请考虑下面的FetchData方法。它旨在避免每次您要从数据库中获取某些数据时都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,但是如果此对象创建可以某种方式存在于FetchData方法中,那就太好了。

有没有更好的方法?

也许FetchData可以修改为直接返回X类型的列表?

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);
                }
            }
        }
    }
}

最佳答案

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();

10-06 08:41