Search Results

Search found 17921 results on 717 pages for 'cocoa design patterns'.

Page 298/717 | < Previous Page | 294 295 296 297 298 299 300 301 302 303 304 305  | Next Page >

  • In M-V-VM where does my code go?

    - by Nate Bross
    So, this is a pretty basic question I hope. I have a web service that I've added through Add Service Reference. It has some methods to get list and get detail of a perticular table in my database. What I'm trying to do is setup a UI as follows: App Load Load service proxy Call the GetList(); method display the results in a ListBox control User Double Clicks item in ListBox, display a modal dialog with a "detail" view I'm extremely new to using MVVM, so any help would be greatly appreciated. Additional information: // Service Interface (simplification): interface IService { IEnumerable<MyObject> GetList(); MyObject GetDetail(int id); } // Data object (simplification) class MyObject { public int ID { get; set; } public string Name { get; set; } } I'm thinking I should have something like this: MainWindow MyObjectViewUserControl Displays list Opens modal window on double click Specific Questions: What would my ViewModel class look like? Where does the code to handle the double click go? Inside the UserControl? Sorry for the long details, but I'm very new to the whole thing and I'm not educated enough to ask the right questions. I checked out the MVVM Sample from wpf.codeplex.com and something isn't quite clicking for me yet, because it seems very confusing.

    Read the article

  • Improving MVP in Scala

    - by Alexey Romanov
    The classical strongly typed MVP pattern looks like this in Scala: trait IView { } trait Presenter[View <: IView] { // or have it as an abstract type member val view : View } case class View1(...) extends IView { ... } case object Presenter1 extends Presenter[View1] { val view = View1(...) } Now, I wonder if there is any nice way to improve on it which I am missing...

    Read the article

  • Make a Method of the Business Layer secure. best practice / best pattern

    - by gsharp
    We are using ASP.NET with a lot of AJAX "Page Method" calls. The WebServices defined in the Page invokes methods from our BusinessLayer. To prevent hackers to call the Page Methods, we want to implement some security in the BusinessLayer. We are struggling with two different issues. First one: public List<Employees> GetAllEmployees() { // do stuff } This Method should be called by Authorized Users with the Role "HR". Second one: public Order GetMyOrder(int orderId) { // do sutff } This Method should only be called by the owner of the Order. I know it's easy to implement the security for each method like: public List<Employees> GetAllEmployees() { // check if the user is in Role HR } or public Order GetMyOrder(int orderId) { // check if the order.Owner = user } What I'm looking for is some pattern/best practice to implement this kind of security in a generic way (without coding the the if then else every time) I hope you get what i mean :-)

    Read the article

  • C# Linq: Can you merge DataContexts?

    - by Andreas Grech
    Say I have one database, and this database has a set of tables that are general to all Clients and some tables that are specific to certain clients. Now what I have in mind is creating a primary DataContext that includes only the tables that are general to all the clients, and then create separate DataContexts that contain only the tables that are specific to the client. Is there a way to kind of "merge" DataContexts so that it becomes one context? So for Client A, I need one DataContext that includes both the general tables and also the tables for that specific client (retrieved from two different DataContexts) ? [Update] What I think I can do is, from the Partial Class of the DataContext instead of letting my DataContext inherit from DataContext I make it inherit from MyDataContext; that way, the tables from MyDataContext and the other DataContext will be available in one DataContext class. What do you think about this approach? Of course with something like this you can only merge two datacontexts at once though...

    Read the article

  • Data Application based on OO Concepts

    - by The King
    Hi... I'm looking for an application developed in C# with following qualities, which is available as source code... Based on OO Architecture Must connect to DB. Must handle atleast a "one to many master child" relationship (eg: Order and items ordered) Should display the data using Datagrid or other similar controls. Reports (either with report buider or otherwise) I want to understand the layering of objects better... Do you have any links... Thanks.

    Read the article

  • Recommendations with hierarchical data on non-relational databases?

    - by Luki
    I'm developing an web application that uses a non-relational database as a backend (django-nonrel + AppEngine). I need to store some hierarchical data (projects/subproject_1/subproject_N/tasks), and I'm wondering which pattern should I use. For now I thought of: Adjacency List (store the item's parent id) Nested sets (store left and right values for the item) In my case, the depth of nesting for a normal user will not exceed 4-5 levels. Also, on the UI, I would like to have a pagination for the items on the first level, to avoid to load too many items at the first page load. From what I understand so far, nested sets are great when the hierarchy is used more for displaying. Adjacency lists are great when editing on the tree is done often. In my case I guess I need the displaying more than the editing (when using nested sets, even if the display would work great, the above pagination could complicate things on editing). Do you have any thoughts and advice, based on your experience with the non-relational databases?

