c# - LINQ Select Based on Another Select -


i find myself stuck on linq in same place. cannot make linq techniques stick in head.

var groupids = context.set<usercontrol>().where(x => x.systemuserid == system.convert.toint32(userid)).select(x => x.systemgroupid); {     var usergroups = context.set<group>().where(g => g.groupid)     {         groups.addrange(usergroups.select(sysgroup => new toolusergroup(sysgroup.groupname, sysgroup.groupid.tostring())));     } }

i'm trying select list of group objects based on groupid property of list selected in first list of usercontrol ids. cannot figure out syntax.

i'm not sure easier writing sql hand ... linq appear me more complex , abstract writing sql.

i assuming, trying select list based on list of items.

var groupids = context.set<usercontrol>()                   .where(x => x.systemuserid ==system.convert.toint32(userid))                   .select(x => x.systemgroupid);                   .tolist();  var usergroups = context.set<group()                         .where(g=>groupids.contains(g.groupid)).tolist();

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