问题
I am trying to send ZPL commands to a Zebra ZT230 printer. The printer and drivers are installed and the printer port is "USB003". The PC communicates perfectly with the printer via either Zebra Printer Setup Utilities or ZebraDesign. I tried the following code:
Private Declare Function CreateFile Lib "kernel32.dll" (ByVal lpFileName As String, ByVal dwDesiredAccess As FileAccess, _
ByVal dwShareMode As UInteger, ByVal lpSecurityAttributes As IntPtr, ByVal dwCreationDisposition As FileMode, _
ByVal dwFlagsAndAttributes As UInteger, ByVal hTemplateFile As IntPtr) As System.Runtime.InteropServices.SafeHandle
' Command to be sent to the printer
Dim command As String = "^XA^FO10,10,^AO,30,20^FDFDTesting^FS^FO10,30^BY3^BCN,100,Y,N,N^FDTesting^FS^XZ"
' Create a buffer with the command
Dim buffer() As Byte = New Byte((command.Length) - 1) {}
buffer = System.Text.Encoding.ASCII.GetBytes(command)
' Use the CreateFile external func to connect to the LPT1 port
Dim printer As System.Runtime.InteropServices.SafeHandle = CreateFile("USB003:", FileAccess.ReadWrite, 0, IntPtr.Zero, FileMode.Open, 0, IntPtr.Zero)
' Aqui verifico se a impressora � v�lida
If (printer.IsInvalid = true) Then
Return
End If
' Open the filestream to the lpt1 port and send the command
Dim lpt1 As FileStream = New FileStream(printer, FileAccess.ReadWrite)
lpt1.Write(buffer, 0, buffer.Length)
' Close the FileStream connection
lpt1.Close
I get an error on this line: Dim printer As System.Runtime.InteropServices.SafeHandle = CreateFile("USB003:", FileAccess.ReadWrite, 0, IntPtr.Zero, FileMode.Open, 0, IntPtr.Zero)
The error message and stack trace is:
Cannot marshal 'return value': Returned SafeHandles cannot be abstract.
at PerfectPotatoInventory.vb.PotatoGlobals.CreateFile(String& lpFileName, FileAccess dwDesiredAccess, UInt32 dwShareMode, IntPtr lpSecurityAttributes, FileMode dwCreationDisposition, UInt32 dwFlagsAndAttributes, IntPtr hTemplateFile) at PerfectPotatoInventory.vb.PotatoGlobals.PrintLabelsTest() in C:\Potatoes\PerfectPotatoInventory.vb\PerfectPotatoInventory.vb\PotatoGlobals.vb:line 798
I am working in VB.net using VS2008 with target x86 and .Net 3.5.
Please advise what I am doing wrong.
回答1:
Add this class to your project
Imports System.IO
Imports System.Drawing.Printing
Imports System.Runtime.InteropServices
Public Class RAWPOSPrinter
' Structure and API declarions:
<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Unicode)> _
Structure DOCINFOW
<MarshalAs(UnmanagedType.LPWStr)> Public pDocName As String
<MarshalAs(UnmanagedType.LPWStr)> Public pOutputFile As String
<MarshalAs(UnmanagedType.LPWStr)> Public pDataType As String
End Structure
<DllImport("winspool.Drv", EntryPoint:="OpenPrinterW", _
SetLastError:=True, CharSet:=CharSet.Unicode, _
ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Public Shared Function OpenPrinter(ByVal src As String, ByRef hPrinter As IntPtr, ByVal pd As Long) As Boolean
End Function
<DllImport("winspool.Drv", EntryPoint:="ClosePrinter", _
SetLastError:=True, CharSet:=CharSet.Unicode, _
ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Public Shared Function ClosePrinter(ByVal hPrinter As IntPtr) As Boolean
End Function
<DllImport("winspool.Drv", EntryPoint:="StartDocPrinterW", _
SetLastError:=True, CharSet:=CharSet.Unicode, _
ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Public Shared Function StartDocPrinter(ByVal hPrinter As IntPtr, ByVal level As Int32, ByRef pDI As DOCINFOW) As Boolean
End Function
<DllImport("winspool.Drv", EntryPoint:="EndDocPrinter", _
SetLastError:=True, CharSet:=CharSet.Unicode, _
ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Public Shared Function EndDocPrinter(ByVal hPrinter As IntPtr) As Boolean
End Function
<DllImport("winspool.Drv", EntryPoint:="StartPagePrinter", _
SetLastError:=True, CharSet:=CharSet.Unicode, _
ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Public Shared Function StartPagePrinter(ByVal hPrinter As IntPtr) As Boolean
End Function
<DllImport("winspool.Drv", EntryPoint:="EndPagePrinter", _
SetLastError:=True, CharSet:=CharSet.Unicode, _
ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Public Shared Function EndPagePrinter(ByVal hPrinter As IntPtr) As Boolean
End Function
<DllImport("winspool.Drv", EntryPoint:="WritePrinter", _
SetLastError:=True, CharSet:=CharSet.Unicode, _
ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)> _
Public Shared Function WritePrinter(ByVal hPrinter As IntPtr, ByVal pBytes As IntPtr, ByVal dwCount As Int32, ByRef dwWritten As Int32) As Boolean
End Function
' SendBytesToPrinter()
' When the function is given a printer name and an unmanaged array of
' bytes, the function sends those bytes to the print queue.
