使用实体框架的C＃中的通用存储库 [英] Generic Repository in C# Using Entity Framework

问题描述

我想通过给出主键数组来检索多个记录，并且必须对所有实体都采用通用方法。

I want to retrieve multiple records by giving array of primary key and I have to make generic method of it for all the entities.

private DbSet<TEntity> _entities;
      /// <summary>
            /// Get entity by identifier
            /// </summary>
            /// <param name="id">Identifier</param>
            /// <returns>Entity</returns>
            public virtual TEntity GetById(object id)
            {
                return Entities.Find(id);
            }




 /// <summary>
        /// Get entity by identifier
        /// </summary>
        /// <param name="id">Identifier</param>
        /// <returns>Entity</returns>
        public virtual List<TEntity> GetByIds(int id[])
        {
               // want to make it generic
            return Entities.Where(x=>id.Contains(id));
        }

    /// <summary>
        /// Gets an entity set
        /// </summary>
        protected virtual DbSet<TEntity> Entities
        {
            get
            {
                if (_entities == null)
                    _entities = _context.Set<TEntity>();

                return _entities;
            }
        }

问题是我的实体没有ID列，例如，产品具有ProductId，订单具有OrderId。我不想将数据库列更改为ID。

problem here is that my Entities doesn't have ID columns, for eg Product has ProductId, Order has OrderId. I don't want to change my db columns to Id.

Entities.Where(x=>id.Contains(id));

我希望我的实体列与现在相同。我可以使用这种数据库结构实现通用搜索方法以查找多个记录吗？

I want my entities columns to be same as they are now. can I achieve a generic search method with this db structure to find multiple records?

推荐答案

您可以使用EF Core提供的元数据服务，例如 FindEntityType 和 FindPrimaryKey 以获取PK属性名称。然后，您可以使用它来使用另一个EF Core提供的有用方法 EF.Property 。

You can use EF Core provided metadata services like FindEntityType and FindPrimaryKey to get the PK property name. Then you can use it to access the PK value inside LINQ to Entities query using another EF Core provided useful method EF.Property.

类似这样的事情：

public virtual List<TEntity> GetByIds(int[] ids)
{
    var idName = _context.Model.FindEntityType(typeof(TEntity))
        .FindPrimaryKey().Properties.Single().Name;
    return Entities
        .Where(x => ids.Contains(EF.Property<int>(x, idName)))
        .ToList();
}

这篇关于使用实体框架的C＃中的通用存储库的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！