我在远程机器上托管了我的网站。我可以通过在线链接访问该网站（例如：xyz.mysite.com）。我需要从该在线网站打印一个标签。我编写了一个下面的代码来打印标签（在我的应用程序中使用了Neodynamic thermal SDK库）。
var pj = new PrintJob();
PrinterSettings myPrinter = new PrinterSettings();
myPrinter.Communication.CommunicationType = CommunicationType.Network;
myPrinter.Communication.NetworkIPAddress = System.Net.IPAddress.Parse("127.0.0.1"); // Used my local network IP address.
myPrinter.Communication.NetworkPort = 9100;
myPrinter.UseDefaultPrinter = true;
myPrinter.ProgrammingLanguage = ProgrammingLanguage.ZPL;
pj.PrinterSettings = myPrinter;
pj.Print(myLabel);
当我在网站上执行打印操作时，面对下面的错误，
获取默认打印机时发生异常。 Win32错误：系统找不到指定的文件。
谁能建议我解决这个问题？
我为这个案例开发了一个websocket qazxsw poi
这是在ConsoleApp上运行的套接字代码c＃：
$(document).ready(function () { var connection = new WebSocket('ws://localhost:2645/service/'); const reader = new FileReader();
$('.sendZPL').on('click', function () {
var tosend = {
TipoArchivo: 0,
nombre: "Etiqueta de Prueba",
code: $(".sendZPL").val(),
Tipo: 4,
Impresora: $(".impresora").val()
}
connection.send(JSON.stringify(tosend));
});
connection.addEventListener('message', function (event) {
reader.readAsText(event.data);
});
reader.addEventListener('loadend', (e) => {
const text = e.srcElement.result;
console.log(text);
$(".serverResponse").val(text);
});
});
RAWPrinterClass class Program
{
private static Server.WebsocketServer websocketServer;
private static System.Diagnostics.EventLog eventLog1= new EventLog();
static void Main( string[] args )
{
if (!System.Diagnostics.EventLog.SourceExists( "MySource" ))
{
System.Diagnostics.EventLog.CreateEventSource(
"MySource", "MyNewLog" );
}
eventLog1.Source = "MySource";
eventLog1.Log = "MyNewLog";
websocketServer = new Server.WebsocketServer();
websocketServer.LogMessage += WebsocketServer_LogMessage;
websocketServer.Start( "http://localhost:2645/tryservice/" );
Console.Read();
}
private static void WebsocketServer_LogMessage( object sender, Server.WebsocketServer.LogMessageEventArgs e )
{
// eventLog1.WriteEntry( e.Message );
Console.ForegroundColor = ConsoleColor.Yellow;
Console.WriteLine( e.Message );
Console.ForegroundColor = ConsoleColor.White;
}
public class WebsocketServer
{
public event OnLogMessage LogMessage;
public delegate void OnLogMessage(Object sender, LogMessageEventArgs e);
public class LogMessageEventArgs : EventArgs
{
public string Message { get; set; }
public LogMessageEventArgs(string Message) {
this.Message = Message;
}
}
public bool started = false;
public async void Start(string httpListenerPrefix)
{
HttpListener httpListener = new HttpListener();
httpListener.Prefixes.Add(httpListenerPrefix);
httpListener.Start();
LogMessage(this, new LogMessageEventArgs("Listening..."));
started = true;
while (started)
{
HttpListenerContext httpListenerContext = await httpListener.GetContextAsync();
if (httpListenerContext.Request.IsWebSocketRequest)
{
ProcessRequest(httpListenerContext);
}
else
{
httpListenerContext.Response.StatusCode = 400;
httpListenerContext.Response.Close();
LogMessage(this, new LogMessageEventArgs("Closed..."));
}
}
}
public void Stop()
{
started = false;
}
private List<string> _printers = new List<string>();
public List<string> Printers { get
{
_printers.Clear();
foreach (string imp in System.Drawing.Printing.PrinterSettings.InstalledPrinters)
{
_printers.Add(imp);
}
return _printers;
}
}
private async void ProcessRequest(HttpListenerContext httpListenerContext)
{
WebSocketContext webSocketContext = null;
try
{
webSocketContext = await httpListenerContext.AcceptWebSocketAsync(subProtocol: null);
LogMessage(this, new LogMessageEventArgs("Connected"));
}
catch (Exception e)
{
httpListenerContext.Response.StatusCode = 500;
httpListenerContext.Response.Close();
LogMessage(this, new LogMessageEventArgs(String.Format("Exception: {0}", e)));
return;
}
WebSocket webSocket = webSocketContext.WebSocket;
try
{
while (webSocket.State == WebSocketState.Open)
{
ArraySegment<Byte> buffer = new ArraySegment<byte>(new Byte[8192]);
WebSocketReceiveResult result = null;
using (var ms = new System.IO.MemoryStream())
