使用linq更新复合键字段

Question

在我们的SQL数据库中，我们有一个带有组合键的表格，其中包含我们需要随时更新的字段。这是我的理解，因为我们正在使用实体框架，我需要先从数据库中删除记录，然后将该行添加回表中。

以下是我创建的用于处理“更新”的简单方法，因为有许多方法将执行此操作。然而，一旦.SaveChanges()方法是.Remove后叫我拿到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. 

不知道我在做什么错了，因为我想删除的记录，然后进行更新，然后添加记录背部。

下面是调用remove/edit方法的方法。当这个方法被调用时，记录没有以任何形式或形式改变。

private static void ProcessAllChanges(ZipCodeIndex information, ZipCodeTerritory zipToUpdate) 
    { 
     try 
     { 
      RemoveRecord(zipToUpdate); 

      if (!string.IsNullOrWhiteSpace(information.newTerritory)) zipToUpdate.IndDistrnId = information.newTerritory; 
      if (!string.IsNullOrWhiteSpace(information.newStateCode)) zipToUpdate.StateCode = information.newStateCode; 
      if (!string.IsNullOrWhiteSpace(information.newDescription)) zipToUpdate.DrmTerrDesc = information.newDescription; 
      if (!string.IsNullOrWhiteSpace(information.newChannelCode)) zipToUpdate.ChannelCode = information.newChannelCode; 
      if (zipToUpdate.EndDate == DateTime.MinValue) zipToUpdate.EndDate = DateTime.MaxValue; 

      EditRecord(zipToUpdate); 
      _updated++; 
     } 
     catch (DbEntityValidationException dbEx) 
     { 
      _msg += "Error during update; "; 
      EventLog.WriteEntry("Monet", "Error during ProcessAllChanges: " + zipToUpdate.ToString() + " |EX| " + dbEx.Message); 
     } 
     catch (Exception ex) 
     { 
      _msg += "Error during update; "; 
      EventLog.WriteEntry("Monet", "Error during ProcessAllChanges: " + zipToUpdate.ToString() + " |MESSAGE| " + ex.Message); 
     } 
    } 

而且这里有两个helper方法被调用

public static void RemoveRecord(ZipCodeTerritory zipCode) 
    { 
     _db = new AgentResources(); 
     _db.ZipCodeTerritory.Attach(zipCode); 
     _db.ZipCodeTerritory.Remove(zipCode); 
     _db.SaveChanges(); 
    } 

    public static void EditRecord(ZipCodeTerritory zipCode) 
    { 
     _db = new AgentResources(); 
     _db.ZipCodeTerritory.Add(zipCode); 
     _db.SaveChanges(); 
    } 

编辑

基于一对夫妇的评论下面我试图创建上下文对象的一个​​单独的实例，但是我使用这种方法收到了同样的错误：

public static void RemoveRecord(ZipCodeTerritory zipCode) 
    { 
     using (AgentResources deleteMe = new AgentResources()) 
     { 
      deleteMe.ZipCodeTerritory.Attach(zipCode); 
      deleteMe.ZipCodeTerritory.Remove(zipCode); 
      deleteMe.SaveChanges();     
     } 
    } 

第二编辑

这是最上面的方法，它调用上面发布的ProcessAllChanges方法。

public static string TerritoryOnly(ZipCodeIndex updateZip) 
    { 
     if (!string.IsNullOrWhiteSpace(updateZip.newEffectiveDate) || !string.IsNullOrWhiteSpace(updateZip.newEndDate)) 
     { 
      return "Neither effective or end date can be present if updating Territory Code only; "; 
     } 

     RefreshProperties(); 

     foreach (var zipCode in updateZip.displayForPaging.Where(x => x.Update)) 
     { 
      ProcessAllChanges(updateZip, zipCode); 
     } 