    Read the article

  • Refactoring Singleton Overuse

    - by drharris
    Today I had an epiphany, and it was that I was doing everything wrong. Some history: I inherited a C# application, which was really just a collection of static methods, a completely procedural mess of C# code. I refactored this the best I knew at the time, bringing in lots of post-college OOP knowledge. To make a long story short, many of the entities in code have turned out to be Singletons. Today I realized I needed 3 new classes, which would each follow the same Singleton pattern to match the rest of the software. If I keep tumbling down this slippery slope, eventually every class in my application will be Singleton, which will really be no logically different from the original group of static methods. I need help on rethinking this. I know about Dependency Injection, and that would generally be the strategy to use in breaking the Singleton curse. However, I have a few specific questions related to this refactoring, and all about best practices for doing so. How acceptable is the use of static variables to encapsulate configuration information? I have a brain block on using static, and I think it is due to an early OO class in college where the professor said static was bad. But, should I have to reconfigure the class every time I access it? When accessing hardware, is it ok to leave a static pointer to the addresses and variables needed, or should I continually perform Open() and Close() operations? Right now I have a single method acting as the controller. Specifically, I continually poll several external instruments (via hardware drivers) for data. Should this type of controller be the way to go, or should I spawn separate threads for each instrument at the program's startup? If the latter, how do I make this object oriented? Should I create classes called InstrumentAListener and InstrumentBListener? Or is there some standard way to approach this? Is there a better way to do global configuration? Right now I simply have Configuration.Instance.Foo sprinkled liberally throughout the code. Almost every class uses it, so perhaps keeping it as a Singleton makes sense. Any thoughts? A lot of my classes are things like SerialPortWriter or DataFileWriter, which must sit around waiting for this data to stream in. Since they are active the entire time, how should I arrange these in order to listen for the events generated when data comes in? Any other resources, books, or comments about how to get away from Singletons and other pattern overuse would be helpful.

    Read the article

  • Stateless singleton VS Static methods

    - by Sebastien Lorber
    Hey, Don't find any good answer to this simple question about helper/utils classes: Why would i create a singleton (stateless) rather than static methods? Why an object instance could be needed while the object has no state? Sometimes i really don't know what to use...

    Read the article

  • Interpreter in C++: Function table storage problem

    - by sub
    In my interpreter I have built-in functions available in the language like print exit input, etc. These functions can obviously be accessed from inside the language. The interpreter then looks for the corresponding function with the right name in a vector and calls it via a pointer stored with its name. So I gather all these functions in files like io.cpp, string.cpp, arithmetic.cpp. But I have to add every function to the function list in the interpreter in order for it to be found. So in these function files I have things like: void print( arg ) { cout << arg.ToString; } I'd add this print function to the interpreter function list with: interpreter.AddFunc( "print", print ); But where should I call the interpreter.AddFunc? I can't just put it there below the print function as it has to be in a function according to the C++ syntax. Where and how should all the functions be added to the list?

    Read the article

  • how to handle exceptions/errors in php?

    - by fayer
    when using 3rd part libraries they tend to throw exceptions to the browser and hence kill the script. eg. if im using doctrine and insert a duplicate record to the database it will throw an exception. i wonder, what is best practice for handling these exceptions. should i always do a try...catch? but doesn't that mean that i will have try...catch all over the script and for every single function/class i use? Or is it just for debugging? i don't quite get the picture. Cause if a record already exists in a database, i want to tell the user "Record already exists". And if i code a library or a function, should i always use "throw new Expcetion($message, $code)" when i want to create an error? Please shed a light on how one should create/handle exceptions/errors. Thanks

    Read the article

  • What Is Utility Services ?

    - by query_bug
    Hai, I need some information about Utility Services Layer. Can someone Please help me in getting information on that as I am supposed to give a presentation on Utility Services Layer. Thanks in advance...

