Visual Basic中,对于文本比较好的处理方式.

VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "电子倒计时器"
   ClientHeight    =   2310
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   4680
   LinkTopic       =   "Form1"
   ScaleHeight     =   2310
   ScaleWidth      =   4680
   StartUpPosition =   3  '窗口缺省
   Begin VB.Timer Timer1 
      Interval        =   1000
      Left            =   3840
      Top             =   720
   End
   Begin VB.TextBox Text1 
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   15.75
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   495
      Left            =   1200
      TabIndex        =   0
      Top             =   600
      Width           =   495
   End
   Begin VB.CommandButton Command1 
      Caption         =   "倒计时"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   495
      Left            =   1560
      TabIndex        =   4
      Top             =   1425
      Width           =   975
   End
   Begin VB.TextBox Text2 
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   15.75
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   495
      Left            =   2280
      TabIndex        =   3
      Top             =   600
      Width           =   495
   End
   Begin VB.Label Label3 
      Caption         =   "秒"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   255
      Left            =   2400
      TabIndex        =   2
      Top             =   240
      Width           =   375
   End
   Begin VB.Label Label2 
      Caption         =   "分钟"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   255
      Left            =   1200
      TabIndex        =   1
      Top             =   240
      Width           =   495
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Dim m As Integer, s As Integer     '声明模块级变量
Private Sub Form_Load()
    Timer1.Interval = 1000         '设置每隔1秒触发1次Timer事件
    Timer1.Enabled = False         '关闭计时器
End Sub
Private Sub Command1_Click()       '“倒计时”
    m = Val(Text1.Text)
    s = Val(Text2.Text)
    Timer1.Enabled = True           '打开计时器
End Sub
Private Sub Timer1_Timer()
    If s > 0 Then
        s = s - 1
    Else
        If m > 0 Then
            m = m - 1
            s = 59
        End If
    End If
    Text1.Text = Format(m, "00")
    Text2.Text = Format(s, "00")
    If s = 0 And m = 0 Then
        Beep                    '响铃，即让喇叭发一声响
        MsgBox "计时结束"
        Unload Me
    End If
End Sub