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  • My mental block - struggling to learn Objective C

    - by iqessar
    Hello people, this would be my first question after signing up! Anyway heres my question, I did Java at university and I was always told I am a good programmer. However I never pursued it as a career - I went into support and management instead. Im pretty much bored with my job, I have therefore started to learn Objective C so that I can develop apps for the iphone. I am currently watching several different Videos / Books. My problem is that when I go through the Apple documentation, although I understand most of it, sometimes I stumble. I believe that because you/we have the Apple documentation (i.e. Framework references) , everything should be clear, and therefore you should have no need to refer to a book or video (in order to learn how to use a particular class). But I alway do refer to a book and video and subsequently feel guilty as I believe the framework reference should be enough. (I therefore feel I am not up to being a programmer) I also believe that you shouldn't need example code in order to learn how to use a particular class because Apple provides documentation for each class, but AGAIN I find my self googling example code and I find my answer like that - again I feel guilty for doing this. Am I right in saying that Apple documentation is simply not clear? and that its ok to refer to a video/book or google? or forums for that matter? I have proffesional programmers who tell me that I am worrying too much and that I should get on with it and use all the resources that I have. I just cant seem to get round this mental block that I have in my head. When I start a programming project I am able to use the excellent search skills that I have to find the code I need, copy and paste it (yes I do understand it) BUT then I feel guilty telling myself that why didn't you think up the code yourself???? Therefore your not a real programmer, your just good at googling. Currently I am going through 20+ books so that I can learn most of the frameworks, syntax etc to develop iphone apps. I believe if I do this, then when I think of a project I can make it quickly. Should I read a few books, like 2-3 and then just start a project /app , and if I get stuck just google it and get the code I need? Can anybody please answer my questions?

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  • What is the typical method to separate connected letters in a word using OCR

    - by Maysam
    I am very new to OCR and almost know nothing about the algorithms used to recognize words. I am just getting familiar to that. Could anybody please advise on the typical method used to recognize and separate individual characters in connected form (I mean in a word where all letters are linked together)? Forget about handwriting, supposing the letters are connected together using a known font, what is the best method to determine each individual character in a word? When characters are written separately there is no problem, but when they are joined together, we should know where every single character starts and ends in order to go to the next step and match them individually with a letter. Is there any known algorithm for that?

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  • Where can an absolute beginner of Kohana PHP go to learn how to use it from the ground up?

    - by Sergio Tapia
    Hi guys! I have a month of free time and I've decided to launch my own website. It's going to be big and have dymanic content where different users with different roles can perform modifications to the site. Place comments, rate stores, list items, etc. This sound like a perfect opportunity for me to expand my horizons and learn a PHP Framework. I've used PHP bare bones before but nothing too complex. As of now, do you think Kohana is a mature framework to use? I've used Zend in the past for a course in Uni but it sucked horribly, I was new to the MVC model, but Zend had pretty much zero workable tutorials and guides for newbies. That's why I hated it. Where can I go to learn how to use Kohana from a retarded starting point? Thank you very much for your time.

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  • How big can I make an Android application's canvas in terms of pixels?

    - by user279112
    I've determined an estimate of the size of my Android emulator's screen in pixels, although I think its resolution can be changed to other numbers. Quite frankly though that doesn't eliminate the general problem of not knowing how many pixels on each axis I have to work with on my Android applications in general. The main problem I'm trying to solve is this: How do I make sure I don't use a faulty resolution on Android applications if I want to keep things' sizes constant (so that if the application screen shrinks, for instances, objects will still show up just as big - there just won't be as many of them being shown) if I wish to do this with a single universal resolution for each program? Failing that, how do I make sure everything's alright if I try to do everything the same way with maybe a few different pre-set resolutions? Mainly it seems like a relevant question that must be answered before I can come across a complete answer for the general problem is how big can I always make my application in pixels, NOT regarding if and when a user resizes the application's screen to something smaller than the maximum size permitted by the phone and its operating system. I really want to try to keep this simple. If I were doing this for a modern desktop, for instance, I know that if I design the application with a 800x600 canvas, the user can still shrink the application to the point they're not doing themselves any favors, but at least I can basically count on it working right and not being too big for the monitor or something. Is there such a magic resolution for Android, assuming that I'm designing for API levels 3+ (Android 1.5+)? Thanks

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  • Looking for resources for learning SharePoint Foundation on the Internet

    - by Kabeer
    Hello. While I am quite comfortable with the .Net world, I am a baby as far as SharePoint technologies are concerned. With the advent of SharePoint 2010 (Foundation especially), I'd like to directly learn the new version. However, I am not getting enough resources on the Internet that can be helpful. Besides knowing to maneuver a SharePoint site, I'd like to understand stuff under the hood from the architecture standpoint and subsequently the APIs. Can the community please guide me to the most suitable resource(s) available on the Internet?

