vb一小时倒计时源代码，格式00:00:00

代码更简洁易懂的，允许自行指定24小时之内的倒计时。指定时，hh是小时数，赋值0-23，mm是分钟数，赋值0-59，ss是秒数，赋值0-59，但mm和ss通常为0。点击倒计时的按钮即可开始。

'窗体内需要建立Command1控件和Timer1控件

Dim timeall As Long '计算倒计时的总秒数

Private Sub Command1_Click()
Timer1.Enabled = True
End Sub

Sub Timer1_Timer()
If timeall = 0 Then
Command1.Caption = "00:00:00"
MsgBox "倒计时结束!"
Timer1.Enabled = False
Else
Command1.Caption = Format(timeall \ 3600, "00") & ":" & Format((timeall \ 60) Mod 60, "00") & ":" & Format(timeall Mod 60, "00")
timeall = timeall - 1
End If
End Sub

Private Sub Form_Activate()
Dim hh%, mm%, ss%
hh = 1: mm = 0: ss = 0 '指定倒计时的时间长度
Command1.Caption = Format(hh, "00") & ":" & Format(mm, "00") & ":" & Format(ss, "00")
timeall = hh * 3600& + mm * 60& + ss - 1
Timer1.Enabled = False
Timer1.Interval = 1000
End Sub