     _msg += _updated + " record(s) updated; "; 

     return _msg; 
    } 

第三编辑

每请求这里是AgentResources完整的类定义，我们DbContext对象

namespace Monet.Models 
{ 
    using System; 
    using System.Data.Entity; 
    using System.Data.Entity.Infrastructure; 

    public partial class AgentResources : DbContext 
    { 
     public AgentResources() 
      : base("name=AgentResources") 
     { 
     } 

     protected override void OnModelCreating(DbModelBuilder modelBuilder) 
     { 
      throw new UnintentionalCodeFirstException(); 
     } 

     public DbSet<AgentContEd> AgentContEd { get; set; } 
     public DbSet<ContEdCourse> ContEdCourse { get; set; } 
     public DbSet<Course> Course { get; set; } 
     public DbSet<CourseToProduct> CourseToProduct { get; set; } 
     public DbSet<Product> Product { get; set; } 
     public DbSet<ProcessControl> ProcessControl { get; set; } 
     public DbSet<AgentIdToTradingPartner> AgentIdToTradingPartner { get; set; } 
     public DbSet<TradingPartner> TradingPartner { get; set; } 
     public DbSet<Notes> Notes { get; set; } 
     public DbSet<CourseMaterials> CourseMaterials { get; set; } 
     public DbSet<TransactionLog> TransactionLog { get; set; } 
     public DbSet<Agent> Agent { get; set; } 
     public DbSet<AgentIdentification> AgentIdentification { get; set; } 
     public DbSet<BatchDashboard> BatchDashboard { get; set; } 
     public DbSet<BatchPrograms> BatchPrograms { get; set; } 
     public DbSet<FollowUpItems> FollowUpItems { get; set; } 
     public DbSet<sysdiagrams> sysdiagrams { get; set; } 
     public DbSet<AgentProductTraining> AgentProductTraining { get; set; } 
     public DbSet<Channel> Channel { get; set; } 
     public DbSet<RelationshipCodes> RelationshipCodes { get; set; } 
     public DbSet<DropDownValues> DropDownValues { get; set; } 
     public DbSet<QueueUpdates> QueueUpdates { get; set; } 
     public DbSet<MarketingLookup> MarketingLookup { get; set; } 
     public DbSet<TransmissionHistory> TransmissionHistory { get; set; } 
     public DbSet<AgentTransmission> AgentTransmission { get; set; } 
     public DbSet<ZipCodeTerritory> ZipCodeTerritory { get; set; } 
    } 
} 

这里是ZipCodeTerritory类

public partial class ZipCodeTerritory 
{ 
    public string ChannelCode { get; set; } //Composite key field 
    public string DrmTerrDesc { get; set; } 
    public string IndDistrnId { get; set; } 
    public string StateCode { get; set; } //Composite key field 
    public string ZipCode { get; set; } //Composite key field 
    public System.DateTime? DisplayEndDate { get; set; } 
    public System.DateTime EndDate { get; set; } //Composite key field 
    public System.DateTime EffectiveDate { get; set; } 
    public string LastUpdateId { get; set; } 
    public Nullable<System.DateTime> LastUpdateDate { get; set; } 
} 

Answer 1

试试这个：

public static void RemoveRecord(ZipCodeTerritory zipCode) 
{ 
    using(var _newdb = new AgentResources()) 
    { 
     ZipCodeTerritory zipCodeRemove = new ZipCodeTerritory(); 
     zipCodeRemove.channelCode = zipCode.channelCode; 
     zipCodeRemove.stateCode = zipCode.stateCode; 
     zipCodeRemove.zipCode= zipCode.zipCode; 
     zipCodeRemove.endDate = zipCode.endDate; 

     _newdb.ZipCodeTerritory.Attach(zipCodeRemove); 
     _newdb.ZipCodeTerritory.Remove(zipCodeRemove); 
     //((IObjectContextAdapter)_newdb).ObjectContext.Refresh(
                // RefreshMode.ClientWins 
                //, zipCode); 
     _newdb.SaveChanges(); 
    } 
}