Fields from Joined DACs are empty on Create Purchase Orders screen

Has anyone else noticed this behavior? 
Our purchasing manager really needs visibility into some of this data available in the linked columns, but we’re not able to show it because the columns are empty, even if we add them to the grid..

This screen uses a PXFieldScope in the data view delegate:

public virtual PXResultset<POFixedDemand> SelectFromFixedDemandView()
{
    //...
    using (new PXFieldScope(query, GetFixedDemandFieldScope()))
    {
        //...
    }
    //...
}

I believe, in practicality, this means that only the specified fields will be returned:

public virtual IEnumerable<Type> GetFixedDemandFieldScope()
{
    yield return typeof(POFixedDemand);
    yield return typeof(Vendor.bAccountID);
    yield return typeof(Vendor.curyID);
    yield return typeof(Vendor.termsID);
    yield return typeof(POVendorInventory.recordID);
    yield return typeof(POVendorInventory.lastPrice);
    yield return typeof(POVendorInventory.addLeadTimeDays);
    yield return typeof(CRLocation.locationID);
    yield return typeof(CRLocation.vLeadTime);
    yield return typeof(CRLocation.vCarrierID);
    yield return typeof(SOOrder.orderType);
    yield return typeof(SOOrder.orderNbr);
    yield return typeof(SOOrder.customerID);
    yield return typeof(SOOrder.customerLocationID);
    yield return typeof(SOOrder.noteID);
    yield return typeof(SOOrder.curyID);
    yield return typeof(SOOrder.branchID);
    yield return typeof(SOLine.orderType);
    yield return typeof(SOLine.orderNbr);
    yield return typeof(SOLine.lineNbr);
    yield return typeof(SOLine.unitPrice);
    yield return typeof(SOLine.inventoryID);
    yield return typeof(SOLine.uOM);
    yield return typeof(SOLine.noteID);
}

Although, if this is correct, in theory, you could override the GetFixedDemandFieldScope and return additional fields.

​@darylbowman I tried this, but it didn’t work. 
After doing more digging I’m more confused than I was before. 
 

I don’t want to copy-paste all the code here, but they’re doing something strange that I haven’t seen before.
The data view query joins multiple other tables (SOOrder for example), and as you mentioned, the PXFieldScope is used to restrict the results to those specific fields. However, for all I can tell the data view delegate operates on, and returns only a POFixedDemand object… 

It would be super helpful to get some insight on this. 
All I really need is to add the AMProdItem.statusID field to this screen. We don’t create purchase orders for custom order prod materials until the production order hits the “Released” status, so we need to make that visible for filtering purposes.

What I ultimately would like to know is, will it be better to create a “Clone” of this screen and implement it the way we want it, or is it feasible to override all the internals necessary to also include the AMProdItem.statusID field on this grid?

Regards,

// Acuminator disable once PX1016 ExtensionDoesNotDeclareIsActiveMethod extension should be constantly active
public class POCreateExt : PXGraphExtension<POCreate>
{
    public delegate IEnumerable<Type> GetFixedDemandFieldScopeDelegate();
    [PXOverride]
    public virtual IEnumerable<Type> GetFixedDemandFieldScope(GetFixedDemandFieldScopeDelegate baseMethod)
    {
        foreach (var type in baseMethod())
            yield return type;

        // Add fields or tables here
        yield return typeof(SOOrder);
    }
}

This works for me:

(before)

(after)

​@darylbowman  Thanks for responding again.
This is still not working in my instance. 
I believe this is being affected by the fact that we have the manufacturing edition, which adds a graph extension that overrides a bunch of these virtual methods.

I’m in over my head and don’t understand how to go about making additional modifications to this! 
I’ll have to do more studying on how to work with multiple graph extensions that need to modify the same logic…..

Try this:

// Acuminator disable once PX1016 ExtensionDoesNotDeclareIsActiveMethod extension should be constantly active
public class POCreateAMExtension_Ext : PXGraphExtension<POCreateAMExtension, POCreate>
{
    public delegate IEnumerable<Type> GetFixedDemandFieldScopeDelegate();
    [PXOverride]
    public virtual IEnumerable<Type> GetFixedDemandFieldScope(GetFixedDemandFieldScopeDelegate baseMethod)
    {
        foreach (var type in baseMethod())
            yield return type;

        // Add fields or tables here
        yield return typeof(SOOrder);
    }
}

Thank you for sharing your solution with the community ​@MichaelShirk!