Question

VB倒计时器 点开始就开始，结束时弹出“时间到”消息框 点击取消弹出“是否取消”息框!

标签上能显示
开始时间：00:00:00
结束时间：00:00:00
共用了00:00:00
共三个标签，点击开始计时时标签上的时间开始计时，点击停止计时时就停止，同时第三个标签显示总用时！

Answer 1

放一个command1按钮，做按键。
放两个text1和text2控件,1用来填分钟数（M），2用来填秒数（S）
放一个timer1定时器，设interval=1000。

*---设置按键功能和TEXT控件检测----*
dim M as integer
dim S as integer

public sub Command1_Click()
if command1.caption="继续" then
command1.caption="停止"
*---分钟和秒钟初始设置----*
M=val(text1.text)
S=val(text2.text)
if M<0 then
msgbox "分钟数应该为正"
text1.setfocuse
exit sub
end if

if S<0 or S>60 then
msgbox "秒数应该为正"
text2.setfocuse
exit sub
end if
timer1.enabled=true
else
command1.caption="继续"
timer1.enabled=false
endif
end sub
*---时钟控件 S60到0循环直到M=0，S=0表示时间到----*
private sub Timer1_timer()
s=s-1
if s<=0 and m>0 then
s=60
m=m-1
exit sub
end if

if M<=0 and S<=0 then
msgbox "时间到"
command1_Click
end if
end sub

Answer 2

Public a
Public b

Private Sub Form_Load()
Timer1.Enabled = False
Command1.Caption = "开始"
Command2.Caption = "暂停"
End Sub
Private Sub Timer1_Timer()
b = b + 1
If b > 59 Then
a = a + 1
b = 0

End If

Label2 = "结束时间为" & Val(Text1.Text) & "分" & Val(Text2.Text) & "秒"
If Val(Text2.Text) <= 0 Then
Text2.Text = 59
Text1.Text = Text1.Text - 1
Else
Text2.Text = Text2.Text - 1

End If

If Val(Text1.Text) = 0 And Val(Text2.Text) = 0 Then

MsgBox "时间到"
Timer1.Enabled = False
Label3 = "所用的时间为" & a & "分" & b & "秒"

End If
End Sub
Private Sub Command1_Click()

a = 0
b = 0
If Val(Text1.Text) = 0 And Val(Text2.Text) = 0 Then
Label1 = "没有输入时间，计时没有执行"
Timer1.Enabled = False
Command1.Caption = "输入时间开始计时"
Label2 = "(∩_∩) ? ! "

Label2.ForeColor = vbBlue

Else
Timer1.Enabled = True
Timer1.Interval = 1000
Label1 = "开始时间为" & Val(Text1.Text) & "分" & Val(Text2.Text) & "秒"

End If
Private Sub Command2_Click()
Timer1.Enabled = False
Label3 = "所用的时间为" & a & "分" & b & "秒"
End Sub