VBA 对象变量或未设置块变量

Question

这段代码的重点是在一个新的工作表中创建一个图表，它确实如此。在此之后，当我单击按钮在一个名为相同的新工作表中再次生成图表时，它应该删除该工作表并创建一个新的生成图表。

它会创建图表，但是当我返回单击按钮时，它会在按钮所在的工作表中生成图表并抛出错误 91：对象变量或未设置块变量。

调试将我指向以下行：

ActiveChart.Location Where:=xlLocationAsNewSheet, Name:="Demand Line Chart"

下面是代码：

Sub HistoricalDemand()
' Creates a line chart for the demand column

For Each ws In Worksheets
         If ws.Name = "Demand Line Chart" Then
                Application.DisplayAlerts = False
                   Sheets("Demand Line Chart").Delete
                Application.DisplayAlerts = True
                Exit For
         End If
        Next

Columns("A:A").Select
Selection.NumberFormat = "[$-en-US]mmm-yy;@"

Range("A:A,E:E").Select
ActiveSheet.Shapes.AddChart2(332, xlLineMarkers).Select
' Try With command here
ActiveChart.SetSourceData Source:=Range("A:A,E:E")
ActiveChart.Location Where:=xlLocationAsNewSheet, Name:="Demand Line Chart"
' Places line chart in a new worksheet called Demand Line Chart
ActiveChart.Axes(xlCategory).Select
Selection.TickLabels.Orientation = 70
Selection.MajorTickMark = xlNone
With ActiveChart
    .Axes(xlCategory).Select
    .Axes(xlCategory).MajorUnit = 2
    .ChartTitle.Select
    .ChartTitle.Text = "Historical Demand"
    .SetElement (msoElementLegendRight)
Selection.Format.TextFrame2.TextRange.Characters.Text = "Historical Demand"
With Selection.Format.TextFrame2.TextRange.Characters(1, 17).ParagraphFormat
    .TextDirection = msoTextDirectionLeftToRight
    .Alignment = msoAlignCenter
End With
ActiveChart.ChartArea.Select
End With
End Sub

Answer 1

使用 VBA 编码时的一些建议：

1. 使用option explicit，这样您就不会出现未定义变量的意外行为
2. 始终缩进您的代码（请参阅www.rubberduckvba.com 一个帮助您处理数据的免费工具）
3. 尝试将您的逻辑定义变量和重用它们分开
4. Avoid using select 除非绝对必要

查看和自定义代码，使其符合您的需求。

您可以通过按F8 并逐行执行来查看代码中发生的情况。

代码：

Public Sub HistoricalDemand()
    ' Creates a line chart for the demand column
    Dim targetSheet As Worksheet
    Dim sourceDataSheet As Worksheet
    Dim sourceDataRange As Range
    Dim targetChart As Shape

    Dim targetSheetName As String
    Dim targetChartTitle As String
    Dim dataLastRow  As Long

    ' Define parameters
    targetSheetName = "Demand Line Chart"
    targetChartTitle = "Historical Demand"

    ' Set a reference to the source data sheet
    Set sourceDataSheet = ThisWorkbook.Worksheets("DATA")

    ' Find last row in data sheet
    dataLastRow = sourceDataSheet.Cells(sourceDataSheet.Rows.Count, 1).End(xlUp).Row

    ' Set reference to the source range
    Set sourceDataRange = sourceDataSheet.Range("A1:A" & dataLastRow & ",E1:E" & dataLastRow)

    ' Delete the sheet if exists
    For Each targetSheet In Worksheets
        If targetSheet.Name = targetSheetName Then
            Application.DisplayAlerts = False
            ' This will delete the matching sheet
            targetSheet.Delete
            Application.DisplayAlerts = True
            Exit For
        End If
    Next

    ' Apply format to the first column (A)
    sourceDataSheet.Range("A1:A" & dataLastRow).NumberFormat = "[$-en-US]mmm-yy;@"

    ' Add the chart
    Set targetChart = sourceDataSheet.Shapes.AddChart2(332, xlLineMarkers)

    ' Apply the target chart settings
    With targetChart.Chart
        .SetSourceData Source:=sourceDataRange
        .Location Where:=xlLocationAsNewSheet, Name:=targetSheetName
        ' Places line chart in a new worksheet called Demand Line Chart
        .Axes(xlCategory).TickLabels.Orientation = 70
        .Axes(xlCategory).MajorTickMark = xlNone

        .Axes(xlCategory).Select
        .Axes(xlCategory).MajorUnit = 2

        .ChartTitle.Text = targetChartTitle
        .SetElement (msoElementLegendRight)
        .ChartTitle.Format.TextFrame2.TextRange.Characters.Text = targetChartTitle
        With .ChartTitle.Format.TextFrame2.TextRange.Characters(1, 17).ParagraphFormat
            .TextDirection = msoTextDirectionLeftToRight
            .Alignment = msoAlignCenter
        End With
    End With

End Sub

让我知道它是否有效