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  • Flash / Actionscript wheel

    - by Shaun
    Hi, I have been asked to create a wheel for navigation similar to on the Visit Provence website. However, I don't know where to start and my Googling effort have been unsuccessful - I guess that I am searching using the wrong terms. It the the way that the wheel moves and interacts with the other segments around it that interests me. I'd really appreciate any tutorials / help that anyone can share.

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  • Ruby on Rails tutorial problem

    - by RailAddict
    Quick question which I hope is easily answered.. I am following this tutorial: http://oreilly.com/pub/a/ruby/archive/rails.html?page=2 and all is going well until I try create a controller and view it in my browser. The server is running and it shows the default page okay (http://127.0.0.1:3000). I ran ruby script\generate controller MyTest in my command line and it generated the correct folders and files. The problem is, when I go to http://127.0.0.1:3000/My%5FTest/ it says: We're sorry, but something went wrong. We've been notified about this issue and we'll take a look at it shortly. This must be something I have overlooked somewhere. Any help is appreciated! ruby 1.8.6 rails 2.3.4 Just checked my development logs. Here is what it says: /!\ FAILSAFE /!\ Thu Sep 24 02:21:04 +0100 2009 Status: 500 Internal Server Error no such file to load -- sqlite3 C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require' C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in require' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active_support/dependencies.rb:156:in require' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active_support/dependencies.rb:521:in new_constants_in' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active_support/dependencies.rb:156:in require' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active_support/core_ext/kernel/requires.rb:7:in require_library_or_gem' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active_support/core_ext/kernel/reporting.rb:11:in silence_warnings' C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.4/lib/active_support/core_ext/kernel/requires.rb:5:in require_library_or_gem' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/sqlite3_adapter.rb:10:in sqlite3_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:223:in send' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:223:in new_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:245:in checkout_new_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:188:in checkout' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:184:in loop' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:184:in checkout' C:/Ruby/lib/ruby/1.8/monitor.rb:242:in synchronize' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:183:in checkout' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:98:in connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:326:in retrieve_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_specification.rb:123:in retrieve_connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_specification.rb:115:in connection' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/query_cache.rb:9:in cache' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/query_cache.rb:28:in call' C:/Ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:361:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/head.rb:9:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/methodoverride.rb:24:in call' C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.4/lib/action_controller/params_parser.rb:15:in call' C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.4/lib/action_controller/session/cookie_store.rb:93:in call' C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.4/lib/action_controller/failsafe.rb:26:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/lock.rb:11:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/lock.rb:11:in synchronize' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/lock.rb:11:in call' C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.4/lib/action_controller/dispatcher.rb:114:in call' C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.4/lib/action_controller/reloader.rb:34:in run' C:/Ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.4/lib/action_controller/dispatcher.rb:108:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.4/lib/rails/rack/static.rb:31:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/urlmap.rb:46:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/urlmap.rb:40:in each' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/urlmap.rb:40:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.4/lib/rails/rack/log_tailer.rb:17:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/content_length.rb:13:in call' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/handler/webrick.rb:46:in service' C:/Ruby/lib/ruby/1.8/webrick/httpserver.rb:104:in service' C:/Ruby/lib/ruby/1.8/webrick/httpserver.rb:65:in run' C:/Ruby/lib/ruby/1.8/webrick/server.rb:173:in start_thread' C:/Ruby/lib/ruby/1.8/webrick/server.rb:162:in start' C:/Ruby/lib/ruby/1.8/webrick/server.rb:162:in start_thread' C:/Ruby/lib/ruby/1.8/webrick/server.rb:95:in start' C:/Ruby/lib/ruby/1.8/webrick/server.rb:92:in each' C:/Ruby/lib/ruby/1.8/webrick/server.rb:92:in start' C:/Ruby/lib/ruby/1.8/webrick/server.rb:23:in start' C:/Ruby/lib/ruby/1.8/webrick/server.rb:82:in start' C:/Ruby/lib/ruby/gems/1.8/gems/rack-1.0.0/lib/rack/handler/webrick.rb:13:in run' C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.4/lib/commands/server.rb:111 C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in gem_original_require' C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require' script/server:3 I have no idea what this means but one thing I noticed is that it says sqlite3 - I am not using that. I am using MySql. Not sure if this is the problem..

