Bagaimana untuk mengambil pengaturan dari pengandar Printer

Visual Basic Printer objek memungkinkan Anda untuk mendapatkan banyak printer pengemudi properti, tapi itu tidak memberikan Anda akses ke semua mereka. Contoh berikut menunjukkan cara untuk mengambil informasi dari pengandar printer yang menggunakan WIN32 API.

Pengaturan printer yang disimpan dalam sebuah struktur yang disebut DEVMODE. Sampel ini mengambil DEVMODE untuk printer default saat ini dan menampilkan pengaturan dalam suatu ListBox. Catatan bahwa ini numerik nilai-nilai yang harus dibandingkan dengan konstanta untuk menentukan maknanya. Artikel ini hanya termasuk konstanta untuk nilai-nilai yang benar-benar menampilkan kode. Lainnya konstanta dapat ditemukan di bagian referensi di akhir artikel ini.

Contoh di bawah ini berisi dua fungsi kustom, StripNulls dan ByteToString. StripNulls hanya mengambil String dan menghapus semua karakter mulai Null pertama. Ini adalah digunakan di tempat RTrim fungsi karena dalam Visual Basic 5.0, string panjang tetap diisi dengan Nulls bukan ruang-ruang yang digunakan dalam Visual Basic 4.0. Fungsi ByteToString mengkonversi array Byte ke String. DEVMODE berisi dua array.

Ada dua catatan khusus tentang contoh berikut ketika berjalan di bawah Windows NT. Pertama, banyak monokrom driver memiliki properti dmColor diatur ke 2, yang berarti mereka melaporkan yang mampu mencetak warna, tapi benar-benar tidak. Juga, beberapa pengaturan untuk "/ Generic teks saja" pengandar printer tidak dapat akurat di bawah NT.

Contoh langkah demi langkah

1. Buka projek Standard EXE yang baru. Form1 dibuat oleh default.
2. Tambah CommandButton dan ListBox ke bentuk.
3. Tambahkan kode berikut untuk Formulir modul:

         Option Explicit
   
         Private Const NULLPTR = 0&
         ' Constants for DEVMODE
         Private Const CCHDEVICENAME = 32
         Private Const CCHFORMNAME = 32
         ' Constants for DocumentProperties
         Private Const DM_MODIFY = 8
         Private Const DM_COPY = 2
         Private Const DM_IN_BUFFER = DM_MODIFY
         Private Const DM_OUT_BUFFER = DM_COPY
         ' Constants for dmOrientation
         Private Const DMORIENT_PORTRAIT = 1
         Private Const DMORIENT_LANDSCAPE = 2
         ' Constants for dmPrintQuality
         Private Const DMRES_DRAFT = (-1)
         Private Const DMRES_HIGH = (-4)
         Private Const DMRES_LOW = (-2)
         Private Const DMRES_MEDIUM = (-3)
         ' Constants for dmTTOption
         Private Const DMTT_BITMAP = 1
         Private Const DMTT_DOWNLOAD = 2
         Private Const DMTT_DOWNLOAD_OUTLINE = 4
         Private Const DMTT_SUBDEV = 3
         ' Constants for dmColor
         Private Const DMCOLOR_COLOR = 2
         Private Const DMCOLOR_MONOCHROME = 1
         ' Constants for dmCollate
         Private Const DMCOLLATE_FALSE = 0
         Private Const DMCOLLATE_TRUE = 1
         Private Const DM_COLLATE As Long = &H8000
         ' Constants for dmDuplex
         Private Const DM_DUPLEX = &H1000&
         Private Const DMDUP_HORIZONTAL = 3
         Private Const DMDUP_SIMPLEX = 1
         Private Const DMDUP_VERTICAL = 2
   
         Private Type DEVMODE
             dmDeviceName(1 To CCHDEVICENAME) As Byte
             dmSpecVersion As Integer
             dmDriverVersion As Integer
             dmSize As Integer
             dmDriverExtra As Integer
             dmFields As Long
             dmOrientation As Integer
             dmPaperSize As Integer
             dmPaperLength As Integer
             dmPaperWidth As Integer
             dmScale As Integer
             dmCopies As Integer
             dmDefaultSource As Integer
             dmPrintQuality As Integer
             dmColor As Integer
             dmDuplex As Integer
             dmYResolution As Integer
             dmTTOption As Integer
             dmCollate As Integer
             dmFormName(1 To CCHFORMNAME) As Byte
             dmUnusedPadding As Integer
             dmBitsPerPel As Integer
             dmPelsWidth As Long
             dmPelsHeight As Long
             dmDisplayFlags As Long
             dmDisplayFrequency As Long
                   
         End Type
   
         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 DocumentProperties Lib "winspool.drv" _ 
         Alias "DocumentPropertiesA" (ByVal hwnd As Long, _ 
         ByVal hPrinter As Long, ByVal pDeviceName As String, _ 
         pDevModeOutput As Any, ByVal pDevModeInput As Long, _ ByVal fMode As Long)
         As Long      
   
         Private Declare Function ClosePrinter Lib "winspool.drv" _
         (ByVal hPrinter As Long) As Long
   
         Private Declare Sub CopyMemory Lib "KERNEL32" Alias "RtlMoveMemory" _
         (hpvDest As Any, hpvSource As Any, ByVal cbCopy As Long)
   
         Function StripNulls(OriginalStr As String) As String
            If (InStr(OriginalStr, Chr(0)) > 0) Then
               OriginalStr = Left(OriginalStr, InStr(OriginalStr, Chr(0)) - 1)
            End If
            StripNulls = Trim(OriginalStr)
         End Function
   
