HOWTO: Print Line-by-Line to a Printer

• Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, version 5.0
• Microsoft Visual Basic Standard, Professional, and Enterprise Editions, 32-bit only, for Windows, version 4.0

SUMMARY

Printing page-by-page is the Windows standard; however, it is sometimes desirable to print to a printer line-by-line rather than page-by-page. One advantage to printing line-by-line is that if there is a power failure while printing, the data lost is one log item, at most. The Visual Basic Printer object does not support this mode, but the Win32 API accomplishes this handily.

MORE INFORMATION

This technique will work only when printing to a local line printer, typically a dot matrix printer. Laser and Ink Jet printers are page printers and will not print in single line mode.

1. Create a new Visual Basic project and place a CommandButton on Form1.

2. Add the following code to Form1:

         Option Explicit
   

         Private Type DOCINFO
             pDocName As String
             pOutputFile As String
             pDatatype As String
         End Type
   
         Private Declare Function ClosePrinter Lib "winspool.drv" (ByVal _
            hPrinter As Long) As Long
         Private Declare Function EndDocPrinter Lib "winspool.drv" (ByVal _
            hPrinter As Long) As Long
         Private Declare Function EndPagePrinter Lib "winspool.drv" (ByVal _
            hPrinter As Long) As Long
         Private Declare Function OpenPrinter Lib "winspool.drv" Alias _
            "OpenPrinterA" (ByVal pPrinterName As String, phPrinter As Long, _
             ByVal pDefault As Long) As Long
         Private Declare Function StartDocPrinter Lib "winspool.drv" Alias _
            "StartDocPrinterA" (ByVal hPrinter As Long, ByVal Level As Long, _
            pDocInfo As DOCINFO) As Long
         Private Declare Function StartPagePrinter Lib "winspool.drv" (ByVal _
            hPrinter As Long) As Long
         Private Declare Function WritePrinter Lib "winspool.drv" (ByVal _
            hPrinter As Long, pBuf As Any, ByVal cdBuf As Long, _
            pcWritten As Long) As Long
   
         Dim lhPrinter As Long
   
         Private Sub Command1_Click()
                Dim lReturn As Long
                Dim lpcWritten As Long
                Dim sWrittenData As String
                sWrittenData = "How's that for Magic !!!!" & vbCrLf
                lReturn = WritePrinter(lhPrinter, ByVal sWrittenData, _
                   Len(sWrittenData), lpcWritten)
         End Sub
   
         Private Sub Form_Load()
             Dim lReturn As Long
             Dim lDoc As Long
             Dim MyDocInfo As DOCINFO
   
             lReturn = OpenPrinter(Printer.DeviceName, lhPrinter, 0)
             If lReturn = 0 Then
                 MsgBox "The Printer Name you typed wasn't recognized."
                 Exit Sub
             End If
             MyDocInfo.pDocName = "AAAAAA"
             MyDocInfo.pOutputFile = vbNullString
             MyDocInfo.pDatatype = vbNullString
             lDoc = StartDocPrinter(lhPrinter, 1, MyDocInfo)
             Call StartPagePrinter(lhPrinter)
         End Sub
   
         Private Sub Form_Unload(Cancel As Integer)
             Dim lReturn As Long
   
             lReturn = EndPagePrinter(lhPrinter)
             lReturn = EndDocPrinter(lhPrinter)
             lReturn = ClosePrinter(lhPrinter)
         End Sub
   
   

3. Make the logging printer the default and run the application. Every time you click Command1, a line should be immediately printed to your printer.

REFERENCES

For more information about using the Win32 API to send data directly to the printer, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q154078
   Title     : HOWTO: Send Raw Data to a Printer Using the Win32 API
               from VB

Keywords          : vb432 VB4WIN vb5all vb5howto kbprint
Version           : WINDOWS:4.0,5.0
Platform          : WINDOWS
Issue type        : kbhowto