c# - Exclude linq join condition based on parameter -

-

i want able dynamically exclude join based on boolean parameters, @ code below, how can exclude join if 'includejoin' variable false or there way dynamically add joins

 class program {     static void main(string[] args)     {         list<foo> foolist = new list<foo>();         foolist.add(new foo{foo_id = 1});         foolist.add(new foo{foo_id = 2});          list<bar> barlist = new list<bar>();         barlist.add(new bar{foo_id = 1});         barlist.add(new bar{foo_id = 1});          iqueryable<foo> fooquery = foolist.asqueryable();         iqueryable<bar> barquery = barlist.asqueryable();          bool includejoin = false;          var foos = f in foolist                     //exclude join if includejoin vairable false!!                    join b in barlist on f.foo_id equals b.foo_id g                    result in g.defaultifempty()                      select new foo { foo_id = f.foo_id };          var results = foos.tolist();     }      public class foo     {         public int foo_id { get; set; }     }      public class bar     {         public int foo_id { get; set; }     } }

i think want possible building 2 different linq queries:

bool includejoin = false;  ienumerable<foo> foos;  if (includejoin) {     foos = f in foolist                  //exclude join if includejoin vairable false!!                 join b in barlist on f.foo_id equals b.foo_id g                 result in g.defaultifempty()                   select new foo { foo_id = f.foo_id }; } else {     foos = f in foolist select new foo { foo_id = f.foo_id }; }  var results = foos.tolist();

with solution, can build 2 independent linq queries result in ienumerable in either way. both result in same type (ienumerable), can use foos.tolist() @ end list values.


Comments

Post a Comment

Popular posts from this blog

python - How to create jsonb index using GIN on SQLAlchemy? -

-
here's current code creating index jsonb. index("mytable_data_idx_id_key", mytable.data['id'].astext, postgresql_using='gin') but got error. sqlalchemy.exc.programmingerror: (psycopg2.programmingerror) data type text has no default operator class access method "gin" hint: must specify operator class index or define default operator class data type. [sql: "create index event_data_idx_id_key on event using gin ((data ->> 'id'))"] is there way create index on sqlalchemy? the postgresql specific sqlalchemy docs @ http://docs.sqlalchemy.org/en/latest/dialects/postgresql.html#operator-classes mention postgresql_ops dictionary provide "operator class" used postgresql, , provide example illustrating use: index('my_index', my_table.c.id, my_table.c.data, postgresql_ops={ 'data': 'text_pattern_ops', ...
Read more

PHP DOM loadHTML() method unusual warning -

-
i had following code works fine on localhost: $document = new domdocument(); $document->loadhtml($p_result); $form = $document->getelementsbytagname('form')->item(0); // code continues using $form variable after same code updated on outside server, loadhtml() failed , issued warning. warning: domdocument::loadhtml() expects parameter 1 valid path, string given in path/name/to/script.php returned null instead of object code pretty gets fatal error. note contents of $p_result absolutely same on outside server , on localhost. but why displays kind of warning , why not work? doesn't loadhtml() expects argument 1 string in first place? why method expects parameter 1 valid path ? just make clear i'm not calling loadhtmlfile() , i'm calling loadhtml() . thanks. you're affected one of php bugs . issue present in php 5.6.8 , 5.6.9. have affected php version on server, , bug-free version on localhost. the bug forbids null ...
Read more

c# - TransactionScope not rolling back although no complete() is called -

-
i'm using transactionscope rollback transaction fail bool errorreported = false; action<importerrorlog> newerrorcallback = e => { errorreported = true; errorcallback(e); }; using (var transaction = new transactionscope()) { foreach (importtaskdefinition task in taskdefinition) { loader.load(streamfile, newerrorcallback, task.destinationtable, processingtaskid); } if (!errorreported) transaction.complete(); } i'm sure there no transactionscope started ahead or after code. i'm using entity framework insert in db. regardless state of errorreported transaction never rolled in case of error. what missing ? transactionscope sets transaction.current . that's does. wants transacted must @ property. i believe ef each time connection opened reason. probably, connection open when scope installed. open connection inside of scope or enlist manually. ef has nasty "design decision": default opens ...
Read more