记录一个下推时，能成功修改目标单里的基础数据字段的方法

using Kingdee.BOS.App.Core.Utils;
using Kingdee.BOS.App.Data;
using Kingdee.BOS.Core.Metadata;
using Kingdee.BOS.Core.Metadata.ConvertElement.PlugIn;
using Kingdee.BOS.Core.Metadata.ConvertElement.PlugIn.Args;
using Kingdee.BOS.Core.Metadata.FieldElement;
using Kingdee.BOS.Core.Metadata.Util;
using Kingdee.BOS.Core.Util;
using Kingdee.BOS.Orm.DataEntity;
using Kingdee.BOS.ServiceHelper;
using Kingdee.BOS.Util;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;

namespace WPBR.FormicPhase2.SCM.ServicePlugIn.ConvertServicePlugIn
{
    [Description("PO下推AP转换插件")]
    [HotUpdate]
    public class PoToApConvertServicePlugIn : AbstractConvertPlugIn
    {
        public override void AfterConvert(AfterConvertEventArgs e)
        {
            base.AfterConvert(e);
            if (e.Result == null) 
            {
                return;
            }

            DynamicObject dynamicObject = e.Result.FindByEntityKey("FBillHead")[0].DataEntity;

            var profitCenter = dynamicObject["FProfitCenter_id"];
            var department = dynamicObject["FDepartment_id"];

            if (department == null || profitCenter == null) 
            {
                return;
            }

            var organize = dynamicObject["SETTLEORGID_Id"];

            var result = DBUtils.ExecuteDynamicObject(e.Context, $"SELECT * FROM MappingConfig_Entity where FOrganization = {organize} and FDepartment = {department} and FProfitCenter ={profitCenter}");

            var mappingData = result.IsEmpty() == false ? result.First() : null;

            if (mappingData != null) 
            {
                var accountPrimaryKey = mappingData["FAccount"];

                var dataField = e.TargetBusinessInfo.GetField("FAccount") as BaseDataField;
                DynamicObject[] results = BusinessDataServiceHelper.Load(this.Context, new[] { accountPrimaryKey }, dataField.RefFormDynamicObjectType);
                
                //set value
                dynamicObject["FAccount"] = results.FirstOrDefault();
            }
        }
    }
}

关键代码就是最后几行，必须把基础资料的DynamicObject获取到，然后直接赋值给目标单的DynamicObject对应的字段。