using CQIE.LabAssist.Models;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using System.Threading.Tasks;
namespace brand.cyt369.com.dal.DbContexts
{
/// <summary>
/// 服务基类
/// </summary>
/// <typeparam name="TService"></typeparam>
public abstract class BaseService<TService> where TService : class, new()
{
protected bool AutoCloseContext { get; set; } = true;
protected static readonly TService m_Instance = new TService();
/// <summary>
/// 单实例
/// </summary>
public static TService Instance
{
get { return m_Instance; }
}
/// <summary>
/// DBContext对象
/// </summary>
protected virtual _DbContext Ctx
{
get
{
return new _DbContext();
}
}
/// <summary>
/// 保存对象
/// </summary>
/// <param name="course"></param>
/// <returns></returns>
protected virtual bool Save<T>(T entity, Expression<Func<T, bool>> predicate = null) where T : class
{
if (entity == null)
{
throw new ArgumentNullException("entity");
}
if (this.AutoCloseContext)
{
using (var db = this.Ctx)
{
if (predicate == null)
{
db.Set<T>().Add(entity);
return db.SaveChanges() > 0;
}
else
{
var item = db.Set<T>().SingleOrDefault(predicate);
if (item == null)
{
db.Set<T>().Add(entity);
return db.SaveChanges() > 0;
}
else
{
var propts = entity.GetType().GetProperties();
foreach (var p in propts)
{
p.SetValue(item, p.GetValue(entity, null), null);
}
db.SaveChanges();
}
return true;
}
}
}
else
{
var db = this.Ctx;
{
if (predicate == null)
{
db.Set<T>().Add(entity);
return db.SaveChanges() > 0;
}
else
{
var item = db.Set<T>().SingleOrDefault(predicate);
if (item == null)
{
db.Set<T>().Add(entity);
return db.SaveChanges() > 0;
}
else
{
var propts = entity.GetType().GetProperties();
foreach (var p in propts)
{
p.SetValue(item, p.GetValue(entity, null), null);
}
db.SaveChanges();
}
return true;
}
}
}
}
/// <summary>
/// 更新对象
/// </summary>
/// <param name="course"></param>
/// <returns></returns>
protected virtual bool Update<T>(T entity, Expression<Func<T, bool>> predicate) where T : class
{
if (entity == null)
{
throw new ArgumentNullException("entity");
}
if (predicate == null)
{
throw new ArgumentNullException("selector");
}
if (this.AutoCloseContext)
{
using (var db = this.Ctx)
{
var item = db.Set<T>().SingleOrDefault(predicate);
if (item != null)
{
var propts = entity.GetType().GetProperties();
foreach (var p in propts)
{
p.SetValue(item, p.GetValue(entity, null), null);
}
db.SaveChanges();
return true;
}
return false;
}
}
else
{
var db = this.Ctx;
{
var item = db.Set<T>().SingleOrDefault(predicate);
if (item != null)
{
var propts = entity.GetType().GetProperties();
foreach (var p in propts)
{
p.SetValue(item, p.GetValue(entity, null), null);
}
db.SaveChanges();
return true;
}
return false;
}
}
}
/// <summary>
/// 删除对象
/// </summary>
/// <param name="courseId"></param>
/// <returns></returns>
protected virtual bool Delete<T>(T entity) where T : class
{
if (entity == null)
{
throw new ArgumentNullException("entity");
}
if (this.AutoCloseContext)
{
using (var db = this.Ctx)
{
db.Set<T>().Remove(entity);
db.SaveChanges();
return true;
}
}
else
{
var db = this.Ctx;
{
db.Set<T>().Remove(entity);
db.SaveChanges();
return true;
}
}
}
/// <summary>
/// 按条件删除
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="predicate"></param>
/// <returns></returns>
protected virtual bool Delete<T>(Expression<Func<T, bool>> predicate) where T : class
{
if (predicate == null)
{
throw new ArgumentNullException("selector");
}
if (this.AutoCloseContext)
{
using (var db = this.Ctx)
{
var entitys = db.Set<T>().Where(predicate);
if (entitys != null)
{
db.Set<T>().RemoveRange(entitys);
db.SaveChanges();
return true;
}
}
}
else
{
var db = this.Ctx;
{
var entitys = db.Set<T>().Where(predicate);
if (entitys != null)
{
db.Set<T>().RemoveRange(entitys);
db.SaveChanges();
return true;
}
}
}
return false;
}
/// <summary>
/// 将对象进行处理后保存数据库
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="predicate"></param>
/// <param name="action"></param>
/// <returns></returns>
protected virtual bool DoAction<T>(Expression<Func<T, bool>> predicate, Action<IQueryable<T>> action) where T : class
{
if (predicate == null)
{
throw new ArgumentNullException("selector");
}
if (action == null)
{
throw new ArgumentNullException("action");
}
if (this.AutoCloseContext)
{
using (var db = this.Ctx)
{
var entitys = db.Set<T>().Where(predicate);
if (entitys != null)
{
action(entitys);
db.SaveChanges();
return true;
}
}
}
else
{
var db = this.Ctx;
{
var entitys = db.Set<T>().Where(predicate);
if (entitys != null)
{
action(entitys);
db.SaveChanges();
return true;
}
}
}
return false;
}
/// <summary>
/// 将对象进行处理后保存数据库
