Beida Jade Bird, Shenzhen Wah _asp.net core supermarket billing system framework series of built ---

1: Create 7 project 

2: JiaHua.Market.Model add a physical layer management information class

/// <summary>
    /// 管理员信息表
    /// </summary>
    public class AdminInfo
    {
        /// <summary>
        /// 管理员Id
        /// </summary>
        [Key]
        public int AdminId { get; set; }
        /// <summary>
        /// 真实姓名
        /// </summary>
        [MaxLength(50)]
        public string RealName { get; set; }
        /// <summary>
        /// 登录名
        /// </summary>
        public string LoginName { get; set; }
        /// <summary>
        /// 登录密码
        /// </summary>
        public string LoginPwd { get; set; }
        /// <summary>
        /// 性别
        /// </summary>
        public short Sex { get; set; }
        /// <summary>
        /// 手机号
        /// </summary>
        public Int64 Telphone { get; set; }
        /// <summary>
        /// 邮箱
        /// </summary>
        public string Email { get; set; }
        /// <summary>
        /// 备注
        /// </summary>
        public string Remark { get; set; }
        /// <summary>
        /// 年龄
        /// </summary>
        public int Age { get; set; }
        /// <summary>
        /// 创建时间
        /// </summary>
        public DateTime CreateTime { get; set; }
        /// <summary>
        /// 最后一次登录时间
        /// </summary>
        public DateTime LastLoginTime { get; set; }
        /// <summary>
        /// 登录时间
        /// </summary>
        public DateTime LoginTime { get; set; }
        /// <summary>
        /// 修改时间
        /// </summary>
        public DateTime UpdateTime { get; set; }
        /// <summary>
        /// 状态1：启用 0：禁用
        /// </summary>
        public short Status { get; set; }
    }

3: Install Nuget package [Note: netcore version 2.1.1 on behalf of their computer]

Select JiaHua.Market.Model project in Nuget the Package Manager Console window, followed by typing the following three command:

Install-Package Microsoft.EntityFrameworkCore.SqlServer -version 2.1.1

Install-Package Microsoft.EntityFrameworkCore.Tools -version 2.1.1

Install-Package Microsoft.EntityFrameworkCore.SqlServer.Design

4: Create a database context update class

/// <summary>
    /// 数据库创建和更新的上下文类
    /// </summary>
    public partial class MarketDbContext : DbContext
    {
        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UseSqlServer("server=localhost;database=Market;uid=sa;pwd=123456;");
        }

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

    }

5: Add the physical layer to the project Web project references Enter the following command in the console Nuget

Add-Migration build001

Generated migration file

Update-Database 

Generating a database as follows

6: Add Storage base classes and interfaces in the data access layer, while adding packet System.Linq.Dynamic.Core Nuget

/// <summary>
    /// 仓储基类
    /// </summary>
    /// <typeparam name="T">实体类型</typeparam>
    public abstract class RepositoryBase<T> : IRepository<T> where T : class
    {
        //定义数据访问上下文对象
        protected readonly SyDbContext _dbContext;

        /// <summary>
        /// 通过构造函数注入得到数据上下文对象实例
        /// </summary>
        /// <param name="dbContext"></param>
        public RepositoryBase(SyDbContext dbContext)
        {
            _dbContext = dbContext;
        }

        #region 同步

        /// <summary>
        /// 判断记录是否存在
        /// </summary>
        /// <param name="predicate">lambda表达式条件</param>
        /// <returns></returns>
        public bool IsExist(Expression<Func<T, bool>> predicate)
        {
            return _dbContext.Set<T>().Any(predicate);
        }

        /// <summary>
        /// 新增实体
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="autoSave">是否立即执行保存</param>
        /// <returns></returns>
        public bool Add(T entity, bool autoSave = true)
        {
            int row = 0;
            _dbContext.Set<T>().Add(entity);
            if (autoSave)
                row = Save();
            return (row > 0);
        }

        /// <summary>
        /// 批量添加
        /// </summary>
        /// <param name="entities">实体列表</param>
        /// <param name="autoSave">是否立即执行保存</param>
        /// <returns></returns>
        public bool AddRange(IEnumerable<T> entities, bool autoSave = true)
        {
            int row = 0;
            _dbContext.Set<T>().AddRange(entities);
            if (autoSave)
                row = Save();
            return (row > 0);
        }

