封装自己的dapper lambda扩展-设计篇(一)

2022-04-23 221

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简介： 封装自己的dapper lambda扩展-设计篇（一）

前言

昨天开源了业务业余时间自己封装的dapper lambda扩展，同时写了篇博文《编写自己的dapper lambda扩展-使用篇》简单的介绍了下其使用，今天将分享下它的设计思路

链式编程

其实就是将多个方法通过点（.）将它们串接起来,让代码更加简洁, 可读性更强。

new SqlConnection("").QuerySet<User>()
                      .Where(a => a.Name == "aasdasd")
                      .OrderBy(a => a.CreateTime)
            　.Top(10)
                      .Select(a => a.Name).ToList();

其原理是类的调用方法的返回值类型为类本身或其基类，选择返回基类的原因是为了做降

级约束，例如我希望使用了Top之后接着Select和ToList，无法再用where或orderBy。

UML图

原型代码

CommandSet

public class CommandSet<T> : IInsert<T>, ICommand<T>
    {
        #region 方法
        public int Insert(T entity)
        {
            throw new NotImplementedException();
        }
        public int Update(T entity)
        {
            throw new NotImplementedException();
        }
        public int Update(Expression<Func<T, T>> updateExpression)
        {
            throw new NotImplementedException();
        }
        public int Delete()
        {
            throw new NotImplementedException();
        }
        public IInsert<T> IfNotExists(Expression<Func<T, bool>> predicate)
        {
            throw new NotImplementedException();
        }
        public ICommand<T> Where(Expression<Func<T, bool>> predicate)
        {
            throw new NotImplementedException();
        }
        #endregion
    }
    public interface ICommand<T>
    {
        int Update(T entity);
        int Update(Expression<Func<T, T>> updateExpression);
        int Delete();
    }
    public interface IInsert<T>
    {
        int Insert(T entity);
    }
    public static class Database
    {
        public static QuerySet<T> QuerySet<T>(this SqlConnection sqlConnection)
        {
            return new QuerySet<T>();
        }
        public static CommandSet<T> CommandSet<T>(this SqlConnection sqlConnection)
        {
            return new CommandSet<T>();
        }
    }

QuerySet

 public class QuerySet<T> : IAggregation<T>
    {
        #region 方法
        public T Get()
        {
            throw new NotImplementedException();
        }
        public List<T> ToList()
        {
            throw new NotImplementedException();
        }
        public PageList<T> PageList(int pageIndex, int pageSize)
        {
            throw new NotImplementedException();
        }
        public List<T> UpdateSelect(Expression<Func<T, T>> @where)
        {
            throw new NotImplementedException();
        }
        public IQuery<TResult> Select<TResult>(Expression<Func<T, TResult>> selector)
        {
            throw new NotImplementedException();
        }
        public IOption<T> Top(int num)
        {
            throw new NotImplementedException();
        }
        public IOrder<T> OrderBy<TProperty>(Expression<Func<T, TProperty>> field)
        {
            throw new NotImplementedException();
        }
        public IOrder<T> OrderByDescing<TProperty>(Expression<Func<T, TProperty>> field)
        {
            throw new NotImplementedException();
        }
        public int Count()
        {
            throw new NotImplementedException();
        }
        public bool Exists()
        {
            throw new NotImplementedException();
        }
        public QuerySet<T> Where(Expression<Func<T, bool>> predicate)
        {
            throw new NotImplementedException();
        }
        #endregion
    }
    public interface IAggregation<T> : IOrder<T>
    {
        int Count();
        bool Exists();
    }
    public interface IOrder<T> : IOption<T>
    {
        IOrder<T> OrderBy<TProperty>(Expression<Func<T, TProperty>> field);
        IOrder<T> OrderByDescing<TProperty>(Expression<Func<T, TProperty>> field);
    }
    public interface IOption<T> : IQuery<T>, IUpdateSelect<T>
    {
        IQuery<TResult> Select<TResult>(Expression<Func<T, TResult>> selector);
        IOption<T> Top(int num);
    }
    public interface IUpdateSelect<T>
    {
        List<T> UpdateSelect(Expression<Func<T, T>> where);
    }
    public interface IQuery<T>
    {
        T Get();
        List<T> ToList();
        PageList<T> PageList(int pageIndex, int pageSize);
    }