主题：[求助]这段代码的解释？

Dim t1 As Date = Date.Now
Dim Sum As Long
For i As Integer = 1 To 10000000
    Sum = Sum + i
Next
Output.Show("计算结束, 耗时: " & (Date.Now - t1).TotalSeconds & "秒")

今天看了帮助文件  开发篇中有这样的一段代码！

问题是 中间为什么要加入  For i As Integer = 1 To 10000000
                                        Sum = Sum + i
                                   Next

和最后的一行Output.Show("计算结束, 耗时: " & (Date.Now - t1).TotalSeconds & "秒")      有什么联系  ？？

多谢了~~