PosPrinter for .net 仅打印一次并挂起

Question

我正在构建 winforms .net 应用程序，我在网络上有一台 E-Pos 打印机，使用下面的代码：在表单加载打印机初始化中：

    explorer = new PosExplorer(this);
        DeviceInfo receiptPrinterDevice = explorer.GetDevice("PosPrinter", Properties.Settings.Default.KitchenPrinter); //May need to change this if you don't use a logicial name or use a different one.
        kitchenPrinter = (PosPrinter)explorer.CreateInstance(receiptPrinterDevice);
       ConnectToPrinter();


    private void ConnectToPrinter()
    {  
        kitchenPrinter.Open();
        kitchenPrinter.Claim(10000);
        kitchenPrinter.DeviceEnabled = true;
     }

打印按钮上的函数调用：

 private void PrintReceipt()
    {

         try
            {  kitchenPrinter.PrintNormal(PrinterStation.Receipt, "test");
              }
            finally
            {

            }
    }

当我想切换到其他形式时，我调用断开连接功能

        DisconnectFromPrinter(kitchenPrinter);
        Reporting frm = new Reporting(curuser);
        frm.Show();
        this.Hide();


  private void DisconnectFromPrinter(PosPrinter kitchenPrinter)
    {

        try
        {
           kitchenPrinter.Release();
            kitchenPrinter.Close();
        }
       catch { }
    }

打印一次成功，下次按打印时抛出异常
ClaimDevice 方法抛出异常。试图对设备执行非法或不受支持的操作，或者使用了无效的参数值。

有什么建议吗？

Answer 1

由于 Release 命令无效并且可能 Claim 命令在我加载我的表单时抛出错误，因为它之前被声明过。

所以我创建了一个单独的 Class 名为 "createPOS"

         class createPOS
{
 public  static PosExplorer explorer;
  public  static PosPrinter kitchenPrinter;
  public static void createPos()
  {
      explorer = new PosExplorer();
      DeviceInfo receiptPrinterDevice = explorer.GetDevice("PosPrinter", Properties.Settings.Default.KitchenPrinter); //May need to change this if you don't use a logicial name or use a different one.
      kitchenPrinter = (PosPrinter)explorer.CreateInstance(receiptPrinterDevice);
      kitchenPrinter.Open();
      kitchenPrinter.Claim(10000);
      kitchenPrinter.DeviceEnabled = true;
  }
      public static void Print(string text){
          if (kitchenPrinter.Claimed)
              PrintTextLine(kitchenPrinter, text);  // kitchenPrinter.PrintNormal(PrinterStation.Receipt, text ); //Print text, then a new line character.
       }
      private static void PrintTextLine(PosPrinter printer, string text)
      {
          if (text.Length < printer.RecLineChars)
              printer.PrintNormal(PrinterStation.Receipt, text + Environment.NewLine); //Print text, then a new line character.
          else if (text.Length > printer.RecLineChars)
              printer.PrintNormal(PrinterStation.Receipt, TruncateAt(text, printer.RecLineChars)); //Print exactly as many characters as the printer allows, truncating the rest, no new line character (printer will probably auto-feed for us)
          else if (text.Length == printer.RecLineChars)
              printer.PrintNormal(PrinterStation.Receipt, text + Environment.NewLine); //Print text, no new line character, printer will probably auto-feed for us.
      }
      private static string TruncateAt(string text, int maxWidth)
      {
          string retVal = text;
          if (text.Length > maxWidth)
              retVal = text.Substring(0, maxWidth);

          return retVal;
      }
  }

并且只有在我初始化打印机后才能访问登录表单

     createPOS.createPos();

在 MainForm 上我调用了打印方法：

        createPOS.Print("This allows me to Print Several times");

通过这种方式，我可以多次打印，甚至可以导航到其他表格并返回，效果很好。

谢谢大家。

PosPrinter for .net 仅打印一次并挂起

PosPrinter for .net Printing only once and Hangs

c#

posprinter