Search Results

Search found 13737 results on 550 pages for 'design consideration'.

Page 125/550 | < Previous Page | 121 122 123 124 125 126 127 128 129 130 131 132  | Next Page >

  • Why do old programming languages continue to be revised?

    - by SunAvatar
    This question is not, "Why do people still use old programming languages?" I understand that quite well. In fact the two programming languages I know best are C and Scheme, both of which date back to the 70s. Recently I was reading about the changes in C99 and C11 versus C89 (which seems to still be the most-used version of C in practice and the version I learned from K&R). Looking around, it seems like every programming language in heavy use gets a new specification at least once per decade or so. Even Fortran is still getting new revisions, despite the fact that most people using it are still using FORTRAN 77. Contrast this with the approach of, say, the typesetting system TeX. In 1989, with the release of TeX 3.0, Donald Knuth declared that TeX was feature-complete and future releases would contain only bug fixes. Even beyond this, he has stated that upon his death, "all remaining bugs will become features" and absolutely no further updates will be made. Others are free to fork TeX and have done so, but the resulting systems are renamed to indicate that they are different from the official TeX. This is not because Knuth thinks TeX is perfect, but because he understands the value of a stable, predictable system that will do the same thing in fifty years that it does now. Why do most programming language designers not follow the same principle? Of course, when a language is relatively new, it makes sense that it will go through a period of rapid change before settling down. And no one can really object to minor changes that don't do much more than codify existing pseudo-standards or correct unintended readings. But when a language still seems to need improvement after ten or twenty years, why not just fork it or start over, rather than try to change what is already in use? If some people really want to do object-oriented programming in Fortran, why not create "Objective Fortran" for that purpose, and leave Fortran itself alone? I suppose one could say that, regardless of future revisions, C89 is already a standard and nothing stops people from continuing to use it. This is sort of true, but connotations do have consequences. GCC will, in pedantic mode, warn about syntax that is either deprecated or has a subtly different meaning in C99, which means C89 programmers can't just totally ignore the new standard. So there must be some benefit in C99 that is sufficient to impose this overhead on everyone who uses the language. This is a real question, not an invitation to argue. Obviously I do have an opinion on this, but at the moment I'm just trying to understand why this isn't just how things are done already. I suppose the question is: What are the (real or perceived) advantages of updating a language standard, as opposed to creating a new language based on the old?

    Read the article

  • How many tiers should my models have in a DB driven web app?

    - by Hanno Fietz
    In my experience, the "Model" in MVC is often not really a single layer. I would regularly have "backend" models and "frontend" models, where the backend ones would have properties that I want to hide from the UI code, and the frontend ones have derived or composite properties which are more meaningful in the context of the UI. Recently, I have started to introduce a third layer in between when database normalization created tables that did not really match the conceptual domain objects anymore. In those projects I have model classes that are equivalent with the DB structure, these become components of objects that represent the domain model, and finally these are filtered and amended for displaying information to the user. Are there patterns or guidelines for how, when and why to organize the data model across application layers?

    Read the article

  • two-part dice pool mechanic

    - by bythenumbers
    I'm working on a dice mechanic/resolution system based off of the Ghost/Echo (hereafter shortened to G/E) tabletop RPG. Specifically, since G/E can be a little harsh with dealing out consequences and failure, I was hoping to soften the system and add a little more player control, as well as offer the chance for players to evolve their characters into something unique, right from creation. So, here's the mechanic: Players roll 2d12 against the two statistics for their character (each is a number from 2-11, and may be rolled above or below depending on the nature of the action attempted, rolling your stat exactly always fails). Depending on the success for that roll, they add dice to the pool rolled for a modified G/E style action. The acting player gets two dice anyhow, and I am debating offering a bonus die for each success, or a single bonus die for succeeding on both of the statistic-compared rolls. One the size of the dice pool is set, the entire pool is rolled, and the players are allowed to assign rolled dice to a goal and a danger. Assigned results are judged as follows: 1-4 means the attempted goal fails, or the danger comes true. 5-8 is a partial success at the goal, or partially avoiding the danger. 9-12 means the goal is achieved, or the danger avoided. My concerns are twofold: Firstly, that the two-stage action is too complicated, with two rolls to judge separately before anything can happen. Secondly, that the statistics involved go too far in softening the game. I've run some basic simulations, and the approximate statistics follow: 2 dice (up to) 3 dice (up to) 4 dice failure ~33% ~25% ~20% partial ~33% ~35% ~35% success ~33% ~40% ~45% I'd appreciate any advice that addresses my concerns or offers to refine my simulation (right now the first roll is statistically modeled as sign(1d12-1d12), where 0 is a success).