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  • Why does calling IEnumerable<string>.Count() create an additional assembly dependency ?

    - by Gishu
    Assume this chain of dll references Tests.dll >> Automation.dll >> White.Core.dll with the following line of code in Tests.dll, where everything builds result.MissingPaths Now when I change this to result.MissingPaths.Count() I get the following build error for Tests.dll "White.UIItem is not defined in an assembly that is not referenced. You must add a reference to White.Core.dll." And I don't want to do that because it breaks my layering. Here is the type definition for result, which is in Automation.dll public class HasResult { public HasResult(IEnumerable<string> missingPaths ) { MissingPaths = missingPaths; } public IEnumerable<string> MissingPaths { get; set; } public bool AllExist { get { return !MissingPaths.Any(); } } } Down the call chain the input param to this ctor is created via (The TreeNode class is in White.Core.dll) assetPaths.Where(assetPath => !FindTreeNodeUsingCache(treeHandle, assetPath)); Why does this dependency leak when calling Count() on IEnumerable ? I then suspected that lazy evaluation was causing this (for some reason) - so I slotted in an ToArray() in the above line but didn't work. Update 2011 01 07: Curiouser and Curiouser! it won't build until I add a White.Core reference. So I add a reference and build it (in order to find the elusive dependency source). Open it up in Reflector and the only references listed are Automation, mscorlib, System.core and NUnit. So the compiler threw away the White reference as it was not needed. ILDASM also confirms that there is no White AssemblyRef entry. Any ideas on how to get to the bottom of this thing (primarily for 'now I wanna know why' reasons)? What are the chances that this is an VS2010/MSBuild bug? Update 2011 01 07 #2 As per Shimmy's suggestion, tried calling the method explcitly as an extension method Enumerable.Count(result.MissingPaths) and it stops cribbing (not sure why). However I moved some code around after that and now I'm getting the same issue at a different location using IEnumerable - this time reading and filtering lines out of a file on disk (totally unrelated to White). Seems like it's a 'symptom-fix'. var lines = File.ReadLines(aFilePath).ToArray(); once again, if I remove the ToArray() it compiles again - it seems that any method that causes the enumerable to be evaluated (ToArray, Count, ToList, etc.) causes this. Let me try and get a working tiny-app to demo this issue... Update 2011 01 07 #3 Phew! More information.. It turns out the problem is just in one source file - this file is LINQ-phobic. Any call to an Enumerable extension method has to be explicitly called out. The refactorings that I did caused a new method to be moved into this source file, which had some LINQ :) Still no clue as to why this class dislikes LINQ. using System; using System.Collections.Generic; using System.IO; using System.Linq; using G.S.OurAutomation.Constants; using G.S.OurAutomation.Framework; using NUnit.Framework; namespace G.S.AcceptanceTests { public abstract class ConfigureThingBase : OurTestFixture { .... private static IEnumerable<string> GetExpectedThingsFor(string param) { // even this won't compile - although it compiles fine in an adjoining source file in the same assembly //IEnumerable<string> s = new string[0]; //Console.WriteLine(s.Count()); // this is the line that is now causing a build failure // var expectedInfo = File.ReadLines(someCsvFilePath)) // .Where(line => !line.StartsWith("REM", StringComparison.InvariantCultureIgnoreCase)) // .Select(line => line.Replace("%PLACEHOLDER%", param)) // .ToArray(); // Unrolling the LINQ above removes the build error var expectedInfo = Enumerable.ToArray( Enumerable.Select( Enumerable.Where( File.ReadLines(someCsvFilePath)), line => !line.StartsWith("REM", StringComparison.InvariantCultureIgnoreCase)), line => line.Replace("%PLACEHOLDER%", param)));

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  • Play 2.0 javaToDo tutorial doesn't compile

