Create missing data on RowSelected

We have a graph extension that manages the tab we added to a screen. The tab displays data from our own DAC. We do not use a DAC extension, not going to go into the reasons right now.

When a user opens the main screen I want to create a record of our data if it does not exist, with some defaulting business logic.

I added a RowSelected event handler on the main DAC and it fires as I expect it to. When I add the code to create our missing record in the event handler Acuminator gives me error "PX1044 Changes to PXCache cannot be performed in event handlers."

I understand the error that Acuminator is raising, but I'm not sure where else to create our record. I cannot remember a section of the university specifically addressing this scenario.

Can anyone tell me how I would handle this scenario? And if possible, point me at the learning material that covers this scenario for broader information.

I got a reply from Acumatica support, you can do this in a view select delegate.

Here's some example code, I haven't tested it though:

public class InventoryItemMaintExtension : PXGraphExtension<InventoryItemMaint>
{
    public SelectFrom<MyCustomTable>.
              Where<MyCustomTable.inventoryID.IsEqual<
              InventoryItem.inventoryID.FromCurrent>>.
              View AdditionalItemData;
    public static bool IsActive() { return true; }

    public IEnumerable additionalItemData()
    {
        var data = AdditionalItemData.SelectSingle();
        if (data is null)
        {
            data = new MyCustomTable();
            AdditionalItemData.Insert(data);
        }

        return AdditionalItemData.Select();
    }
}

[PXCacheName("Additional Item Data")]
[Serializable]
public class MyCustomTable : IBqlTable
{
    #region CashAccountID
    [Inventory]
    [PXDefault]
    public virtual int? InventoryID { get; set; }
    public abstract class inventoryID : PX.Data.BQL.BqlInt.Field<inventoryID> { }

    #endregion

    #region Required
    [PXDBBool()]
    [PXDefault(false)]
    [PXUIField(DisplayName = "Required")]
    public virtual bool? Required { get; set; }
    public abstract class required : PX.Data.BQL.BqlBool.Field<required> { }
    #endregion
}