[英]The instance of entity type Menu cannot be tracked
I started a new asp.net core project.我开始了一个新的 asp.net 核心项目。 As you know in Core version 2.1 has dependency injection.如您所知,Core 2.1 版具有依赖注入。
I have a model called MenuModel to create a table in my database.我有一个名为 MenuModel 的 model 来在我的数据库中创建一个表。 I added an interface called IMenuRepository for my model and a class call MenuRepository that implements my Interface.我为我的 model 添加了一个名为 IMenuRepository 的接口,并为实现我的接口的 class 调用 MenuRepository 添加了一个接口。
I try to edit my menu in my repository like this我尝试像这样在我的存储库中编辑我的菜单
public async Task Edit(Menu menu)
{
menu.UpdatedBy = _userId;
menu.UpdatedDate = DateTime.Now;
_db.Entry(menu).State = EntityState.Modified;
await _db.SaveChangesAsync();
}
I added this line of code to my startup.cs for dependency injection我将这行代码添加到我的 startup.cs 中以进行依赖注入
services.AddTransient<IMenuRepository, MenuRepository>();
I found another question that asked the same question and the answer says I have to change my startup.cs code like:我发现另一个问同样问题的问题,答案说我必须更改我的 startup.cs 代码,例如:
services.AddScoped<IMenuRepository, MenuRepository>();
I did and I tried the others as well but I get this error always.我做了,我也尝试了其他的,但我总是得到这个错误。 I searched a couple of times but I can't find any solution to my problem.我搜索了几次,但找不到任何解决问题的方法。
One time I detached my model from my DatabaseContext before editing and I got the same error as well.有一次我在编辑之前将 model 从我的 DatabaseContext 中分离出来,我也遇到了同样的错误。
I tried with this code to update but no result我尝试使用此代码进行更新,但没有结果
_db.Update(menu);
Here is my error description:这是我的错误描述:
**An unhandled exception occurred while processing the request. **处理请求时发生未处理的异常。
InvalidOperationException: The instance of entity type 'Menu' cannot be tracked because another instance with the same key value for {'MenuId'} is already being tracked. InvalidOperationException:无法跟踪实体类型“Menu”的实例,因为已经在跟踪具有相同键值 {'MenuId'} 的另一个实例。 When attaching existing entities, ensure that only one entity instance with a given key value is attached.附加现有实体时,请确保仅附加一个具有给定键值的实体实例。 Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the conflicting key values.考虑使用“DbContextOptionsBuilder.EnableSensitiveDataLogging”来查看冲突的键值。 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap.ThrowIdentityConflict(InternalEntityEntry entry)** Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap.ThrowIdentityConflict(InternalEntityEntry 条目)**
On the other hand, I have a part of the code for publishing and unpublish menu that changes the record status and that edit the menu like this and it works perfectly.另一方面,我有一部分用于发布和取消发布菜单的代码,它可以更改记录状态并像这样编辑菜单,并且效果很好。
public async Task Publish(int id)
{
Menu menu = await Find(id);
menu.UpdatedBy = _userId;
menu.UpdatedDate = DateTime.Now;
menu.Status = eStatus.Published;
_db.Entry(menu).State = EntityState.Modified;
}
The difference is only I send the menu id to publish method and send menu obj to edit.不同之处仅在于我将菜单 id 发送到发布方法,并将菜单 obj 发送到编辑。
After searching in different languages I found the answer to my question在用不同的语言搜索后,我找到了我的问题的答案
I changed my edit method to this:我将编辑方法更改为:
public async Task Edit(Menu menu)
{
menu.UpdatedBy = _userId;
menu.UpdatedDate = DateTime.Now;
var editVersion = await Find(menu.MenuId);
if (editVersion != null)
{
_db.Entry(editVersion).CurrentValues.SetValues(menu);
}
await _db.SaveChangesAsync();
}
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