' Returns True on success or False on failure.
Public Shared Function SendBytesToPrinter(ByVal szPrinterName As String, ByVal pBytes As IntPtr, ByVal dwCount As Int32) As Boolean
Dim hPrinter As IntPtr ' The printer handle.
Dim dwError As Int32 ' Last error - in case there was trouble.
Dim di As DOCINFOW ' Describes your document (name, port, data type).
Dim dwWritten As Int32 ' The number of bytes written by WritePrinter().
Dim bSuccess As Boolean ' Your success code.
' Set up the DOCINFO structure.
di = New DOCINFOW
With di
.pDocName = "RAW DOC"
.pDataType = "RAW"
End With
' Assume failure unless you specifically succeed.
bSuccess = False
If OpenPrinter(szPrinterName, hPrinter, 0) Then
If StartDocPrinter(hPrinter, 1, di) Then
If StartPagePrinter(hPrinter) Then
' Write your printer-specific bytes to the printer.
bSuccess = WritePrinter(hPrinter, pBytes, dwCount, dwWritten)
EndPagePrinter(hPrinter)
End If
EndDocPrinter(hPrinter)
End If
ClosePrinter(hPrinter)
End If
' If you did not succeed, GetLastError may give more information
' about why not.
If bSuccess = False Then
dwError = Marshal.GetLastWin32Error()
End If
Return bSuccess
End Function ' SendBytesToPrinter()
' SendFileToPrinter()
' When the function is given a file name and a printer name,
' the function reads the contents of the file and sends the
' contents to the printer.
' Presumes that the file contains printer-ready data.
' Shows how to use the SendBytesToPrinter function.
' Returns True on success or False on failure.
Public Shared Function SendFileToPrinter(ByVal szPrinterName As String, ByVal szFileName As String) As Boolean
' Open the file.
Dim fs As New FileStream(szFileName, FileMode.Open)
' Create a BinaryReader on the file.
Dim br As New BinaryReader(fs)
' Dim an array of bytes large enough to hold the file's contents.
Dim bytes(fs.Length) As Byte
Dim bSuccess As Boolean
' Your unmanaged pointer.
Dim pUnmanagedBytes As IntPtr
' Read the contents of the file into the array.
bytes = br.ReadBytes(fs.Length)
' Allocate some unmanaged memory for those bytes.
pUnmanagedBytes = Marshal.AllocCoTaskMem(fs.Length)
' Copy the managed byte array into the unmanaged array.
Marshal.Copy(bytes, 0, pUnmanagedBytes, fs.Length)
' Send the unmanaged bytes to the printer.
bSuccess = SendBytesToPrinter(szPrinterName, pUnmanagedBytes, fs.Length)
' Free the unmanaged memory that you allocated earlier.
Marshal.FreeCoTaskMem(pUnmanagedBytes)
Return bSuccess
End Function ' SendFileToPrinter()
' When the function is given a string and a printer name,
' the function sends the string to the printer as raw bytes.
Public Shared Sub SendStringToPrinter(ByVal szPrinterName As String, ByVal szString As String)
Dim pBytes As IntPtr
Dim dwCount As Int32
' How many characters are in the string?
dwCount = szString.Length()
' Assume that the printer is expecting ANSI text, and then convert
' the string to ANSI text.
pBytes = Marshal.StringToCoTaskMemAnsi(szString)
' Send the converted ANSI string to the printer.
SendBytesToPrinter(szPrinterName, pBytes, dwCount)
Marshal.FreeCoTaskMem(pBytes)
End Sub
End Class
Then in your code, call the following:
RAWPOSPrinter.SendStringToPrinter("<NAME OF PRINTER AS IT APPEARS IN DEVICES AND PRINTERS>", "<YOUR ZEBRA COMMAND STRING>")
回答2:
Using the Zebra .Net SDK you can call the following function: PrinterUtil.SendContents Method (String, String)
Where the first string is the ZPL to send and the second string is the printer connection string. More detail can be found here: http://techdocs.zebra.com/link-os/2-14/pc_net/
来源：https://stackoverflow.com/questions/53330880/sending-raw-text-to-printer-via-usb