Question

在VB中，先设立一个Label，它的值设为3，但是它是隐藏的，我希望把鼠标移到Label上时，Label的值就会显现

把鼠标移开，label就会隐藏，并且要记录下Label显现出来的时间，也就是从鼠标放到label上和移开label的中间所经历的时间，精确到毫秒。请问应该如何编程？

Answer 1

窗体上添加2个标签，1个Timer
你那个Label1适当大一点？
代码如下：
Option Explicit
Private LL As String
Private n As Double
Private YesNo As Boolean
Private Sub Form_Load()
LL = "3"
Timer1.Interval = 1
Timer1.Enabled = False
End Sub
Private Sub Form_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
If YesNo Then
Label1.Caption = ""
Timer1.Enabled = False
Label2.Caption = "时间： " & n & " 毫秒"
YesNo = False
End If
End Sub
Private Sub Label1_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
If Not YesNo Then
YesNo = True
n = 0
Timer1.Enabled = True
Label1.Caption = LL
End If
End Sub
Private Sub Timer1_Timer()
n = n + 1
End Sub

追问

不错，可以运行，但貌似Timer精确度不高啊，感觉时间不准。该如何解决？谢谢！

追答

时间已经设置成每毫秒1次的频率，误差你自己想办法解决了。实在对不起。
我不知道你是如何判断毫秒精度的？

追问

TIMer 控件不能做精确计时，只能用于粗略计时，而且最小周期不能小于80MS，这个在VB关于TIMER的控制介绍中明确说明过的。参见：http://zhidao.baidu.com/question/210743343.html 。他是怎么做的？不太明白啊

追答

这个关于Timer我还是第1次知道，因为没有这方面的经验。
不过这个方法是采用API的方法，我知道的，我给个代码：你自己把它移植到你的那个程序里，先按照我说的体会一下，它可以返回计算机时间的毫秒。在窗体上添加8个文本框，和一个按钮，毫秒在Text8里：
Option Explicit
Private Declare Sub GetSystemTime Lib "kernel32" (lpSystemTime As SYSTEMTIME)
Private Type SYSTEMTIME
wYear As Integer
wMonth As Integer
wDayOfWeek As Integer
wDay As Integer
wHour As Integer
wMinute As Integer
wSecond As Integer
wMilliseconds As Integer
End Type
Private Sub Command1_Click()
Dim nian As String, yue As String, MyWeek As String, ri As String
Dim Myh As String, MyM As String, MyS As String, MyHM As String
Dim nowtime As SYSTEMTIME
GetSystemTime nowtime
Text1.Text = nowtime.wYear
Text2.Text = nowtime.wMonth
Text3.Text = nowtime.wDayOfWeek
Text4.Text = nowtime.wDay
Text5.Text = nowtime.wHour
Text6.Text = nowtime.wMinute
Text7.Text = nowtime.wSecond
Text8.Text = nowtime.wMilliseconds
End Sub
你可以通过两次毫秒的差来获得你需要的值。

Answer 2

显示隐藏可以用以下代码：
Private Sub Form_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
Label1.ForeColor = Form1.BackColor
End Sub

Private Sub Label1_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
Label1.ForeColor = RGB(0, 0, 0)
End Sub

计时的话肯定要用tmer,你自己去研究以下吧