Search Results

Search found 44734 results on 1790 pages for 'model based design'.

Page 362/1790 | < Previous Page | 358 359 360 361 362 363 364 365 366 367 368 369  | Next Page >

  • Derived class linker - is this wrong?

    - by bobobobo
    We have this situation: A B ^ ^ | / C so class A { } class B { } class C : public A, public B { } Now, B wants to access a property in C. How do you do this? The solution I came up with is to place a pointer in B to an instance of C, which is only active (not null) if this B is in fact a C.

    Read the article

  • singleton vs factory?

    - by fayer
    i've got 3 Log classes that all implements iLog interface: DatabaseLog FileLog ScreenLog there can only be one instance of them. initially i though of using single pattern for each class but then i thought why not use a factory for instantiation instead, cause then i wont have to create single pattern for each one of them and for all future Log classes. and maybe someone would want them as multiple objects in the future. so my questions is: should i use factory or singleton pattern here?

    Read the article

  • Repository pattern with lazying loading using POCO

    - by Simon G
    Hi, I'm in the process of starting a new project and creating the business objects and data access etc. I'm just using plain old clr objects rather than any orms. I've created two class libraries: 1) Business Objects - holds all my business objects, all this objects are light weight with only properties and business rules. 2) Repository - this is for all my data access. The majority of my objects will have child list in and my question is what is the best way to lazy load these values as I don't want to bring back unnecessary information if I dont need to. I've thought about when using the "get" on the child property to check if its "null" and if it is call my repository to get the child information. This has two problems from what I can see: 1) The object "knows" how to get itself I would rather no data access logic be held in the object. 2) This required both classes to reference each other which in visual studio throws a circular dependency error. Does anyone have any suggestions on how to overcome this issue or any recommendations on my projects layout and where it can be improved? Thanks

    Read the article

  • Private constructor and public parameter constructor -C#

    - by Amutha
    I heard that private constructor prevent object creation from outside world. When i have a code public class Product { public string Name { get;set;} public double Price {get;set;} Product() { } public Product(string _name,double _price) { } } here still i can declare public constructor(parameter),won't it spoil the purpose of private constructor? When do we need both private and public constructor(parameter) in code? I need detailed explanation please.

    Read the article

  • Are soft deletes a good idea?

    - by Khou
    Are soft deletes a good idea or a bad idea? Instead of actually deleting a record in your database, you would just flag it as "IsDeleted" = true, and upon recovery of the record you could just flag it as "False". Is this a good idea?

    Read the article

  • Fastest gap sequence for shell sort ?

    - by Tony
    According to Marcin Ciura's Optimal (best known) sequence of increments for shell sort algorithm. The best sequence for shellsort is 1, 4, 10, 23, 57, 132, 301, 701... But how can I generate such a sequence ? In Marcin Ciura's paper he said : Both Knuth’s and Hibbard’s sequences are relatively bad, because they are defined by simple linear recurrences but most algorithm books I searched , they all tend to use Knuth’s sequence : k = 3k + 1 ; because it's easy to generate , what's your way of generating shellsort sequence ?

    Read the article

  • Recommend .NET data access layer/middle tier

    - by Simon G
    Hi, I'm currently creating an MVC application that will likely to expand to include a silverlight, wpf and possible windows phone all using the same data. So I've created a class library to keep all my objects in and I've created the MVC app. My question is what would be the best way to access the data? Taking into account possible expansion in the future. Should I use web services/WCF? RIA Services? Remoting? Or something else. What have people used in the past and what do you recommend? Thanks