        /// <summary>
        /// 更新实体
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="autoSave">是否立即执行保存</param>
        public bool Update(T entity, bool autoSave = true)
        {
            int row = 0;
            _dbContext.Update(entity);
            if (autoSave)
                row = Save();
            return (row > 0);
        }

        /// <summary>
        /// 更新实体部分属性
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="autoSave">是否立即执行保存</param>
        /// <param name="updatedProperties">要更新的字段</param>
        /// <returns></returns>
        public bool Update(T entity, bool autoSave = true, params Expression<Func<T, object>>[] updatedProperties)
        {
            int row = 0;
            //告诉EF Core开始跟踪实体的更改，
            //因为调用DbContext.Attach方法后，EF Core会将实体的State值
            //更改回EntityState.Unchanged，
            _dbContext.Attach(entity);
            if (updatedProperties.Any())
            {
                foreach (var property in updatedProperties)
                {
                    //告诉EF Core实体的属性已经更改。将属性的IsModified设置为true后，
                    //也会将实体的State值更改为EntityState.Modified，
                    //这样就保证了下面SaveChanges的时候会将实体的属性值Update到数据库中。
                    _dbContext.Entry(entity).Property(property).IsModified = true;
                }
            }

            if (autoSave)
                row = Save();
            return (row > 0);
        }

        /// <summary>
        /// 更新实体部分属性,泛型方法
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="autoSave">是否立即执行保存</param>
        /// <param name="updatedProperties">要更新的字段</param>
        /// <returns></returns>
        public bool Update<Entity>(Entity entity, bool autoSave = true, params Expression<Func<Entity, object>>[] updatedProperties) where Entity : class
        {
            int row = 0;
            //告诉EF Core开始跟踪实体的更改，
            //因为调用DbContext.Attach方法后，EF Core会将实体的State值
            //更改回EntityState.Unchanged，
            _dbContext.Attach(entity);
            if (updatedProperties.Any())
            {
                foreach (var property in updatedProperties)
                {
                    //告诉EF Core实体的属性已经更改。将属性的IsModified设置为true后，
                    //也会将实体的State值更改为EntityState.Modified，
                    //这样就保证了下面SaveChanges的时候会将实体的属性值Update到数据库中。
                    _dbContext.Entry(entity).Property(property).IsModified = true;
                }
            }

            if (autoSave)
                row = Save();
            return (row > 0);
        }

        /// <summary>
        /// 批量更新实体
        /// </summary>
        /// <param name="entities">实体列表</param>
        /// <param name="autoSave">是否立即执行保存</param>
        public bool UpdateRange(IEnumerable<T> entities, bool autoSave = true)
        {
            int row = 0;
            _dbContext.UpdateRange(entities);
            if (autoSave)
                row = Save();
            return (row > 0);
        }

        /// <summary>
        /// 根据lambda表达式条件获取单个实体
        /// </summary>
        /// <param name="predicate">lambda表达式条件</param>
        /// <returns></returns>
        public T GetModel(Expression<Func<T, bool>> predicate)
        {
            return _dbContext.Set<T>().FirstOrDefault(predicate);
        }

        /// <summary>
        /// 删除实体
        /// </summary>
        /// <param name="entity">要删除的实体</param>
        /// <param name="autoSave">是否立即执行保存</param>
        public bool Delete(T entity, bool autoSave = true)
        {
            int row = 0;
            _dbContext.Set<T>().Remove(entity);
            if (autoSave)
                row = Save();
            return (row > 0);
        }

        /// <summary>
        /// 批量删除
        /// </summary>
        /// <param name="T">对象集合</param>
        /// <returns></returns>
        public bool Delete(IEnumerable<T> entities)
        {
            _dbContext.Set<T>().RemoveRange(entities);
            int row = _dbContext.SaveChanges();
            return (row > 0);
        }

        /// <summary>
        /// 批量删除
        /// </summary>
        /// <param name="T">对象集合</param>
        /// <param name="autoSave">是否立即执行保存</param>
        /// <returns></returns>
        public bool Delete(IEnumerable<T> entities, bool autoSave = true)
        {
            int row = 0;
            _dbContext.Set<T>().RemoveRange(entities);
            if (autoSave)
                row = Save();
            return (row > 0);
        }

