vb读取条形码实例

【实例简介】

这是通过rs232串口学习的好例子
【实例截图】

【核心代码】

VERSION 5.00
Object = "{648A5603-2C6E-101B-82B6-000000000014}#1.1#0"; "MSCOMM32.OCX"
Begin VB.Form Form1 
   Caption         =   "Bar Code Reader"
   ClientHeight    =   3465
   ClientLeft      =   2250
   ClientTop       =   2370
   ClientWidth     =   7080
   LinkTopic       =   "Form1"
   ScaleHeight     =   3465
   ScaleWidth      =   7080
   Begin VB.ListBox List1 
      BeginProperty Font 
         Name            =   "Times New Roman"
         Size            =   14.25
         Charset         =   0
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   2580
      Left            =   3465
      TabIndex        =   4
      Top             =   450
      Width           =   3435
   End
   Begin VB.CommandButton Command2 
      Caption         =   "结束系统"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   855
      Left            =   495
      TabIndex        =   2
      Top             =   2280
      Width           =   1935
   End
   Begin MSCommLib.MSComm MSComm1 
      Left            =   2700
      Top             =   2430
      _ExtentX        =   1005
      _ExtentY        =   1005
      _Version        =   393216
      CommPort        =   2
      DTREnable       =   -1  'True
      RThreshold      =   1
   End
   Begin VB.Label lblCode 
      AutoSize        =   -1  'True
      Caption         =   "?????"
      BeginProperty Font 
         Name            =   "Times New Roman"
         Size            =   14.25
         Charset         =   0
         Weight          =   700
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      ForeColor       =   &H000000FF&
      Height          =   330
      Left            =   270
      TabIndex        =   3
      Top             =   450
      Width           =   750
   End
   Begin VB.Label Label1 
      AutoSize        =   -1  'True
      Caption         =   "条形码列表"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   240
      Index           =   1
      Left            =   3480
      TabIndex        =   1
      Top             =   120
      Width           =   1200
   End
   Begin VB.Label Label1 
      AutoSize        =   -1  'True
      Caption         =   "现在条形码值"
      BeginProperty Font 
         Name            =   "宋体"
         Size            =   12
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   240
      Index           =   0
      Left            =   240
      TabIndex        =   0
      Top             =   120
      Width           =   1440
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Dim GotStr$  '接收到的数据

''''''''''''''''''''''''''''''''''''''''''''''
'使用命令按钮控件
'将OFF字符串指令以Output指令送出，关闭噪音计
'接着关闭通信端口，并结束系统
'''''''''''''''''''''''''''''''''''''''''''''
Private Sub Command2_Click()
  MSComm1.PortOpen = False
  End
End Sub

''''''''''''''''''''''''''''''''''''''''''''''
'窗体的加载事件
'清空ListBox控件
'首先打开通信端口
'''''''''''''''''''''''''''''''''''''''''''''
Private Sub Form_Load()
  List1.Clear
  MSComm1.PortOpen = True
End Sub

''''''''''''''''''''''''''''''''''''''''''''''
'通信控件的事件程序
'由读条形码器所传的信息均以事件的方式接收
'确定一笔数据接收完毕后，就清空缓冲区
'''''''''''''''''''''''''''''''''''''''''''''
Private Sub MSComm1_OnComm()
  Dim CrPos%
  Select Case MSComm1.CommEvent
    ' 借着取代底下每一个 case 语句来处理每个事件与错误
    ' 事件
        Case comEvCD    ' CD 线的状态发生变化.
        Case comEvCTS   ' CTS 线的状态发生变化.
        Case comEvDSR   ' DSR 线的状态发生变化.
        Case comEvRing  ' Ring Indicator 变化.
        Case comEvReceive   ' 收到 RThreshold # of
            GotStr = GotStr   Trim(MSComm1.Input)  '将数据不断地接入
            CrPos = InStr(1, GotStr, Chr(13)) '判断是否遇到结尾字符
            '若已收到结尾字符则进行以下的作业
            If CrPos <> 0 Then
              '显示新值
              lblCode.Caption = GotStr
              '填入List控件
              List1.AddItem Mid(GotStr, 1, CrPos - 1)
              List1.ListIndex = List1.ListCount - 1
              GotStr = ""  '清空接收字符串
            End If
        Case comEvSend  ' 传输缓存区有 Sthreshold 个字符                            '
    End Select

End Sub