帮助Microsoft Opos打印

问题描述

有一台epson TM-T20II pos打印机。

Hi, have an epson TM-T20II pos printer.

我在这部分遇到问题，用代码测试打印机，打印机在usb端口上有效b $ b

i'm having problems in this part to test the printer with code, printer is instaled on usb port

    Public Shared Function GetAndInitPosPrinter() As Microsoft.PointOfService.PosPrinter
        Dim pe As New PosExplorer()
        Dim ppdi = pe.GetDevice(DeviceType.PosPrinter, "MyPosPrinter1")
        Dim pp As Microsoft.PointOfService.PosPrinter = pe.CreateInstance(ppdi) 'error says i need to determine a null object
        pp.Open()
        pp.Claim(250)
        pp.DeviceEnabled = True
        Return pp
    End Function

推荐答案

你需要检查GetDevice之前是否成功尝试使用它返回的设备。

You need to check that GetDevice has succeeded before trying to use the device it returns.

应该在POS论坛上询问有关POS的问题：

https://social.msdn.microsoft.com/Forums/vstudio/en-US/home?forum=posfordotnet

Questions about POS should be asked in the POS forum:
https://social.msdn.microsoft.com/Forums/vstudio/en-US/home?forum=posfordotnet

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