vb.net中声明createfile

  正在进行的一个项目需要操作热敏打印机，为了客户使用的方便，支持各种类型的方式进行打印，今天需要使用LTP方式进行打印。打印过程中需要使用createfile，

  首先我们在一个模块文件或者类文件中进行createfile的声明：

   Public Structure SECURITY_ATTRIBUTES
        Dim nLength As Long
        Dim lpSecurityDescriptor As Long
        Dim bInheritHandle As Long
    End Structure
    Public Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Integer, ByVal dwShareMode As Integer, ByVal lpSecurityAttributes As SECURITY_ATTRIBUTES, ByVal dwCreationDisposition As Integer, ByVal dwFlagsAndAttributes As Integer, ByVal hTemplateFile As Integer) As Integer
     Public Const GENERIC_READ = &H80000000
         Public Const GENERIC_WRITE = &H40000000
         Public Const OPEN_EXISTING = 3
         Public Const INVALID_HANDLE_VALUE = -1

    注意前面的SECURITY_ATTRIBUTES的结构声明，如果没有这个会报未定义类型：SECURITY_ATTRIBUTES

    在使用时我们参照下面vb.net代码：

  Dim iHandle As IntPtr

  Dim lps As SECURITY_ATTRIBUTES

  iHandle = CreateFile("", GENERIC_READ Or GENERIC_WRITE, 0, lps, OPEN_EXISTING, 0, 0)

以上内容适用于.net framework老版本，新版本已经调整，使用方法如下：

  <DllImport("kernel32.dll", SetLastError:=True, CharSet:=CharSet.Unicode)> _

Public Function CreateFile(ByVal lpFileName As String, ByVal dwDesiredAccess As System.UInt32, ByVal dwShareMode As System.UInt32, ByVal lpSecurityAttributes As IntPtr, ByVal dwCreationDisposition As System.UInt32, ByVal dwFlagsAndAttributes As System.UInt32, ByVal hTemplateFile As IntPtr) As Microsoft.Win32.SafeHandles.SafeFileHandle

    End Function

    Public Const FILE_ATTRIBUTE_NORMAL As Short = &H80

    Public Const INVALID_HANDLE_VALUE As Short = -1

    Public Const GENERIC_READ As Long = &H80000000

    Public Const GENERIC_WRITE As UInteger = &H40000000

    Public Const CREATE_NEW As UInteger = 1

    Public Const CREATE_ALWAYS As UInteger = 2

    Public Const OPEN_EXISTING As UInteger = 3

   Dim handleValue As Microsoft.Win32.SafeHandles.SafeFileHandle = Nothing

        handleValue = CreateFile("", GENERIC_WRITE, 0, IntPtr.Zero, OPEN_EXISTING, 0, IntPtr.Zero)

        Dim fs As New FileStream(handleValue, FileAccess.ReadWrite)