Search Results

Search found 25346 results on 1014 pages for 'framework design'.

Page 112/1014 | < Previous Page | 108 109 110 111 112 113 114 115 116 117 118 119  | Next Page >

  • EF4 CTP5 Conflicting changes detected. This may happen when trying to insert multiple entities with the same key.

    - by user658332
    hi, I am new to EF4 CTP5. I am just hanging at one problem.. I am using CodeFirst without Database, so when i execute application, it generated DB for me. here is my scenario, i have following Class structure... public class KVCalculationWish { public KVCalculationWish() { } public int KVCalculationWishId { get; set; } public string KVCalculationWishName { get; set; } public int KVSingleOfferId { get; set; } public virtual KVSingleOffer SingleOffer { get; set; } public int KVCalculationsForPersonId { get; set; } public virtual KVCalculationsForPerson CaculationsForPerson { get; set; } } public class KVSingleOffer { public KVSingleOffer() { } public int KVSingleOfferId { get; set; } public string KVSingleOfferName { get; set; } public KVCalculationWish CalculationWish { get; set; } } public class KVCalculationsForPerson { public KVCalculationsForPerson() { } public int KVCalculationsForPersonId { get; set; } public string KVCalculationsForPersonName { get; set; } public KVCalculationWish CalculationWish { get; set; } } public class EntiyRelation : DbContext { public EntiyRelation() { } public DbSet<KVCalculationWish> CalculationWish { get; set; } public DbSet<KVSingleOffer> SingleOffer { get; set; } public DbSet<KVCalculationsForPerson> CalculationsForPerson { get; set; } protected override void OnModelCreating(System.Data.Entity.ModelConfiguration.ModelBuilder modelBuilder) { base.OnModelCreating(modelBuilder); modelBuilder.Entity<KVCalculationWish>().HasOptional(m => m.SingleOffer).WithRequired(p => p.CalculationWish); modelBuilder.Entity<KVCalculationWish>().HasOptional(m => m.CaculationsForPerson).WithRequired(p => p.CalculationWish); } } i want to use KVCalcuationWish object in KVCalcuationsForPerson and KVSingleOffer class. So when i am creating object of KVCalcuationForPerson and KVSingleOffer class i initialize both object with New KVCalcuationWish object. like this KVCalculationsForPerson calcPerson = new KVCalculationsForPerson(); KVCalculationWish wish = new KVCalculationWish() { CaculationsForPerson = calcPerson }; calcPerson.KVCalculationsForPersonName = "Person Name"; calcPerson.CalculationWish = wish; KVSingleOffer singleOffer = new KVSingleOffer(); KVCalculationWish wish1 = new KVCalculationWish() { SingleOffer = singleOffer }; singleOffer.KVSingleOfferName = "Offer Name"; singleOffer.CalculationWish = wish1; but my problem is when i save this records using following code try { db.CalculationsForPerson.Add(calcPerson); db.SingleOffer.Add(singleOffer); db.SaveChanges(); } catch (Exception ex) { } i can save successfully in DB, but in Table KVCalcuationWish i am not able to get the ID of SingleOffer and CalcuationsForPerson class object. Following is the data of KVCalcuationWish table. KVCalcuationWishID KVCalcuationWishName KVSingleOfferID KVCalcuationsForPersonID 1 NULL 0 0 Following is the data of KVSingleOFfer Table KVSingleOfferID KVSingleOfferName 1 Offer Name Follwing is the data of KVCalcuationsForPerson Table KVSingleOfferID KVSingleOfferName 1 Person Name I want to have following possible output in KVCalcuationWish table. KVCalcuationWishID KVCalcuationWishName KVSingleOfferID KVCalcuationsForPersonID 1 NULL 1 NULL 2 NULL NULL 1 so what i want to achieve is ...... when i am save KVSingleOffer object i want separate record to be inserted and when i save KVCalcuationsForPerson object another separate record should be save to KVCalcuationwish table. Is that possible? Sorry for long description... but i really hang on this situation... Thanks & Regards, Joyous Suhas

    Read the article

  • How to rollback in EF4?

