Barcode Scan Class: To Create a Barcode Scan Class

This activity will walk you through the process of creating a barcode scan class.

Story

Suppose that you need to create a barcode-driven version of the Physical Inventory Review (IN305000) form. The form should have only one scan mode. For this form, you need to define a barcode scan class and configure this mode.

Process Overview

You will define the INScanCount barcode scan class as a descendant of the WarehouseManagementSystem<TSelf,TGraph> base scan class.

In the INScanCount class, you will create a host class as an empty descendant for INPICountEntry, the graph object of the Physical Inventory Review (IN305000) form.

You will then implement the CreateScanModes() abstract method of the base class to make the barcode scan class usable. In the method, you will use the yield return construction to avoid array creation.

System Preparation

Before you begin performing the steps of this activity, you need to prepare an MYOB Acumatica instance and the PhoneRepairShop customization project by performing the Test Instance: To Deploy an Instance prerequisite activity.

Step 1: Creating a Barcode Scan Class

To create a barcode scan class, do the following:

In the PhoneRepairShop_Code Visual Studio project, add a reference to the PX.BarcodeProcessing.dll file.
Create the INScanCount class and make it public.
Add the using directives shown in the following code to the file.
```
using PX.BarcodeProcessing;
using PX.Objects.IN;
using PX.Objects.IN.WMS;
```
In the INScanCount class, add a host class to apply the barcode scan class to, as shown in the following code.
```
public class INScanCount
{
    public class Host : INPICountEntry { }
}
```
To simplify referencing the nested components of the barcode scan class, add the following line before the INScanCount class declaration. The WarehouseManagementSystem<TSelf,TGraph> class is a descendant of the BarcodeDrivenStateMachine<TSelf, TGraph> class, which contains warehouse-related logic and components.
```
using WMSBase = WarehouseManagementSystem<INScanCount, INScanCount.Host>;
```

Derive the INScanCount class from WMSBase. The following code shows the result of this step.

using PX.BarcodeProcessing;
using PX.Objects.IN;
using PX.Objects.IN.WMS;

namespace PhoneRepairShop
{
    using WMSBase = WarehouseManagementSystem<INScanCount, INScanCount.Host>;
    public class INScanCount: WMSBase
    {
        public class Host : INPICountEntry { }
    }
}

Fix or suppress the PX1016 error that is displayed by Acuminator.

Step 2: Making the Barcode Scan Class Usable

To make the barcode scan class usable, do the following:

Add the using directives shown in the following code to the file.
```
using System.Collections.Generic;
using PX.Data;
```
To make the barcode-driven part of the graph extension work, implement the CreateScanModes() abstract method as follows.
```
public class INScanCount : WMSBase
{
    ...
         
    protected override IEnumerable<ScanMode<INScanCount>> CreateScanModes() 
    {
        yield return new CountMode(); 
    }
}
```
Tip: You will implement the CountMode scan mode in Barcode Scan Mode: To Define the Required Properties.

To facilitate access to the important members of the host graph, add the following members.

public class INScanCount : WMSBase
{
    ...
  
    public virtual INPIHeader Document => DocumentView.Current;
    public virtual PXSelectBase<INPIHeader> DocumentView => Graph.PIHeader;
    public virtual PXSelectBase<INPIDetail> Details => Graph.PIDetail;

    ...
}

Add the following supplementary method, which will be reused in further implementation of the custom barcode-driven form.

public class INScanCount : WMSBase
{
    ...
  
    protected virtual bool IsDocumentStatusEditable(string status) => 
        status == INPIHdrStatus.Counting;
    ...
}

To define when the document with which the barcode scan class works can be edited by the barcode processing, override the DocumentIsEditable member of the WMSBase class.
```
public class INScanCount : WMSBase
{
    ...
  
    public override bool DocumentIsEditable => 
        base.DocumentIsEditable && IsDocumentStatusEditable(Document.Status);

    ...
}
```