AutoMapper“锁定”网站并引发IndexOutOfRangeException

Question

I am using AutoMapper on my web site. It works great, but about once every two weeks I get a yellow page (see stack trace below), and the only way to resolve this is to restart the site (recycle app pool). AutoMapper version: 2.0.9999 (as seen on file properties).

Any ideas what this can be caused by? Is this a failure of the configuration step (which happens once)?

[IndexOutOfRangeException: Index was outside the bounds of the array.]
  System.Collections.Generic.Enumerator.MoveNext() +75
  System.Linq.Enumerable.FirstOrDefault(IEnumerable`1 source, Func`2 predicate) +166
  AutoMapper.ConfigurationStore.FindExplicitlyDefinedTypeMap(Type sourceType, Type destinationType) +147
  AutoMapper.ConfigurationStore.FindTypeMap(Object source, Type sourceType, Type destinationType, String profileName) +169
  AutoMapper.ConfigurationStore.FindTypeMapFor(Object source, Type sourceType, Type destinationType) +279
  AutoMapper.MappingEngine.Map(Object source, Type sourceType, Type destinationType) +71
  AutoMapper.MappingEngine.Map(TSource source) +190
  AutoMapper.Mapper.Map(TSource source) +105
  WowReforge.ViewModels.ReforgeViewModel.LoadToonGear(IDictionary`2 gear, IDictionary`2 itemsRefInfo) +307
  ...

Answer 1

Looking at the System.Linq.Enumerable FirstOrDefault in ILSpy, there is call to IEnumerator.MoveNext, like it's indicated in the stacktrace that you provided. But it does not indicate what implementation of IEnumerator it is. From that it is hard to tell what can actually happen in MoveNext.

What are the objects involved in the mapping? What type of collections are you using?

If you are using an implementation of IEnumerator of your own, could it be that you are doing something wrong when providing a value for Current or calculating the indexes wrong in your MoveNext method?