打印开始时如何打开CashDrawer

问题描述

嗨！我是创建POS系统的新手。



我想在打印开始时打开我的现金抽屉。我在互联网上找到了一些代码，但它们似乎没有用。它总是给我这个错误：对象引用没有设置为对象的实例。



这是我的代码：

Hi! I am new in creating POS systems.

I want to open my cash drawer when printing starts. I have found some codes in the internet but they do not seem to work. It always gives me this error: Object reference not set to an instance of an object.

This is my codes:

using Microsoft.PointOfService;

CashDrawer myCashDrawer = null;
       PosExplorer explorer;

        public void CashDrawerClass()
        {
            try
            {
                explorer = new PosExplorer();
                DeviceInfo ObjDevicesInfo = explorer.GetDevice("C4141");
                bool check = ObjDevicesInfo.IsDefault;
                myCashDrawer = (CashDrawer)explorer.CreateInstance(ObjDevicesInfo);
            }
            catch (Exception ex)
            {
                MessageBox.Show("CashDrawerClass: " + ex.Message);
            }
        }

        public void OpenCashDrawer()
        {
            try
            {
                myCashDrawer.Open();
                myCashDrawer.Claim(1000);
                myCashDrawer.DeviceEnabled = true;
                myCashDrawer.OpenDrawer();
                myCashDrawer.DeviceEnabled = false;
                myCashDrawer.Release();
                myCashDrawer.Close();
            }
            catch (NullReferenceException ex)
            {
                MessageBox.Show("OpenCashDrawer: " + ex.Message);
            }
        }

现金抽屉已连接到我的打印机。

The cash drawer is connected to my printer.

推荐答案

if (ObjDevicesInfo == null)
   Report an error.

2.检查 myCashDrawer 被赋予一个值。

myCashDrawer.Open();

当你调用OpenCashDrawer（）时，最明显的事情，除了看起来有点凌乱的设计/实现方面，我看不到任何类似的东西

when you call OpenCashDrawer(), the most obvious thing, apart from it looking a bit messy design/implementation-wise, is I dont see anything that looks like

myCashDrawer = new CashDrawer();

可能将参数传递给CashDrawer对象的实例化

possibly with arguments being passed into the instantiation of the CashDrawer Object

这篇关于打印开始时如何打开CashDrawer的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！