While this book is really, really great...I've found that there are a couple of things I do differently. the first being that rather than create a custom reader for each provider, I place the following function in the DataAccess.cs class

 protected T GetField<T>(IDataReader Reader, string ColumnName)
        {
            int i = Reader.GetOrdinal(ColumnName);

            if (i == -1 || Reader.IsDBNull(i))
                return default(T);
            else
            {
                if (typeof(T).IsEnum == true)
                {
                    return (T)Enum.ToObject(typeof(T), Reader.GetInt32(i));
                }

                return (T)Reader.GetValue(i);
            }
        }


Then you all it easily from any of your functions...

myObject=new myObject(GetField<int>(reader, "MyID"));


use of generics can be maximized, and get rid of some of the errors you may encounter with casting..

matt...

[email protected]

matt,

i do a similar type thing with the following in DataAccess.cs:

      /// <summary>
      /// Cast DBNull using generics
      /// </summary>
      public static T CastTo<T>(object value)
      {
          return value != DBNull.Value ? (T)value : default(T);
      }

I then in the provider call it as such (in this case the DAL/Provider/SearchProvider.cs):

        protected virtual SearchItemEntity GetSearchItemFromReader(IDataReader reader)
        {
            return new SearchItemEntity(
                DataAccess.CastTo<string>(reader["linkID"]),
                DataAccess.CastTo<string>(reader["descriptiontext"]),
                DataAccess.CastTo<string>(reader["category"]),
                DataAccess.CastTo<string>(reader["title"]),
                DataAccess.CastTo<string>(reader["source"]),
                DataAccess.CastTo<DateTime>(reader["lasteditdate"]));
        }

i 'think' this is a similar use of generics to what you're doing above ;)



jimi

http://www.originaltalent.com

matt,

similarly, i use delegates in the BLL/Articles/Articles.cs (and all BLL/*.* classes where appropriate). having read up on it, it's supposedly more efficient and more performant:

        /// <summary>
        /// Returns a list of Article objects filled with the data taken from the input list of ArticleDetails
        /// </summary>
        private static List<Article> GetArticleListFromArticleDetailsList(List<ArticleD etails> recordset)
        {
            List<Article> articles = new List<Article>();
            recordset.ForEach(delegate(ArticleDetails record)
            {
                articles.Add(GetArticleFromArticleDetails(record)) ;
            });
            return articles;
        }

can't say i've got that much data yet to be able to compare, but i've convinced myself :D

jimi

http://www.originaltalent.com

They are quite efficient. Yours does basically the same thing as mine, though I"m storing the Int32 value of some enums in the database, so I had to accomodate converting that back into my enum for use in code...all I do is pass in the enum type when I call GetField.


GetField<EnumCategories>(reader, "CategoryType")

and it returns the proper enum for the code...I like what you did though, fast and efficient.