    - by chsn
    I'm trying to follow the Play2.0 JavaToDO tutorial and for some reason it just doesn't want to work. Have looked through stackoverflow and other online resources, but haven't find an answer to this and it's driving me crazy. Attached code of the Application.java package controllers; import models.Task; import play.data.Form; import play.mvc.Controller; import play.mvc.Result; public class Application extends Controller { static Form<Task> taskForm = form(Task.class); public static Result index() { return redirect(routes.Application.tasks()); } public static Result tasks() { return ok( views.html.index.render(Task.all(), taskForm)); } public static Result newTask() { return TODO; } public static Result deleteTask(Long id) { return TODO; } } Attached code of the Task java package models; import java.util.List; import javax.persistence.Entity; import play.data.Form; import play.data.validation.Constraints.Required; import play.db.ebean.Model.Finder; import play.mvc.Result; import controllers.routes; @Entity public class Task { public Long id; @Required public String label; // search public static Finder<Long,Task> find = new Finder( Long.class, Task.class); // display tasks public static List<Task> all() { return find.all(); } // create task public static void create(Task task) { task.create(task); } // delete task public static void delete(Long id) { find.ref(id).delete(id); // find.ref(id).delete(); } // create new task public static Result newTask() { Form<Task> filledForm = taskForm.bindFromRequest(); if(filledForm.hasErrors()) { return badRequest( views.html.index.render(Task.all(), filledForm) ); } else { Task.create(filledForm.get()); return redirect(routes.Application.tasks()); } } } I get a compile error on Task.java on the line static Form<Task> taskForm = form(Task.class); As I'm working on eclipse (the project is eclipsified before import), it's telling me that taskForm cannot be resolved and it also underlines every play 2 command e.g. "render(), redirect(), bindFromRequest()" asking me to create a method for it. Any ideas how to solve the compilations error and also how to get Eclipse to recognize the play2 commands? EDIT: updated Application.java package controllers; import models.Task; import play.data.Form; import play.mvc.Controller; import play.mvc.Result; public class Application extends Controller { // create new task public static Result newTask() { Form<Task> filledForm = form(Task.class).bindFromRequest(); if(filledForm.hasErrors()) { return badRequest( views.html.index.render(Task.all(), filledForm) ); } else { Task.newTask(filledForm.get()); return redirect(routes.Application.tasks()); } } public static Result index() { return redirect(routes.Application.tasks()); } public static Result tasks() { return ok( views.html.index.render(Task.all(), taskForm)); } public static Result deleteTask(Long id) { return TODO; } } Updated task.java package models; import java.util.List; import javax.persistence.Entity; import play.data.Form; import play.data.validation.Constraints.Required; import play.db.ebean.Model; import play.db.ebean.Model.Finder; import play.mvc.Result; import controllers.routes; @Entity public class Task extends Model { public Long id; @Required public String label; // Define a taskForm static Form<Task> taskForm = form(Task.class); // search public static Finder<Long,Task> find = new Finder( Long.class, Task.class); // display tasks public static List<Task> all() { return find.all(); } // create new task public static Result newTask(Task newTask) { save(task); } // delete task public static void delete(Long id) { find.ref(id).delete(id); // find.ref(id).delete(); } }

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  • How can I create a generaic ValidationAttribute in C#?

    - by sabbour
    I'm trying to create a UniqueAttribute using the System.ComponentModel.DataAnnotations.ValidationAttribute I want this to be generic as in I could pass the Linq DataContext, the table name, the field and validate if the incoming value is unique or not. Here is a non-compilable code fragment that I'm stuck at right now: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.ComponentModel.DataAnnotations; using System.Data.Linq; using System.ComponentModel; namespace LinkDev.Innovation.Miscellaneous.Validation.Attributes { public class UniqueAttribute : ValidationAttribute { public string Field { get; set; } public override bool IsValid(object value) { string str = (string)value; if (String.IsNullOrEmpty(str)) return true; // this is where I'm stuck return (!Table.Where(entity => entity.Field.Equals(str)).Any()); } } } I should be using this in my model as follows: [Required] [StringLength(10)] [Unique(new DataContext(),"Groups","name")] public string name { get; set; }

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  • Subsonic 3.0.0.4 Does not Update

    - by geocine
    I tried 3 variants but doesn't seem to update (I am using Linq Templates and MSSQL) Luna.Data.GameDBDB db = new Luna.Data.GameDBDB(); db.Update<Luna.Record.TB_ITEM>() .Set(x => x.ITEM_DURABILITY == Convert.ToInt32(quantity)) .Where(x => x.ITEM_DBIDX == Convert.ToInt32(dbdidx)) .Execute(); Here is the other one var db = new Luna.Data.GameDBDB(); var query = (from p in db.TB_ITEMS where p.ITEM_DBIDX == Convert.ToInt32(dbidx) select p).Single(); query.ITEM_DURABILITY = Convert.ToInt32(quantity); db.tp TP_ITEM_UPDATE(); and the other one var db = new Luna.Data.GameDBDB(); var query = (from p in db.TB_ITEMS where p.ITEM_DBIDX == Convert.ToInt32(dbidx) select p).Single(); query.ITEM_DURABILITY = Convert.ToInt32(quantity); db.Update<Luna.Data.TB_ITEM>(); However it worked using LINQ-to-SQL LunaDataContext db = new LunaDataContext(); var query = (from p in db.TB_ITEMs where p.ITEM_DBIDX == Convert.ToInt32(dbidx) select p).Single(); query.ITEM_DURABILITY = Convert.ToInt32(quantity); db.SubmitChanges(); Is this a bug in 3.0.0.4, the database record couldn't be updated using Linq Templates and ActiveRecord.

