How to modify the ItemInfo view on "Add Items" button of the Sales Order form?

Have you tried resolving your issue using a Data View Delegate as shown below?

public class SOOrderSiteStatusLookupMyExt : PXGraphExtension<SOOrderSiteStatusLookupExt, SOOrderEntry>
{
    public virtual IEnumerable itemInfo()
    {
        var myItems = // define your items;

        foreach (var item in myItems)
        {
            yield return item;
        }
    }
}

There’s actually already a data view delegate in AddItemLookupBaseExt which is what SOOrderSiteStatusLookupExt is based on:

You could try extending / overriding this method.

Alternatively, you could override CreateItemInfoView() to return your own version of CreateWhere():

Thank you both! I think I am getting close as overwriting the itemInfo() method allowed me to blank the item results by doing so. Is it possible that unless its a specific order type I can call the base method instead? I tried below but the adapter is null and just errors out on me. How can I call the base itemInfo() if it's not the order type I want to have the new data? Trying to avoid adding an entirely new button. 

        public delegate IEnumerable ItemInfoDelegate(PXAdapter adapter);
        public virtual IEnumerable itemInfo(PXAdapter adapter, ItemInfoDelegate baseMethod)
        {
            PXTrace.WriteInformation("itemInfo called");
            SOOrder order = Base.Document.Current;
            PXTrace.WriteInformation(order.CustomerID.ToString());
            if (order != null)
            {
                PXTrace.WriteInformation(order.OrderType);
                SOOrderExt orderExt = order.GetExtension<SOOrderExt>();

                PXTrace.WriteInformation(InstallType.INSTALLTYPE);
                if (String.Equals(order.OrderType, InstallType.INSTALLTYPE, StringComparison.OrdinalIgnoreCase)
                    && !(String.IsNullOrWhiteSpace(orderExt.UsrModel)
                        || String.IsNullOrWhiteSpace(orderExt.UsrMake)
                        || String.IsNullOrWhiteSpace(orderExt.UsrYear)))
                {
                    var items = PXSelectJoin<InventoryItem,
                         InnerJoin<InventoryInstalls,
                             On<InventoryItem.inventoryCD, Equal<InventoryInstalls.inventoryID>>>,
                        Where<InventoryInstalls.model, Equal<Required<SOOrderExt.usrModel>>,
                        And<InventoryInstalls.year, Equal<Required<SOOrderExt.usrYear>>,
                        And<InventoryInstalls.make, Equal<Required<SOOrderExt.usrMake>>>>>>
                .Select(new PXGraph(), orderExt.UsrModel, orderExt.UsrYear, orderExt.UsrMake);

                    foreach (PXResult<InventoryItem, InventoryInstalls> rec in items)
                    {
                        yield return rec;
                    }
                }
                else
                {
                    baseMethod(adapter);
                }
            }

        }

Thanks!

You need to return the result of the baseMethod since your return type is IEnumerable:

return baseMethod(adapter);

Also, you need to add the [PXOverride] attribute above your overridden method. At this point, it is probably creating a new data view delegate.

Thanks ​@darylbowman and ​@aleksandrsechin for the help thus far! With the PXOverride, I get the following error:

The System.Collections.IEnumerable itemInfo(PX.Data.PXAdapter, ItemInfoDelegate) method in the PX.Objects.SO.GraphExtensions.SOOrderEntryExt.SOOrderGraphExt graph extension is marked as [PXOverride], but its signature is not compatible with the original method.

I figured this was because the original method didn't have any actual parameters, so I tested without the additional parameters, and it no longer gave me that error. But I needed something to return so I am currently just returning an empty PXDelegateResult to avoid error during the test. 

public delegate IEnumerable ItemInfoDelegate(PXAdapter adapter);
[PXOverride]
//public virtual IEnumerable itemInfo(PXAdapter adapter, ItemInfoDelegate baseMethod)
public virtual IEnumerable itemInfo()
{
     PXTrace.WriteInformation("itemInfo called");
     var rows = new PXDelegateResult();

     return rows;
}

Is there something in Base1 that I should be setting the delegate to, so it just does default behavior if a condition isn't met? 

Additionally, I’ve followed the trail back and see that TItemInfo parameter is used in the AddItemLookupBaseExt and is pulling from SOOrderSiteStatusSelected DAC. Can I just create a similar view pulling from the same table with additional conditions and overwrite ItemInfo view when orderType is changed? 

I will see if I can override the “CreateWhere()” as Daryl mentioned also. But I think I would run into the issue of not begin able to call the original method if my condition isn't met also. So, think I am just missing a piece here. 

Thanks!