{
do
{
result = await webSocket.ReceiveAsync(buffer, CancellationToken.None);
ms.Write(buffer.Array, buffer.Offset, result.Count);
}
while (!result.EndOfMessage);
ms.Seek(0, System.IO.SeekOrigin.Begin);
if (result.MessageType == WebSocketMessageType.Text)
{
using (var reader = new System.IO.StreamReader(ms, Encoding.UTF8))
{
var r = System.Text.Encoding.UTF8.GetString(ms.ToArray());
var t = Newtonsoft.Json.JsonConvert.DeserializeObject<Datos>(r);
bool valid = true;
byte[] toBytes = Encoding.UTF8.GetBytes("Error..."); ;
if (t != null)
{
if (t.Impresora.Trim() == string.Empty)
{
var printers = "";
Printers.ForEach(print => {
printers += print + "\n";
});
toBytes = Encoding.UTF8.GetBytes("No se Indicó la Impresora\nLas Impresoras disponibles son:\n" + printers);
valid = false;
}
else if(!Printers.Contains(t.Impresora))
{
var printers = "";
Printers.ForEach(print =>
{
printers += print + "\n";
});
toBytes = Encoding.UTF8.GetBytes("Impresora no valida\nLas Impresoras disponibles son:\n" + printers);
valid = false;
}
if (t.nombre.Trim() == string.Empty)
{
toBytes = Encoding.UTF8.GetBytes("No se Indicó el nombre del Documento");
valid = false;
}
if (t.code== null)
{
toBytes = Encoding.UTF8.GetBytes("No hay datos para enviar a la Impresora");
valid = false;
}
if (valid && print.RawPrinter.SendStringToPrinter(t.Impresora, t.code, t.nombre))
{
LogMessage(this, new LogMessageEventArgs(String.Format("Enviado: {0} => {1} => {2}", t.Impresora, t.nombre, t.code)));
toBytes = Encoding.UTF8.GetBytes("Correcto...");
}
await webSocket.SendAsync(new ArraySegment<byte>(toBytes, 0, int.Parse(toBytes.Length.ToString())), WebSocketMessageType.Binary, result.EndOfMessage, CancellationToken.None);
}
else
{
toBytes = Encoding.UTF8.GetBytes("Error...");
await webSocket.SendAsync(new ArraySegment<byte>(toBytes, 0, int.Parse(toBytes.Length.ToString())), WebSocketMessageType.Binary, result.EndOfMessage, CancellationToken.None);
}
}
}
}
}
}
catch (Exception e)
{
LogMessage(this, new LogMessageEventArgs(String.Format("Exception: {0} \nLinea:{1}", e, e.StackTrace)));
}
finally
{
if (webSocket != null)
webSocket.Dispose();
}
}
}
public class Datos {
public enum TipoArchivo { zpl, pdf, doc, json, text}
public string nombre { get; set; }
public string code { get; set; }
public TipoArchivo Tipo { get; set; } = TipoArchivo.text;
public string Impresora { get; set; } = "";
}
}
：
link
我用 public class RawPrinter
{
// Structure and API declarions:
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public class DOCINFOA
{
[MarshalAs(UnmanagedType.LPStr)]
public string pDocName;
[MarshalAs(UnmanagedType.LPStr)]
public string pOutputFile;
[MarshalAs(UnmanagedType.LPStr)]
public string pDataType;
}
[DllImport("winspool.Drv", EntryPoint = "OpenPrinterA", SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool OpenPrinter([MarshalAs(UnmanagedType.LPStr)]
string szPrinter, ref IntPtr hPriknter, IntPtr pd);
[DllImport("winspool.Drv", EntryPoint = "ClosePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool ClosePrinter(IntPtr hPrinter);
[DllImport("winspool.Drv", EntryPoint = "StartDocPrinterA", SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool StartDocPrinter(IntPtr hPrinter, Int32 level, [In(), MarshalAs(UnmanagedType.LPStruct)]
DOCINFOA di);
[DllImport("winspool.Drv", EntryPoint = "EndDocPrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool EndDocPrinter(IntPtr hPrinter);
[DllImport("winspool.Drv", EntryPoint = "StartPagePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool StartPagePrinter(IntPtr hPrinter);
[DllImport("winspool.Drv", EntryPoint = "EndPagePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool EndPagePrinter(IntPtr hPrinter);
[DllImport("winspool.Drv", EntryPoint = "WritePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool WritePrinter(IntPtr hPrinter, IntPtr pBytes, Int32 dwCount, ref Int32 dwWritten);
// SendBytesToPrinter()
// When the function is given a printer name and an unmanaged array
// of bytes, the function sends those bytes to the print queue.