    - by Jaxidian
    In my research about rolling back transactions in EF4, it seems everybody refers to this blog post or offers a similar explanation. In my scenario, I'm wanting to do this in a unit testing scenario where I want to rollback practically everything I do within my unit testing context to keep from updating the data in the database (yeah, we'll increment counters but that's okay). In order to do this, is it best to follow the following plan? Am I missing some concept or anything else major with this (aside from my SetupMyTest and PerformMyTest functions won't really exist that way)? using (var ts = new TransactionScope()) { // Arrange SetupMyTest(context); // Act PerformMyTest(context); var numberOfChanges = context.SaveChanges(false); // if there's an issue, chances are that an exception has been thrown by now. // Assert Assert.IsTrue(numberOfChanges > 0, "Failed to _____"); // transaction will rollback because we do not ever call Complete on it }

    Read the article

  • Database with "Open Schema" - Good or Bad Idea?

    - by Claudiu
    The co-founder of Reddit gave a presentation on issues they had while scaling to millions of users. A summary is available here. What surprised me is point 3: Instead, they keep a Thing Table and a Data Table. Everything in Reddit is a Thing: users, links, comments, subreddits, awards, etc. Things keep common attribute like up/down votes, a type, and creation date. The Data table has three columns: thing id, key, value. There’s a row for every attribute. There’s a row for title, url, author, spam votes, etc. When they add new features they didn’t have to worry about the database anymore. They didn’t have to add new tables for new things or worry about upgrades. This seems like a terrible idea to me, but it seems to have worked out for Reddit. Is it a good idea in general, though? Or is it a peculiarity of Reddit that happened to work out for them?

    Read the article

  • Parametrized Strategy Pattern

    - by ott
    I have several Java classes which implement the strategy pattern. Each class has variable number parameters of different types: interface Strategy { public data execute(data); } class StrategyA implements Strategy { public data execute(data); } class StrategyB implements Strategy { public StrategyB(int paramA, int paramB); public data execute(data); } class StrategyB implements Strategy { public StrategyB(int paramA, String paramB, double paramC); public data execute(data); } Now I want that the user can enter the parameters in some kind of UI. The UI should be chosen at runtime, i.e. the strategies should be independent of it. The parameter dialog should not be monolithic and there should be the possibility to make it behave and look different for each strategy and UI (e.g. console or Swing). How would you solve this problem?

    Read the article

  • Using EF 4 on .NET 3.5 SP1

    - by KiD0M4N
    Hi guys, I was using the latest EF 4 bits in Visual Studio 2010 RC and have fallen in love with it. However, I have to develop a small web application using .NET 3.5 SP1 (VS 2008) for work... I was wondering if it was possible to somehow utilize EF 4 in .NET 3.5 SP1/VS 2008. Regards, Karan Misra

    Read the article

  • Strategy pattern and "action" classes explosion

    - by devoured elysium
    Is it bad policy to have lots of "work" classes(such as Strategy classes), that only do one thing? Let's assume I want to make a Monster class. Instead of just defining everything I want about the monster in one class, I will try to identify what are its main features, so I can define them in interfaces. That will allow to: Seal the class if I want. Later, other users can just create a new class and still have polymorphism by means of the interfaces I've defined. I don't have to worry how people (or myself) might want to change/add features to the base class in the future. All classes inherit from Object and they implement inheritance through interfaces, not from mother classes. Reuse the strategies I'm using with this monster for other members of my game world. Con: This model is rigid. Sometimes we would like to define something that is not easily achieved by just trying to put together this "building blocks". public class AlienMonster : IWalk, IRun, ISwim, IGrowl { IWalkStrategy _walkStrategy; IRunStrategy _runStrategy; ISwimStrategy _swimStrategy; IGrowlStrategy _growlStrategy; public Monster() { _walkStrategy = new FourFootWalkStrategy(); ...etc } public void Walk() { _walkStrategy.Walk(); } ...etc } My idea would be next to make a series of different Strategies that could be used by different monsters. On the other side, some of them could also be used for totally different purposes (i.e., I could have a tank that also "swims"). The only problem I see with this approach is that it could lead to a explosion of pure "method" classes, i.e., Strategy classes that have as only purpose make this or that other action. In the other hand, this kind of "modularity" would allow for high reuse of stratagies, sometimes even in totally different contexts. What is your opinion on this matter? Is this a valid reasoning? Is this over-engineering? Also, assuming we'd make the proper adjustments to the example I gave above, would it be better to define IWalk as: interface IWalk { void Walk(); } or interface IWalk { IWalkStrategy WalkStrategy { get; set; } //or something that ressembles this } being that doing this I wouldn't need to define the methods on Monster itself, I'd just have public getters for IWalkStrategy (this seems to go against the idea that you should encapsulate everything as much as you can!) Why? Thanks

    Read the article

  • How to store the path of a game pawn in a turn based game ?

