'Microsoft.PointOfService.Management.Explorer'的類型初始值設定項引發異常。 C＃打印POS

Question

private void Form1_Load(object sender, EventArgs e) 
{ 
    PrintReceipt(); 
} 

private void PrintReceipt() 
{ 
    PosPrinter printer = GetReceiptPrinter(); 

    try 
    { 
     ConnectToPrinter(printer); 

     PrintReceiptHeader(printer, "ABCDEF Pte. Ltd.", "123 My Street, My City,", "My State, My Country", "012-3456789", DateTime.Now, "ABCDEF"); 

     PrintLineItem(printer, "Item 1", 10, 99.99); 
     PrintLineItem(printer, "Item 2", 101, 0.00); 
     PrintLineItem(printer, "Item 3", 9, 0.1); 
     PrintLineItem(printer, "Item 4", 1000, 1); 

     PrintReceiptFooter(printer, 1, 0.1, 0.1, "THANK YOU FOR CHOOSING ABC Ptr. Ltd."); 
    } 
    finally 
    { 
     DisconnectFromPrinter(printer); 
    } 
} 

private void DisconnectFromPrinter(PosPrinter printer) 
{ 
    printer.Release(); 
    printer.Close(); 
} 

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

private PosPrinter GetReceiptPrinter() 
{ 
    PosExplorer posExplorer = new PosExplorer(this); 

    //May need to change this if you don't use a logicial name or use a different one. 
    DeviceInfo receiptPrinterDevice = posExplorer.GetDevice("Generic/Text Only"); 

    return (PosPrinter)posExplorer.CreateInstance(receiptPrinterDevice); 
} 

private void PrintReceiptFooter(PosPrinter printer, int subTotal, double tax, double discount, string footerText) 
{ 
    string offSetString = new string(' ', printer.RecLineChars/2); 

    PrintTextLine(printer, new string('-', (printer.RecLineChars/3) * 2)); 
    PrintTextLine(printer, offSetString + String.Format("SUB-TOTAL  {0}", subTotal.ToString("#0.00"))); 
    PrintTextLine(printer, offSetString + String.Format("TAX   {0}", tax.ToString("#0.00"))); 
    PrintTextLine(printer, offSetString + String.Format("DISCOUNT  {0}", discount.ToString("#0.00"))); 
    PrintTextLine(printer, offSetString + new string('-', (printer.RecLineChars/3))); 
    PrintTextLine(printer, offSetString + String.Format("TOTAL   {0}", (subTotal - (tax + discount)).ToString("#0.00"))); 
    PrintTextLine(printer, offSetString + new string('-', (printer.RecLineChars/3))); 
    PrintTextLine(printer, String.Empty); 

    //Embed 'center' alignment tag on front of string below to have it printed in the center of the receipt. 
    PrintTextLine(printer, System.Text.ASCIIEncoding.ASCII.GetString(new byte[] { 27, (byte)'|', (byte)'c', (byte)'A' }) + footerText); 

    //Added in these blank lines because RecLinesToCut seems to be wrong on my printer and 
    //these extra blank lines ensure the cut is after the footer ends. 
    PrintTextLine(printer, String.Empty); 
    PrintTextLine(printer, String.Empty); 
    PrintTextLine(printer, String.Empty); 
    PrintTextLine(printer, String.Empty); 
    PrintTextLine(printer, String.Empty); 

    //Print 'advance and cut' escape command. 
    PrintTextLine(printer, System.Text.ASCIIEncoding.ASCII.GetString(new byte[] { 27, (byte)'|', (byte)'1', (byte)'0', (byte)'0', (byte)'P', (byte)'f', (byte)'P' })); 
} 

private void PrintLineItem(PosPrinter printer, string itemCode, int quantity, double unitPrice) 
{ 
    PrintText(printer, TruncateAt(itemCode.PadRight(9), 9)); 
    PrintText(printer, TruncateAt(quantity.ToString("#0.00").PadLeft(9), 9)); 
    PrintText(printer, TruncateAt(unitPrice.ToString("#0.00").PadLeft(10), 10)); 
    PrintTextLine(printer, TruncateAt((quantity * unitPrice).ToString("#0.00").PadLeft(10), 10)); 
} 

private void PrintReceiptHeader(PosPrinter printer, string companyName, string addressLine1, string addressLine2, string taxNumber, DateTime dateTime, string cashierName) 
{ 
    PrintTextLine(printer, companyName); 
    PrintTextLine(printer, addressLine1); 
    PrintTextLine(printer, addressLine2); 
    PrintTextLine(printer, taxNumber); 
    PrintTextLine(printer, new string('-', printer.RecLineChars/2)); 
    PrintTextLine(printer, String.Format("DATE : {0}", dateTime.ToShortDateString())); 
    PrintTextLine(printer, String.Format("CASHIER : {0}", cashierName)); 
    PrintTextLine(printer, String.Empty); 
    PrintText(printer, "item  "); 
    PrintText(printer, "qty  "); 
    PrintText(printer, "Unit Price "); 
    PrintTextLine(printer, "Total  "); 
    PrintTextLine(printer, new string('=', printer.RecLineChars)); 
    PrintTextLine(printer, String.Empty); 
} 

private void PrintText(PosPrinter printer, string text) 
{ 
    if (text.Length <= printer.RecLineChars) 
     printer.PrintNormal(PrinterStation.Receipt, text); //Print text 
    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. 
} 

private 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 string TruncateAt(string text, int maxWidth) 
{ 
    string retVal = text; 
    if (text.Length > maxWidth) 
     retVal = text.Substring(0, maxWidth); 

    return retVal; 
} 

收到錯誤的下面一行GetReceiptPrinter方法：

PosExplorer posExplorer = new PosExplorer(this); 

我使用的是TEP 220 EPSON USB打印機。任何幫助，將不勝感激。

Answer 1

我使用你的代碼來適應我的項目，它與這個小小的改變一起工作。

添加了此信息的app.config：

<runtime> 
     <NetFx40_LegacySecurityPolicy enabled="true"/> 
    </runtime> 

而且

DeviceInfo receiptPrinterDevice = posExplorer.GetDevice(DeviceType.PosPrinter,"MYPRINTER"); 

我希望它hepls。