Look at the call stack. The real exception was thrown here : System.RuntimeType.GetPropertyImpl(String name, BindingFlags bindingAttr, Binder binder, Type returnType, Type[] types, ParameterModifier[] modifiers) - it just wasn't caught till your line......

If you step into that you'll at least know which property was being looked at and which flags were set.


>How should I load the source libraries?
>
>The error is thrown on this line
>
> _dbSet.Attach(entity); // Error here
>
>
>
>>I'd be *very* surprised if this was case related.
>>
>>Since the exception is thrown by Type.GetProperty() when it cannot uniquely identify a property based on the supplied parameters then seeing the class definition for the EntityEntry involved would be helpful.
>>
>>IAC, I'd suggest loading the source libraries so that you can step into the process and discover what the 'name' parameter is when Type.GetProperty() throws the exception.
>>
>>>Update. http://forums.asp.net/t/1775469.aspx?System+Reflection+AmbiguousMatchException+Ambiguous+match+found+
>>>
>>>
>>>Re: System.Reflection.AmbiguousMatchException: Ambiguous match found.
>>>Aug 02, 2012 12:16 PM|LINK
>>>
>>>I had a similar issue: I am using POCO object with Entity Framework 4, and I got the same exception when adding a new object with 'AddObject'.
>>>
>>>The problem in my case was that an entity had two members with the same name and different casing. One was a field from the database, and one was a navigation property. Just renaming one of the two solved the problem.
>>>
>>>This sounds like my issue but the classes are auto-generated :( What should I do?
>>>
>>>---------------------------------------------
>>>Hi everybody,
>>>
>>>I am getting the following error:
>>>
>>>System.Reflection.AmbiguousMatchException was unhandled by user code
>>> HResult=-2147475171
>>> Message=Ambiguous match found.
>>> Source=mscorlib
>>> StackTrace:
>>> at System.RuntimeType.GetPropertyImpl(String name, BindingFlags bindingAttr, Binder binder, Type returnType, Type[] types, ParameterModifier[] modifiers)
>>> at System.Type.GetProperty(String name, BindingFlags bindingAttr)
>>> at System.Linq.Expressions.Expression.PropertyOrField(Expression expression, String propertyOrFieldName)
>>> at System.Data.Entity.Core.Objects.Internal.EntityProxyFactory.CreateBaseGetter(Type declaringType, PropertyInfo propertyInfo)
>>> at System.Data.Entity.Core.Objects.Internal.PocoPropertyAccessorStrategy.GetNavigationPropertyValue(RelatedEnd relatedEnd)
>>> at System.Data.Entity.Core.Objects.Internal.EntityWrapper`1.GetNavigationPropertyValue(RelatedEnd relatedEnd)
>>> at System.Data.Entity.Core.Objects.EntityEntry.TakeSnapshotOfRelationships()
>>> at System.Data.Entity.Core.Objects.Internal.EntityWrapperWithoutRelationships`1.TakeSnapshotOfRelationships(EntityEntry entry)
>>>etc.
>>>
>>>on this line of code:
>>>
>>>

>>> public virtual void Update(T entity)
>>>        {
>>>            EntityState entityState =  _siriusContext.GetEntityState(entity) ;
>>>            if (entityState == EntityState.Detached)
>>>            {
>>>                _dbSet.Attach(entity); // Error here
>>>            }
>>>

>>>
>>>Do you know what this may be about? The table has character 10 primary key but I'm not sure if this is relevant or not. I haven't gotten this error before.
>>>
>>>Thanks in advance.