如何解决 System.Data.Entity.Core.OptimisticConcurrencyException 的这个错误

Question

异常类型：

System.DataEntity.Core.OptimisticConcurrencyException

信息 ：

存储更新、插入或删除语句影响了意外的行数 (0)。 自加载实体以来，实体可能已被修改或删除。 刷新 ObjectStateManager 条目。

堆栈跟踪：

System.Data.Entity.Core.Mapping.Update.Internal.UpdateTranslator.ValidateRow>sAffected(Int64, System.Data.Entity.Core.Mapping.Update.Internal.UpdateCommand)
System.Data.Entity.Core.Mapping.Update.Internal.UpdateTranslator.Update() System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[[System.Int32, mscorlib]](System.Func1, System.Data. Entity.Infrastructure.IDbExecutionStrategy, Boolean, Boolean)
System.Data.Entity.Core.Objects.ObjectContext.SaveChangesToStore(System.Data.Entity.Core.Objects.SaveOptions, System.Data.Entity.Infrastructure.IDbExecutionStrategy, Boolean)
System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[System.Int32, mscorlib]
System.Data.Entity.Core.Objects.ObjectContext.SaveChangesInternal(System.Data.Entity.Core.Objects.SaveOptions, Boolean) System.Data.Entity.Internal.InternalContext.SaveChanges()

代码 1) EfRepository：

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Data.Entity.Validation;
using System.Linq;
using Nop.Core;
using Nop.Core.Data;
namespace Nop.Data
{
    /// <summary>
    /// Entity Framework repository
    /// </summary>
    public partial class EfRepository<T> : IRepository<T> where T : BaseEntity
    {
        #region Fields
        private readonly IDbContext _context;
        private IDbSet<T> _entities;
        #endregion
        #region Ctor
        /// <summary>
        /// Ctor
        /// </summary>
        /// <param name="context">Object context</param>
        public EfRepository(IDbContext context)
        {
            this._context = context;
        }

        #endregion 
        #region Methods
        /// <summary>
        /// Get entity by identifier
        /// </summary>
        /// <param name="id">Identifier</param>
        /// <returns>Entity</returns>
        public virtual T GetById(object id)
        {
            //see some suggested performance optimization (not tested)
            //http://stackoverflow.com/questions/11686225/dbset-find-method-ridiculously-slow-compared-to-singleordefault-on-id/11688189#comment34876113_11688189
            return this.Entities.Find(id);
        }
        /// <summary>
        /// Insert entity
        /// </summary>
        /// <param name="entity">Entity</param>
        public virtual void Insert(T entity)
        {
            try
            {
                if (entity == null)
                    throw new ArgumentNullException("entity");

                this.Entities.Add(entity);

                this._context.SaveChanges();
            }
            catch (DbEntityValidationException dbEx)
            {
                var msg = string.Empty;

                foreach (var validationErrors in dbEx.EntityValidationErrors)
                    foreach (var validationError in validationErrors.ValidationErrors)
                        msg += string.Format("Property: {0} Error: {1}", validationError.PropertyName, validationError.ErrorMessage) + Environment.NewLine;
 var fail = new Exception(msg, dbEx);
                //Debug.WriteLine(fail.Message, fail);
                throw fail;
            }
        }

        /// <summary>
        /// Insert entities
        /// </summary>
        /// <param name="entities">Entities</param>
        public virtual void Insert(IEnumerable<T> entities)
        {
            try
            {
                if (entities == null)
                    throw new ArgumentNullException("entities");

                foreach (var entity in entities)
                    this.Entities.Add(entity);

                this._context.SaveChanges();
            }
            catch (DbEntityValidationException dbEx)
            {
                var msg = string.Empty;

                foreach (var validationErrors in dbEx.EntityValidationErrors)
                    foreach (var validationError in validationErrors.ValidationErrors)
                        msg += string.Format("Property: {0} Error: {1}", validationError.PropertyName, validationError.ErrorMessage) + Environment.NewLine;

                var fail = new Exception(msg, dbEx);
                //Debug.WriteLine(fail.Message, fail);
                throw fail;
            }
        }

        /// <summary>
        /// Update entity
        /// </summary>
        /// <param name="entity">Entity</param>
        public virtual void Update(T entity)
        {
            try
            {
                if (entity == null)
                    throw new ArgumentNullException("entity");

                this._context.SaveChanges();
            }
            catch (DbEntityValidationException dbEx)
            {
                var msg = string.Empty;

                foreach (var validationErrors in dbEx.EntityValidationErrors)
                    foreach (var validationError in validationErrors.ValidationErrors)
                        msg += Environment.NewLine + string.Format("Property: {0} Error: {1}", validationError.PropertyName, validationError.ErrorMessage);

                var fail = new Exception(msg, dbEx);
                //Debug.WriteLine(fail.Message, fail);
                throw fail;
            }
        }

        /// <summary>
        /// Delete entity
        /// </summary>
        /// <param name="entity">Entity</param>
        public virtual void Delete(T entity)
        {
            try
            {
                if (entity == null)
                    throw new ArgumentNullException("entity");

                this.Entities.Remove(entity);

                this._context.SaveChanges();
            }
            catch (DbEntityValidationException dbEx)
            {
                var msg = string.Empty;

                foreach (var validationErrors in dbEx.EntityValidationErrors)
                    foreach (var validationError in validationErrors.ValidationErrors)
                        msg += Environment.NewLine + string.Format("Property: {0} Error: {1}", validationError.PropertyName, validationError.ErrorMessage);

                var fail = new Exception(msg, dbEx);
                //Debug.WriteLine(fail.Message, fail);
                throw fail;
            }
        }

