Step 2: Adding a Workflow Extension

In this step, you will create an extension for the workflow defined for the Invoices (SO303000) form. Do the following:

Find the name of the class that defines the workflow for the Invoices form. To do this, explore the contents of the PX.Objects/SO/Workflow folder of the MYOB Acumatica source code. There you can find the class you need to extend: SOInvoiceEntry_Workflow, which is an extension of the SOInvoiceEntry graph.
In the code of the SOInvoiceEntry_Workflow class, notice that the states of the workflow are defined in the ARDocStatus class. You will need this class in the next step.
In the Workflows folder of the PhoneRepairShop_Code project, create the SOInvoiceRepairOrder_Workflow.cs file.
In the SOInvoiceRepairOrder_Workflow.cs file, define the SOInvoiceOrder_Workflow class, as the following code shows.
```
    public class SOInvoiceOrder_Workflow : PXGraphExtension<SOInvoiceEntry_Workflow,
        SOInvoiceEntry>
    {
        public sealed override void Configure(PXScreenConfiguration config)
        {
            Configure(config.GetScreenConfigurationContext<SOInvoiceEntry, 
                                                           ARInvoice>());
        }

        protected static void Configure(WorkflowContext<SOInvoiceEntry,
                                                        ARInvoice> context)
        {
        }
    }
```
In the code above, you have defined an extension of the SOInvoiceEntry_Workflow class. As a second parameter of the extension, you have specified the graph of the Invoices form. In the extension, you have overridden the Configure(PXScreenConfiguration) method, which initializes the screen configuration, and declared the static Configure(WorkflowContext) method where you will update the workflow.
Make sure that you have added the needed using directives.
Save your changes.