Vb.net ick（ByVal发送者作为System.Object，ByVal e作为System.EventArgs）处理按钮1。单击 如果是真的话 '允许用户选择一个文件。 Dim ofd作为新的OpenFileDialog（） 如果DialogResult.OK=ofd.ShowDialog（Me），则 '允许用户选择打印机。 将pd设置为新的打印对话框（） pd.PrinterSettings=新的PrinterSettings（） 如果DialogResult.OK=pd.ShowDialog（Me），则 '将文件打印到打印机。 SendFileToPrinter（pd.PrinterSettings.PrinterName，ofd.FileName） 如果结束 如果结束 如果结束 端接头 末级

我有一些OpenPrinter的C代码，应该很容易翻译

[DllImport("winspool.drv", EntryPoint = "OpenPrinter", SetLastError = true)]
internal static extern bool OpenPrinter(string pPrinterName, ref IntPtr phPrinter, PRINTER_DEFAULTS pDefault);

[DllImport("winspool.drv", EntryPoint = "ClosePrinter", SetLastError = true)]
internal static extern int ClosePrinter(IntPtr hPrinter);

[StructLayout(LayoutKind.Sequential)]
public class PRINTER_DEFAULTS
{
    public string pDatatype;
    public IntPtr pDevMode;
    public int DesiredAccess;
}

public struct OpenPrinterAccessCodes
{
    public const int DELETE = 0x10000; // DELETE - Allowed to delete printers
    public const int READ_CONTROL = 0x20000; // READ_CONTROL - Allowed to read printer information
    public const int WRITE_DAC = 0x40000; // WRITE_DAC - Allowed to write device access control info
    public const int WRITE_OWNER = 0x80000; // WRITE_OWNER - Allowed to change the object owner
    public const int SERVER_ACCESS_ADMINISTER = 0x1;
    public const int SERVER_ACCESS_ENUMERATE = 0x2;
    public const int PRINTER_ACCESS_ADMINISTER = 0x4;
    public const int PRINTER_ACCESS_USE = 0x8;
    public const int STANDARD_RIGHTS_REQUIRED = 0xF0000;
    public const int PRINTER_ALL_ACCESS = (STANDARD_RIGHTS_REQUIRED | PRINTER_ACCESS_ADMINISTER | PRINTER_ACCESS_USE);
    public const int SERVER_ALL_ACCESS = (STANDARD_RIGHTS_REQUIRED | SERVER_ACCESS_ADMINISTER | SERVER_ACCESS_ENUMERATE);

    public const int MAX_PORTNAME_LEN = 64;
    public const int MAX_NETWORKNAME_LEN = 49;
    public const int MAX_SNMP_COMMUNITY_STR_LEN = 33;
    public const int MAX_QUEUENAME_LEN = 33;
    public const int MAX_IPADDR_STR_LEN = 16;

    public const int ERROR_INSUFFICIENT_BUFFER = 122;
    public const int ERROR_INVALID_FLAGS = 1004;
}
    public IntPtr OpenPrinterHandle(string printerName)
    {
        var def = new PRINTER_DEFAULTS { pDatatype = null, pDevMode = IntPtr.Zero, DesiredAccess = OpenPrinterAccessCodes.PRINTER_ALL_ACCESS };
        var hPrinter = IntPtr.Zero;
        if (!OpenPrinter(printerName, ref hPrinter, def))
        {
            var lastWin32Error = new Win32Exception(Marshal.GetLastWin32Error());
            Logger.Log("Failed open Printer: " + lastWin32Error.Message);
            throw lastWin32Error;
        }
        return hPrinter;
    }

    public void ClosePrinterHandle(IntPtr hPrinter)
    {
        ClosePrinter(hPrinter);
    }

87（0x57）是错误\无效\参数，“参数不正确”。换句话说，调用OpenPrinter中的一个参数错误

的Win32 API参考告诉我们以下哪一个：

pDefault[in]指向打印机默认结构的指针。此值可以为空

您在调用中将此设置为

InPtr.Zero

，但声明InPtr.Zero“表示已初始化为零的指针或句柄”，并继续特别警告它不等同于

Nothing

因此，对OpenPrinter的正确调用应该是：

OpenPrinter（szPrinterName.Normalize（），hPrinter，Nothing）

[DllImport("winspool.drv", EntryPoint = "OpenPrinter", SetLastError = true)]
internal static extern bool OpenPrinter(string pPrinterName, ref IntPtr phPrinter, PRINTER_DEFAULTS pDefault);

[DllImport("winspool.drv", EntryPoint = "ClosePrinter", SetLastError = true)]
internal static extern int ClosePrinter(IntPtr hPrinter);

[StructLayout(LayoutKind.Sequential)]
public class PRINTER_DEFAULTS
{
    public string pDatatype;
    public IntPtr pDevMode;
    public int DesiredAccess;
}

public struct OpenPrinterAccessCodes
{
    public const int DELETE = 0x10000; // DELETE - Allowed to delete printers
    public const int READ_CONTROL = 0x20000; // READ_CONTROL - Allowed to read printer information
    public const int WRITE_DAC = 0x40000; // WRITE_DAC - Allowed to write device access control info
    public const int WRITE_OWNER = 0x80000; // WRITE_OWNER - Allowed to change the object owner
    public const int SERVER_ACCESS_ADMINISTER = 0x1;
    public const int SERVER_ACCESS_ENUMERATE = 0x2;
    public const int PRINTER_ACCESS_ADMINISTER = 0x4;
    public const int PRINTER_ACCESS_USE = 0x8;
    public const int STANDARD_RIGHTS_REQUIRED = 0xF0000;
    public const int PRINTER_ALL_ACCESS = (STANDARD_RIGHTS_REQUIRED | PRINTER_ACCESS_ADMINISTER | PRINTER_ACCESS_USE);
    public const int SERVER_ALL_ACCESS = (STANDARD_RIGHTS_REQUIRED | SERVER_ACCESS_ADMINISTER | SERVER_ACCESS_ENUMERATE);

    public const int MAX_PORTNAME_LEN = 64;
    public const int MAX_NETWORKNAME_LEN = 49;
    public const int MAX_SNMP_COMMUNITY_STR_LEN = 33;
    public const int MAX_QUEUENAME_LEN = 33;
    public const int MAX_IPADDR_STR_LEN = 16;

    public const int ERROR_INSUFFICIENT_BUFFER = 122;
    public const int ERROR_INVALID_FLAGS = 1004;
}
    public IntPtr OpenPrinterHandle(string printerName)
    {
        var def = new PRINTER_DEFAULTS { pDatatype = null, pDevMode = IntPtr.Zero, DesiredAccess = OpenPrinterAccessCodes.PRINTER_ALL_ACCESS };
        var hPrinter = IntPtr.Zero;
        if (!OpenPrinter(printerName, ref hPrinter, def))
        {
            var lastWin32Error = new Win32Exception(Marshal.GetLastWin32Error());
            Logger.Log("Failed open Printer: " + lastWin32Error.Message);
            throw lastWin32Error;
        }
        return hPrinter;
    }

    public void ClosePrinterHandle(IntPtr hPrinter)
    {
        ClosePrinter(hPrinter);
    }