2

专家们，

在运行时第一次使用实体框架函数时，我得到了这个System.ArgumentException（已经添加了具有相同键的项目）。奇怪的是：如果我使用调试模式，它工作正常。在编译相同的代码后，在发布模式中没有任何更改，它立即崩溃，并在本文顶部提到异常。

有谁知道更多关于这种奇怪行为的信息？我该如何解决？我无法向我的客户推出调试版本:(

此时抛出异常：

try
{
  var blub = context.ExecuteStoreQuery<int>(QueryString);
}
catch (Exception ex)
{
  // ...
}

堆栈跟踪：

System.ArgumentException: An item with the same key has already been added.
   at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
   at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boo
lean add)
   at System.Data.Metadata.Edm.ObjectItemAttributeAssemblyLoader.LoadRelationshi
pTypes()
   at System.Data.Metadata.Edm.ObjectItemAttributeAssemblyLoader.LoadTypesFromAs
sembly()
   at System.Data.Metadata.Edm.ObjectItemAssemblyLoader.Load()
   at System.Data.Metadata.Edm.ObjectItemAttributeAssemblyLoader.Load()
   at System.Data.Metadata.Edm.AssemblyCache.LoadAssembly(Assembly assembly, Boo
lean loadReferencedAssemblies, ObjectItemLoadingSessionData loadingData)
   at System.Data.Metadata.Edm.AssemblyCache.LoadAssembly(Assembly assembly, Boo
lean loadReferencedAssemblies, ObjectItemLoadingSessionData loadingData)
   at System.Data.Metadata.Edm.AssemblyCache.LoadAssembly(Assembly assembly, Boo
lean loadReferencedAssemblies, ObjectItemLoadingSessionData loadingData)
   at System.Data.Metadata.Edm.AssemblyCache.LoadAssembly(Assembly assembly, Boo
lean loadReferencedAssemblies, ObjectItemLoadingSessionData loadingData)
   at System.Data.Metadata.Edm.AssemblyCache.LoadAssembly(Assembly assembly, Boo
lean loadReferencedAssemblies, KnownAssembliesSet knownAssemblies, EdmItemCollec
tion edmItemCollection, Action`1 logLoadMessage, Object& loaderCookie, Dictionar
y`2& typesInLoading, List`1& errors)
   at System.Data.Metadata.Edm.ObjectItemCollection.LoadAssemblyFromCache(Object
ItemCollection objectItemCollection, Assembly assembly, Boolean loadReferencedAs
semblies, EdmItemCollection edmItemCollection, Action`1 logLoadMessage)
   at System.Data.Metadata.Edm.MetadataWorkspace.ImplicitLoadAssemblyForType(Typ
e type, Assembly callingAssembly)
   at System.Data.Objects.ObjectContext.ExecuteStoreQueryInternal[TElement](Stri
ng commandText, String entitySetName, MergeOption mergeOption, Object[] paramete
rs)
4

1 回答 1

2

首先，确保即使您进行了干净的发布构建（我的意思是在运行构建之前没有二进制文件，仅源代码），您也会收到错误。如果您不这样做，则修复您的项目设置（例如，隔离调试和发布构建目标文件夹）。

如果错误只发生一次，然后应用程序正常工作，则您必须遇到一些同步问题。虽然这很奇怪，因为元数据加载似乎是同步的。但无论如何，EF 对象都不是线程安全的。不要在跨线程场景中使用它们。

如果上面说的没有帮助，那么也许我的研究结果会对你有所帮助。这是与错误相关的 EF 源代码的摘录：

//---------------------------------------------------------------------- 
// <copyright file="ObjectItemAttributeAssemblyLoader.cs" company="Microsoft">
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
// 
// @owner       [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 

using System.Collections.Generic;
using System.Data.Entity;
using System.Data.Objects.DataClasses;
using System.Diagnostics; 
using System.Reflection;

namespace System.Data.Metadata.Edm 
{
  /// <summary> 
  /// Class for representing a collection of items for the object layer.
  /// Most of the implemetation for actual maintainance of the collection is
  /// done by ItemCollection
  /// </summary> 
  internal sealed class ObjectItemAttributeAssemblyLoader :
      ObjectItemAssemblyLoader
  { 
    // ...