         Function ByteToString(ByteArray() As Byte) As String
           Dim TempStr As String
           Dim I As Integer
   
           For I = 1 To CCHDEVICENAME
               TempStr = TempStr & Chr(ByteArray(I))
           Next I
           ByteToString = StripNulls(TempStr)
         End Function
   
         Function GetPrinterSettings(szPrinterName As String, hdc As Long) _
         As Boolean
         Dim hPrinter As Long
         Dim nSize As Long
         Dim pDevMode As DEVMODE
         Dim aDevMode() As Byte
         Dim TempStr As String
   
           If OpenPrinter(szPrinterName, hPrinter, NULLPTR) <> 0 Then
              nSize = DocumentProperties(NULLPTR, hPrinter, szPrinterName, _
              NULLPTR, NULLPTR, 0)
             If nSize < 1 Then
               GetPrinterSettings = False
               Exit Function
             End If
             ReDim aDevMode(1 To nSize)
             nSize = DocumentProperties(NULLPTR, hPrinter, szPrinterName, _
             aDevMode(1), NULLPTR, DM_OUT_BUFFER)
             If nSize < 0 Then
               GetPrinterSettings = False
               Exit Function
             End If
            Call CopyMemory(pDevMode, aDevMode(1), Len(pDevMode))
   
   
            List1.Clear   ' empty the ListBox
            List1.AddItem "Printer Name: " & _
            ByteToString(pDevMode.dmDeviceName)
   
            If pDevMode.dmOrientation = DMORIENT_PORTRAIT Then
               TempStr = "PORTRAIT"
            ElseIf pDevMode.dmOrientation = DMORIENT_LANDSCAPE Then
               TempStr = "LANDSCAPE"
            Else
               TempStr = "UNDEFINED"
            End If
            List1.AddItem "Orientation: " & TempStr
   
            Select Case pDevMode.dmPrintQuality
               Case DMRES_DRAFT
                   TempStr = "DRAFT"
               Case DMRES_HIGH
                   TempStr = "HIGH"
               Case DMRES_LOW
                   TempStr = "LOW"
               Case DMRES_MEDIUM
                   TempStr = "MEDIUM"
               Case Else   ' positive value
                   TempStr = CStr(pDevMode.dmPrintQuality) & " dpi"
            End Select
            List1.AddItem "Print Quality: " & TempStr
   
            Select Case pDevMode.dmTTOption
               Case DMTT_BITMAP    ' default for dot-matrix printers
                   TempStr = "TrueType fonts as graphics"
               Case DMTT_DOWNLOAD  ' default for HP printers that use PCL
                   TempStr = "Downloads TrueType fonts as soft fonts"
               Case DMTT_SUBDEV    ' default for PostScript printers
                   TempStr = "Substitute device fonts for TrueType fonts"
               Case Else
                   TempStr = "UNDEFINED"
            End Select
            List1.AddItem "TrueType Option: " & TempStr
   
            ' Windows NT drivers often return COLOR from Monochrome printers
            If pDevMode.dmColor = DMCOLOR_MONOCHROME Then
               TempStr = "MONOCHROME"
            ElseIf pDevMode.dmColor = DMCOLOR_COLOR Then
               TempStr = "COLOR"
            Else
               TempStr = "UNDEFINED"
            End If
            List1.AddItem "Color or Monochrome: " & TempStr
   
            If pDevMode.dmScale = 0 Then
               TempStr = "NONE"
            Else
               TempStr = CStr(pDevMode.dmScale)
            End If
            List1.AddItem "Scale Factor: " & TempStr
   
           If pDevMode.dmFields And DM_COLLATE Then
               If pDevMode.dmCollate = DMCOLLATE_FALSE Then
                  TempStr = "Collating is supported, but turned off"
               ElseIf pDevMode.dmCollate = DMCOLLATE_TRUE Then
                  TempStr = "Collating is supported and turned on"
               End If
            Else
               TempStr = "Collating is unsupported"
            End If
            List1.AddItem TempStr        
            If pDevMode.dmFields And DM_DUPLEX Then
               If pDevMode.dmDuplex = DMDUP_SIMPLEX Then
                  TempStr = "Duplex is supported, but turned off (1)"
               ElseIf pDevMode.dmDuplex = DMDUP_VERTICAL Then
                  TempStr = "Duplex is set to VERTICAL (2)"
               ElseIf pDevMode.dmDuplex = DMDUP_HORIZONTAL Then
                  TempStr = "Duplex is set to HORIZONTAL (3)"
               Else
                  TempStr = "Duplex is set to undefined value of " & _
                     pDevMode.dmDuplex
               End If
            Else
               TempStr = "Duplex is unsupported"
            End If
            List1.AddItem TempStr
   
            List1.AddItem "Y Resolution: " & pDevMode.dmYResolution & " dpi"
            List1.AddItem "Copies: " & CStr(pDevMode.dmCopies)
            ' Add any other items of interest ...
   
            Call ClosePrinter(hPrinter)
            GetPrinterSettings = True
         Else
            GetPrinterSettings = False
         End If
         End Function
   
         Private Sub Command1_Click()
         If GetPrinterSettings(Printer.DeviceName, Printer.hdc) = False Then
            List1.AddItem "No Settings Retrieved!"
            MsgBox "Unable to retrieve Printer settings.", , "Failure"
         End If
         End Sub
   
   					

4. Menjalankan proyek dan klik pada Command1. Default yang digunakan printer pengaturan akan ditampilkan di ListBox.

Untuk menemukan konstanta tambahan, silakan Cari di DEVMODE di baik Win32 Programmer's referensi atau Jaringan Pengembang Microsoft (MSDN) Perpustakaan CD-ROM.