    - by panzerschreck
    Hello, I have a square grid, for a turn based game ( grid is similar to the chess board ), but the moves in the games are different based on whether you have lapped your opponent pawn at least once or not. i.e if you have not lapped (beaten any of the opponents pawns) in the outer most grid as below if you have lapped your opponent pawn once at least, then you get to reach home,this way.Any player having all his pawns reaching "home" first wins. The ones in yellow are safe-houses, i.e both the opponent pawn and the player's pawn get to stay in the same grid, this is not considered to be lapping ( the opponent ).The lapped pawn will return to its start point. Now the question is, what is the effective way to store the paths for the all the pawns.we will have 4 pawns for the player and 4 opponent pawns. Is there any pattern to store such static information, in a elegant way ? Thanks for your time

    Read the article

  • Factory pattern vs ease-of-use?

    - by Curtis White
    Background, I am extending the ASP.NET Membership with custom classes and extra tables. The ASP.NET MembershipUser has a protected constructor and a public method to read the data from the database. I have extended the database structure with custom tables and associated classes. Instead of using a static method to create a new member, as in the original API: I allow the code to instantiate a simple object and fill the data because there are several entities. Original Pattern #1 Protected constructor > static CreateUser(string mydata, string, mydata, ...) > User.Data = mydata; > User.Update() My Preferred Pattern #2 Public constructor > newUser = new MembershipUser(); > newUser.data = ... > newUser.ComplextObject.Data = ... > newUser.Insert() > newUser.Load(string key) I find pattern #2 to be easier and more natural to use. But method #1 is more atomic and ensured to contain proper data. I'd like to hear any opinions on pros/cons. The problem in my mind is that I prefer a simple CRUD/object but I am, also, trying to utilize the underlying API. These methods do not match completely. For example, the API has methods, like UnlockUser() and a readonly property for the IsLockedOut

    Read the article

  • Concrete Types or Interfaces for return types?

    - by SDReyes
    Today I came to a fundamental paradox of the object programming style, concrete types or interfaces. Whats the better election for a method's return type: a concrete type or an interface? In most cases, I tend to use concrete types as the return type for methods. because I believe that an concrete type is more flexible for further use and exposes more functionality. The dark side of this: Coupling. The angelic one: A concrete type contains per-se the interface you would going to return initially, and extra functionality. What's your thumb's rule? Is there any programming principle for this? BONUS: This is an example of what I mean http://stackoverflow.com/questions/491375/readonlycollection-or-ienumerable-for-exposing-member-collections

    Read the article

  • What makes static initialization functions good, bad, or otherwise?

    - by Richard Levasseur
    Suppose you had code like this: _READERS = None _WRITERS = None def Init(num_readers, reader_params, num_writers, writer_params, ...args...): ...logic... _READERS = new ReaderPool(num_readers, reader_params) _WRITERS = new WriterPool(num_writers, writer_params) ...more logic... class Doer: def __init__(...args...): ... def Read(self, ...args...): c = _READERS.get() try: ...work with conn finally: _READERS.put(c) def Writer(...): ...similar to Read()... To me, this is a bad pattern to follow, some cons: Doers can be created without its preconditions being satisfied The code isn't easily testable because ConnPool can't be directly mocked out. Init has to be called right the first time. If its changed so it can be called multiple times, extra logic has to be added to check if variables are already defined, and lots of NULL values have to be passed around to skip re-initializing. In the event of threads, the above becomes more complicated by adding locking Globals aren't being used to communicate state (which isn't strictly bad, but a code smell) On the other hand, some pros: its very convenient to call Init(5, "user/pass", 2, "user/pass") It simple and "clean" Personally, I think the cons outweigh the pros, that is, testability and assured preconditions outweigh simplicity and convenience.

