VB高手帮忙！

Private Sub Command1_Click()
a = Text1.Text
Timer1.Enabled = True
End Sub

Private Sub Form_Load()
b = Text2.Text
End Sub

Private Sub Timer1_Timer()
a = a - 1
Label4.Caption = a
If a = 0 Then
Timer1.Enabled = False
MsgBox b, vbSystemModal, "时间到"
End If
End Sub

另外timer1.interval = 1000
刚开始时timer1.Enabled

请高手帮忙看看问题出在了哪儿？

补充：刚开始时timer1.Enabled = true

追问：dim a as ?

答案：a应定义成全局变量吧，否则
Private Sub Timer1_Timer()
a = a - 1
中的a未定义
没有用循环
Dim a%, b$
Private Sub Command1_Click()
a = Val(Text1.Text)
Timer1.Enabled = True
End Sub
Private Sub Form_Load()
Text1.Text = 20
Timer1.Interval = 1000
Timer1.Enabled = False
b = "时间到了"
End Sub
Private Sub Timer1_Timer()
a = a - 1
Label4.Caption = a
If a = 0 Then
Timer1.Enabled = False
MsgBox b, vbSystemModal, "提示"
End If
End Sub
 
把以上代码直接复制到一个新的工程中运行即可。
把if a=0写到a=a-1前面就可以了

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