如何优化此代码？

Question

每当单元格值（1,2）发生更改时，它会将该值和单元格的值（10,19）分别粘贴到列A & B中 我的Excel VBA使Excel在单元格的值1,2）变化：

Dim a As Variant 

Dim j As Integer 
Dim b As Variant 
Dim l As Integer 




Private Sub Worksheet_Change(ByVal Target As Range) 

If Cells(j + 3, 1).Value = Cells(j + 2, 1).Value Then 
      j = j 
      Else 
      j = j + 1 

     End If 

    If l < j Then 
b = Cells(10, 19).Value 
Cells(j + 1, 2).Value = b 

End If 
l = j 
a = Cells(1, 2).Value 
Cells(j + 3, 1).Value = a 


End Sub 

Private Sub Combobox1_Change() 
Cells(1, 2) = Combobox1.Value 

End Sub 

我该如何防止这种情况发生？

Answer 1

首先，您的格式设置很难阅读。
其次，在更改值时不会禁用事件，导致最终的堆栈溢出或内存不足错误，这会使速度变慢。

格式化，并提高代码：

Dim a 
Dim j As Integer 
Dim b 
Dim l As Integer 

Private Sub Worksheet_Change(ByVal Target As Range) 
If Intersect(Target, "A:A") Is Nothing Then Exit Sub 'don't run unless change in column A 

Application.EnableEvents = False 'stop executing this code until we are done 
If Cells(j + 3, 1).Value = Cells(j + 2, 1).Value Then 
    j = j 
Else 
    j = j + 1 
End If 

If l < j Then 
    b = Cells(10, 19).Value 
    Cells(j + 1, 2).Value = b 
End If 

l = j 
a = Cells(1, 2).Value 
Cells(j + 3, 1).Value = a 
Application.EnableEvents = True 
End Sub 

Private Sub Combobox1_Change() 
Cells(1, 2) = Combobox1.Value 
End Sub