c# linq update单个字段

Posted 2020-09-09 Danlis

1.更新单个字段

/// <summary>
        /// 更新字段
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="conditions">where 筛选对象</param>
        /// <param name="updateLamda">更新字段</param>
        /// <returns></returns>
        public IEnumerable<T> Update<T>( Expression<Func<T, bool>> conditions,Func<T, dynamic> updateLamda) where T : ModelBase
        {            
            List<T> setList;
            if (conditions!=null)
            {
                setList= this.Set<T>().Where(conditions).ToList();
            }
            else
            {
                setList = this.Set<T>().ToList();
            }
            foreach (var item in setList)
            {
                SetValue<T>(item, updateLamda);
                this.Entry<T>(item).State = EntityState.Modified;
            }
            this.SaveChanges();
            return setList;
        }

        public dynamic SetValue<T>(T entity, Func<T, dynamic> expr)
        {
            return expr(entity);
        }

更新单个字段

action中的使用：

public ActionResult Edit()
        {
            using (ActivityDbContext dbContext = new ActivityDbContext())
            {
                 dbContext.Update<Order>(u => u.ID==1,u =>u.UserName= u.OrderNumber.Replace("1", "xx"));
//第一个lambda表达式是用来筛选的，第二个则是进行替换的，在方法编写里面，用了dynamic动态对象，因为没办法确定改了哪个属性，只不过暂时只能改一个，改多个还不会(-_-)
            }

            return View();
        }

 

2.lambda修改对象的属性

public dynamic SetValue<T>(T entity, Func<T, dynamic> expr)
        {
            return expr(entity);
        }

 

添加对象自身方法

    public static class UpdateObject
    {
        public static dynamic SetValue2<T>(this T obj, Func<T, dynamic> expr)
        {
            return expr(obj);
        }
        public static dynamic SetValue2<T>(this T obj, List<Func<T, dynamic>> expr)
        {
            foreach (var item in expr)
            {
                item(obj);
            }
            return obj;
        }

    }

 

 

 1     class Program
 2     {
 3         static void Main(string[] args)
 4         {
 5 
 6             #region 修改对象属性方法
 7             GetProperty p = new GetProperty() { Name1 = "1" };
 8             //SetValue<GetProperty>(p, u => u.Name1 = "2");
 9             Console.WriteLine(p.Name1);
10             //p.SetValue2<GetProperty>(u => u.Name2 = u.Name2 + 1 + 2);
11             p.SetValue2<GetProperty>(new List<Func<GetProperty, dynamic>>() { new Func<GetProperty, dynamic>(u => u.Name2 = u.Name2 + 1), new Func<GetProperty, dynamic>(u => u.Name3 = u.Name3 + 1) });
12             Console.WriteLine(p.Name2);
13             Console.WriteLine(p.Name3); 
14             #endregion
15             Console.ReadKey();
16         }
17 
18         public static string GetPropertyName<T>(Expression<Func<T,string>> expr)
19         {
20             var name = ((MemberExpression)expr.Body).Member.Name;
21             return name;
22         }
23 
24         public static dynamic SetValue<T>(T entity, Func<T, dynamic> expr)
25         {
26             return expr(entity);
27         }
28 
29         public static dynamic SetValue<T>(T entity,List< Func<T, dynamic>> expr)
30         {
31             foreach (var item in expr)
32             {
33                 item(entity);
34             }
35             return entity;
36         }
37 
38     }
39 
40     public static class UpdateObject
41     {
42         public static dynamic SetValue2<T>(this T obj, Func<T, dynamic> expr)
43         {
44             return expr(obj);
45         }
46         public static dynamic SetValue2<T>(this T obj, List<Func<T, dynamic>> expr)
47         {
48             foreach (var item in expr)
49             {
50                 item(obj);
51             }
52             return obj;
53         }
54 
55     }
56 
57     public class GetProperty{
58         public string Name1 { get; set; }
59         public string Name2 { get; set; }
60         public string Name3 { get; set; }
61     }

控制台-修改对象属性