条形码编程实例

条形码编程实例
一、条形码的读取
用过键盘口式的扫条码工具的朋友就知道，它就如同在鍵盘上按下数字鍵一样，基本不需任何编程和处理。但如果你使用的是其它接口的话，可能你就要为该设备编写通讯代码了。以下有一段简单的25针串口的条码读取器通讯代码。

Option Explicit
Dim sData As String
Private Sub Form_Load()
 With MSComm1 
   .CommPort = 3 '设为COM3，试运行的系统而定，你可提供一个Combox让用户选择。
   .PortOpen = True　'打开通讯端口
 End With
End Sub

     
Private Sub MSComm1_OnComm()
  
  Dim EndPos As Integer
  Select Case MSComm1.CommEvent
    Case comEvReceive '当有数据传送过来时
      sData = sData & Trim(MSComm1.Input)
      '检索回车,通常读卡机每组数据結尾都返回一个回车作为结束符
      EndPos = InStr(1, sData, Chr(13))
      If EndPos = 0 Then '如果未结束就继续努力
      Else '读完一组。
        lblBarCode.Caption = sData '显示一组条形码
        With lstBarCode
          .AddItem Mid(sData, 1, EndPos - 1) '添加一组条形码到列表
        End With
        sData = "" '清空
      End If
  End Select
End Sub

     
Private Sub cmdEnd_Click()
  MSComm1.PortOpen = False '关闭端口
  End
End Sub

二、条形码的生成
看完以上关于条码读取的代码是否觉得很容易呢？对，在VB上编程本来就不难。以下关于条形码生成的代码也是很容易理解，只需使用一个OFFICE的附带的BarCode控件就可以轻松打印出11种不同标准的条形码，足以满足我们的要求。想起我书架上的一本书中的一篇用Turbo C编写条形码打印程序文章，长篇大论，那时不知看了n天，打了n小时字结果也不尽人意，现在真是幸福多了:)。废话说完，得回归正题。且看条形码生成的代码及有关说明。
源代码主要由两个窗体（frmMain主窗体和frmOption条码设置窗体）和两个模块组成(modGetScreen.bas、SysDLG32.bas)。考虑到篇幅，这里只列出部分较为关键的代码。
新建一个标准工程，添加一个名为(Microsoft Access BarCode Control9)的条形码部件，并添加一个条码控件到窗口，并将窗口改名为frmMain，如图所示。由于控件比较多，这里不便细说，详细内容请看源代码。
模块modGetScreen.bas代码如下：
Option Explicit
声明BitBlt、GetDesktopWindow、GetWindowDC、ReleaseDC这几个API函数略
Public RegUser As Boolean

Sub GetObjImage1(Obj As Object, OwnerForm As PictureBox, Picture1 As PictureBox)
  'hDC
  Dim hWndDesk As Long
  Dim hDCDesk As Long
  '区域表达变量
  Dim x As Long
  Dim y As Long
  Dim w As Long
  Dim h As Long

     
  x = Obj.Left  Screen.TwipsPerPixelX
  y = Obj.Top  Screen.TwipsPerPixelY
  w = Obj.Width  Screen.TwipsPerPixelX
  h = Obj.Height  Screen.TwipsPerPixelY
  hDCDesk = OwnerForm.hdc
  '取出图像
  Call BitBlt(Picture1.hdc, 0, 0, w, h, hDCDesk, x, y, vbSrcCopy)
  Call ReleaseDC(hWndDesk, hDCDesk)

     
End Sub  

主窗体frmMain.frm部分代码如下：
 

Private Sub cmdPrint_Click()
 '生成条形码图像
  Dim r As Long, i As Integer, t As String,cfile As String '临时变量
  t = BarCode
  For i = 0 To Val(Times) - 1
    
    BarCode1.Value = BarCode + i
    DoEvents 
    Picture1.Refresh
   
    GetObjImage1 BarCode1, Conel, Picture1
    
    If RegUser = False Then '如果未注册添加MASK标记
      Picture1.PaintPicture Picture2.Picture, 300, 300
    End If
    
    If Dir(SavePath, vbDirectory) = "" Then MkDir SavePath
    
    SavePath = SavePath & IIf(Right(SavePath, 1) <> "", "", "")
    
    cfile = SavePath & BarCode1.Value & ".bmp"
 
    SavePicture Picture1.Image, cfile '将条形码保存为图像文件以便打印
  Next
  BarCode = t

     
End Sub

条形码设置窗体frmOption.frm代码如下：

Option Explicit
'条形码设置模块
   
Private Sub cboBig_Click()
  BarCode1.Style = cboBig.ListIndex '改变标准
End Sub

     
Private Sub cboDirection_Click()
  BarCode1.Direction = cboDirection.ListIndex '改变方向
End Sub

     
Private Sub cboLine_Click()
  BarCode1.LineWeight = cboLine.ListIndex '改变线宽
End Sub

     
Private Sub cboSmall_Click()
  BarCode1.SubStyle = cboSmall.ListIndex '改变样式
End Sub

     
Private Sub Check1_Click()
  BarCode1.ShowData = Check1.Value '是否显示数据
End Sub

     
Private Sub cmdChange_Click()
 '设置长、宽大小
 BarWidth = BarCode1.Height
 BarHeight = BarCode1.Width
 cmdRefresh_Click
End Sub

     
Private Sub cmdOK_Click()
'传送条形码设定到主界面
  With frmMain.BarCode1
    .LineWeight = BarCode1.LineWeight
    .Style = BarCode1.Style
    .SubStyle = BarCode1.SubStyle
    .Direction = BarCode1.Direction
    .Width = BarCode1.Width
    .Height = BarCode1.Height
    .ShowData = BarCode1.ShowData
    Me.Hide
  End With
  With frmMain
    .Picture1.Width = .BarCode1.Width
    .Picture1.Height = .BarCode1.Height
    .Conel.Width = .BarCode1.Width
    .Conel.Height = .BarCode1.Height
  End With
End Sub

     
Private Sub cmdRefresh_Click()
  BarCode1.Width = BarWidth
  BarCode1.Height = BarHeight
End Sub

     
Private Sub Form_Load()
 LoadBarInfo
 BarWidth = BarCode1.Width
 BarHeight = BarCode1.Height
End Sub

     
Sub LoadBarInfo() '初始化选项
 LoadBigClass cboBig
 LoadSmallClass cboSmall
 LoadLineSize cboLine
 LoadDirection cboDirection
End Sub
Sub LoadBigClass(cbo As ComboBox) '条码标准
  With cbo
    .AddItem "UPC-A"
    .AddItem "UPC-E"
    .AddItem "EAN-13"
    .AddItem "EAN-8"
    .AddItem "Case Code"
    .AddItem "Codabar (NW-T)"
    .AddItem "Code-39"
    .AddItem "Code-128"
    .AddItem "U.S. Postnet"
    .AddItem "U.S. Postal FIM"
    .AddItem "JP Post"
    .ListIndex = 2
  End With
End Sub
Sub LoadSmallClass(cbo As ComboBox) '条码样式
  With cbo
    .AddItem "Standard"
    .AddItem "2-Digit Supplement"
    .AddItem "5-Digit Supplement"
    .AddItem "POS Case Code"
    .ListIndex = 0
  End With
End Sub