        /// <summary>
        /// Delete entities
        /// </summary>
        /// <param name="entities">Entities</param>
        public virtual void Delete(IEnumerable<T> entities)
        {
            try
            {
                if (entities == null)
                    throw new ArgumentNullException("entities");

                foreach (var entity in entities)
                    this.Entities.Remove(entity);

                this._context.SaveChanges();
            }
            catch (DbEntityValidationException dbEx)
            {
                var msg = string.Empty;

                foreach (var validationErrors in dbEx.EntityValidationErrors)
                    foreach (var validationError in validationErrors.ValidationErrors)
                        msg += Environment.NewLine + string.Format("Property: {0} Error: {1}", validationError.PropertyName, validationError.ErrorMessage);

                var fail = new Exception(msg, dbEx);
                //Debug.WriteLine(fail.Message, fail);
                throw fail;
            }
        }

        #endregion

        #region Properties

        /// <summary>
        /// Gets a table
        /// </summary>
        public virtual IQueryable<T> Table
        {
            get
            {
                return this.Entities;
            }
        }

        /// <summary>
        /// Gets a table with "no tracking" enabled (EF feature) Use it only when you load record(s) only for read-only operations
        /// </summary>
        public virtual IQueryable<T> TableNoTracking
        {
            get
            {
                return this.Entities.AsNoTracking();
            }
        }

        /// <summary>
        /// Entities
        /// </summary>
        protected virtual IDbSet<T> Entities
        {
            get
            {
                if (_entities == null)
                    _entities = _context.Set<T>();
                return _entities;
            }
        }

        #endregion
    }
}

上下文

using System.Collections.Generic;
using System.Data.Entity;
using Nop.Core;

namespace Nop.Data
{
    public interface IDbContext
    {
        /// <summary>
        /// Get DbSet
        /// </summary>
        /// <typeparam name="TEntity">Entity type</typeparam>
        /// <returns>DbSet</returns>
        IDbSet<TEntity> Set<TEntity>() where TEntity : BaseEntity;

        /// <summary>
        /// Save changes
        /// </summary>
        /// <returns></returns>
        int SaveChanges();

        /// <summary>
        /// Execute stores procedure and load a list of entities at the end
        /// </summary>
        /// <typeparam name="TEntity">Entity type</typeparam>
        /// <param name="commandText">Command text</param>
        /// <param name="parameters">Parameters</param>
        /// <returns>Entities</returns>
        IList<TEntity> ExecuteStoredProcedureList<TEntity>(string commandText, params object[] parameters)
            where TEntity : BaseEntity, new();

        /// <summary>
        /// Creates a raw SQL query that will return elements of the given generic type.  The type can be any type that has properties that match the names of the columns returned from the query, or can be a simple primitive type. The type does not have to be an entity type. The results of this query are never tracked by the context even if the type of object returned is an entity type.
        /// </summary>
        /// <typeparam name="TElement">The type of object returned by the query.</typeparam>
        /// <param name="sql">The SQL query string.</param>
        /// <param name="parameters">The parameters to apply to the SQL query string.</param>
        /// <returns>Result</returns>
        IEnumerable<TElement> SqlQuery<TElement>(string sql, params object[] parameters);

        /// <summary>
        /// Executes the given DDL/DML command against the database.
        /// </summary>
        /// <param name="sql">The command string</param>
        /// <param name="doNotEnsureTransaction">false - the transaction creation is not ensured; true - the transaction creation is ensured.</param>
        /// <param name="timeout">Timeout value, in seconds. A null value indicates that the default value of the underlying provider will be used</param>
        /// <param name="parameters">The parameters to apply to the command string.</param>
        /// <returns>The result returned by the database after executing the command.</returns>
        int ExecuteSqlCommand(string sql, bool doNotEnsureTransaction = false, int? timeout = null, params object[] parameters);
    }
}

Answer 1

这表明您尝试更新的实体已在后台/其他用户会话中被删除/修改。 我认为你们已经在表中添加了行版本并启用了并发控制。 例外是告诉您发生了并发修改。 您可以通过重新加载实体并重试操作来处理此问题。

Answer 2

如果这是使用实体框架的 MVC 应用程序，则可能是您没有在视图中嵌入主键。 当我在我的应用程序中创建一个新的编辑视图时发生了这种情况，而忽略了将它放在编辑视图的表单中： @Html.HiddenFor(model => model.XfmrTapID)

当我的控制器的 HttpPost ActionMethod 试图处理表单返回的内容时，它欺骗性地给了我 OptimisticConcurrencyException。 如果它是一个新的 MVC 视图，请确保检查它。

Answer 3

public virtual void Insert(T entity)
        {
            try
            {
                if (entity == null)
                  throw new ArgumentNullException("entity");
                this.Entities.Add(entity);
                this._context.SaveChanges();
            }
           catch  (System.Data.Entity.Infrastructure.DbUpdateConcurrencyException ex)
           {
              //Safely ignore this exception
           }
           catch (System.Data.Entity.Core.OptimisticConcurrencyException)
           {
            //Safely ignore this exception
           }                
           catch (DbEntityValidationException dbEx)
           {

            var msg = string.Empty;
            foreach (var validationErrors in dbEx.EntityValidationErrors)
                foreach (var validationError in validationErrors.ValidationErrors)
                    msg += string.Format("Property: {0} Error: {1}", validationError.PropertyName, validationError.ErrorMessage) + Environment.NewLine;
            var fail = new Exception(msg, dbEx);
            //Debug.WriteLine(fail.Message, fail);
            throw fail;
         }
    }