在SaveChanges中获取实体框架中的错误

Question

我收到此错误：

  

类型的例外   ＆＃39; System.Data.Entity.Infrastructure.DbUpdateConcurrencyException＆＃39;   发生在EntityFramework.dll中但未在用户代码中处理

     

其他信息：存储更新，插入或删除语句   影响了意外的行数（0）。实体可能已经存在   自实体加载后修改或删除。刷新   ObjectStateManager条目。

dbContext.Productos.Add(producto);
dbContext.Entry(producto).State = System.Data.Entity.EntityState.Modified;
dbContext.SaveChanges();
 }

关于这里有什么问题的任何想法？

感谢。

我的堆栈跟踪是：

[OptimisticConcurrencyException: Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries.]
   System.Data.Entity.Core.Mapping.Update.Internal.UpdateTranslator.ValidateRowsAffected(Int64 rowsAffected, UpdateCommand source) +232
   System.Data.Entity.Core.Mapping.Update.Internal.UpdateTranslator.Update() +493
   System.Data.Entity.Core.EntityClient.Internal.EntityAdapter.<Update>b__2(UpdateTranslator ut) +32
   System.Data.Entity.Core.EntityClient.Internal.EntityAdapter.Update(T noChangesResult, Func`2 updateFunction) +272
   System.Data.Entity.Core.EntityClient.Internal.EntityAdapter.Update() +143
   System.Data.Entity.Core.Objects.ObjectContext.<SaveChangesToStore>b__35() +34
   System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction(Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess) +448
   System.Data.Entity.Core.Objects.ObjectContext.SaveChangesToStore(SaveOptions options, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction) +219
   System.Data.Entity.Core.Objects.<>c__DisplayClass2a.<SaveChangesInternal>b__27() +71
   System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Func`1 operation) +213
   System.Data.Entity.Core.Objects.ObjectContext.SaveChangesInternal(SaveOptions options, Boolean executeInExistingTransaction) +408
   System.Data.Entity.Core.Objects.ObjectContext.SaveChanges(SaveOptions options) +39
   System.Data.Entity.Internal.InternalContext.SaveChanges() +320

[DbUpdateConcurrencyException: Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries.]
   System.Data.Entity.Internal.InternalContext.SaveChanges() +366
   System.Data.Entity.Internal.LazyInternalContext.SaveChanges() +56
   System.Data.Entity.DbContext.SaveChanges() +52
   Clase5.Data.ProductoRepositorio.Insertar(Producto producto) in c:\Users\Juan\Downloads\Clase_5_-_Codigo_fuente\Clase5\Clase4\Data\ProductoRepositorio.cs:27
   Clase5.Controllers.ProductoController.TresCrearProducto(Producto producto) in c:\Users\Juan\Downloads\Clase_5_-_Codigo_fuente\Clase5\Clase4\Controllers\ProductoController.cs:43
   lambda_method(Closure , ControllerBase , Object[] ) +180
   System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) +14
   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +211
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +27
   System.Web.Mvc.Async.<>c__DisplayClass42.<BeginInvokeSynchronousActionMethod>b__41() +28
   System.Web.Mvc.Async.<>c__DisplayClass8`1.<BeginSynchronous>b__7(IAsyncResult _) +10
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +57
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +48
   System.Web.Mvc.Async.<>c__DisplayClass39.<BeginInvokeActionMethodWithFilters>b__33() +57
   System.Web.Mvc.Async.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49() +223
   System.Web.Mvc.Async.<>c__DisplayClass37.<BeginInvokeActionMethodWithFilters>b__36(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +57
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +48
   System.Web.Mvc.Async.<>c__DisplayClass2a.<BeginInvokeAction>b__20() +24
   System.Web.Mvc.Async.<>c__DisplayClass25.<BeginInvokeAction>b__22(IAsyncResult asyncResult) +102
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +57
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +43
   System.Web.Mvc.<>c__DisplayClass1d.<BeginExecuteCore>b__18(IAsyncResult asyncResult) +14
   System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +23
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +57
   System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +23
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +47
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
   System.Web.Mvc.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult) +25
   System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +23
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +47
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9657896
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

Answer 1

您已在Producto实体中实现了字段级并发。转到Producto实体的EDMX设计器。逐个浏览每列的属性。选择可视实体设计器中的列 - ＆gt;按F4。检查属性Concurrency Mode的值。它应该设置为None。请查看下面的快照，作为我的某个实体Employee的示例。如果对于任何列，您会将值视为Fixed，那么这就是错误的根本原因。

如果您真的想要进行字段级并发，那么请改用RowVersion。

Answer 2

您是否将AutoDetectChangesEnabled设置为false？如果您已经这样做，请在SaveChanges之前手动调用DetectChanges，不要直接更改Entry State。