不缓存for循环的值

Question

执行for循环时，正在缓存To之后的值。

    Dim m As Integer = 1

    For x As Integer = 0 To m
        Console.WriteLine(x)
        m = 10
    Next

输出

    0
    1

有没有办法不缓存m值？我能解决它的唯一方法是将For转换为While循环。

Answer 1

无法对其进行多次评估。来自For..Next Statement Documentation (Visual Basic) (MSDN)

For counter [ As datatype ] = start To end [ Step step ]
    [ statements ]
    [ Continue For ]
    [ statements ]
    [ Exit For ]
    [ statements ]
Next [ counter ]

  

当For ... Next循环开始时，Visual Basic会评估开始，结束和步骤。 Visual Basic仅在此时评估这些值。