    Read the article

  • Example with Visitor Pattern

    - by devoured elysium
    public class Song { public string Genre { get; protected set; } public string Name { get; protected set; } public string Band { get; protected set; } public Song(string name, string band, string genre) { Name = name; Genre = genre; Band = band; } } public interface IMusicVisistor { void Visit(List<Song> items); } public class MusicLibrary { List<Song> _songs = new List<Song> { ...songs ... }; public void Accept(IMusicVisitor visitor) { visitor.Visit(_songs); } } and now here's one Visitor I made: public class RockMusicVisitor : IMusicVisitor { public List<Song> Songs { get; protected set; } public void Visit(List<Song> items) { Songs = items.Where(x => x.Genre == "Rock").ToList(); } } Why is this any better than just putting a public property Songs and then letting any kind of class do with it anything that it wants to? This example comes from this post.

    Read the article

  • TryGetObjectByKey... empty ObjectSets

    - by Rickjaah
    When I use TryGetObjectByKey on my ObjectContext, it returns an error. An item with a duplicate value already exists. When I look at my objectContext, I see that the ObjectSets are empty. What Am I doing wrong... When I enumerate the ObjectSet by hand, by using ToArray on it, or by using the debugger, it does work. LazyLoadingEnabled = true. I reuse 2 tables from another EDMX, but they are in different namespaces and they are not the objectSets i try to approach.

    Read the article

  • Extend base type and automatically update audit information on Entity

    - by Nix
    I have an entity model that has audit information on every table (50+ tables) CreateDate CreateUser UpdateDate UpdateUser Currently we are programatically updating audit information. Ex: if(changed){ entity.UpdatedOn = DateTime.Now; entity.UpdatedBy = Environment.UserName; context.SaveChanges(); } But I am looking for a more automated solution. During save changes, if an entity is created/updated I would like to automatically update these fields before sending them to the database for storage. Any suggestion on how i could do this? I would prefer to not do any reflection, so using a text template is not out of the question. A solution has been proposed to override SaveChanges and do it there, but in order to achieve this i would either have to use reflection (in which I don't want to do ) or derive a base class. Assuming i go down this route how would I achieve this? For example EXAMPLE_DB_TABLE CODE NAME --Audit Tables CREATE_DATE CREATE_USER UPDATE_DATE UPDATE_USER And if i create a base class public abstract class IUpdatable{ public virtual DateTime CreateDate {set;} public virtual string CreateUser { set;} public virtual DateTime UpdateDate { set;} public virtual string UpdateUser { set;} } The end goal is to be able to do something like... public overrride void SaveChanges(){ //Go through state manager and update audit infromation //FOREACH changed entity in state manager if(entity is IUpdatable){ //If state is created... update create audit. //if state is updated... update update audit } } But I am not sure how I go about generating the code that would extend the interface.

    Read the article

  • EF 4 - associations with keys that dont match

    - by Steve Ward
    We're using POCOs and have 2 entities: Item and ItemContact. There are 1 or more contacts per item. Item has as a primary key: ItemID LanguageCode ItemContact has: ItemID ContactID We cant add an association with a referrential constraint as they have differing keys. There isnt a strict primary / foreign key as languageCode isnt in ItemContact and ContactID isnt in Item. How can we go about mapping this with an association for contacts for an item if there isnt a direct link but I still want to see the contacts for an item? One of the entities originates in a database view so it is not possible to add foreign keys to the database Thanks Stephen Ward

    Read the article

  • Creating colour schemes based on an existing scheme

    - by Neil Barnwell
    I have a colour scheme based around yellow, for warning messages on a website. It amounts to a slightly orange bordered box, with a pale yellow fill. The exact colours are: #FED626 (border) #FFF7C0 (fill) I want to know if it's possible to convert this scheme mathematically or algorithmically somehow, to come up with a blue version where the border is the "same amount" of blue as this one is yellow. Is this possible, or do I just "pin the tail on the donkey" on a colour pallet to get roughly the right one? I ask, because I'd quite like to be able to calculate this on the fly, to perhaps implement something in .less. To give you an idea, I tried swopping the red and blue values on those two, and came up with this: #26D6FE (border) #C0F7FF (fill) That wasn't too hard, but think about if I wanted a pink colour scheme... :)

    Read the article

  • Question regarding factory pattern

    - by eriks
    I have a factory class to build objects of base class B. The object (D) that uses this factory received a list of strings representing the actual types. What is the correct implementation: the factory receives an Enum (and uses switch inside the Create function) and D is responsible to convert the string to Enum. the factory receives a string and checks for a match to a set of valid strings (using ifs') other implementation i didn't think of.

