与 NHibernate ICriteria/QueryOver 查询的外连接中的条件相等

我该如何做equalsNhibernate/QueryOver/ICriteria 中外连接的条件？

我发现比较的唯一方法surveyRequest.Survey.Id with surveyID下面是与IsIn.

SystemUser systemUser= null;
SurveyRequests surveyRequest = null;

var query = Session.QueryOver<SystemUser>(() => systemUser)
    .Left.JoinAlias(
        () => systemUser.SurveyRequests, 
        () => surveyRequest,
        Restrictions.On(()=>surveyRequest.Survey.Id).IsIn(new object []{surveyID }))
//                                                   ^^^^

（我正在重用早期的查询问题 https://stackoverflow.com/a/15113972/521554.)

我们可以使用.Where()部分Restrictions

var query = Session.QueryOver<SystemUser>(() => systemUser)
    .Left.JoinAlias(
        () => systemUser.SurveyRequests, 
        () => surveyRequest,
        //Restrictions.On(()=>surveyRequest.Survey.Id).IsIn(new object []{surveyID }))
        Restrictions.Where(()=>surveyRequest.Survey.Id == surveyID ))