怎样确定打印机没有纸?

[bubugao]

怎样确定打印机没有纸?

[lvjack]

回复人： dev_uoboy(过程编程→面向对象) ( ) 信誉：105 2002-3-7 21:25:02 得分:100
使用PRINTER_INFO_2结构的Status域。
比如塞纸、缺纸、忙等。
如果需要例子的话，我可以写出来
.h文件

#ifndef MainUnitH
#define MainUnitH
//---------------------------------------------------------------------------
#include <Classes.hpp>
#include <Controls.hpp>
#include <StdCtrls.hpp>
#include <Forms.hpp>
#include <ComCtrls.hpp>
//---------------------------------------------------------------------------
class TMainForm : public TForm
{
__published: // IDE-managed Components
TLabel *Label1;
TComboBox *PrinterComboBox;
TLabel *Label2;
TEdit *CommentEdit;
TButton *SetCommentButton;
TStatusBar *StatusBar;
void __fastcall FormCreate(TObject *Sender);
void __fastcall SetCommentButtonClick(TObject *Sender);
void __fastcall PrinterComboBoxClick(TObject *Sender);
private: // User declarations
void __fastcall UpdateStatusBar();
AnsiString __fastcall GetComment(char *szPrinterName);
void __fastcall SetComment(char *szPrinterName, AnsiString &asComment);
public: // User declarations
__fastcall TMainForm(TComponent* Owner);
};
//---------------------------------------------------------------------------
extern PACKAGE TMainForm *MainForm;
//---------------------------------------------------------------------------
#endif

.cpp文件

#include <vcl.h>
#pragma hdrstop

#include "MainUnit.h"
#include <printers.hpp> // Include VCL's TPrinter
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TMainForm *MainForm;
//---------------------------------------------------------------------------
__fastcall TMainForm::TMainForm(TComponent* Owner)
: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TMainForm::FormCreate(TObject *Sender)
{
PrinterComboBox->Items = Printer()->Printers;
PrinterComboBox->ItemIndex = 0;
UpdateStatusBar();
}
//---------------------------------------------------------------------------
void __fastcall TMainForm::UpdateStatusBar()
{
char szDeviceName[CCHDEVICENAME], // 打应机名
szDriverName[MAX_PATH],
szPortName[MAX_PATH];
THandle hPrnDevMode;

PrinterComboBox
Printer()->PrinterIndex = PrinterComboBox->ItemIndex;
// 取得名字
Printer()->GetPrinter(szDeviceName, szDriverName, szPortName, hPrnDevMode);

StatusBar->SimpleText = "Comment: "+GetComment(szDeviceName);
}
//---------------------------------------------------------------------------
AnsiString __fastcall TMainForm::GetComment(char *szPrinterName)
{
HANDLE hPrinter;
PRINTER_DEFAULTS pd;

DWORD dwNeeded;

PRINTER_INFO_2 *pPrtInfo2; // PRINTER_INFO_2 结构指针.

AnsiString asComment;


ZeroMemory(&pd, sizeof(PRINTER_DEFAULTS));

pd.DesiredAccess = PRINTER_ALL_ACCESS;

if(!OpenPrinter(szPrinterName, &hPrinter, &pd))
{
throw Exception("Call to OpenPrinter() failed");
}

if(!GetPrinter(hPrinter, 2, NULL, 0, &dwNeeded))
{
if(GetLastError() != ERROR_INSUFFICIENT_BUFFER)
{
ClosePrinter(hPrinter);
throw Exception("1st call to GetPrinter() failed");
}
}

pPrtInfo2 = (PRINTER_INFO_2*) malloc(dwNeeded);
if(pPrtInfo2 == NULL)
{
ClosePrinter(hPrinter);
throw Exception("Call to malloc() failed");
}

// 填充 PRINTER_INFO_2
if(!GetPrinter(hPrinter, 2, (LPBYTE)pPrtInfo2,
dwNeeded, &dwNeeded))
{
free(pPrtInfo2);
ClosePrinter(hPrinter);
throw Exception("2nd call to GetPrinter() failed");
}

asComment = pPrtInfo2->pComment;

free(pPrtInfo2);
ClosePrinter(hPrinter);

return asComment;
}
//---------------------------------------------------------------------------
void __fastcall TMainForm::SetComment(char *szPrinterName,
AnsiString &asComment)
{
HANDLE hPrinter;
PRINTER_DEFAULTS pd;


DWORD dwNeeded;

PRINTER_INFO_2 *pPrtInfo2;


ZeroMemory(&pd, sizeof(PRINTER_DEFAULTS));
pd.DesiredAccess = PRINTER_ALL_ACCESS;

if(!OpenPrinter(szPrinterName, &hPrinter, &pd))
{
throw Exception("Call to OpenPrinter() failed");
}

if(!GetPrinter(hPrinter, 2, NULL, 0, &dwNeeded))
{
if(GetLastError() != ERROR_INSUFFICIENT_BUFFER)
{
ClosePrinter(hPrinter);
throw Exception("1st call to GetPrinter() failed");
}
}

pPrtInfo2 = (PRINTER_INFO_2*) malloc(dwNeeded);
if(pPrtInfo2 == NULL)
{
ClosePrinter(hPrinter);
throw Exception("Call to malloc() failed");
}

if(!GetPrinter(hPrinter, 2, (LPBYTE)pPrtInfo2,
dwNeeded, &dwNeeded))
{
free(pPrtInfo2);
ClosePrinter(hPrinter);
throw Exception("2nd call to GetPrinter() failed");
}

pPrtInfo2->pComment = asComment.c_str();

if(!SetPrinter(hPrinter, 2, (LPBYTE)pPrtInfo2, 0))
{
free(pPrtInfo2);
ClosePrinter(hPrinter);
throw Exception("Call to SetPrinter() failed");
}

free(pPrtInfo2);
ClosePrinter(hPrinter);
}
//---------------------------------------------------------------------------

void __fastcall TMainForm::SetCommentButtonClick(TObject *Sender)
{
char szDeviceName[CCHDEVICENAME],
szDriverName[MAX_PATH],
szPortName[MAX_PATH];
THandle hPrnDevMode;


Printer()->PrinterIndex = PrinterComboBox->ItemIndex;

Printer()->GetPrinter(szDeviceName, szDriverName, szPortName, hPrnDevMode);

SetComment(szDeviceName, CommentEdit->Text);
CommentEdit->Text = "";
UpdateStatusBar();
}
//---------------------------------------------------------------------------
void __fastcall TMainForm::PrinterComboBoxClick(TObject *Sender)
{
UpdateStatusBar();
}