c# - 从 DbDataReader 读取/序列化时避免代码重复？

Question

考虑下面的FetchData方法。它旨在避免每次要从数据库获取某些数据时重复数据库查询代码。

List<MyData> myData = new List<MyData();
FetchData((IDataReader reader) =>
   {
       myData.Add(new MyData(reader.GetString(0), reader.GetInt32(1)));
   }, "usp_get_my_data");

它可以工作，但如果这个对象创建能够以某种方式存在于 FetchData 方法中，那就太好了。

有更好的方法吗？

也许FetchData可以修改为直接返回某种类型X的列表？

protected void FetchData(Action<IDataReader> processor, String query)
{
    using (var connection = CreateConnection())
    {
        connection.ConnectionString = ConnectionString;
        connection.Open();

        using (var command = connection.CreateCommand())
        {
            command.CommandType = CommandType.StoredProcedure;
            command.CommandText = query;

            using (IDataReader reader = command.ExecuteReader())
            {
                while (reader.read())
                {
                    processor(reader);
                }
            }
        }
    }
}

Answer 1

也许使用泛型？

protected IEnumerable<T> FetchData<T>(Func<IDataReader, T> processor, String query)
{
    using (var connection = CreateConnection())
    {
        connection.ConnectionString = ConnectionString;
        connection.Open();

        using (var command = connection.CreateCommand())
        {
            command.CommandType = CommandType.StoredProcedure;
            command.CommandText = query;

            using (IDataReader reader = command.ExecuteReader())
            {
                while (reader.read())
                {
                    yield return processor(reader);
                }
            }
        }
    }
}

然后您可以根据需要使用枚举:

var myData = FetchData<MyData>(reader => new MyData(reader.GetString(0), reader.GetInt32(1)), "usp_get_my_data").ToList();