System.InvalidOperationException: The instance of entity type 'ProjectAssignment' cannot be tracked because another instance with the same key value for {'ProjectID'} is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached. Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the conflicting key values.
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap`1.Add(TKey key, InternalEntityEntry entry)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.St
我用Worker(ID和其他列)和Project(ID和其他列)Entity和ProjectAssignment(许多Project的许多Project ID)Crossbound创建了一个项目。但是当我尝试获取ProjectAssignment数据时,会出现Application Insights中的错误。奇怪的是,id不会更早出现。
这是https://github.com/Streamc/ContosoObserve1/tree/master/Proj_s
context.Database.EnsureCreated();
var ProjectAssignments = new ProjectAssignment[]
{
new ProjectAssignment
{
ProjectID = Projects.Single( i => i.ID == 1).ID,
WorkerID = Workers.Single( i => i.ID == 1).ID,
},
new ProjectAssignment
{
ProjectID = Projects.Single( i => i.ID == 1).ID,
WorkerID = Workers.Single( i => i.ID == 2).ID,
},
new ProjectAssignment
{
ProjectID = Projects.Single( i => i.ID == 1).ID,
WorkerID = Workers.Single( i => i.ID == 3).ID,
},
new ProjectAssignment
{
ProjectID = Projects.Single( i => i.ID == 2).ID,
WorkerID = Workers.Single( i => i.ID == 1).ID,
},
new ProjectAssignment
{
ProjectID = Projects.Single( i => i.ID == 3).ID,
WorkerID = Workers.Single( i => i.ID == 1).ID,
},
new ProjectAssignment
{
ProjectID = Projects.Single( i => i.ID == 4).ID,
WorkerID = Workers.Single( i => i.ID == 1).ID,
},
new ProjectAssignment
{
ProjectID = Projects.Single( i => i.ID == 2).ID,
WorkerID = Workers.Single( i => i.ID == 2).ID,
},
new ProjectAssignment
{
ProjectID = Projects.Single( i => i.ID == 2).ID,
WorkerID = Workers.Single( i => i.ID == 3).ID,
},
new ProjectAssignment
{
ProjectID = Projects.Single( i => i.ID == 2).ID,
WorkerID = Workers.Single( i => i.ID == 4).ID,
}
};
foreach (ProjectAssignment ss in ProjectAssignments)
{
context.ProjectAssignments.Add(ss);
}
context.SaveChanges();
public class ProjectAssignment
{
[Key]
public int ProjectID { get; set; }
public int WorkerID { get; set; }
public Project Project { get; set; }
public Worker Worker { get; set; }
}
public class Worker
{
public int ID { get; set; }
public string Firstname { get; set; }
public string Lastname { get; set; }
public string Fathername { get; set; }
public string email { get; set; }
public string Company_name { get; set; }
public ICollection<ProjectAssignment> ProjectAssignment { get; set; }
}
public class Project
{
public int ID { get; set; }
public string Name { get; set; }
public string Customer_Company { get; set; }
public string Executive_Company { get; set; }
public int ManagerID { get; set; }
public int WorkerID { get; set; }
public DateTime Begin_date { get; set; }
public DateTime End_date { get; set; }
public int Priority { get; set; }
public string Test_comment { get; set; }
public ICollection<ProjectAssignment> ProjectAssignment { get; set; }
}
答案 0 :(得分:1)
仔细阅读错误消息:
实体类型的实例&#39; ProjectAssignment&#39;无法跟踪,因为已经跟踪了另一个具有{&#39; ProjectID&#39;}键值的实例。
所以问题是我们有两个或更多ProjectAssignment
具有相同的ProjectID
。
如果我们查看代码,我们会看到我们分配了两次相同的ProjectID
:
var ProjectAssignments = new ProjectAssignment[] {
new ProjectAssignment {
ProjectID = Projects.Single( i => i.ID == 1).ID, // ID == "1"
WorkerID = Workers.Single( i => i.ID == 1).ID,
},
new ProjectAssignment {
ProjectID = Projects.Single( i => i.ID == 1).ID, // ID == "1", again
WorkerID = Workers.Single( i => i.ID == 2).ID,
},
// ...
}
根本原因似乎是ProjectID
被建模为主键而不是外键。主键必须是唯一的。您可能想要的是由ProjectID
和WorkerID
组成的composite primary key。
查看Github项目中的ProjectContext
,此组合密钥已经到位:
modelBuilder.Entity<ProjectAssignment>().HasKey(c => new { c.ProjectID, c.WorkerID });
但它与[Key]
上的ProjectAssignment.ProjectID
注释相冲突。删除此[Key]
属性!