DataReaderExtension.cs

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.Linq;

namespace Extensions
{
    public static class DataReaderExtension
    {
        public static async IAsyncEnumerable<T> MapperAsync<T>(this DbDataReader reader) where T : class, new()
        {
            if (reader is { HasRows: false }) yield break;

            while (await reader.ReadAsync())
            {
                yield return reader.MapObject<T>();
            }
        }

        private static T MapObject<T>(this IDataRecord reader) where T : class, new()
        {
            var type = typeof(T);
            var propertyInfos = type.GetProperties().ToDictionary(info => info.Name.ToUpper());
            var objectType = new T();

            for (var index = 0; index < reader.FieldCount; index++)
            {
                var key = reader.GetName(index).ToUpper();
                if (propertyInfos.TryGetValue(key, out var propertyInfo) && propertyInfo.CanWrite)
                {
                    propertyInfo.SetValue(objectType, reader.GetValueOrDefault(index, propertyInfo.PropertyType), null);
                }
            }

            return objectType;
        }

        private static object GetValueOrDefault(this IDataRecord reader, int index, Type propertyType) =>
            reader.IsDBNull(index)
                ? null
                : Convert.ChangeType(reader.GetValue(index), propertyType);
    }
}