    Read the article

  • I need an approach to the problem of preventing inserting duplicate records into the database

    - by Maurice
    Apologies is this question is asked on the incorrect "stack" A webservice that I call returns a list of data. The data from the webservice is updated periodically, so a call to the webservice done in one hour could return the same data as a call done in an hour. Also, the data is returned based on a start and end date. We have multiple users that can run the webservice search, and duplicate data is most likely to be returned (especially for historical data). However I don't want to insert this duplicate data in the database. I've created a db table in which the data is stored (most important columns are) Id int autoincrement PK Date date not null --The date to which the data set belongs. LastUpdate date not null --The date the data set was last updated. UserName varchar(50) --The name of the user doing the search. I use sql server 2008 express with c# 4.0 and visual studio 2010. Entity Framework is used as the ORM. If stored procedures could be avoided in the proposed solution, then that will be a plus. Another way of looking interpreting what I'm asking a solution for is as follows: I have a million unique records in my table. A user does a new search. The search results from the user contains around 300k of the data that is already in the db. An efficient solution to finding an inserting only the unique records is needed.

    Read the article

  • Who can change the View in MVC?

    - by Luke
    I'm working on a thick client graph displaying and manipulation application. I'm trying to apply the MVC pattern to our 3D visualization component. Here is what I have for the Model, View, and Controller: Model - The graph and it's metadata. This includes vertices, edges, and the attributes of each. It does not contain position information, icons, colors, or anything display related. View - This would commonly be called a scene graph. It includes the 3D display information, texture information, color information, and anything else that is related specifically to the visualization of the model. Controller - The controller takes the view and displays it in a Window using OpenGL (but it could potentially be any 3D graphics package). The application has various "layouts" that change the position of the vertices in the display. For instance, one layout may arrange the vertices in a circle. Is it common for these layouts to access and change the view directly? Should they go through the Controller to access the View? If they go through the Controller, should they just ask for direct access to the View or should each change go through the controller? I realize this is a bit different from the standard MVC example where there a finite number of Views. In this case, the View can change in an infinite number of ways. Perhaps I'm shattering some basic principle of MVC here. Thanks in advance!

    Read the article

  • How to make an Actor follow my finger

    - by user48352
    I'm back with another question that may be really simple. I've a texture drawn on my spritebatch and I'm making it move up or down (y-axis only) with Libgdx's Input Handler: touchDown and touchUp. @Override public boolean touchDown(int screenX, int screenY, int pointer, int button) { myWhale.touchDownY = screenY; myWhale.isTouched = true; return true; } @Override public boolean touchUp(int screenX, int screenY, int pointer, int button) { myWhale.isTouched = false; return false; } myWhale is an object from Whale Class where I move my texture position: public void update(float delta) { this.delta = delta; if(isTouched){ dragWhale(); } } public void dragWhale() { if(Gdx.input.getY(0) - touchDownY < 0){ if(Gdx.input.getY(0)<position.y+height/2){ position.y = position.y - velocidad*delta; } } else{ if(Gdx.input.getY(0)>position.y+height/2){ position.y = position.y + velocidad*delta; } } } So the object moves to the center of the position where the person is pressing his/her finger and most of the time it works fine but the object seems to take about half a second to move up or down and sometimes when I press my finger it wont move. Maybe there's another simplier way to do this. I'd highly appreciate if someone points me on the right direction.

    Read the article

  • How common are circular references? Would reference-counting GC work just fine?

    - by user9521
    How common are circular references? The less common they are, the fewer hard cases you have if you are writing in a language with only reference counting-GC. Are there any cases where it wouldn't work well to make one of the references a "weak" reference so that reference counting still works? It seems like you should be able to have a language only use reference counting and weak references and have things work just fine most of the time, with the goal of efficiency. You could also have tools to help you detect memory leaks caused by circular references. Thoughts, anyone? It seems that Python uses references counting (I don't know if it uses a tracing collector occasionally or not for sure) and I know that Vala uses reference counting with weak references; I know that it's been done before, but how well would it work?

