在 SaveChanges 的实体框架中出现错误

Posted 2023-03-31

【中文标题】在 SaveChanges 的实体框架中出现错误

【英文标题】：Getting error in Entity Framework at SaveChanges

【发布时间】：2014-11-19 17:45:01

【问题描述】：

我收到此错误：

类型异常 'System.Data.Entity.Infrastructure.DbUpdateConcurrencyException' 发生在 EntityFramework.dll 中，但未在用户代码中处理

附加信息：存储更新、插入或删除语句 影响了意外数量的行 (0)。实体可能已经 自加载实体后修改或删除。刷新 ObjectStateManager 条目。

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

知道这里出了什么问题吗？

谢谢。

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

【问题讨论】：

删除这一行：dbContext.Entry(producto).State = System.Data.Entity.EntityState.Modified;

@codebased 还是一样的错误..

需要看看它是否真的发生在 producto 或者您试图保存多个对象？

你做的第一行Productos.Add(producto)第二行你做的Entry(producto).State = EntityState.Modified，你想添加一个新的实体或者修改现有的实体，是什么？

@codebased 这是下载所有文件的链接..你能看看你是否能得到错误吗？我已经阅读了每一行并且无法处理它..mega.co.nz/…

【参考方案1】：

您已在Producto 实体中实现了字段级并发。转至 Producto 实体的 EDMX 设计器。逐一浏览每一列的属性。在可视实体设计器中选择列 -> 按 F4。检查属性Concurrency Mode 的值。它应该设置为无。看看下面的快照作为我的一个实体Employee 的示例。如果对于任何列，您看到的值为 Fixed，那么这就是您的错误的根本原因。

如果您真的想进行字段级并发，请改用RowVersion。

【参考方案2】：

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