        /// <summary>
        /// 获取实体集合
        /// </summary>
        /// <returns></returns>
        public virtual IQueryable<T> GetList()
        {
            return _dbContext.Set<T>().AsQueryable();
        }

        /// <summary>
        /// 根据lambda表达式条件获取单个实体
        /// </summary>
        /// <param name="predicate">lambda表达式条件</param>
        /// <returns></returns>
        public virtual IQueryable<T> GetList(Expression<Func<T, bool>> predicate)
        {
            return _dbContext.Set<T>().Where(predicate);
        }

        /// <summary>
        /// 根据lambda表达式条件获取实体集合
        /// </summary>
        /// <param name="top">前几条</param>
        /// <param name="predicate">查询条件</param>
        /// <param name="ordering">排序</param>
        /// <param name="args">条件参数</param>
        /// <returns></returns>
        public virtual IQueryable<T> GetList(int top, string predicate, string ordering, params object[] args)
        {
            var result = _dbContext.Set<T>().AsQueryable();

            if (!string.IsNullOrWhiteSpace(predicate))
                result = result.Where(predicate, args);

            if (!string.IsNullOrWhiteSpace(ordering))
                result = result.OrderBy(ordering);

            if (top > 0)
            {
                result = result.Take(top);
            }
            return result;
        }

        /// <summary>
        /// 分页查询,返回实体对象
        /// </summary>
        /// <param name="pageIndex">当前页</param>
        /// <param name="pageSize">页大小</param>
        /// <param name="predicate">条件</param>
        /// <param name="ordering">排序</param>
        /// <param name="args">条件参数</param>
        /// <returns></returns>
        public virtual IQueryable<T> GetPagedList(int pageIndex, int pageSize, string predicate, string ordering, params object[] args)
        {
            var result = (from p in _dbContext.Set<T>()
                          select p).AsQueryable();

            if (!string.IsNullOrWhiteSpace(predicate))
                result = result.Where(predicate, args);

            if (!string.IsNullOrWhiteSpace(ordering))
                result = result.OrderBy(ordering);

            return result.Skip((pageIndex - 1) * pageSize).Take(pageSize);
        }

        /// <summary>
        /// 获取记录总数
        /// </summary>
        /// <param name="predicate">查询条件</param>
        /// <param name="args">条件参数</param>
        /// <returns></returns>
        public virtual int GetRecordCount(string predicate, params object[] args)
        {
            if (string.IsNullOrWhiteSpace(predicate))
            {
                return _dbContext.Set<T>().Count();
            }
            else
            {
                return _dbContext.Set<T>().Where(predicate, args).Count();
            }
        }

        /// <summary>
        /// 事务性保存
        /// </summary>
        public int Save()
        {
            int result = _dbContext.SaveChanges();
            return result;
        }

        #endregion
    }

/// <summary>
    /// 定义泛型仓储接口
    /// </summary>
    /// <typeparam name="TEntity">实体类型</typeparam>
    public interface IRepository<T> where T : class
    {
        #region 同步

        /// <summary>
        /// 判断记录是否存在
        /// </summary>
        /// <param name="predicate">lambda表达式条件</param>
        /// <returns></returns>
        bool IsExist(Expression<Func<T, bool>> predicate);

        /// <summary>
        /// 新增实体
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="autoSave">是否立即执行保存</param>
        /// <returns></returns>
        bool Add(T entity, bool autoSave = true);

        /// <summary>
        /// 批量添加
        /// </summary>
        /// <param name="entities">实体列表</param>
        /// <param name="autoSave">是否立即执行保存</param>
        /// <returns></returns>
        bool AddRange(IEnumerable<T> entities, bool autoSave = true);

        /// <summary>
        /// 更新实体
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="autoSave">是否立即执行保存</param>
        bool Update(T entity, bool autoSave = true);

        /// <summary>
        /// 更新部分属性
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="autoSave">是否立即执行保存</param>
        /// <param name="updatedProperties">要更新的字段</param>
        /// <returns></returns>
        bool Update(T entity, bool autoSave = true, params Expression<Func<T, object>>[] updatedProperties);