    Read the article

  • EF4 CTP5 - Map foreign key without object references?

    - by anon
    I feel like this should have a simple answer, but I can't find it. I have 2 POCOs: public class Category { public int Id { get; set; } public string Name { get; set; } } public class Product { public int Id { get; set; } public int CategoryId { get; set; } } Notice that there are no object references on either POCO. With Code-First, how do I make EF4 CTP5 define a relationship between the two database tables? (I know this is an unusual scenario, but I am exploring what's possible and what's not with Code-First)

    Read the article

  • Empty data problem - data layer or DAL?

    - by luckyluke
    I designing the new App now and giving the following question a lot of thought. I consume a lot of data from the warehouse, and the entities have a lot of dictionary based values (currency, country, tax-whatever data) - dimensions. I cannot be assured though that there won't be nulls. So I am thinking: create an empty value in each of teh dictionaries with special keyID - ie. -1 do the ETL (ssis) do the correct stuff and insert -1 where it needs to let the DAL know that -1 is special (Static const whatever thing) don't care in the code to check for nullness of dictionary entries because THEY will always have a value But maybe I should be thinking: import data AS IS let the DAL do the thinking using empty record Pattern still don't care in the code because business layer will have what it needs from DAL. I think is more of a approach thing but maybe i am missing something important here... What do You think? Am i clear? Please don't confuse it with empty record problem. I do use emptyCustomer think all the time and other defaults too.

    Read the article

  • 'Generic' ViewModel

    - by Ian MacPherson
    Using EF 4, I have several subtypes of a 'Business' entity (customers, suppliers, haulage companies etc). They DO need to be subtypes. I am building a general viewmodel which calls into a service from which a generic repository is accessed. As I have 4 subtypes, it would be good to have a 'generic' viewmodel used for all of these. Problem is of course is that I have to call a specific type into my generic repository, for example: BusinessToRetrieve = _repository .LoadEntity<Customer>(o => o.CustomerID == customerID); It would be good to be able to call <SomethingElse>, somethingElse being one or other of the subtypes), otherwise I shall have to create 4 near identical viemodels, which seems a waste of course! The subtype entity name is available to the viewmodel but I've been unable to figure out how to make the above call convert this into a type. An issue with achieving what I want is that presumably the lambda expression being passed in wouldn't be able to resolve on a 'generic' call ?

    Read the article

  • Factory Method Pattern clarification

    - by nettguy
    My understanding of Factory Method Pattern is (Correct me if i am wrong) Factory Method Pattern "Factory Method allow the client to delegates the product creation (Instance Creation) to the subclass". There are two situation in which we can go for creating Factory Method pattern. (i) When the client is restricted to the product (Instance) creation. (ii) There are multiple products available.But a decision to be made which product instance need to be returned. If you want to create Abstract Method pattern You need to have abstract product Concrete Product Factory Method to return the appropriate product. Example : public enum ORMChoice { L2SQL, EFM, LS, Sonic } //Abstract Product public interface IProduct { void ProductTaken(); } //Concrete Product public class LinqtoSql : IProduct { public void ProductTaken() { Console.WriteLine("OR Mapping Taken:LinqtoSql"); } } //concrete product public class Subsonic : IProduct { public void ProductTaken() { Console.WriteLine("OR Mapping Taken:Subsonic"); } } //concrete product public class EntityFramework : IProduct { public void ProductTaken() { Console.WriteLine("OR Mapping Taken:EntityFramework"); } } //concrete product public class LightSpeed : IProduct { public void ProductTaken() { Console.WriteLine("OR Mapping Taken :LightSpeed"); } } public class Creator { //Factory Method public IProduct ReturnORTool(ORMChoice choice) { switch (choice) { case ORMChoice.EFM:return new EntityFramework(); break; case ORMChoice.L2SQL:return new LinqtoSql(); break; case ORMChoice.LS:return new LightSpeed(); break; case ORMChoice.Sonic:return new Subsonic(); break; default: return null; } } } **Client** Button_Click() { Creator c = new Creator(); IProduct p = c.ReturnORTool(ORMChoice.L2SQL); p.ProductTaken(); } Is my understanding of Factory Method is correct?

