asp.net-mvc-3 – AutoMapper线程问题(缺少类型映射配置或不支持

private List<CaseCommentModel> GetCaseCommentModels(string caseId) {
    var comments = CaseService.GetAllCaseCommentsByCaseId(caseId);

    Mapper.Reset();
    Mapper.CreateMap<CrmCaseComment,CaseCommentModel>();

    var caseCommentModels = Mapper.Map<List<CrmCaseComment>,List<CaseCommentModel>>(comments);

    return caseCommentModels;
}

private List<CaseAttachmentModel> GetCaseAttachmentModels(string caseId) {
    var attachments = AttachmentService.GetAttachmentsByParentId(caseId);

    Mapper.Reset();
    Mapper.CreateMap<CrmAttachment,CaseAttachmentModel>();

    var caseAttachmentModels = Mapper.Map<List<CrmAttachment>,List<CaseAttachmentModel>>(attachments);

    return caseAttachmentModels;
}

有时两种反应都会成功但是,如果我刷新页面,有时会出现以下异常：

缺少类型映射配置或不支持的映射

我可以从成功失败的两个请求转到不做任何代码更改;只需刷新页面即可.这是一个线程问题还是我错误地使用了映射器？