        /// <summary>
        /// 更新实体部分属性,泛型方法
        /// </summary>
        /// <param name="entity">实体</param>
        /// <param name="autoSave">是否立即执行保存</param>
        /// <param name="updatedProperties">要更新的字段</param>
        /// <returns></returns>
        bool Update<Entity>(Entity entity, bool autoSave = true, params Expression<Func<Entity, object>>[] updatedProperties) where Entity : class;

        /// <summary>
        /// 批量更新实体
        /// </summary>
        /// <param name="entities">实体列表</param>
        /// <param name="autoSave">是否立即执行保存</param>
        bool UpdateRange(IEnumerable<T> entities, bool autoSave = true);

        /// <summary>
        /// 删除实体
        /// </summary>
        /// <param name="entity">要删除的实体</param>
        /// <param name="autoSave">是否立即执行保存</param>
        bool Delete(T entity, bool autoSave = true);

        /// <summary>
        /// 批量删除
        /// </summary>
        /// <param name="T">对象集合</param>
        /// <returns></returns>
        bool Delete(IEnumerable<T> entities);

        /// <summary>
        /// 批量删除
        /// </summary>
        /// <param name="T">对象集合</param>
        /// <param name="autoSave">是否立即执行保存</param>
        /// <returns></returns>
        bool Delete(IEnumerable<T> entities, bool autoSave = true);

        /// <summary>
        /// 获取实体集合
        /// </summary>
        /// <returns></returns>
        IQueryable<T> GetList();

        /// <summary>
        /// 根据lambda表达式条件获取实体集合
        /// </summary>
        /// <param name="top">前几条</param>
        /// <param name="predicate">查询条件</param>
        /// <param name="ordering">排序</param>
        /// <param name="args">条件参数</param>
        /// <returns></returns>
        IQueryable<T> GetList(int top, string predicate, string ordering, params object[] args);

        /// <summary>
        /// 根据lambda表达式条件获取实体集合
        /// </summary>
        /// <param name="predicate">lambda表达式条件</param>
        /// <returns></returns>
        IQueryable<T> GetList(Expression<Func<T, bool>> predicat);

        /// <summary>
        /// 根据lambda表达式条件获取单个实体
        /// </summary>
        /// <param name="predicate">lambda表达式条件</param>
        /// <returns></returns>
        T GetModel(Expression<Func<T, bool>> predicate);

        /// <summary>
        /// 分页查询
        /// </summary>
        /// <param name="pageIndex">当前页</param>
        /// <param name="pageSize">页大小</param>
        /// <param name="predicate">条件</param>
        /// <param name="ordering">排序</param>
        /// <param name="args">条件参数</param>
        /// <returns></returns>
        IQueryable<T> GetPagedList(int pageIndex, int pageSize, string predicate, string ordering, params object[] args);

        /// <summary>
        /// 获取记录总数
        /// </summary>
        /// <param name="predicate">查询条件</param>
        /// <param name="args">条件参数</param>
        /// <returns></returns>
        int GetRecordCount(string predicate, params object[] args);

        /// <summary>
        /// 保存
        /// </summary>
        int Save();

        #endregion
    }

7: Adding a context-based database access in a data access layer

/// <summary>
    /// 数据库上下文访问类
    /// </summary>
    public class SyDbContext:DbContext
    {
        public virtual DbSet<AdminInfo> AdminInfo { get; set; }

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="options"></param>
        public SyDbContext(DbContextOptions<SyDbContext> options) : base(options)
        {

        }

    }

8: business layer to add AdminInfoService, IAdminInfoService

 

9: appsetting.json added layer web connection string

"ConnectionStrings": {
    "ConnectionString": "server=localhost;database=Market;uid=sa;pwd=123456;"
  }

10: Modify CreateWebHostBuilder method program.cs

public static IWebHostBuilder CreateWebHostBuilder(string[] args)
        {
            var configuration = new ConfigurationBuilder()
                .SetBasePath(Environment.CurrentDirectory)
                .AddJsonFile("appsettings.json")//读取配置文件，获取启动的端口号
                .Build();
            return WebHost.CreateDefaultBuilder(args)
                .UseConfiguration(configuration)
                .UseStartup<Startup>();
        }