For Each 循环的逆序 [英] Reverse order of For Each loop

问题描述

VB 最强大的功能之一是能够在不引用索引的情况下遍历集合中的对象 - for each 循环.

One of the most powerful things about VB is ability to loop through objects in a collection WITHOUT referring to the index - for each loop.

我发现只想从集合中删除对象非常有用.

I find it very useful only want to remove objects from a collection.

从预定义的对象(例如电子表格上的行)中删除对象时，如果我使用索引并从最大的开始并返回到第一个，则代码会更简单.(使用迭代器的步骤 -1)(否则需要一个偏移量，因为一旦活动对象被删除，For each 会将枚举器指针移回前一个对象)

When doing removing objects from a predefined such as rows on a spread sheet the code is simpler if I use indexing and start at the largest and work back to the first. (Step -1 with an iterator) (otherwise requires an offset as the For each moves the enumerator pointer back to the previous object once the active one is deleted)

例如

For intA = 10 to 1 step -1 
    ' ...
Next

当使用 For Each 时怎么样?下一个例如.

What about when using a For Each | Next eg.

For each rngCell in Selection.Cells
    ' ...
Next

如何使用 for each 循环语法向后循环?

How could I loop backwards using the for each loop syntax?

推荐答案

使用 for each 循环语法无法向后循环.

It's not possible to loop backwards using the for each loop syntax.

作为替代方案，您可以使用 For i = a To 1 Step -1 循环:

As an alternative you can use a For i = a To 1 Step -1 loop:

Sub reverseForEach()
    Dim i As Long, rng As Range

    Set rng = ActiveSheet.Range("A1:B2")

    For i = rng.Cells.Count To 1 Step -1

        Debug.Print rng.item(i).Address
        ' Or shorthand rng(i) as the Item property 
        ' is the default property for the Range object.
        ' Prints: $B$2, $A$2, $B$1, $A$1

    Next i

End Sub

这适用于所有具有 Item 属性的集合.例如工作表、区域或形状.

This works with all collections that have the Item property. For instance Worksheets, Areas or Shapes.

注意:在 Range 对象上使用时循环的顺序是从右到左，然后向上.

Note: The order of the loop when using on the Range object is from right to left, then up.

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