fix: changed File.Open method to fix issue lukevp#234 (comment)

Author: AsimSheikh7

ESCPOS_NET.ConsoleTest/Program.cs

@@ -126,6 +126,7 @@ static void Main(string[] args)
                         if (int.TryParse(c, out int chosen) && chosen > 0)
                         {
                             usbPort = usboptions[chosen - 1].DevicePath;
+                            Console.WriteLine(usbPort);
                         }
                     }
                     printer = new USBPrinter(usbPort);

ESCPOS_NET/Printers/USBPrinter.cs

@@ -12,8 +12,8 @@ public USBPrinter(string usbPath)
             //keeping separate file streams performs better
             //while using 1 file stream printers were having intermittent issues while printing
             //your milege may vary
-            _rfile = File.Open(usbPath, FileMode.Open, FileAccess.Read);
-            _wfile = File.Open(usbPath, FileMode.Open, FileAccess.Write);
+            _rfile = DeviceFile.OpenDevice(usbPath, FileAccess.Read);
+            _wfile = DeviceFile.OpenDevice(usbPath, FileAccess.Write);
             Writer = new BinaryWriter(_wfile);
             Reader = new BinaryReader(_rfile);
         }

ESCPOS_NET/Utils/DeviceFile.cs

@@ -0,0 +1,38 @@
+using System;
+using System.IO;
+using System.Runtime.InteropServices;
+using Microsoft.Win32.SafeHandles;
+
+public static class DeviceFile
+{
+    [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
+    public static extern SafeFileHandle CreateFile(
+        string lpFileName,
+        uint dwDesiredAccess,
+        uint dwShareMode,
+        IntPtr lpSecurityAttributes,
+        uint dwCreationDisposition,
+        uint dwFlagsAndAttributes,
+        IntPtr hTemplateFile);
+
+    public static FileStream OpenDevice(string devicePath, FileAccess access)
+    {
+        const uint OPEN_EXISTING = 3;
+        const uint FILE_ATTRIBUTE_NORMAL = 0x80;
+        uint desiredAccess = access == FileAccess.Read ? 0x80000000 : 0x40000000; // GENERIC_READ or GENERIC_WRITE
+
+        SafeFileHandle handle = CreateFile(
+            devicePath,
+            desiredAccess,
+            0, // No sharing
+            IntPtr.Zero,
+            OPEN_EXISTING,
+            FILE_ATTRIBUTE_NORMAL,
+            IntPtr.Zero);
+
+        if (handle.IsInvalid)
+            throw new IOException("Unable to open device", Marshal.GetLastWin32Error());
+
+        return new FileStream(handle, access);
+    }
+}