    Read the article

  • Generic Abstract Singleton with Custom Constructor in C#

    - by Heka
    I want to write a generic singleton with an external constructor. In other words the constructor can be modified. I have 2 designs in my mind but I don't know whether they are practical or not. First one is to enforce derived class' constructor to be non-public but I do not know if there is a way of it? Second one is to use a delegate and call it inside the constructor? It isn't necessarily to be a constructor. The reason I chose custom constructor is doing some custom initializations. Any suggestions would be appreciated :)

    Read the article

  • Connecting data to a GUI - OOP

    - by tau
    I have an application with several graphs and tables on it. I worked fast and just made classes like Graph and Table that each contained a request object (pseudo-code): class Graph { private request; public function setDateRange(dateRange) { request.setDateRange(dateRange); } public function refresh() { request.getData(function() { //refresh the display }); } } Upon a GUI event (say, someone changes the date range dropdown), I'd just call the setters on the Graph instance and then refresh it. Well, when I added other GUI elements like tables and whatnot, they all basically had similar methods (setDateRange and other things common to the request). What are some more elegant OOP ways of doing this? The application is very simple and I don't want to over-architect it, but I also don't want to have a bunch of classes with basically the same methods that are just routing to a request object. I also don't want to set up each GUI class as inheriting from the request class, but I'm open to any ideas really.

    Read the article

  • Searching for the right pattern to handle login data

    - by stevebot
    Hi all, I'm working on a controller that handles logins for a Web app. These logins will come from multiple clients but will all contain the same data. However, depending on the client, this data will be interpreted into common entities for our webapp differently. For instance, we have a user code that gets sent in, and in one case we may use the first four digits of the code, and in another case 12 digits of the code to map to a field on a User entity. Instead of handling this all in the controller and having big nasty if blocks of logic, I would like to use a pattern to handle how this information gets ingested into our application. What are your opinions?

    Read the article

  • Conceptually, how does replay work in a game?

    - by SnOrfus
    I was kind of curious as to how replay might be implemented in a game. Initially, I thought that there would be just a command list of every player/ai action that was taken in the game, and it then 're-plays' the game and lets the engine render as usual. However, I have looked at replays in FPS/RTS games, and upon careful inspection even things like the particles and graphical/audible glitches are consistent (and those glitches are generally *in*consistent). So How does this happen. In fixed camera angle games I though it might just write every frame of the whole scene to a stream that gets stored and then just replays the stream back, but that doesn't seem like enough for games that allow you to pause and move the camera around. You'd have to store the locations of everything in the scene at all points in time (No?). So for things like particles, that's a lot of data to push which seems like a significant draw on the game's performance whilst playing.

    Read the article

  • What is the best practice for accessing Model using MVVM pattern

    - by Dzenand
    I have a database that communicates with webservices with my Model (own thread) and exposes Data Objects. My UI application consists of different Views and ViewModels and Custom Controls. I'm using ServiceProvider (IServiceProvider) to access the Model and route the events to the UI thread. Communication between the ViewModels is handeled by a Messenger. Is this way to go? I was also wondering what is the best way to strucutre the DataObjects At the moment i have the DataObjects that have a hierarchy structure but does not support INotifyProperty though the children list are of type of ObservableCollection. I have no possiblity to implement notifypropertychange on the properties. I was wondering the best way of making them MVVM friendly. Implementing a partial class and adding all the properties or commands that are necessary or wrapping all the DataObjects and keep the Model list and MVVM list in sync. All thoughts and ideas are appreciated.

    Read the article

  • Passing ViewModel for backbone.js from MVC3 Server-Side

    - by Roman
    In ASP.NET MVC there is Model, View and Controller. MODEL represents entities which are stored in database and essentially is all the data used in a application (for example, generated by EntityFramework, "DB First" approach). Not all data from model you want to show in the view (for example, hashs of passwords). So you create VIEW MODEL, each for every strongly-typed-razor-view you have in application. Like this: using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace MyProject.ViewModels.SomeController.SomeAction { public class ViewModel { public ViewModel() { Entities1 = new List<ViewEntity1>(); Entities2 = new List<ViewEntity2>(); } public List<ViewEntity1> Entities1 { get; set; } public List<ViewEntity2> Entities2 { get; set; } } public class ViewEntity1 { //some properties from original DB-entity you want to show } public class ViewEntity2 { } } When you create complex client-side interfaces (I do), you use some pattern for javascript on client, MVC or MVVM (I know only these). So, with MVC on client you have another model (Backbone.Model for example), which is third model in application. It is a bit much. Why don`t we use the same ViewModel model on a client (in backbone.js or another framework)? Is there a way to transfer CS-coded model to JS-coded? Like in MVVM pattern, with knockout.js, when you can do like this: in SomeAction.cshtml: <div style="display: none;" id="view_model">@Json.Encode(Model)</div> after that in Javascript-code var ViewModel = ko.mapping.fromJSON($("#view_model").get(0).innerHTML); now you can extend your ViewModel with some actions, event handlers, etc: ko.utils.extend(ViewModel, { some_function: function () { //some code } }); So, we are not building the same view model on the client again, we are transferring existing view model from server. At least, data. But knockout.js is not suitable for me, you can`t build complex UI with it, it is just data-binding. I need something more structural, like backbone.js. The only way to build ViewModel for backbone.js I can see now is re-writing same ViewModel in JS from server with hands. Is there any ways to transfer it from server? To reuse the same viewmodel on server view and client view?

