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如何解決 System.Data.Entity.Core.OptimisticConcurrencyException 的這個錯誤

[英]How to solve this error of System.Data.Entity.Core.OptimisticConcurrencyException

異常類型:

System.DataEntity.Core.OptimisticConcurrencyException

信息 :

存儲更新、插入或刪除語句影響了意外的行數 (0)。 自加載實體以來,實體可能已被修改或刪除。 刷新 ObjectStateManager 條目。

堆棧跟蹤:

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()

代碼 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);
    }
}

這表明您嘗試更新的實體已在后台/其他用戶會話中被刪除/修改。 我認為你們已經在表中添加了行版本並啟用了並發控制。 例外是告訴您發生了並發修改。 您可以通過重新加載實體並重試操作來處理此問題。

如果這是使用實體框架的 MVC 應用程序,則可能是您沒有在視圖中嵌入主鍵。 當我在我的應用程序中創建一個新的編輯視圖時發生了這種情況,而忽略了將它放在編輯視圖的表單中: @Html.HiddenFor(model => model.XfmrTapID)

當我的控制器的 HttpPost ActionMethod 試圖處理表單返回的內容時,它欺騙性地給了我 OptimisticConcurrencyException。 如果它是一個新的 MVC 視圖,請確保檢查它。

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;
         }
    }

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