Imports System.IO
Imports System.Runtime.InteropServices

Public Class zebraPrinterClass
    <StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi)>
    Public Class DOCINFOA
        <MarshalAs(UnmanagedType.LPStr)>
        Public pDocName As String
        <MarshalAs(UnmanagedType.LPStr)>
        Public pOutputFile As String
        <MarshalAs(UnmanagedType.LPStr)>
        Public pDataType As String
    End Class

    <DllImport("winspool.Drv", EntryPoint:="OpenPrinterA", SetLastError:=True, CharSet:=CharSet.Ansi, ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)>
    Public Shared Function OpenPrinter(<MarshalAs(UnmanagedType.LPStr)> ByVal szPrinter As String, <Out> ByRef hPrinter As IntPtr, ByVal pd As IntPtr) As Boolean
    End Function

    <DllImport("winspool.Drv", EntryPoint:="ClosePrinter", SetLastError:=True, ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)>
    Public Shared Function ClosePrinter(ByVal hPrinter As IntPtr) As Boolean
    End Function
    '
    <DllImport("winspool.Drv", EntryPoint:="StartDocPrinterA", SetLastError:=True, CharSet:=CharSet.Ansi, ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)>
    Public Shared Function StartDocPrinter(ByVal hPrinter As IntPtr, ByVal level As Int32, <[In], MarshalAs(UnmanagedType.LPStruct)> ByVal di As DOCINFOA) As Boolean
    End Function

    <DllImport("winspool.Drv", EntryPoint:="EndDocPrinter", SetLastError:=True, ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)>
    Public Shared Function EndDocPrinter(ByVal hPrinter As IntPtr) As Boolean
    End Function

    <DllImport("winspool.Drv", EntryPoint:="StartPagePrinter", SetLastError:=True, ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)>
    Public Shared Function StartPagePrinter(ByVal hPrinter As IntPtr) As Boolean
    End Function

    <DllImport("winspool.Drv", EntryPoint:="EndPagePrinter", SetLastError:=True, ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)>
    Public Shared Function EndPagePrinter(ByVal hPrinter As IntPtr) As Boolean
    End Function

    <DllImport("winspool.Drv", EntryPoint:="WritePrinter", SetLastError:=True, ExactSpelling:=True, CallingConvention:=CallingConvention.StdCall)>
    Public Shared Function WritePrinter(ByVal hPrinter As IntPtr, ByVal pBytes As IntPtr, ByVal dwCount As Int32, <Out> ByRef dwWritten As Int32) As Boolean
    End Function

    <DllImport("winspool.Drv")>
    Public Shared Function SetDefaultPrinter(name As String) As Boolean
    End Function


    Public Shared Function SendBytesToPrinter(ByVal szPrinterName As String, ByVal pByte As IntPtr, ByVal dwCount As Int32) As Boolean
        Dim dwError As Int32 = 0, dwWritten As Int32 = 0
        Dim hPrinter As IntPtr = New IntPtr(0)
        Dim di As DOCINFOA = New DOCINFOA
        Dim bSuccess As Boolean = False
        di.pDocName = "My VB.NET RAW Document"
        di.pDataType = "RAW"

        If OpenPrinter(szPrinterName.Normalize, hPrinter, IntPtr.Zero) Then
            If StartDocPrinter(hPrinter, 1, di) Then
                If StartPagePrinter(hPrinter) Then
                    bSuccess = WritePrinter(hPrinter, pByte, dwCount, dwWritten)
                    EndPagePrinter(hPrinter)
                End If
                EndDocPrinter(hPrinter)
            End If
            ClosePrinter(hPrinter)
        End If

        If bSuccess = False Then
            dwError = Marshal.GetLastWin32Error
        End If

        Return bSuccess
    End Function

    Public Shared Function SendFileToPrinter(ByVal szPrinterName As String, ByVal szFileName As String) As Boolean
        Dim fs As FileStream = New FileStream(szFileName, FileMode.Open)
        Dim br As BinaryReader = New BinaryReader(fs)
        Dim bytes As Byte() = New Byte(fs.Length - 1) {}
        Dim bSuccess As Boolean = False
        Dim pUnmanagedBytes As IntPtr = New IntPtr(0)
        Dim nLength As Integer
        nLength = Convert.ToInt32(fs.Length)
        bytes = br.ReadBytes(nLength)
        pUnmanagedBytes = Marshal.AllocCoTaskMem(nLength)
        Marshal.Copy(bytes, 0, pUnmanagedBytes, nLength)
        bSuccess = SendBytesToPrinter(szPrinterName, pUnmanagedBytes, nLength)
        Marshal.FreeCoTaskMem(pUnmanagedBytes)

        Return bSuccess
    End Function

    Public Shared Function SendStringToPrinter(ByVal szPrinterName As String, ByVal szString As String) As Boolean
        Try
            Dim pBytes As IntPtr
            Dim dwCount As Int32
            dwCount = (szString.Length + 1) * Marshal.SystemMaxDBCSCharSize
            pBytes = Marshal.StringToCoTaskMemAnsi(szString)
            SendBytesToPrinter(szPrinterName, pBytes, dwCount)
            Marshal.FreeCoTaskMem(pBytes)
            Return True
        Catch ex As Exception
            MsgBox("SendStringToPrinter Error ::" & ex.Message)
            Return False
        End Try

    End Function
End Class