// Returns true on success, false on failure.
public static bool SendBytesToPrinter(string szPrinterName, IntPtr pBytes, Int32 dwCount, string DocName = "")
{
Int32 dwError = 0;
Int32 dwWritten = 0;
IntPtr hPrinter = new IntPtr(0);
DOCINFOA di = new DOCINFOA();
bool bSuccess = false;
// Assume failure unless you specifically succeed.
di.pDocName = string.IsNullOrEmpty(DocName) ? "My C#.NET RAW Document" : DocName;
di.pDataType = "RAW";
// Open the printer.
if (OpenPrinter(szPrinterName.Normalize(), ref hPrinter, IntPtr.Zero))
{
// Start a document.
if (StartDocPrinter(hPrinter, 1, di))
{
// Start a page.
if (StartPagePrinter(hPrinter))
{
// Write your bytes.
bSuccess = WritePrinter(hPrinter, pBytes, dwCount, ref dwWritten);
EndPagePrinter(hPrinter);
}
EndDocPrinter(hPrinter);
}
ClosePrinter(hPrinter);
}
// If you did not succeed, GetLastError may give more information
// about why not.
if (bSuccess == false)
{
dwError = Marshal.GetLastWin32Error();
}
return bSuccess;
}
public static bool SendFileToPrinter(string szPrinterName, string szFileName)
{
// Open the file.
FileStream fs = new FileStream(szFileName, FileMode.Open);
// Create a BinaryReader on the file.
BinaryReader br = new BinaryReader(fs);
// Dim an array of bytes big enough to hold the file's contents.
Byte[] bytes = new Byte[fs.Length];
bool bSuccess = false;
// Your unmanaged pointer.
IntPtr pUnmanagedBytes = new IntPtr(0);
int nLength = 0;
nLength = Convert.ToInt32(fs.Length);
// Read the contents of the file into the array.
bytes = br.ReadBytes(nLength);
// Allocate some unmanaged memory for those bytes.
pUnmanagedBytes = Marshal.AllocCoTaskMem(nLength);
// Copy the managed byte array into the unmanaged array.
Marshal.Copy(bytes, 0, pUnmanagedBytes, nLength);
// Send the unmanaged bytes to the printer.
bSuccess = SendBytesToPrinter(szPrinterName, pUnmanagedBytes, nLength);
// Free the unmanaged memory that you allocated earlier.
Marshal.FreeCoTaskMem(pUnmanagedBytes);
return bSuccess;
}
public static bool SendStringToPrinter(string szPrinterName, string szString, string DocName = "")
{
IntPtr pBytes = default(IntPtr);
Int32 dwCount = default(Int32);
// How many characters are in the string?
dwCount = szString.Length;
// Assume that the printer is expecting ANSI text, and then convert
// the string to ANSI text.
pBytes = Marshal.StringToCoTaskMemAnsi(szString);
// Send the converted ANSI string to the printer.
var t= SendBytesToPrinter(szPrinterName, pBytes, dwCount, DocName);
Marshal.FreeCoTaskMem(pBytes);
return t;
}
}
来解决我的问题。