    Read the article

  • Where do you put your dependencies?

    - by The All Foo
    If I use the dependency injection pattern to remove dependencies they end up some where else. For example, Snippet 1, or what I call Object Maker. I mean you have to instantiate your objects somewhere...so when you move dependency out of one object, you end up putting it another one. I see that this consolidates all my dependencies into one object. Is that the point, to reduce your dependencies so that they all reside in a single ( as close to as possible ) location? Snippet 1 - Object Maker <?php class ObjectMaker { public function makeSignUp() { $DatabaseObject = new Database(); $TextObject = new Text(); $MessageObject = new Message(); $SignUpObject = new ControlSignUp(); $SignUpObject->setObjects($DatabaseObject, $TextObject, $MessageObject); return $SignUpObject; } public function makeSignIn() { $DatabaseObject = new Database(); $TextObject = new Text(); $MessageObject = new Message(); $SignInObject = new ControlSignIn(); $SignInObject->setObjects($DatabaseObject, $TextObject, $MessageObject); return $SignInObject; } public function makeTweet( $DatabaseObject = NULL, $TextObject = NULL, $MessageObject = NULL ) { if( $DatabaseObject == 'small' ) { $DatabaseObject = new Database(); } else if( $DatabaseObject == NULL ) { $DatabaseObject = new Database(); $TextObject = new Text(); $MessageObject = new Message(); } $TweetObject = new ControlTweet(); $TweetObject->setObjects($DatabaseObject, $TextObject, $MessageObject); return $TweetObject; } public function makeBookmark( $DatabaseObject = NULL, $TextObject = NULL, $MessageObject = NULL ) { if( $DatabaseObject == 'small' ) { $DatabaseObject = new Database(); } else if( $DatabaseObject == NULL ) { $DatabaseObject = new Database(); $TextObject = new Text(); $MessageObject = new Message(); } $BookmarkObject = new ControlBookmark(); $BookmarkObject->setObjects($DatabaseObject,$TextObject,$MessageObject); return $BookmarkObject; } }

    Read the article

  • ASP.NET MVC Filters: How to set Viewdata for Dropdown based on action paramter

    - by CRice
    Hi, Im loading an entity 'Member' from its id in route data. [ListItemsForMembershipType(true)] public ActionResult Edit(Member someMember) {...} The attribute on the action loads the membership type list items for a dropdown box and sticks it in viewdata. This is fine for add forms, and search forms (it gets all active items) but I need the attribute to execute BASED ON THE VALUE someMember.MembershipTypeId, because its current value must always be present when loading the item (i.e. all active items, plus the one from the loaded record). So the question is, what is the standard pattern for this? How can my attribute accept the value or should I be loading the viewdata for the drop down in a controller supertype or during model binding or something else? It is in an attribute now because the code to set the viewdata would otherwise be duplicated in each usage in each action.

    Read the article

  • Best practice for passing configuration to each GUI object

    - by Laimoncijus
    Hi, I am writing an application, where I do have few different windows implemented, where each window is a separate class. Now I need somehow to pass a single configuration object to all of them. My GUI is designed in way, where I have one main window, which may create some child windows of its own, and these child windows can have their own childs (so there is no possibility to create all windows in initialization part and feed the config object to all of them from the very beginning)... What would be best practice for sharing this configuration object between them? Always passing via constructor or maybe making it somewhere as final public static and let each window object to access it when needed? Thanks

    Read the article

< Previous Page | 294 295 296 297 298 299 300 301 302 303 304 305  | Next Page >