    Read the article

  • Expiring timed actions a good idea?

    - by Bart van Heukelom
    We have an online game where players sometimes have to wait a while (say 30 minutes) before a process they intiated completes. This encourages them to come back later. An example of this is growing crops in Farmville or basically any action in the Sims Play4Free. Now, however, there is the idea to let these processes expire, so if the player doesn't 'reap' them in time (e.g. within 4 hours) they are aborted. I'm a bit sceptical about this. How will this make players come back more often? Is not the reward of reaping the process enough for that? Can we expect players to fit their daily schedule around our game, maybe even set the alarm clock at night? Won't this just cause players to give up on starting these processes in the first place? I realise this may be too subjective for this site, so I'll end with a concrete question: Do (m)any other online free-to-play games employ this technique?

    Read the article

  • How were some language communities (eg, Ruby and Python) able to prevent fragmentation while others (eg, Lisp or ML) were not?

    - by chrisaycock
    The term "Lisp" (or "Lisp-like") is an umbrella for lots of different languages, such as Common Lisp, Scheme, and Arc. There is similar fragmentation is other language communities, like in ML. However, Ruby and Python have both managed to avoid this fate, where innovation occurred more on the implementation (like PyPy or YARV) instead of making changes to the language itself. Did the Ruby and Python communities do something special to prevent language fragmentation?

    Read the article

  • Identifying which pattern fits better.

    - by Daniel Grillo
    I'm developing a software to program a device. I have some commands like Reset, Read_Version, Read_memory, Write_memory, Erase_memory. Reset and Read_Version are fixed. They don't need parameters. Read_memory and Erase_memory need the same parameters that are Length and Address. Write_memory needs Lenght, Address and Data. For each command, I have the same steps in sequence, that are something like this sendCommand, waitForResponse, treatResponse. I'm having difficulty to identify which pattern should I use. Factory, Template Method, Strategy or other pattern. Edit I'll try to explain better taking in count the given comments and answers. I've already done this software and now I'm trying to refactoring it. I'm trying to use patterns, even if it is not necessary because I'm taking advantage of this little software to learn about some patterns. Despite I think that one (or more) pattern fits here and it could improve my code. When I want to read version of the software of my device, I don't have to assembly the command with parameters. It is fixed. So I have to send it. After wait for response. If there is a response, treat (or parse) it and returns. To read a portion of the memory (maximum of 256 bytes), I have to assembly the command using the parameters Len and Address. So I have to send it. After wait for response. If there is a response, treat (or parse) it and returns. To write a portion in the memory (maximum of 256 bytes), I have to assembly the command using the parameters Len, Address and Data. So I have to send it. After wait for response. If there is a response, treat (or parse) it and returns. I think that I could use Template Method because I have almost the same algorithm for all. But the problem is some commands are fixes, others have 2 or 3 parameters. I think that parameters should be passed on the constructor of the class. But each class will have a constructor overriding the abstract class constructor. Is this a problem for the template method? Should I use other pattern?

    Read the article

  • Why don't languages include implication as a logical operator?

    - by Maciej Piechotka
    It might be a strange question, but why there is no implication as a logical operator in many languages (Java, C, C++, Python Haskell - although as last one have user defined operators its trivial to add it)? I find logical implication much clearer to write (particularly in asserts or assert-like expressions) then negation with or: encrypt(buf, key, mode, iv = null) { assert (mode != ECB --> iv != null); assert (mode == ECB || iv != null); assert (implies(mode != ECB, iv != null)); // User-defined function }

    Read the article

  • Options for Application Registry

    - by Matt Felzani
    I work for a small software company (about 200 people building 8-10 applications) and I was hoping to get some advice on products that might be out there to manage the information of which clients are using which versions of our products? The most fundamental relationship would be that a "product" has "versions" and a given "version" is used by a "client." Uses would be: Determine which clients use which products Determine which clients are on which versions of a product Determine which clients are exposed to which vulnerabilities because of the version they use Determine which clients cannot move to a new version because of a vulnerability in the new version that they may hit Determine which clients should be approached for an upgrade Any thoughts or product reviews would be greatly appreciated! Thanks in advance.

