Question

我有一个相当庞大的林克-到先伯恩的询问。我现在需要增加一个过滤器,该过滤器是根据在t-sql书写的用户界定功能,即必须把参数输入。在我的案件中,我需要通过一个手提式编码,即用户类型和传输到t-sql功能中,以便用距离这一页的距离进行过滤。这样做是可能的,还是需要用伊玛普里亚办法重写我的询问吗?

Answer 1

i) 找到解决办法:

Note the NHibernate query (nquery) which has RegisterCustomAction:

private void CallZipSqlFunction(ListingQuerySpec spec, IQueryable<Listing> query)
        {

            var nQuery = query as NHibernate.Linq.Query<Listing>;

            //todo: find some way to paramaterize this or use linq-to-nh and not criteria to call the function
            // so i don thave to check for escape chars in zipcode
            if (spec.ZipCode.Contains(" "))
                throw new SecurityException("invalid character");

            //yuck!
            var functionString = "dbo.GetDistanceForListing( " + spec.ZipCode + " ,{alias}.ID) as Distance";
            //create a projection representing the function call
            var distance = Projections.SqlProjection(functionString, new[] { "Distance" }, new IType[] { NHibernateUtil.String });

            //create a filter based on the projection
            var filter = Expression.Le(distance, spec.ZipCodeRadius.Value);

            //add the distance projection as order by
            nQuery.QueryOptions.RegisterCustomAction(x => x.AddOrder(Order.Asc(distance)));

            //add teh distance filter
            nQuery.QueryOptions.RegisterCustomAction(x => x.Add(filter));
        }

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