c++ cli - Should I use a reference or an instance of C# objects in a C++/CLI class? -


in managed c++ class, should using reference or instance of c# class i've implemented in library?

consider example:

// mymanagedclass.h #pragma once  using namespace system::collections::generic; using namespace my::namespace::mycsharplib;  namespace my::namespace::mymanagedlib {     public ref class mymanagedclass     {     public:         mycsharpclass myinst; // have instance!         mycsharpclass ^myref; // need gcnew          list<mycsharpclass ^> listinst; // have instance!         list<mycsharpclass ^> ^listref; // need gcnew     }; }

and managed class called c# code:

// driver.cs using my.namespace.mycsharplib; using my.namespace.mymanagedlib;  public class driver {     private static void main(string[] args)     {         mymanagedclass mmc = new mymanagedclass();         dostuff(mmc);     } }

my gut tells me should using myref , listref because that's i'd doing if implemented in c#. why allowed directly instantiate instance of mycsharpclass? repercussions of doing this? if class ever has 1 collection of mycsharpclass objects, there harm directly initializing collection?

c++/cli has feature called stack semantics, using when declare reference type member though value type (mycsharpclass myinst;).

gcnew still being called, don't see code because compiler inject automatically default constructor. beware generate code dispose myinst!

below (pseudo) c++/cli code equivalent of msil compiler emit class:

constructor:

mymanagedclass() {     myinst = gcnew mycsharpclass(); }

dispose:

void dispose(bool dispose) {     if (dispose)     {         try         {             this->~mymanagedclass();         }                 {             delete myinst;         }     } }

edit:

regarding question repercussions: manually allocating gcnew means when mymanagedclass objects die, object pointed myref still hang around until garbage collector cleans up; whereas using stack semantics have more deterministic means of controlling object lifetimes without having write dispose method yourself.

it means when using stack semantics must careful share objects with...


Comments

Post a Comment

Popular posts from this blog

java - Spring Data JPA: Why findOne(id) executing delete query internally? -

i have 1 application using @manytomany annotation link 2 different entities 1 parent entity. not sure if have implemented properly. when execute .findone() on parent entity's repository find it, @ first fetch data along executing delete queries internally delete record mapping table (a table jpa creates after adding @manytomany annotation.). following generated sql queries , code snippet: java class @entity @table(name = "inventory") public class inventory { @id long id; // many other properties @manytomany(fetch=fetchtype.lazy) private list<stream> streams; @manytomany(fetch=fetchtype.lazy) private list<subject> subjects; } there no other annotation i've put in stream , subject entity class link inventory class. when run app, create following tables: inventory stream subject inventory_stream inventory_subject (inventory_stream , inventory_subject, 2 tables created automatically, don't k...
Read more

python - Mongodb How to add addtional information when aggregating? -

i beginner , wrote line pipeline works, wanna add other information output, screen name , or number of tweets.i tried add under $group gave me syntax error everytime here pipeline: def make_pipeline(): # complete aggregation pipeline pipeline = [ { '$match': { "user.statuses_count": {"$gt":99 }, "user.time_zone": "brasilia" } }, { "$group": { "_id": "$user.id", "followers": { "$max": "$user.followers_count" } } }, { "$sort": { "followers": -1 } }, { "$limit" : 1 } ]; i using on example : { "_id" : objectid("5304e2e3cc9e684aa98bef97"), "text" : "first week of school on :p", "in_reply_to_status_id" : null, "retweet_count" : null, ...
Read more

java - Incorrect order of records in M-M relationship in hibernate -

Image
i have 4 records in bridge table in mysql database. using @manytomany in hibernate, accurate order of employees incorrect incorrect of projects. following required material figure out doing mistake. this source. @entity @table(name="project") public class projectbean { @id @generatedvalue @column(name="project_id") private int projectid; @column(name="title") private string projecttitle; @manytomany(mappedby="projects") private collection<employeebean> employees; public projectbean() { employees = new arraylist<employeebean>(); } //getters & setters } @entity @table(name="employee") public class employeebean { @id @generatedvalue @column(name="employee_id") private int employee_id; @column(name="first_name") private string ...
Read more