VB.Net实现超市打印小票和开钱箱功能

Imports System.IO
Public Class pos
    Const GENERIC_READ = &H80000000
    Const GENERIC_WRITE = &H40000000
    Const OPEN_EXISTING = 3

Private yhflag = 0
    Public Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Integer, ByVal dwShareMode As Integer, ByVal lpSecurityAttributes As Integer, ByVal dwCreationDisposition As Integer, ByVal dwFlagsAndAttributes As Integer, ByVal hTemplateFile As Integer) As IntPtr

 

    Private Sub kaiqianxiang()
        Dim iHandle As IntPtr
        iHandle = CreateFile("LPT1", GENERIC_READ Or GENERIC_WRITE, 0, 0, OPEN_EXISTING, 0, 0)
        If (iHandle.ToInt32 = -1) Then
            MsgBox("没有连接打印机或者打印机端口不是LPT1")
            Exit Sub
        Else
            ' MsgBox("打印机连接成功!")

            Dim fs As New FileStream(iHandle, FileAccess.ReadWrite)
            Dim sr As New StreamReader(fs)   '读数据  
            Dim sw As New StreamWriter(fs, System.Text.Encoding.Default)   '写数据  
            sw.Write((Chr(27)).ToString() + "p" + (Chr(0)).ToString() + ((Chr(60))).ToString() + ((Chr(255))).ToString())
            sw.Close()
            fs.Close()
        End If

    End Sub
    Private Sub print()
        Try
            Dim iHandle As IntPtr
            iHandle = CreateFile("LPT1", GENERIC_READ Or GENERIC_WRITE, 0, 0, OPEN_EXISTING, 0, 0)

            If (iHandle.ToInt32 = -1) Then
                MsgBox("没有连接打印机或者打印机端口不是LPT1")
                Exit Sub
            Else
                ' MsgBox("打印机连接成功!")

                Dim fs As New FileStream(iHandle, FileAccess.ReadWrite)
                Dim sr As New StreamReader(fs)   '读数据  
                Dim sw As New StreamWriter(fs, System.Text.Encoding.Default)   '写数据  

                sw.Write("打印了还等什么")
                sw.WriteLine() ''得让他分行
                sw.WriteLine()

                sw.Write((Chr(27)).ToString() + "p" + (Chr(0)).ToString() + ((Chr(60))).ToString() + ((Chr(255))).ToString())  '''''''开钱箱
                sw.Close()
                fs.Close()

        Catch ex As Exception
            MsgBox("没有连接打印机！")
        End Try

    End Sub