专家，
我在运行时首次使用实体框架函数时，得到了 System.ArgumentException （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。在编译相同的代码而没有在发布模式中进行任何更改之后，它会立即崩溃，并在此帖子的顶部提到异常。
有没有人更了解这种奇怪的行为？我该如何解决？我无法向客户推出调试版本：（
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)
答案 0 :(得分：2)
首先，确保即使您进行清理版本构建也会出现错误（我的意思是在运行构建之前没有二进制文件，仅限源代码）。如果不这样做，则修复项目设置（例如，隔离调试和发布构建目标文件夹）。
如果错误仅发生一次，之后应用程序正常运行，则必须存在一些同步问题。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对象不是线程安全的。不要在跨线程场景中使用它们。
如果上述说法没有帮助，那么我的研究结果可能会对您有所帮助。以下是与错误相关的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RelationshipNamespaceName的组合。有趣的是，评论说他们检查重复的密钥，但方法TryFindNullParametersInRelationshipAttribute仅检查属性的属性不是null。我想这是一个错误。
但更重要的是，所描述的错误必定已经发生，因为在程序集中的某个位置，您有多个EdmRelationshipAttribute具有RelationshipName和RelationshipNamespaceName属性的相同组合。可能有多种原因：
不幸的是，抓住破裂关系的名称将非常困难。您可能必须在System.Data.Metadata.Edm.ObjectItemAttributeAssemblyLoader.LoadRelationshipTypes()设置断点并在反汇编中跟踪它。我会说这几乎是不可能的，因为Dictionary.Insert方法即将被称为很多次。
如果所有这些仍未建议解决方案，那么您需要准备一份您的问题的副本并在此处发布。否则没人能帮忙。