Acumatica, add a column to data grid

I need to add "Subaccount Description" column to the DB grid on "Account by Subaccount" form (GL403000). The DAC "GLHistoryEnquiryResult" contains SubCD field which I want to use to link to "Sub" table to get the description. I extended the DAC as the following and modified ASPX. The column header is displayed, but no data in the new column. I tried to extend AccountHistoryBySubEnq Graph. But still not work.

public class GLHistoryEnquiryResultExt : PXCacheExtension<GLHistoryEnquiryResult>
{
    [PXString(60, IsUnicode = true)]
    [PXUIField(DisplayName = "Subaccount Description")]
    [PXDBScalar(typeof(Search<Sub.description, Where<Sub.subCD, Equal<GLHistoryEnquiryResult.subCD>>>))]
    public virtual string UsrSubaccountDescription { get; set; }
    public abstract class usrSubaccountDescription : PX.Data.BQL.BqlString.Field<usrSubaccountDescription> { }
}

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This is for Acumatica 2024 R1 version. Has anyone done this before? I am new to Acumatica. If anyone has a example of adding a column to data grid, that would be helpful. Thanks!

Solution

GLHistoryEnquiryResult is an unbound DAC, it doesn't exist in the database. More over, your new field is an unbound field, so there are two reasons why PXDBScalar doesn't work here. EnqResult view (the view behind the grid) has a dataview delegate, this delegate creates GLHistoryEnquiryResult records. You need to override this delegate, and populate Sub description there. I combined the DAC and Graph extensions into one file in the example, but it’s better to split them into two separate files.

using System;
using System.Collections;
using System.Linq;
using PX.Data;
using PX.Data.BQL;
using PX.Data.BQL.Fluent;

namespace PX.Objects.GL
{
    public class GLHistoryEnquiryResultExt : PXCacheExtension<GLHistoryEnquiryResult>
    {
        [PXString(60, IsUnicode = true)]
        [PXUIField(DisplayName = "Subaccount Description")]
        public virtual string UsrSubaccountDescription { get; set; }
        public abstract class usrSubaccountDescription : PX.Data.BQL.BqlString.Field<usrSubaccountDescription> { }
    }

    public class AccountHistoryBySubEnqExt : PXGraphExtension<AccountHistoryBySubEnq>
    {
        [PXOverride]
        public virtual IEnumerable enqResult(Func<IEnumerable> baseMethod)
        {
            var result = baseMethod.Invoke().RowCast<GLHistoryEnquiryResult>().ToList();
            foreach (var row in result)
            {
                var sub = (Sub)SelectFrom<Sub>
                    .Where<Sub.subCD.IsEqual<@P.AsString>>
                    .View.Select(Base, row.SubCD);

                var rowExt = Base.EnqResult.Cache.GetExtension<GLHistoryEnquiryResultExt>(row);
                rowExt.UsrSubaccountDescription = sub?.Description;
            }

            return result;
        }
    }
}