分享一个老外写的Entityframework的知识库

/// <summary>

    /// Repository base class used with DbContext

    /// Via http://dotnetspeak.com/index.php/2011/03/repository-pattern-with-entity-framework/

    /// </summary>

    /// <typeparam name="TContext">Type of DdContext that this repositiory operates on</typeparam>

    public class EFRepository<TContext> : IDisposable

        where TContext : DbContext, IObjectContextAdapter, new()

    {

        private TContext context;



        public TContext Context

        {

            get { return context; }

        }



        private EFRepository()

        {



        }



        /// <summary>

        /// Create new instance of repository

        /// </summary>

        /// <param name="connecstionStringName">Connection string name from .config file</param>

        public EFRepository(string connecstionStringName)

        {

            context = new TContext();

            context.Database.Connection.ConnectionString =

                ConfigurationManager.ConnectionStrings[connecstionStringName].ConnectionString;

        }



        /// <summary>

        /// Dipose repository

        /// </summary>

        public void Dispose()

        {

            if (context != null)

            {

                context.Dispose();

                context = null;

            }

        }





        /// <summary>

        /// Select data from database

        /// </summary>

        /// <typeparam name="TItem">Type of data to select</typeparam>

        /// <returns></returns>

        public IQueryable<TItem> Select<TItem>()

           where TItem : class, new()

        {

            PropertyInfo property = GetDbSet(typeof(TItem));



            DbSet<TItem> set = property.GetValue(context, null) as DbSet<TItem>;



            return set;

        }



        /// <summary>

        /// Insert new item into database

        /// </summary>

        /// <typeparam name="TItem">Type of item to insert</typeparam>

        /// <param name="item">Item to insert</param>

        /// <returns>Inserted item</returns>

        public TItem Insert<TItem>(TItem item)

            where TItem : class, new()

        {

            DbSet<TItem> set = GetDbSet(typeof(TItem)).GetValue(context, null) as DbSet<TItem>;

            set.Add(item);

            context.SaveChanges();

            return item;

        }



        /// <summary>

        /// Update na item

        /// </summary>

        /// <typeparam name="TItem">Type of item to update</typeparam>

        /// <param name="item">Item to update</param>

        /// <returns>Updated item</returns>

        public TItem Update<TItem>(TItem item)

            where TItem : class, new()

        {

            DbSet<TItem> set = GetDbSet(typeof(TItem)).GetValue(context, null) as DbSet<TItem>;

            set.Attach(item);

            context.Entry(item).State = System.Data.EntityState.Modified;

            context.SaveChanges();

            return item;

        }/// <summary>

        /// Delete an item

        /// </summary>

        /// <typeparam name="TItem">Type of item to delete</typeparam>

        /// <param name="item">Item to delete</param>

        public void Delete<TItem>(TItem item)

           where TItem : class, new()

        {

            DbSet<TItem> set = GetDbSet(typeof(TItem)).GetValue(context, null) as DbSet<TItem>;

            var entry = context.Entry(item);

            if (entry != null)

            {

                entry.State = System.Data.EntityState.Deleted;

            }

            else

            {

                set.Attach(item);

            }

            context.Entry(item).State = System.Data.EntityState.Deleted;

            context.SaveChanges();

        }



        private PropertyInfo GetDbSet(Type itemType)

        {

            var properties = typeof(TContext).GetProperties().Where(item => item.PropertyType.Equals(typeof(DbSet<>).MakeGenericType(itemType)));



            return properties.First();

        }