    Read the article

  • Procedural object generation and unique identification

    - by 2080
    My question relates to procedural content generation and data management of the emerging objects in a database. I assume a networked game, with a server-client model. Unspecified objects in the game world are generated while the game is running with procedural algorithms (for example perlin noise). The players (/clients) can modify the properties of these objects, but have to notify the server of these changes. How could this communication address unique objects, so that both the server and the client know of which object they are speaking? Not only the inner properties of the objects can differ, but also visible, such as the position. When the player wants to select one of these objects the game has to find out the id - does anyone know which methods or algorithms can accomplish that?

    Read the article

  • How should I architect a personal schedule manager that runs 24/7?

    - by Crawford Comeaux
    I've developed an ADHD management system for myself that's attempting to change multiple habits at once. I know this is counter to conventional wisdom, but I've tried the conventional for years & am now trying it my way. (just wanted to say that to try and prevent it from distracting people from the actual question) Anyway, I'd like to write something to run on a remote server that monitors me, helps me build/avoid certain habits, etc. What this amounts to is a system that: runs 24/7 may have multiple independent tasks to run at once may have tasks that require other tasks to run first lets tasks be scheduled by specific time, recurrence (ie. "run every 5 mins"), or interval (ie. "run from 2pm to 3pm") My first naive attempt at this was just a single PHP script scheduled to run every minute by cron (language was chosen in order to use a certain library, but no longer necessary). The logic behind when to run this or that portion of code got hairy pretty quick. So my question is how should I approach this from here? I'm not tied to any one language, though I'm partial to python/javascript. Thoughts: Could be done as a set of scripts that include a scheduling mechanism with one script per bit of logic...but the idea just feels wrong to me. Building it as a daemon could be helpful, but still unsure what to do about dozens of if-else statements for detecting the current time

    Read the article

  • Preferred lambda syntax?

    - by Roger Alsing
    I'm playing around a bit with my own C like DSL grammar and would like some oppinions. I've reserved the use of "(...)" for invocations. eg: foo(1,2); My grammar supports "trailing closures" , pretty much like Ruby's blocks that can be passed as the last argument of an invocation. Currently my grammar support trailing closures like this: foo(1,2) { //parameterless closure passed as the last argument to foo } or foo(1,2) [x] { //closure with one argument (x) passed as the last argument to foo print (x); } The reason why I use [args] instead of (args) is that (args) is ambigious: foo(1,2) (x) { } There is no way in this case to tell if foo expects 3 arguments (int,int,closure(x)) or if foo expects 2 arguments and returns a closure with one argument(int,int) - closure(x) So thats pretty much the reason why I use [] as for now. I could change this to something like: foo(1,2) : (x) { } or foo(1,2) (x) -> { } So the actual question is, what do you think looks best? [...] is somewhat wrist unfriendly. let x = [a,b] { } Ideas?

    Read the article

  • How to had operation with character/items on binary with concrete operations on C++?

    - by Piperoman
    I have the next problem. A item can had a lot of states: NORMAL = 0000000 DRY = 0000001 HOT = 0000010 BURNING = 0000100 WET = 0001000 COLD = 0010000 FROZEN = 0100000 POISONED= 1000000 A item can had some states at same time but not all of them Is impossible to be dry and wet at same time. If you COLD a WET item, it turns into FROZEN. If you HOT a WET item, it turns into NORMAL A item can be BURNING and POISON Etc. I have try to set binary flags to states, and use AND to set operation to combine different states, checking before if is possible or not to do it, or change to another status. Exist a concrete patron to solve this problem efficiently without had a interminable switch that check every states with everynew states? It is relative easy to check 2 different states, but if exist a third state it is not trivial to do.

    Read the article

  • Is premature optimization really the root of all evil?

    - by Craig Day
    A colleague of mine today committed a class called ThreadLocalFormat, which basically moved instances of Java Format classes into a thread local, since they are not thread safe and "relatively expensive" to create. I wrote a quick test and calculated that I could create 200,000 instances a second, asked him was he creating that many, to which he answered "nowhere near that many". He's a great programmer and everyone on the team is highly skilled so we have no problem understanding the resulting code, but it was clearly a case of optimizing where there is no real need. He backed the code out at my request. What do you think? Is this a case of "premature optimization" and how bad is it really?

    Read the article

  • Provide an OnChange event for an internal property which is controlled externally?

