使用Asp.Net Core MVC 開發項目實踐[第二篇:EF Core]

在項目中使用EF Core還是比較容易的,在這裏我們使用的版本是EF Core 2.2.

1.使用nuget獲取EF Core包

這個示例項目使用的是SQLSERVER,所以還需要下載Microsoft.EntityFrameworkCore.SqlServer這個包

2.在Startup類的Configure方法中設置默認的數據庫訪問連接字符串

 //數據庫連接字符串
Framework.Core.Configuration.AddItem("ConnectionStrings",Configuration.GetSection("ConnectionStrings").Value);

 

PS：我這裏並沒有使用DI注入的方式去使用EFCORE的實例,還是使用傳統的New的方式,所以並不需要在Startup中進行注入

3.在Mango.EFCore類庫項目中創建一個EFDbContext類繼承自DbContext我們就能在其它地方使用EFCore了,代碼如下:

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata;
using Mango.Entity;
namespace Mango.Framework.EFCore
{
    public class EFDbContext : DbContext
    {
        public EFDbContext()
        {

        }

        public EFDbContext(DbContextOptions<EFDbContext> options): base(options)
        {
        }
        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            if (!optionsBuilder.IsConfigured)
            {
                optionsBuilder.UseSqlServer(Core.Configuration.GetItem("ConnectionStrings"));
            }
        }
        #region Entity DbSet<>
        public virtual DbSet<m_WebSiteConfig> m_WebSiteConfig { get; set; }
        public virtual DbSet<m_PostsRecords> m_PostsRecords { get; set; }
        public virtual DbSet<m_WebSiteNavigation> m_WebSiteNavigation { get; set; }

        public virtual DbSet<m_Sms> m_Sms { get; set; }

        public virtual DbSet<m_ManagerAccount> m_ManagerAccount { get; set; }
        public virtual DbSet<m_ManagerMenu> m_ManagerMenu { get; set; }
        public virtual DbSet<m_ManagerPower> m_ManagerPower { get; set; }
        public virtual DbSet<m_ManagerRole> m_ManagerRole { get; set; }
        public virtual DbSet<m_Message> m_Message { get; set; }
        public virtual DbSet<m_Navigation> m_Navigation { get; set; }
        public virtual DbSet<m_NavigationClassify> m_NavigationClassify { get; set; }
        public virtual DbSet<m_Posts> m_Posts { get; set; }
        public virtual DbSet<m_PostsChannel> m_PostsChannel { get; set; }
        public virtual DbSet<m_PostsAnswer> m_PostsAnswer { get; set; }
        public virtual DbSet<m_PostsAnswerRecords> m_PostsAnswerRecords { get; set; }
        public virtual DbSet<m_PostsAttention> m_PostsAttention { get; set; }
        public virtual DbSet<m_PostsComments> m_PostsComments { get; set; }
        public virtual DbSet<m_PostsCommentsRecords> m_PostsCommentsRecords { get; set; }
        public virtual DbSet<m_PostsTags> m_PostsTags { get; set; }
        public virtual DbSet<m_User> m_User { get; set; }
        public virtual DbSet<m_UserGroup> m_UserGroup { get; set; }
        public virtual DbSet<m_UserGroupMenu> m_UserGroupMenu { get; set; }
        public virtual DbSet<m_UserGroupPower> m_UserGroupPower { get; set; }
        #endregion
    }
}

4.接下來我們在Mango.Repository倉儲類庫項目中使用EFCore，代碼示例如下:

using System;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using Mango.Framework.EFCore;
using Microsoft.EntityFrameworkCore;
using System.Data.SqlClient;
namespace Mango.Repository
{
    public class AuthorizationRepository
    {
        private EFDbContext _dbContext = null;
        public AuthorizationRepository()
        {
            _dbContext = new EFDbContext();
        }
        /// <summary>
        /// 根據用戶組獲取權限
        /// </summary>
        /// <param name="GroupId"></param>
        /// <returns></returns>
        public List<Models.UserGroupPowerModel> GetPowerData(int groupId)
        {
            var query = from ugp in _dbContext.m_UserGroupPower
                        join ugm in _dbContext.m_UserGroupMenu
                        on ugp.MId equals ugm.MId
                        where ugp.GroupId == groupId
                        select new Models.UserGroupPowerModel()
                        {
                            GroupId=ugp.GroupId.Value,
                            MId=ugm.MId.Value,
                            MName=ugm.MName,
                            AreaName=ugm.AreaName,
                            ControllerName=ugm.ControllerName,
                            ActionName=ugm.ActionName
                        };
            return query.ToList();
        }
    }
}

 

以上介紹了EFCore的基本使用示例,其實我們平常在項目中會將一些常用的增刪改統一封裝起來,我們創建一個CommonRepository類,代碼如下:

using System;
using System.Reflection;
using System.Collections.Generic;
using System.Text;
using Mango.Framework.EFCore;
using Microsoft.EntityFrameworkCore;
using System.ComponentModel.DataAnnotations;
namespace Mango.Repository
{
    public class CommonRepository
    {
        private EFDbContext _dbContext = null;
        public CommonRepository()
        {
            _dbContext = new EFDbContext();
        }
        /// <summary>
        /// 添加記錄
        /// </summary>
        /// <typeparam name="TEntity"></typeparam>
        /// <param name="entity"></param>
        /// <returns></returns>
        public bool Add<TEntity>(TEntity entity) where TEntity:class
        {
            _dbContext.Add(entity);
            return _dbContext.SaveChanges() > 0;
        }
        /// <summary>
        /// 根據Id獲取指定記錄
        /// </summary>
        /// <typeparam name="TEntity"></typeparam>
        /// <param name="Id"></param>
        /// <returns></returns>
        public TEntity Find<TEntity>(int Id) where TEntity : class
        {
            return _dbContext.Find<TEntity>(Id);
        }
        /// <summary>
        /// 更新記錄
        /// </summary>
        /// <typeparam name="TEntity"></typeparam>
        /// <param name="entity"></param>
        /// <param name="IsFind"></param>
        /// <returns></returns>
        public bool Update<TEntity>(TEntity entity, bool isFind) where TEntity : class
        {
            _dbContext.Update(entity);

            return _dbContext.SaveChanges() > 0;
        }
        /// <summary>
        /// 更新記錄(修改指定的列)
        /// </summary>
        /// <typeparam name="TEntity"></typeparam>
        /// <param name="entity"></param>
        /// <param name="properties"></param>
        /// <returns></returns>
        public bool Update<TEntity>(TEntity entity) where TEntity : class
        {
            _dbContext.Entry(entity).State = EntityState.Unchanged;
            //
            Type type= entity.GetType();
            //處理實體類屬性
            PropertyInfo[] properties = type.GetProperties();
            foreach (var property in properties)
            {
                object value = property.GetValue(entity, null);
                var key = property.GetCustomAttribute<KeyAttribute>();
                if (value != null&& key==null)
                {
                    _dbContext.Entry(entity).Property(property.Name).IsModified = true;
                }
            }
            return _dbContext.SaveChanges() > 0;
        }
        /// <summary>
        /// 刪除記錄
        /// </summary>
        /// <typeparam name="TEntity"></typeparam>
        /// <param name="entity"></param>
        /// <returns></returns>
        public bool Delete<TEntity>(TEntity entity) where TEntity : class
        {
            _dbContext.Remove(entity);
            return _dbContext.SaveChanges() > 0;
        }
    }
}

PS:這篇EFCore的基礎使用就到此爲止,詳情請下載源代碼查看,下一篇將講解如何基於EFCore進行一些基礎的擴展