假设你不使用三态复选框，那么 .Value 只能是 True 或 False ，所以我们应该能够得到这样的一些东西：

（假设您的代码在UserForm中运行，以便 Controls 可以直接访问）

  Dim mthIdx as Long 
 Dim nm as String 
 Dim c As Control 

使用ActiveSheet.PivotTables（PivotTable1）。PivotFields（month）
对于mthIdx = 1至12 
 nm =CheckBox& mthIdx 
设置c =控件（nm）
 .PivotItems（mthIdx）.Visible = c.Value 
下一个
结束
 / pre> 

（与子句不是必需的，但通常情况下解决嵌套COM参考资料尽可能不频繁）
 
I have a user form in Excel VBA with a check box for each month.

Selecting one or more cause the required month to be shown on the sheet, I copy-pasted the code 12 times and it works but I'm sure there is a better way doing it with a For loop.

This is a part of my code (it goes on 12 times):
    If CheckBox1.Value = True Then
        ActiveSheet.PivotTables("PivotTable1").PivotFields("month").PivotItems("1").Visible = True
    Else
       ActiveSheet.PivotTables("PivotTable1").PivotFields("month").PivotItems("1").Visible = False
    End If

    If CheckBox2.Value = True Then
        ActiveSheet.PivotTables("PivotTable1").PivotFields("month").PivotItems("2").Visible = True
    Else
       ActiveSheet.PivotTables("PivotTable1").PivotFields("month").PivotItems("2").Visible = False
    End If
I tried writing:
for i in range 1 to 12
and then writing my code but there seem to be a problem when I put "i" instead of the numbers.
Assuming you aren't using Tristate checkboxes, then the .Value can only be True or False, so we should be able to get away with something like this:

(Assumes your code runs inside the UserForm, so that Controls is directly accessible)
Dim mthIdx as Long
Dim nm as String
Dim c As Control

With ActiveSheet.PivotTables("PivotTable1").PivotFields("month")
    For mthIdx = 1 To 12
        nm = "CheckBox" & mthIdx
        Set c = Controls(nm)
        .PivotItems(mthIdx).Visible = c.Value
    Next
End With
(The With clause isn't strictly necessary, but it's usually a good idea to resolve nested COM references as infrequently as possible)