EntityFrameworkCore 扩展类 AddOrUpdate

现在项目用了前后端分离，所以每次提供接口的时候都是

Edit一个api接口，然后Add一个api接口，

然后做了一个后端项目突然想起来EF之前好像有个扩展类 AddOrUpdate，

于是网上找了下:代码如下

 1 public static class ContextExtensions  
 2 {  
 3     public static void AddOrUpdate(this DbContext ctx, object entity)  
 4     {  
 5         var entry = ctx.Entry(entity);  
 6         switch (entry.State)  
 7         {  
 8             case EntityState.Detached:  
 9                 ctx.Add(entity);  
10                 break;  
11             case EntityState.Modified:  
12                 ctx.Update(entity);  
13                 break;  
14             case EntityState.Added:  
15                 ctx.Add(entity);  
16                 break;  
17             case EntityState.Unchanged:  
18                 //item already in db no need to do anything  
19                 break;
20 
21             default:  
22                 throw new ArgumentOutOfRangeException();  
23         }  
24     }  
25 }

参考：

https://www.michaelgmccarthy.com/2016/08/24/entity-framework-addorupdate-is-a-destructive-operation/

https://docs.microsoft.com/zh-cn/ef/ef6/saving/change-tracking/entity-state