    /// <summary>
    /// This method loads all the relationship type that this entity takes part in
    /// </summary> 
    /// <param name="entityType"></param>
    /// <param name="context"></param> 
    private void LoadRelationshipTypes() 
    {
      foreach (EdmRelationshipAttribute roleAttribute in
               SourceAssembly.GetCustomAttributes(typeof(EdmRelationshipAttribute), false /*inherit*/)) 
      {
        // Check if there is an entry already with this name
        if (TryFindNullParametersInRelationshipAttribute(roleAttribute))
        { 
          // don't give more errors for these same bad parameters
          continue; 
        } 

        bool errorEncountered = false; 

        // return error if the role names are the same
        if (roleAttribute.Role1Name == roleAttribute.Role2Name)
        { 
          SessionData.EdmItemErrors.Add(new EdmItemError(
              System.Data.Entity.Strings.SameRoleNameOnRelationshipAttribute(roleAttribute.RelationshipName, roleAttribute.Role2Name),
                       null)); 
          errorEncountered = true; 
        }


        if (!errorEncountered)
        {
          AssociationType associationType = new AssociationType(
            roleAttribute.RelationshipName, roleAttribute.RelationshipNamespaceName,
            roleAttribute.IsForeignKey, DataSpace.OSpace); 
          SessionData.TypesInLoading.Add(associationType.FullName, associationType);
          TrackClosure(roleAttribute.Role1Type); 
          TrackClosure(roleAttribute.Role2Type); 

          // prevent lifting of loop vars 
          string r1Name = roleAttribute.Role1Name;
          Type r1Type = roleAttribute.Role1Type;
          RelationshipMultiplicity r1Multiplicity = roleAttribute.Role1Multiplicity;
          AddTypeResolver(() => 
            ResolveAssociationEnd(associationType, r1Name, r1Type, r1Multiplicity));

          // prevent lifting of loop vars 
          string r2Name = roleAttribute.Role2Name;
          Type r2Type = roleAttribute.Role2Type; 
          RelationshipMultiplicity r2Multiplicity = roleAttribute.Role2Multiplicity;
          AddTypeResolver(() =>
            ResolveAssociationEnd(associationType, r2Name, r2Type, r2Multiplicity));

          // get assembly entry and add association type to the list of types in the assembly
          Debug.Assert(!CacheEntry.ContainsType(associationType.FullName), "Relationship type must not be present in the list of types"); 
          CacheEntry.TypesInAssembly.Add(associationType); 
        }
      } 
    }

    // ...
  }
}

该方法中使用的唯一字典是SessionData.TypesInLoading. 关键是RelationshipName和的组合RelationshipNamespaceName。有趣的是，评论说他们检查重复的键，但该方法TryFindNullParametersInRelationshipAttribute只检查属性的属性不是nulls。我想这是一个错误。

但更重要的是，必须发生所描述的错误，因为在您的程序集中的某个地方，您有多个EdmRelationshipAttribute具有相同组合的RelationshipName和RelationshipNamespaceName属性。可能有多种原因：

  1. EDMX 文件不正确。
  2. 不当复制的程序集，
  3. 发布配置，将其构建结果输出到与调试配置相同的文件夹，
  4. 手动生成 EF 映射程序集的错误，
  5. 等等

不幸的是，要找出破裂关系的名字将非常困难。您可能必须System.Data.Metadata.Edm.ObjectItemAttributeAssemblyLoader.LoadRelationshipTypes()在反汇编中设置断点并跟踪它。我会说这几乎是不可能的，因为该Dictionary.Insert方法将被多次调用。

如果所有这些仍然不能提出解决方案，那么您确实需要为您的问题准备一份副本并将其发布在此处。否则没有人能帮上忙。

于 2012-04-18T15:06:37.790 回答