    - by NGLN
    For fun and by request I am updating this ImageGrid component, a kind of listbox for images that has a FileNames property of type TStrings. For ease of writing, I have been misusing its FileNames.Objects property for bitmap storage. But since the TStrings type suggests that users of the component could or would want to use the Objects property for custom data, e.g. like TListBox.Items, I am rewriting the component to store the bitmaps elsewhere and leave FileNames.Objects untouched for unknown future usage. Now I am wondering whether to provide an OnChange event. And if so, whether to fire it when one or more FileNames.Objects changes. Trying to answer it myself, I dove in Delphi's own VCL and stumbled on: TMemo: has an OnChange event, but ignores Lines.Objects TListBox: has no OnChange event, but is capable of storing Items.Objects TStringGrid: has no OnChange event, but is capable of storing Objects, Rows.Objects, Cols.Objects So now I am somewhat puzzeled, because I cannot imagine Borland's developers didn't add events for several Objects properties out of ease. Sure, when a user changes a FileNames.Object in my component, he knows he does and could implement appropriate interaction himself. But wouldn't it be convenient when the component does automatically? What would you expect from this component in this regard?

    Read the article

  • Nested Entities and calculation on leaf entity property - SQL or NoSQL approach

    - by Chandu
    I am working on a hobby project called Menu/Recipe Management. This is how my entities and their relations look like. A Nutrient has properties Code and Value An Ingredient has a collection of Nutrients A Recipe has a Collection of Ingredients and occasionally can have a collection of other recipes A Meal has a Collection of Recipes and Ingredients A Menu has a Collection of Meals The relations can be depicted as In one of the pages, for a selected menu I need to display the effective nutrients information calculated based on its constituents (Meals, Recipes, Ingredients and the corresponding nutrients). As of now am using SQL Server to store the data and I am navigating the chain from my C# code, starting from each meal of the menu and then aggregating the nutrient values. I think this is not an efficient way as this calculation is being done every time the page is requested and the constituents change occasionally. I was thinking about a having a background service that maintains a table called MenuNutrients ({MenuId, NutrientId, Value}) and will populate/update this table with the effective nutrients when any of the component (Meal, Recipe, Ingredient) changes. I feel that a GraphDB would be a good fit for this requirement, but my exposure to NoSQL is limited. I want to know what are the alternative solutions/approaches to this requirement of displaying the nutrients of a given menu. Hope my description of the scenario is clear.

    Read the article

  • C#.NET: How to update multiple .NET pages when a particular event occurs in one .Net page? In another words how to use Observer pattern(Publish and subscribe to events)

    Problem: Suppose you have a scenario in which you have to update multiple pages when an event occurs in main page. For example imagine you have a main page where you are dispalying a tab control. This tab control has 3 tab pages where you are loading 3 different user controls. On click of an update button in main page imagine if you have do something in all the 3 tab panels. In other words an event in main page has to be handled in many other pages. An event in main page which contains the tab control has to be handled in all the tab panels(user controls) Answer: Use Observer pattern Define a base page for the page that contains the tab control. Main page which contains the tab: Baseline_Baseline Basepage for the above main page: BaselineBasePage User control that has to be udpated for an event in main page: Baseline_PriorNonDeloitte Source Code: public class BaselineBasePage : System.Web.UI.Page { IList lstControls = new List(); public void Add(IObserver userControl) { lstControls.Add(userControl); } public void Remove(IObserver userControl) { lstControls.Remove(userControl); } public void RemoveAllUserControls() { lstControls.Clear(); } public void Update(SaveEventArgs e) { foreach (IObserver LobjControl in lstControls) { LobjControl.Save(e); } } } public interface IObserver { void Update(SaveEventArgs e); } public partial class Baseline_Baseline : BaselineBasePage { . . . this.Add(_ucPI); this.Add(_ucPI1); protected void abActionBar_saveClicked(object sender, EventArgs e) { SaveEventArgs se = new SaveEventArgs(); se.TabType = (BaselineTabType)tcBaseline.ActiveTabIndex; this.Update(se); } } Public class Baseline_PriorNonDeloitte : System.Web.UI.UserControl,IObserver { public void Update(SaveEventArgs e) { } } More info at: http://www.dofactory.com/Patterns/PatternObserver.aspx span.fullpost {display:none;}

    Read the article

  • What's the best way to expose a Model object in a ViewModel?

