Getting error in Entity Framework at SaveChanges - entity-framework

Question

I'm getting this error:
An exception of type
'System.Data.Entity.Infrastructure.DbUpdateConcurrencyException'
occurred in EntityFramework.dll but was not handled in user code
Additional information: 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.
dbContext.Productos.Add(producto);
dbContext.Entry(producto).State = System.Data.Entity.EntityState.Modified;
dbContext.SaveChanges();
}
Any idea about what is wrong here?
Thanks.
My stack trace is:
[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

You have implemented a field level concurrency in Producto entity. Go to the EDMX designer of your Producto entity. Go through properties of each column one by one. Select the column in the visual entity designer -> Press F4. Check the value of the property Concurrency Mode. It should be set to None. Have a look at below snapshot as sample for one of my entities Employee. If for any of the columns, you see the value as Fixed then that's the root cause of your error.
If you are really thinking of doing field level concurrency then use RowVersion instead.

Answer 2

Have you set AutoDetectChangesEnabled to false? If you have done that,please call DetectChanges manually before SaveChanges, don't change the Entry State directly.