    Read the article

  • EF4 and multiple abstract levels

    - by Cedric
    I need to use inheritance with EF4 and the TPH model created from DB. I created a new projet to test simples classes. There is my class model: There is my table in SQL SERVER 2008 : VEHICLE ID : int PK Owner : varchar(50) Consumption : float FirstCirculationDate : date Type : varchar(50) Discriminator : varchar(10) I added a condition in my EDMX on the Discriminator field to differentiate the Scooter, Car, Motorbike and Bike entities. MotorizedVehicle and Vehicle are Abstract. But when I compile, this error appears : Error 3032: Problem in mapping fragments starting at lines 78, 85:EntityTypes EF4InheritanceModel.Scooter, EF4InheritanceModel.Motorbike, EF4InheritanceModel.Car, EF4InheritanceModel.Bike are being mapped to the same rows in table Vehicle. Mapping conditions can be used to distinguish the rows that these types are mapped to. Edit : To Ladislav : I try it and error change to become it for all of my entities : Error 3034: Problem in mapping fragments starting at lines 72, 86:An entity is mapped to different rows within the same table. Ensure these two mapping fragments do not map two groups of entities with overlapping keys to two distinct groups of rows. To Henk (with Ladislay suggestion) : There are all of mappings details : What's wrong ? Thanks

    Read the article

  • Maintaining state and data context between requests in ASP.NET + EF4

    - by Nick
    I have a EF4/ASP.NET web application that is structured to use POCOs and generic repositories, based essentially on this excellent article. The application is relatively sophisticated with one page that involves selection and linking of multiple entities to build up a complex user profile. This requires access to multiple entity types (20 or so) and associated repositories across multiple posts. When a repository is first accessed it uses the existing data context if exists, else it creates a new context. The problem is that if the lifetime of the context is only per-request (as suggested in the article) then you have to deal with multiple contexts and the complexity around detaching and attaching entities from contexts. My solution is to share the context between posts by creating a single View Model that includes all required repositories (initialised to share the same context) plus any associated data and store this model in a Session variable, retrieving from Session on subsequent page requests. Therefore maintaining the same context across all posts until the profile is saved. This works fine BUT I am concerned that I don't actually know exactly what is stored in the model session variable or more importantly the size of the Session variable. So two questions I suppose: firstly should I look for a better solution to handle the shared context across posts issue (any suggestions welcome)? And secondly what is actually stored in the Session when it includes a repository plus context? Any help appreciated!

    Read the article

  • Overlay 2d weapon sprite over character sprite ?

    - by Mr.Gando
    Hello, I'm working on a game where my character needs to be able to have different weapons. For that I think that somehow overlaying the weapon over the moving sprite would be the correct choice, but I'm not sure about how could I do this. Assuming my Character spritesheet looks like this: And my preliminar weapon spritesheet ( haven't decided on a fixed square size for the weapon yet ), looks like this: How would you make the overlay to set the weapon correctly over the character hand for each of his frames? I know that one way would be just to have a weapon frame the same size as my character sprites, and overlay those too, but I think that if the game has way too much weapons (say 15 different kinds of one hand weaps) this could get pretty insane ( having one weapon sprite sheet the same size as the character sprite sheet for each type of weapon ) Do you guys have any advice on how to implement this? (supporting overlaying the weapon sprites over the character sprites) Thanks!

    Read the article

  • c# Attribute Question

    - by Petoj
    Well i need some help here i don't know how to solve this problem. the function of the attribute is to determine if the function can be run... So what i need is the following: The consumer of the attribute should be able to determine if it can be executed. The owner of the attribute should be able to tell the consumer that now it can/can't be executed (like a event). It must have a simple syntax. This is what i have so far but it only implements point 1, 3. [AttributeUsage(AttributeTargets.Method, AllowMultiple = false)] public class ExecuteMethodAttribute : Attribute { private Func<object, bool> canExecute; public Func<object, bool> CanExecute { get { return canExecute; } } public ExecuteMethodAttribute() { } public ExecuteMethodAttribute(Func<object, bool> canExecute) { this.canExecute = canExecute; } }

    Read the article

< Previous Page | 108 109 110 111 112 113 114 115 116 117 118 119  | Next Page >