    - by Angel
    In a WPF MVVM application, I exposed my model object into my viewModel by creating an instance of Model class (which cause dependency) into ViewModel. Instead of creating separate VM properties, I wrap the Model properties inside my ViewModel Property. My model is just an entity framework generated proxy class: public partial class TblProduct { public TblProduct() { this.TblPurchaseDetails = new HashSet<TblPurchaseDetail>(); this.TblPurchaseOrderDetails = new HashSet<TblPurchaseOrderDetail>(); this.TblSalesInvoiceDetails = new HashSet<TblSalesInvoiceDetail>(); this.TblSalesOrderDetails = new HashSet<TblSalesOrderDetail>(); } public int ProductId { get; set; } public string ProductCode { get; set; } public string ProductName { get; set; } public int CategoryId { get; set; } public string Color { get; set; } public Nullable<decimal> PurchaseRate { get; set; } public Nullable<decimal> SalesRate { get; set; } public string ImagePath { get; set; } public bool IsActive { get; set; } public virtual TblCompany TblCompany { get; set; } public virtual TblProductCategory TblProductCategory { get; set; } public virtual TblUser TblUser { get; set; } public virtual ICollection<TblPurchaseDetail> TblPurchaseDetails { get; set; } public virtual ICollection<TblPurchaseOrderDetail> TblPurchaseOrderDetails { get; set; } public virtual ICollection<TblSalesInvoiceDetail> TblSalesInvoiceDetails { get; set; } public virtual ICollection<TblSalesOrderDetail> TblSalesOrderDetails { get; set; } } Here is my ViewModel: public class ProductViewModel : WorkspaceViewModel { #region Constructor public ProductViewModel() { StartApp(); } #endregion //Constructor #region Properties private IProductDataService _dataService; public IProductDataService DataService { get { if (_dataService == null) { if (IsInDesignMode) { _dataService = new ProductDataServiceMock(); } else { _dataService = new ProductDataService(); } } return _dataService; } } //Get and set Model object private TblProduct _product; public TblProduct Product { get { return _product ?? (_product = new TblProduct()); } set { _product = value; } } #region Public Properties public int ProductId { get { return Product.ProductId; } set { if (Product.ProductId == value) { return; } Product.ProductId = value; RaisePropertyChanged("ProductId"); } } public string ProductName { get { return Product.ProductName; } set { if (Product.ProductName == value) { return; } Product.ProductName = value; RaisePropertyChanged(() => ProductName); } } private ObservableCollection<TblProduct> _productRecords; public ObservableCollection<TblProduct> ProductRecords { get { return _productRecords; } set { _productRecords = value; RaisePropertyChanged("ProductRecords"); } } //Selected Product private TblProduct _selectedProduct; public TblProduct SelectedProduct { get { return _selectedProduct; } set { _selectedProduct = value; if (_selectedProduct != null) { this.ProductId = _selectedProduct.ProductId; this.ProductCode = _selectedProduct.ProductCode; } RaisePropertyChanged("SelectedProduct"); } } #endregion //Public Properties #endregion // Properties #region Commands private ICommand _newCommand; public ICommand NewCommand { get { if (_newCommand == null) { _newCommand = new RelayCommand(() => ResetAll()); } return _newCommand; } } private ICommand _saveCommand; public ICommand SaveCommand { get { if (_saveCommand == null) { _saveCommand = new RelayCommand(() => Save()); } return _saveCommand; } } private ICommand _deleteCommand; public ICommand DeleteCommand { get { if (_deleteCommand == null) { _deleteCommand = new RelayCommand(() => Delete()); } return _deleteCommand; } } #endregion //Commands #region Methods private void StartApp() { LoadProductCollection(); } private void LoadProductCollection() { var q = DataService.GetAllProducts(); this.ProductRecords = new ObservableCollection<TblProduct>(q); } private void Save() { if (SelectedOperateMode == OperateModeEnum.OperateMode.New) { //Pass the Model object into Dataservice for save DataService.SaveProduct(this.Product); } else if (SelectedOperateMode == OperateModeEnum.OperateMode.Edit) { //Pass the Model object into Dataservice for Update DataService.UpdateProduct(this.Product); } ResetAll(); LoadProductCollection(); } #endregion //Methods } Here is my Service class: class ProductDataService:IProductDataService { /// <summary> /// Context object of Entity Framework model /// </summary> private MaizeEntities Context { get; set; } public ProductDataService() { Context = new MaizeEntities(); } public IEnumerable<TblProduct> GetAllProducts() { using(var context=new R_MaizeEntities()) { var q = from p in context.TblProducts where p.IsDel == false select p; return new ObservableCollection<TblProduct>(q); } } public void SaveProduct(TblProduct _product) { using(var context=new R_MaizeEntities()) { _product.LastModUserId = GlobalObjects.LoggedUserID; _product.LastModDttm = DateTime.Now; _product.CompanyId = GlobalObjects.CompanyID; context.TblProducts.Add(_product); context.SaveChanges(); } } public void UpdateProduct(TblProduct _product) { using (var context = new R_MaizeEntities()) { context.TblProducts.Attach(_product); context.Entry(_product).State = EntityState.Modified; _product.LastModUserId = GlobalObjects.LoggedUserID; _product.LastModDttm = DateTime.Now; _product.CompanyId = GlobalObjects.CompanyID; context.SaveChanges(); } } public void DeleteProduct(int _productId) { using (var context = new R_MaizeEntities()) { var product = (from c in context.TblProducts where c.ProductId == _productId select c).First(); product.LastModUserId = GlobalObjects.LoggedUserID; product.LastModDttm = DateTime.Now; product.IsDel = true; context.SaveChanges(); } } } I exposed my model object in my viewModel by creating an instance of it using new keyword, also I instantiated my DataService class in VM. I know this will cause a strong dependency. So: What's the best way to expose a Model object in a ViewModel? What's the best way to use DataService in VM?