    Read the article

  • How to display and update data in MVC2

    - by Picflight
    Table Product Product Id Product Name Table ProductSupplier ProductSupplierId ProductId SupplierId Table Supplier SupplierId SupplierName I have the above 3 tables in my database, ProductSupplier is the lookup table. Each Product can have many suppliers. I am using Entity Framework. Using Web Forms it was fairly easy to display a Product on a web page and bind a repeater with the suppliers information. Also, with Web Forms it was easy to Add new Product and suppliers, the linkage seemed easy. How do you do this sort of functionality in MVC? In the Create View below, I want to be able to Add the Supplier as well. Is there a better approach that I might be missing here? This is how I did it with Web Forms. Beyond the code below I am totally lost. I can show data in a list and also display the Suppliers for each Product, but how do I Add and Edit. Should I break it into different views? With Web Forms I could do it all in one page. namespace MyProject.Mvc.Models { [MetadataType(typeof(ProductMetaData))] public partial class Product { public Product() { // Initialize Product this.CreateDate = System.DateTime.Now; } } public class ProductMetaData { [Required(ErrorMessage = "Product name is required")] [StringLength(50, ErrorMessage = "Product name must be under 50 characters")] public object ProductName { get; set; } [Required(ErrorMessage = "Description is required")] public object Description { get; set; } } public class ProductFormViewModel { public Product Product { get; private set; } public IEnumerable<ProductSupplier> ProductSupplier { get; private set; } public ProductFormViewModel() { Product = new Product(); } public ProductFormViewModel(Product product) { Product = product; ProductSupplier = product.ProductSupplier; } } } ProductRepository public Product GetProduct(int id) { var p = db.Product.FirstOrDefault(por => por.ProductId == id); p.ProductSupplier.Attach(p.ProductSupplier.CreateSourceQuery().Include("Product").ToList()); return p; } Product Create View <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<MyProject.Mvc.Models.ProductFormViewModel>" %> <%= Html.ValidationSummary("Please correct the errors and try again.") %> <% using (Html.BeginForm()) {%> <fieldset> <legend>Fields</legend> <div class="editor-label"> <%= Html.LabelFor(model => model.Product.ProductId) %> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Product.ProductId) %> <%= Html.ValidationMessageFor(model => model.Product.ProductId) %> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.Product.ProductName) %> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Product.ProductName) %> <%= Html.ValidationMessageFor(model => model.Product.ProductName) %> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.Product.Description) %> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Product.Description) %> <%= Html.ValidationMessageFor(model => model.Product.Description) %> </div> <p> <input type="submit" value="Create" /> </p> </fieldset> <% } %>

    Read the article

  • learning inkscape for webapp/website

    - by creativz
    Hello, I'm quite impressed with Incskape, it's very powerfull. That's why I wanted to start learning it. But how should I start (to learn it efficiently)? Should I read a book (anybody can recommend me a good one?) or just (inefficiently) do some tutorials on the internet. I really want to learn it to make professional graphics for a webapp or website. So how should I tackle it? Thanks!

    Read the article

  • Help:Graph contest problem: maybe a modified Dijkstra or another alternative algorithm

    - by newba
    Hi you all, I'm trying to do this contest exercise about graphs: XPTO is an intrepid adventurer (a little too temerarious for his own good) who boasts about exploring every corner of the universe, no matter how inhospitable. In fact, he doesn't visit the planets where people can easily live in, he prefers those where only a madman would go with a very good reason (several millions of credits for instance). His latest exploit is trying to survive in Proxima III. The problem is that Proxima III suffers from storms of highly corrosive acids that destroy everything, including spacesuits that were especially designed to withstand corrosion. Our intrepid explorer was caught in a rectangular area in the middle of one of these storms. Fortunately, he has an instrument that is capable of measuring the exact concentration of acid on each sector and how much damage it does to his spacesuit. Now, he only needs to find out if he can escape the storm. Problem The problem consists of finding an escape route that will allow XPTOto escape the noxious storm. You are given the initial energy of the spacesuit, the size of the rectangular area and the damage that the spacesuit will suffer while standing in each sector. Your task is to find the exit sector, the number of steps necessary to reach it and the amount of energy his suit will have when he leaves the rectangular area. The escape route chosen should be the safest one (i.e., the one where his spacesuit will be the least damaged). Notice that Rodericus will perish if the energy of his suit reaches zero. In case there are more than one possible solutions, choose the one that uses the least number of steps. If there are at least two sectors with the same number of steps (X1, Y1) and (X2, Y2) then choose the first if X1 < X2 or if X1 = X2 and Y1 < Y2. Constraints 0 < E = 30000 the suit's starting energy 0 = W = 500 the rectangle's width 0 = H = 500 rectangle's height 0 < X < W the starting X position 0 < Y < H the starting Y position 0 = D = 10000 the damage sustained in each sector Input The first number given is the number of test cases. Each case will consist of a line with the integers E, X and Y. The following line will have the integers W and H. The following lines will hold the matrix containing the damage D the spacesuit will suffer whilst in the corresponding sector. Notice that, as is often the case for computer geeks, (1,1) corresponds to the upper left corner. Output If there is a solution, the output will be the remaining energy, the exit sector's X and Y coordinates and the number of steps of the route that will lead Rodericus to safety. In case there is no solution, the phrase Goodbye cruel world! will be written. Sample Input 3 40 3 3 7 8 12 11 12 11 3 12 12 12 11 11 12 2 1 13 11 11 12 2 13 2 14 10 11 13 3 2 1 12 10 11 13 13 11 12 13 12 12 11 13 11 13 12 13 12 12 11 11 11 11 13 13 10 10 13 11 12 8 3 4 7 6 4 3 3 2 2 3 2 2 5 2 2 2 3 3 2 1 2 2 3 2 2 4 3 3 2 2 4 1 3 1 4 3 2 3 1 2 2 3 3 0 3 4 10 3 4 7 6 3 3 1 2 2 1 0 2 2 2 4 2 2 5 2 2 1 3 0 2 2 2 2 1 3 3 4 2 3 4 4 3 1 1 3 1 2 2 4 2 2 1 Sample Output 12 5 1 8 Goodbye cruel world! 5 1 4 2 Basically, I think we have to do a modified Dijkstra, in which the distance between nodes is the suit's energy (and we have to subtract it instead of suming up like is normal with distances) and the steps are the ....steps made along the path. The pos with the bester binomial (Energy,num_Steps) is our "way out". Important : XPTO obviously can't move in diagonals, so we have to cut out this cases. I have many ideas, but I have such a problem implementing them... Could someone please help me thinking about this with some code or, at least, ideas? Am I totally wrong?

