c# - Does Creating a Variable to hold a cast Save Overhead -

-

when need save big list of custom objects between postbacks on asp.net project, save them in session variable, cast them list<> in property this

    public partial class mypage : page     {          private list<mystorageobject> mylist          {                 {return (list<mystorageobject>) session["mysessionstring"]; }                 set { session["mysessionstring"] = value; }          }     }

then put list of objects in there, , call in later postback. think pretty standard way make objects last longer page lifecycle.

but question is, when i'm using list more once, i'm going few things it, can't think every time access it, it's casting object list<> if create variable looks it's avoiding casting.

   private void dostuffwithmylist()    {        var x = mylist;         //assuming i'm going call list 20 times in method        x.first();      // more efficient / cleaner        mylist.first(); // this?         //or both converted same thing in end anyway    }

yes, in first case (using x) you're accessing property once , reusing returned value.

in second case (using mylist multiple times) you'll looking value in session every time use it. it's casting, that's likely cheaper session lookup.

fundamentally i'd regard first version cleaner, makes clearer you're trying reuse same value several times.


Comments

Post a Comment

Popular posts from this blog

java - Jmockit String final length method mocking Issue -

-
using jmockit 1.2 jar, trying mock string's length method getting unexpected invocation exception: failed: test java.lang.illegalstateexception: missing invocation mocked type @ point; please make sure such invocations appear after declaration of suitable mock field or parameter @ stringdemo.testa$1.<init>(testa.java:17) @ stringdemo.testa.test(testa.java:13) i using testng: @test public void test() throws exception { new expectations() { @mocked("length") string astring; { astring.length(); result = 2; } }; system.out.println(a.showa("test")); } } actual class a: public class { public static int showa(string str){ int a= str.length(); return a; } } this wrong way of recording expected results. shouldn't mock , record string's length() method, record showa() instead. here solution @suppresswarnings("unused...
Read more

What is the difference between data design and data model(ERD) -

-
i have google question , find answer in day. know, data design many many table have list column,and mark pk , fk. why er-diagram have find this? data design process of designing database. main output of data design detailed logical data model of database. some people data design includes of needed logical , physical design choices , physical storage parameters needed generate design in data definition language. technically, database analysis, database analysts (dbas) trained do. while person can both data design , database analysis, these 2 different tasks. data design models data. database analysis takes model , applies 1 or more database engines (relational, hierarchical, nosql). a logical data model 1 of main outputs of data design. data model represented entity relationship diagram, or er diagram.
Read more

ios - Can NSManagedObject conform to NSCoding -

-
i need transfer single object across device. right converting nsmanagedobject dictionary , archiving , sending nsdata. upon receiving unarchiving it. transfer nsmanagedobject archiving , unarchiving instead of creating intermediate data object. @interface test : nsmanagedobject<nscoding> @property (nonatomic, retain) nsstring * title; @end @implementation test @dynamic title; - (id)initwithcoder:(nscoder *)coder { self = [super init]; if (self) { self.title = [coder decodeobjectforkey:@"title"]; //<crash } return self; } - (void)encodewithcoder:(nscoder *)coder { [coder encodeobject:self.title forkey:@"title"]; } @end nsdata *archivedobjects = [nskeyedarchiver archiveddatawithrootobject:testobj]; nsdata *objectsdata = archivedobjects; if ([objectsdata length] > 0) { nsarray *objects = [nskeyedunarchiver unarchiveobjectwithdata:objectsdata]; } the problem above code is. crashes @ self.title in initwithcoder sa...
Read more