Nasýl yapýlýr: bir yazýcý sürücüsü ayarlarý Al

Yazýcý sürücüsünün özelliklerini çoðuna ulaþmak Visual Basic yazýcý nesnesini saðlar, ancak bu eriþim bunlarýn tümüne vermez. Aþaðýdaki örnek, wýn32 API kullanarak yazýcý sürücüsü bilgilerini almak gösterilmiþtir.

Bir yazýcý ayarlarýný DEVMODE adlý bir yapýda saklanýr. Bu örnek geçerli bir varsayýlan yazýcý DEVMODE alýr ve bir liste kutusu içinde ayarlarýný görüntüler. Bu, ne anlama geldiðini öðrenmek için sabitlere karþýlaþtýrmasý sayýsal bir deðer olduðunu unutmayýn. Bu makale yalnýzca kodunu gerçekten görüntüler deðerleri sabitler içerir. Diðer sabitler, bu makalenin sonunda <a1>Baþvurular</a1> bölümünde bulunabilir.

Aþaðýdaki örnek, iki özel iþlevler, StripNulls ve ByteToString içerir. StripNulls yalnýzca bir dize alýr ve ilk olan null baþlayarak tüm karakterleri kaldýrýr. Visual Basic 5. 0'da, sabit uzunluklu dizeler Boþlara ile Visual Basic 4. 0'da kullanýlan boþluk yerine sýfýr bu RTrim iþlevi yerine kullanýlýr. ByteToString iþlevi, bir dize içinde bir bayt dizisi dönüþtürür. DEVMODE iki dizi içerir.

Var olan iki özel hakkýnda notlar Windows NT altýnda çalýþtýrýldýðýnda, aþaðýdaki örnek. Birinci, sürücüler, 2'ye yayýmlanmasýný, renkli yazdýrma yeteneði, bir rapor anlamýna gelir, dmColor özelliði ancak gerçekten olmayan birçok tek renkli'i týklatýn. Ayrýca, bazý ayarlar "Genel / salt metin" yazýcý sürücüsü için NT altýnda doðru olmayabilir.

Adým adým örnek

1. Yeni standart exe DOSYASý bir proje açýn. Varsayýlan olarak, Form1 oluþturulur.
2. Bir KomutDüðmesi ve bir ListBox forma ekleyin.
3. Formun modüle aþaðýdaki kodu ekleyin:

         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. Projeyi çalýþtýrýn ve üzerinde Command1'ý týklatýn. Geçerli varsayýlan yazýcý ayarlarýný bir liste içinde görüntülenir.

Ek sabitler bulmak için lütfen DEVMODE üzerinde ya da Win32 Programcý arama baþvuru ya da Microsoft Developer Network (MSDN) kitaplýðý CD-ROM'dan olur.