    Read the article

  • Dealing with the lack of closures in Objective-C

    - by Sean Clark Hess
    Maybe it's just the fact that I've been using http://nodejs.org/ lately, but the lack of closures in Objective-C (iphone) has been really hard to work around. For example, I'm creating service classes. Each service class can have several methods, each of which makes a different URL request. I can use the delegate pattern, but that means that I have to create a new service each time I want to call a method on it (because it has to store the delegate and selector for that request, and new method calls would overwrite them). Even more difficult for me is the fact that I can't easily keep local variables around in the scope for a callback. I have to store anything I want to send back to the delegate on the service class itself, which makes it harder to have more than one method on each class. How do you pros do it? Should I just quit whining and do it another way?

    Read the article

  • Tree data structure in iphone with coredata

    - by ebabchick
    Hi, I am looking to store a tree structure in CoreData for iphone. Can someone give me some tips on the best way to go about this? Basically I want to have a bunch of folders that people can dive into in a table view, and I want to have leaves of the tree be photos. The thing is, I want to be able to let the user edit these folders on-the-fly and add folders and content (photos) at their discretion. I'm relatively new to CoreData. Any help would be appreciated. Thanks.

    Read the article

  • Using C# and Repository Factory and the error: The requested database is not defined in configurati

    - by odiseh
    hi I am using Repository factory for visual studio 2008 for a personal project. It generated a class called ProductRepository which inherits from Repository. The ProductRepository has a constructor which gets a database name as string and passes it to its base (I mean Repository ). So when I try to debug my project step by step, I pass my database name to ProductRepository but it raises the following error: The requested database is not defined in configuration. What's wrong?

    Read the article

  • Difference between Singleton implemention using pointer and using static object

    - by Anon
    EDIT: Sorry my question was not clear, why do books/articles prefer implementation#1 over implementation#2? What is the actual advantage of using pointer in implementation of Singleton class vs using a static object? Why do most books prefer this class Singleton { private: static Singleton *p_inst; Singleton(); public: static Singleton * instance() { if (!p_inst) { p_inst = new Singleton(); } return p_inst; } }; over this class Singleton { public: static Singleton& Instance() { static Singleton inst; return inst; } protected: Singleton(); // Prevent construction Singleton(const Singleton&); // Prevent construction by copying Singleton& operator=(const Singleton&); // Prevent assignment ~Singleton(); // Prevent unwanted destruction };

    Read the article

  • Database change management tools?

