Custom string list value should be set to my grid field

@oshadarodrigo64 

The issue you're facing is that the string list you've created in the DAC is an association between keys and values. In your case, "A", "B", "C", etc. are the keys, while "SPRING", "HARVEST", "XPT", etc. are the values. When you try to access the Usrdiscountcoden2 field in your event handler, you're getting the key ("A") instead of its associated value ("SPRING").

You can solve this issue by creating a method in your graph extension that translates the keys into their corresponding values. Here's an example:

public class SOLineExt : PXCacheExtension<SOLine>
{
    //...
    public abstract class usrdiscountcoden2 : PX.Data.BQL.BqlString.Field<usrdiscountcoden2> { }

    [PXDBString(1)]
    [PXStringList(new string[]
    {"A", "B", "C", "D","E","F","G", }, new string[]
    {"SPRING",
     "HARVEST",
    "XPT",
    "TESTTIRE",
    "SPECIAL",
    "REBATE",
    "DISCOUNT"
    })]
    [PXUIField(DisplayName="New Discount Code")]
    public virtual string Usrdiscountcoden2 { get; set; }

    //...
}

public class APProformaEntry_Extension : PXGraphExtension<GRIProformaInvoice.APProformaEntry>
{
    //...

    protected void APProformaItemList_RowInserted(PXCache cache, PXRowInsertedEventArgs e)
    {
        //...

        row.SODiscountCode = GetStringValueFromKey(lines.Usrdiscountcoden2);

        //...
    }

    private string GetStringValueFromKey(string key)
    {
        switch(key)
        {
            case "A":
                return "SPRING";
            case "B":
                return "HARVEST";
            case "C":
                return "XPT";
            case "D":
                return "TESTTIRE";
            case "E":
                return "SPECIAL";
            case "F":
                return "REBATE";
            case "G":
                return "DISCOUNT";
            default:
                return null;
        }
    }
    //...
}

This GetStringValueFromKey method will take the key as an input and return the corresponding value. Thus, it solves the issue of getting the key instead of the value. Be aware that it's essential to keep the GetStringValueFromKey method updated if you modify the list in the DAC.