第7章编程第1题a.frm

一本学习Visual Basic编程的好书

VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   2370
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   4680
   LinkTopic       =   "Form1"
   ScaleHeight     =   2370
   ScaleWidth      =   4680
   StartUpPosition =   3  '窗口缺省
   Begin VB.TextBox Text4 
      Height          =   375
      Left            =   2520
      TabIndex        =   4
      Text            =   " "
      Top             =   1320
      Width           =   1695
   End
   Begin VB.CommandButton Command1 
      Caption         =   "检验"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   375
      Left            =   2760
      TabIndex        =   3
      Top             =   480
      Width           =   975
   End
   Begin VB.TextBox Text3 
      Height          =   375
      Left            =   480
      TabIndex        =   2
      Text            =   "  "
      Top             =   1680
      Width           =   975
   End
   Begin VB.TextBox Text2 
      Height          =   375
      Left            =   480
      TabIndex        =   1
      Text            =   " "
      Top             =   960
      Width           =   975
   End
   Begin VB.TextBox Text1 
      Height          =   375
      Left            =   480
      TabIndex        =   0
      Text            =   " "
      Top             =   240
      Width           =   975
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Private Sub Command1_Click()
    Dim a As String, b As String, c As String
    a = Trim(Text1.Text)
    b = Trim(Text2.Text)
    c = Trim(Text3.Text)
    If che(a) And che(b) And che(c) Then
        Text4.Text = Val(a) + Val(b) + Val(c)
    Else
        Text4.Text = "存在非数字字符"
    End If
End Sub
Function che(x As String) As Boolean
    If Len(Str(Val(x))) <> Len(x) Then
        che = True
    Else
        che = False
    End If
End Function