    Read the article

  • Pro/con of using Angular directives for complex form validation/ GUI manipulation

    - by tengen
    I am building a new SPA front end to replace an existing enterprise's legacy hodgepodge of systems that are outdated and in need of updating. I am new to angular, and wanted to see if the community could give me some perspective. I'll state my problem, and then ask my question. I have to generate several series of check boxes based on data from a .js include, with data like this: $scope.fieldMappings.investmentObjectiveMap = [ {'id':"CAPITAL PRESERVATION", 'name':"Capital Preservation"}, {'id':"STABLE", 'name':"Moderate"}, {'id':"BALANCED", 'name':"Moderate Growth"}, // etc {'id':"NONE", 'name':"None"} ]; The checkboxes are created using an ng-repeat, like this: <div ng-repeat="investmentObjective in fieldMappings.investmentObjectiveMap"> ... </div> However, I needed the values represented by the checkboxes to map to a different model (not just 2-way-bound to the fieldmappings object). To accomplish this, I created a directive, which accepts a destination array destarray which is eventually mapped to the model. I also know I need to handle some very specific gui controls, such as unchecking "None" if anything else gets checked, or checking "None" if everything else gets unchecked. Also, "None" won't be an option in every group of checkboxes, so the directive needs to be generic enough to accept a validation function that can fiddle with the checked state of the checkbox group's inputs based on what's already clicked, but smart enough not to break if there is no option called "NONE". I started to do that by adding an ng-click which invoked a function in the controller, but in looking around Stack Overflow, I read people saying that its bad to put DOM manipulation code inside your controller - it should go in directives. So do I need another directive? So far: (html): <input my-checkbox-group type="checkbox" fieldobj="investmentObjective" ng-click="validationfunc()" validationfunc="clearOnNone()" destarray="investor.investmentObjective" /> Directive code: .directive("myCheckboxGroup", function () { return { restrict: "A", scope: { destarray: "=", // the source of all the checkbox values fieldobj: "=", // the array the values came from validationfunc: "&" // the function to be called for validation (optional) }, link: function (scope, elem, attrs) { if (scope.destarray.indexOf(scope.fieldobj.id) !== -1) { elem[0].checked = true; } elem.bind('click', function () { var index = scope.destarray.indexOf(scope.fieldobj.id); if (elem[0].checked) { if (index === -1) { scope.destarray.push(scope.fieldobj.id); } } else { if (index !== -1) { scope.destarray.splice(index, 1); } } }); } }; }) .js controller snippet: .controller( 'SuitabilityCtrl', ['$scope', function ( $scope ) { $scope.clearOnNone = function() { // naughty jQuery DOM manipulation code that // looks at checkboxes and checks/unchecks as needed }; The above code is done and works fine, except the naughty jquery code in clearOnNone(), which is why I wrote this question. And here is my question: after ALL this, I think to myself - I could be done already if I just manually handled all this GUI logic and validation junk with jQuery written in my controller. At what point does it become foolish to write these complicated directives that future developers will have to puzzle over more than if I had just written jQuery code that 99% of us would understand with a glance? How do other developers draw the line? I see this all over Stack Overflow. For example, this question seems like it could be answered with a dozen lines of straightforward jQuery, yet he has opted to do it the angular way, with a directive and a partial... it seems like a lot of work for a simple problem. Specifically, I suppose I would like to know: how SHOULD I be writing the code that checks whether "None" has been selected (if it exists as an option in this group of checkboxes), and then check/uncheck the other boxes accordingly? A more complex directive? I can't believe I'm the only developer that is having to implement code that is more complex than needed just to satisfy an opinionated framework.