    - by zodeus
    We are currently in the process of solidifying a database change management process. We run MySql 5 running on RedHat 5. I have selected LiquiBase as the tool because it's open source and allows us to expand its functionality later if needed. It also seems to be one of the few free projects that are still active. Has anyone here had any experience using LiquiBase or other Db versioning tools? Company Background: We are an SaaS company providing a 7/24 hosted application. There are dozens of instances running different versions of the same database and we need a way to manage the deploy process as it's starting to get out of control. The databases have hundreds of tables and we typically do releases once every 3 months.

    Read the article

  • Logic / Probability Question: Picking from a bag

    - by Rosarch
    I'm coding a board game where there is a bag of possible pieces. Each turn, players remove randomly selected pieces from the bag according to certain rules. For my implementation, it may be easier to divide up the bag initially into pools for one or more players. These pools would be randomly selected, but now different players would be picking from different bags. Is this any different? If one player's bag ran out, more would be randomly shuffled into it from the general stockpile.

    Read the article

  • Is this the correct way of speaking to a "Content Manager" Class?

    - by DeanMc
    I am creating a silverlight site. I am currently breaking out my ideas into pieces of functionality. One of the idea's I have is the concept of a content manager. This is essentially a UI control with 4 regions. Top, Bottom, Right & Left. I also have a collection of objects that are considered "Menu Items". These are controls that function as a way to navigate around, similar to links. The idea I have is to implement an IMenuItem interface. Among the standard pieces of information (Text, PageReference, etc) I was also going to hold a reference to the content manager. My idea behind this thinking is that I can pass the PageReference to a property on the ContentManager and then call a method which knows how to update the content manager accordingly. Is this the best way of implementing this or is their some sort of pattern for it?

    Read the article

  • Database per application VS One big database for all applications

    - by Jorge Vargas
    Hello, I'm designing a few applications that will share 2 or 3 database tables and all of the other tables will be independent of each app. The shared databases contain mostly user information, and there might occur the case where other tables need to be shared, but that's my instinct speaking. I'm leaning over the one database for all applications solution because I want to have referential integrity, and I won't have to keep the same information up to date in each of the databases, but I'm probably going to end with a database of 100+ tables where only groups of ten tables will have related information. The database per application approach helps me keep everything more organized, but I don't know a way to keep the related tables in all databases up to date. So, the basic question is: which of both approaches do you recommend? Thanks, Jorge Vargas.

    Read the article

  • Visitor pattern and compiler code generation, how to get children attributes?

    - by LeleDumbo
    I'd like to modify my compiler's code generator to use visitor pattern since the current approach must use multiple conditional statement to check the real type of a child before generating the corresponding code. However, I have problems to get children attributes after they're visited. For instance, in binary expression I use this: LHSCode := GenerateExpressionCode(LHSNode); RHSCode := GenerateExpressionCode(RHSNode); CreateBinaryExpression(Self,LHS,RHS); In visitor pattern the visit method is usually void, so I can't get the expression code from LHS and RHS. Keeping shared global variables isn't an option since expression code generation is recursive thus could erase previous values kept in the variables. I'll just show the binary expression as this is the most complicated part (for now): function TLLVMCodeGenerator.GenerateExpressionCode( Expr: TASTExpression): TLLVMValue; var BinExpr: TASTBinaryExpression; UnExpr: TASTUnaryExpression; LHSCode, RHSCode, ExprCode: TLLVMValue; VarExpr: TASTVariableExpression; begin if Expr is TASTBinaryExpression then begin BinExpr := Expr as TASTBinaryExpression; LHSCode := GenerateExpressionCode(BinExpr.LHS); RHSCode := GenerateExpressionCode(BinExpr.RHS); case BinExpr.Op of '<': Result := FBuilder.CreateICmp(ccSLT, LHSCode, RHSCode); '<=': Result := FBuilder.CreateICmp(ccSLE, LHSCode, RHSCode); '>': Result := FBuilder.CreateICmp(ccSGT, LHSCode, RHSCode); '>=': Result := FBuilder.CreateICmp(ccSGE, LHSCode, RHSCode); '==': Result := FBuilder.CreateICmp(ccEQ, LHSCode, RHSCode); '<>': Result := FBuilder.CreateICmp(ccNE, LHSCode, RHSCode); '/\': Result := FBuilder.CreateAnd(LHSCode, RHSCode); '\/': Result := FBuilder.CreateOr(LHSCode, RHSCode); '+': Result := FBuilder.CreateAdd(LHSCode, RHSCode); '-': Result := FBuilder.CreateSub(LHSCode, RHSCode); '*': Result := FBuilder.CreateMul(LHSCode, RHSCode); '/': Result := FBuilder.CreateSDiv(LHSCode, RHSCode); end; end else if Expr is TASTPrimaryExpression then if Expr is TASTBooleanConstant then with Expr as TASTBooleanConstant do Result := FBuilder.CreateConstant(Ord(Value), ltI1) else if Expr is TASTIntegerConstant then with Expr as TASTIntegerConstant do Result := FBuilder.CreateConstant(Value, ltI32) else if Expr is TASTUnaryExpression then begin UnExpr := Expr as TASTUnaryExpression; ExprCode := GenerateExpressionCode(UnExpr.Expr); case UnExpr.Op of '~': Result := FBuilder.CreateXor( FBuilder.CreateConstant(1, ltI1), ExprCode); '-': Result := FBuilder.CreateSub( FBuilder.CreateConstant(0, ltI32), ExprCode); end; end else if Expr is TASTVariableExpression then begin VarExpr := Expr as TASTVariableExpression; with VarExpr.VarDecl do Result := FBuilder.CreateVar(Ident, BaseTypeLLVMTypeMap[BaseType]); end; end; Hope you understand it :)

