當引用單元格時下標超出範圍錯誤

Question

我的代碼的目標是獲取單元格的舊值，並在輸入新值時對其進行檢查。如果舊值更改爲新值，則更新指定單元格中的日期。

我的代碼的問題是，我似乎無法找到一種方法來解決這個錯誤，而不會破壞我的代碼，因此我無法修復這一行代碼。我知道我的陣列超出界限或者沿着這些界限，但我無法弄清楚如何避開它。

這裏是我的代碼：

Dim oldValue() 

Public Sub Worksheet_SelectionChange(ByVal Target As Range) 
oldValue = Me.Range("D4", "D21").Value 
End Sub 

Private Sub Worksheet_Change(ByVal Target As Range) 
If Not Intersect(Target, Me.Range("D4:D21")) Is Nothing Then 
    Dim c As Range 
    For Each c In Intersect(Target, Me.Range("D4:D21")) 
     'Here's where my code is breaking "Subscript out of range error" 
     If oldValue(c.Row) <> c.Value Then 
      'Update value in column L (8 columns to the right of column D) 
      c.Offset(0, 7).Value = Date 'or possibly "= Now()" if you need the time of day that the cell was updated 
     End If 
    Next 
End If 
End Sub 

如果它打破，我已經定義，如果舊值更改爲新的值，然後更新日期。但它給我一個錯誤，我找不到解決的辦法。

我該如何解決我的代碼，使其在範圍內，任何建議？

編輯：我現在已經修好了我的代碼：

Dim oldValue As Variant 

Public Sub Worksheet_SelectionChange(ByVal Target As Range) 
'I changed "D4", "D21" to the following: 
oldValue = Me.Range("D4:D21").Value 
End Sub 

Private Sub Worksheet_Change(ByVal Target As Range) 
If Not Intersect(Target, Me.Range("D4:D21")) Is Nothing Then 
    'Application.EnableEvents = False 
    Dim c As Range 
    For Each c In Intersect(Target, Me.Range("D4:D21")) 
     'Check value against what is stored in "oldValue" (row 4 is in position 1, row 5 in position 2, etc) 
     'I also changed the array reference 
     If oldValue(c.Row - 3, 1) <> c.Value Then 
      'Update value in column L (8 columns to the right of column D) 
      c.Offset(0, 7).Value = Date 'or possibly "= Now()" if you need the time of day that the cell was updated 
     End If 
    Next 
    'Application.EnableEvents = True 
End If 
End Sub 

Answer 1

Dim oldValue as Variant 

.... 

' oldValue is a 2D array 
' and there is a shift between c.Row and the index of oldValue 
If oldValue(c.Row - 3, 1) <> c.Value Then ...