即使linq到sql join存在，也不会过滤子集合

I have a LINQ query:

我有一个LINQ查询:

var result = from mt in MessageTypes
            join mtfmt in MessageTypeField_MessageTypes
                on new { MessageTypeID = mt.ID, MessageTypeFieldID = messageTypeFieldId } equals new { MessageTypeID = mtfmt.MessageTypeID, MessageTypeFieldID = mtfmt.MessageTypeFieldID }
            where (mt.StatusID == (int)status)
            select mt;
var result