    Read the article

  • JQuery fadeIn() moving other CSS elements on fadeIn()

    - by Infiniti Fizz
    Hi, I've just been learning some jQUery to get a basic image gallery going on a website I'm creating for a hotel but it's currently not going to plan. I've got it so the arrows will cycle through images (no animation yet) but I decided that the arrows should fade in when the image is hovered over and fade out when not but this is messing up the CSS somehow. The arrows start faded out by calling: $('.arrowRight').fadeOut(0);$('.arrowLeft').fadeOut(0); at the start of the jQuery ready() function. This is fine, but when you hover over the image and the arrows fade in, the image shifts to the right and I don't know why. I suppose it could be because the left arrow now fading in means it is getting pushed over by it but the arrow has the following css: position:relative; top: -90px; left: 25px; Should a relative element be able to alter a normal element's position? If you need to try it out, just hover over the large (placeholder) image and they image will jump across when the arrows fade in and jump back when they fade out. Any ideas why this is happening? I'm a jQuery noob. Here is a link to the page: BeanSheaf Hotel Temporary Space Thanks for your time, InfinitiFizz

    Read the article

  • How to explain to users the advantages of dumb primary key?

    - by Hao
    Primary key attractiveness I have a boss(and also users) that wants primary key to be sophisticated/smart/attractive control number(sort of like Social Security number, or credit card number format) I just padded the primary key(in Views) with zeroes to appease their desire to make the control number sophisticated,smart and attractive. But they wanted it as: first 2 digits as client code, then 4 digits as year year, then last 4 digits as transaction number on that client on a given year, then reset the transaction number of client to 1 when next year flows. Each client's transaction starts with 1. e.g. WM20090001, WM20090002, BB2009001, WM20100001, BB20100001 But as I wanted to make things as simple as possible, I forgo embedding their suggested smartness in primary key, I just keep the primary key auto increments regardless of client and year. But to make it not dull-looking(they really are adamant to make the primary key as smart control number), I made the primary key appears to them smart, on view query, I put the client code and four digit year code on front of the eight-zero padded autoincrement key, i.e. WM200900000001. Sort of slug-like information on autoincremented primary key. Keeping primary key autoincrement regardless of any other information, we are able keep other potential side effects problem when they edit a record, for example, if they made a mistake of entering the transaction on WM, then they edit the client code to BB, if we use smart primary key, the primary keys of WM customer will have gaps in their control number. Or worse yet, instead of letting the control numbers have gaps/holes, the user will request that subsequent records of that gap should shift up to that gap and have their subsequent primary keys re-adjust(decremented). How do you deal with these user requests(reasonable or otherwise)? Do you yield to their request? Or just continue using dumb primary key and explain them the repercussions of having a very smart/sophisticated primary key and educate them the significant advantages of having a dumb primary key? P.S. quotable quote(http://articles.techrepublic.com.com/5100-10878_11-1044961.html): "If you hold your tongue the first time users ask what is for them a reasonable request, things will work a lot better in the end."

    Read the article

< Previous Page | 358 359 360 361 362 363 364 365 366 367 368 369  | Next Page >