一个结构化的计算框架是，找到一个单元格作为相对定位的基准，并命名它。然后，使用Offset来相对基准位置操作其他单元格。这样，只要保证这个框架单元格相对位置不变，就可以灵活的移动它，并且不需要修改VBA代码。

代码8.11假定已在工作薄"Test Report"中定义如下的名称：
REPORT_TITLE
REPORT_DATE
COLUMN_HEADING
ROW_HEADING
DATA
COLUMN_TOTAL
ROW_TOTAL

代码清单8.11：一个更加灵活的处理结构化范围的过程

Sub RigidProcedureDeRigidized()
    Dim ws As Worksheet
    If Not WorksheetExists(ThisWorkbook, "Test Report") Then
        MsgBox "Can't find required worksheet 'Test Report'", vbOKOnly
        Exit Sub
    End If
    Set ws = ThisWorkbook.Worksheets("Test Report") 

    If RangeNameExists(ws, "REPORT_TITLE") Then
        ws.Range("REPORT_TITLE").Font.Bold = True
    End If 

    If RangeNameExists(ws, "REPORT_DATE") Then
        With ws.Range("REPORT_DATE")
            .Font.Bold = True
            .NumberFormat = "mmm-yy"
            .EntireColumn.AutoFit
        End With
    End If 

    If RangeNameExists(ws, "ROW_HEADING") Then
        ws.Range("ROW_HEADING").Font.Bold = True
    End If 

    If RangeNameExists(ws, "COLUMN_HEADING") Then
        ws.Range("COLUMN_HEADING").Font.Bold = True
    End If 

    If RangeNameExists(ws, "DATA") Then
        ws.Range("DATA").NumberFormat = "#,##0"
    End If 

    If RangeNameExists(ws, "COLUMN_TOTAL") Then
        With ws.Range("COLUMN_TOTAL")
            .Formula = "=SUM(R[-9]C:R[-1]C)"
            .Font.Bold = True
            .NumberFormat = "#,##0"
        End With
    End If 

    If RangeNameExists(ws, "ROW_TOTAL") Then
        With ws.Range("ROW_TOTAL")
            .Formula = "=SUM(RC[-12]:RC[-1])"
            .Font.Bold = True
            .NumberFormat = "#,##0"
        End With
    End If 

    Set ws = Nothing
End Sub 

8.3.2 接受工作表输入

代码清单8.12：确认一个有正确数据的范围

Function ReadCurrencyCell(rg As Range) As Currency
    Dim cValue As Currency
    cValue =  

    On Error GoTo ErrHandler 

    If IsEmpty(rg) Then GoTo ExitFunction
    If Not IsNumeric(rg) Then GoTo ExitFunction 

    cValue = rg.Value 

ExitFunction:
    ReadCurrencyCell = cValue
    Exit Function 

ErrHandler:
    ReadCurrencyCell =
End Function