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="predicate"></param>
/// <param name="action"></param>
/// <returns></returns>
protected virtual bool DoAction<T>(Expression<Func<T, bool>> predicate, Action<T> action) where T : class
{
if (predicate == null)
{
throw new ArgumentNullException("selector");
}
if (action == null)
{
throw new ArgumentNullException("action");
}
if (this.AutoCloseContext)
{
using (var db = this.Ctx)
{
var entitys = db.Set<T>().Where(predicate).FirstOrDefault();
if (entitys != null)
{
action(entitys);
db.SaveChanges();
return true;
}
}
}
else
{
var db = this.Ctx;
{
var entitys = db.Set<T>().Where(predicate).FirstOrDefault();
if (entitys != null)
{
action(entitys);
db.SaveChanges();
return true;
}
}
}
return false;
}
/// <summary>
/// 查询列表
/// </summary>
/// <param name="name"></param>
/// <returns></returns>
protected virtual IQueryable<T> Get<T>(Expression<Func<T, bool>> predicate = null) where T : class
{
var db = this.Ctx;
var query = from o in db.Set<T>()
select o;
if (predicate != null)
{
query = query.Where(predicate);
}
return query;
}
protected virtual IQueryable<TEntity> Get<TEntity, TProperty>(Expression<Func<TEntity, TProperty>> includeExpression, Expression<Func<TEntity, bool>> predicate = null) where TEntity : class
{
if (includeExpression == null)
{
throw new ArgumentNullException("includeExpression");
}
var db = this.Ctx;
var query = from o in db.Set<TEntity>().Include(includeExpression)
select o;
if (predicate != null)
{
query = query.Where(predicate);
}
return query;
}
/// <summary>
/// 获取一个对象
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="predicate"></param>
/// <returns></returns>
protected virtual T GetOne<T>(Expression<Func<T, bool>> predicate = null) where T : class
{
if (this.AutoCloseContext)
{
using (var db = this.Ctx)
{
var query = from o in db.Set<T>()
select o;
if (predicate != null)
{
query = query.Where(predicate);
}
return query.FirstOrDefault();
}
}
else
{
var db = this.Ctx;
{
var query = from o in db.Set<T>()
select o;
if (predicate != null)
{
query = query.Where(predicate);
}
return query.FirstOrDefault();
}
}
}
protected virtual TEntity GetOne<TEntity, TProperty>(Expression<Func<TEntity, TProperty>> includeExpression, Expression<Func<TEntity, bool>> predicate = null) where TEntity : class
{
if (includeExpression == null)
{
throw new ArgumentNullException("includeExpression");
}
if (this.AutoCloseContext)
{
using (var db = this.Ctx)
{
var query = from o in db.Set<TEntity>().Include(includeExpression)
select o;
if (predicate != null)
{
query = query.Where(predicate);
}
return query.FirstOrDefault();
}
}
else
{
var db = this.Ctx;
{
var query = from o in db.Set<TEntity>().Include(includeExpression)
select o;
if (predicate != null)
{
query = query.Where(predicate);
}
return query.FirstOrDefault();
}
}
}
/// <summary>
/// 分页查询
/// </summary>
/// <typeparam name="TSource"></typeparam>
/// <typeparam name="TKey"></typeparam>
/// <param name="page"></param>
/// <param name="rows"></param>
/// <param name="total"></param>
/// <param name="items"></param>
/// <param name="keySelector"></param>
/// <returns></returns>
protected virtual IQueryable<TSource> Pagination<TSource, TKey>(int page, int rows, ref int total, IQueryable<TSource> items, Expression<Func<TSource, TKey>> keySelector, Expression<Func<TSource, TKey>> thenSelector = null, bool isDesc = true, bool isThenDesc = true)
{
var orderItems = isDesc ? items.OrderByDescending(keySelector) : items.OrderBy(keySelector);
if (thenSelector != null)
{
orderItems = isThenDesc ? orderItems.ThenByDescending(thenSelector) : orderItems.ThenBy(thenSelector);
}
total = items.Count();
if ((page - 1) > 0)
{
items = orderItems.Skip((page - 1) * rows);
items = items.Take(rows);
}
else
{
items = orderItems.Take(rows);
}
return items;
}
protected virtual IQueryable<TSource> Pagination<TSource, TKey1, TKey2>(int page, int rows, ref int total, IQueryable<TSource> items, Expression<Func<TSource, TKey1>> keySelector, Expression<Func<TSource, TKey2>> thenSelector = null, bool isDesc = true, bool isThenDesc = true)
{
var orderItems = isDesc ? items.OrderByDescending(keySelector) : items.OrderBy(keySelector);
if (thenSelector != null)
{
orderItems = isThenDesc ? orderItems.ThenByDescending(thenSelector) : orderItems.ThenBy(thenSelector);
}
total = items.Count();
if ((page - 1) > 0)
{
items = orderItems.Skip((page - 1) * rows);
items = items.Take(rows);
}
else
{
items = orderItems.Take(rows);
}
return items;
}
}
}
标签：predicate,服务,c#,db,query,基类,var,return,null From： https://blog.csdn.net/weixin_62232239/article/details/143581341