dsToObj.cs

// Install System.Data.DataSetExtensions from NUGET

using System;
using System.Linq;
using System.Data;

public class newClass
{
  public object DataSetToObject() 
  {
      DataTable search = new DataTable();
      search = utilities.sql.storedProcToTable([connectionName], [StoredProecude]);
  
      List<object> summaryByDay = new List<object>();
            foreach (DataTable tbl in ds.Tables)
            {
                summaryByDay.Add(
                    new SummaryByDay
                    {
                        date = tbl.Rows[0]["runDate"].ToString(),
                        summary = tbl.AsEnumerable().Select(row =>
                        new summary
                        {
                            DocType = row.Field<string>("DocType")
                        }).ToList()
                    }
                );
            }
  }
}

  public class SummaryByDay
  {
      public string date { get; set; }
      public ICollection<summary> summary { get; set; }
  }
  
  public class summary
        {
            public string DocType { get; set; }
        }