    Read the article

  • Using "prevent execution of method" flags

    - by tpaksu
    First of all I want to point out my concern with some pseudocode (I think you'll understand better) Assume you have a global debug flag, or class variable named "debug", class a : var debug = FALSE and you use it to enable debug methods. There are two types of usage it as I know: first in a method : method a : if debug then call method b; method b : second in the method itself: method a : call method b; method b : if not debug exit And I want to know, is there any File IO or stack pointer wise difference between these two approaches. Which usage is better, safer and why?

    Read the article

  • Visually and audibly unambiguous subset of the Latin alphabet?

    - by elliot42
    Imagine you give someone a card with the code "5SBDO0" on it. In some fonts, the letter "S" is difficult to visually distinguish from the number five, (as with number zero and letter "O"). Reading the code out loud, it might be difficult to distinguish "B" from "D", necessitating saying "B as in boy," "D as in dog," or using a "phonetic alphabet" instead. What's the biggest subset of letters and numbers that will, in most cases, both look unambiguous visually and sound unambiguous when read aloud? Background: We want to generate a short string that can encode as many values as possible while still being easy to communicate. Imagine you have a 6-character string, "123456". In base 10 this can encode 10^6 values. In hex "1B23DF" you can encode 16^6 values in the same number of characters, but this can sound ambiguous when read aloud. ("B" vs. "D") Likewise for any string of N characters, you get (size of alphabet)^N values. The string is limited to a length of about six characters, due to wanting to fit easily within the capacity of human working memory capacity. Thus to find the max number of values we can encode, we need to find that largest unambiguous set of letters/numbers. There's no reason we can't consider the letters G-Z, and some common punctuation, but I don't want to have to go manually pairwise compare "does G sound like A?", "does G sound like B?", "does G sound like C" myself. As we know this would be O(n^2) linguistic work to do =)...

    Read the article

  • Managing accounts on a private website for a real-life community

    - by Smudge
    I'm looking at setting-up a walled-in website for a real-life community of people, and I was wondering if anyone has any experience with managing member accounts for this kind of thing. Some conditions that must be met: This community has a set list of real-life members, each of whom would be eligible for one account on the website. We don't expect or require that they all sign-up. It is purely opt-in, but we anticipate that many of them would be interested in the services we are setting up. Some of the community members emails are known, but some of them have fallen off the grid over the years, so ideally there would be a way for them to get back in touch with us through the public-facing side of the site. (And we'd want to manually verify the identity of anyone who does so). Their names are known, and for similar projects in the past we have assigned usernames derived from their real-life names. This time, however, we are open to other approaches, such as letting them specify their own username or getting rid of usernames entirely. The specific web technology we will use (e.g. Drupal, Joomla, etc) is not really our concern right now -- I am more interested in how this can be approached in the abstract. Our database already includes the full member roster, so we can email many of them generated links to a page where they can create an account. (And internally we can require that these accounts be paired with a known member). Should we have them specify their own usernames, or are we fine letting them use their registered email address to log-in? Are there any paradigms for walled-in community portals that help address security issues if, for example, one of their email accounts is compromised? We don't anticipate attempted break-ins being much of a threat, because nothing about this community is high-profile, but we do want to address security concerns. In addition, we want to make the sign-up process as painless for the members as possible, especially given the fact that we can't just make sign-ups open to anyone. I'm interested to hear your thoughts and suggestions! Thanks!

    Read the article

< Previous Page | 121 122 123 124 125 126 127 128 129 130 131 132  | Next Page >