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  • An unhandled exception of type 'System.StackOverflowException' occurred in mscorlib.dll

    - by mazhar
    Ok the thing is that I am using asp.net mvc with linq to sql. I have a scenario where there are two tables group and features with many to many relationship with the third table groupfeatures. I have drag and drop all three table in the dbml file. The thing is that it runs fine with group but when I call the Feature things the above error occured and the compilers stops at this line in ((())). public partial class EgovtDataContext : System.Data.Linq.DataContext { private static System.Data.Linq.Mapping.MappingSource mappingSource = new AttributeMappingSource(); #region Extensibility Method Definitions partial void OnCreated(); partial void InsertGroup(Group instance); partial void UpdateGroup(Group instance); partial void DeleteGroup(Group instance); partial void InsertFeature(Feature instance); partial void UpdateFeature(Feature instance); partial void DeleteFeature(Feature instance); partial void InsertGroupFeature(GroupFeature instance); partial void UpdateGroupFeature(GroupFeature instance); partial void DeleteGroupFeature(GroupFeature instance); #endregion (((public EgovtDataContext() : base(global::System.Configuration.ConfigurationManager.ConnectionStrings["egovtsConnectionString"].ConnectionString, mappingSource)))) The code in both the controller Group and features file is ditto copied. Note the group things are working, the features things are not. FeaturesRepository.cs public IQueryable<Feature> FindAllFeatures() { return db.Features; } FeaturesController.cs FeaturesRepository FeatureRepository = new FeaturesRepository(); public ActionResult Index() { var Feature = FeatureRepository.FindAllFeatures(); return View(Feature); } So what could be wrong?

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  • Specifying ASP.NET MVC attributes for auto-generated data models

    - by Lyubomyr Shaydariv
    Hello to everyone. I'm very new to ASP.NET MVC (as well as ASP.NET in general), and going to gain some knowledge for this technology, so I'm sorry I can ask some trivial questions. I have installed ASP.NET MVC 3 RC1 and I'm trying to do the following. Let's consider that I have a model that's completely auto-generated from a table using the "LINQ to SQL Classes" template in VS2010. The template generates 3 files (two .cs files and one .layout file respectively), and the generated partial class is expected to be used as an MVC model. Let's also consider, a single DB column, that's mapped into the model, may look like this: [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_Name", DbType = "VarChar(128)")] public string Name { get { return this._Name; } set { if ( (this._Name != value) ) { // ... generated stuff goes here } } } The ASP.NET MVC engine also provides a beautiful declarative way to specify some additional stuff, like RequiredAttribute, DisplayNameAttribute and other nice attributes. But since the mapped model is a purely auto-genereated model, I've realized that I should not change the model manually, and specify the fields like: [Required] [DisplayName("Project name")] [StringLength(128)] [global::System.Data.Linq.Mapping.ColumnAttribute(Storage = "_Name", DbType = "VarChar(128)")] public string Name { ... though this approach works perfectly... until I change the model in the DBML-designer removing the ASP.NET MVC attributes automatically. So, how do I specify ASP.NET MVC attributes for the DBML models and their fields safely? Thanks in advance, and Merry Christmas.

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  • Problem with Unit testing of ASP.NET project (NullReferenceException when running the test)

    - by Alex
    Hi, I'm trying to create a bunch of MS visual studio unit tests for my n-tiered web app but for some reason I can't run those tests and I get the following error - "Object reference not set to an instance of an object" What I'm trying to do is testing of my data access layer where I use LINQ data context class to execute a certain function and return a result,however during the debugging process I found out that all the tests fail as soon as they get to the LINQ data context class and it has something to do with the connection string but I cant figure out what is the problem. The debugging of tests fails here(the second line): public EICDataClassesDataContext() : base(global::System.Configuration.ConfigurationManager.ConnectionStrings["EICDatabaseConnectionString"].ConnectionString, mappingSource) { OnCreated(); } And my test is as follows: TestMethod()] public void OnGetCustomerIDTest() { FrontLineStaffDataAccess target = new FrontLineStaffDataAccess(); // TODO: Initialize to an appropriate value string regNo = "jonh"; // TODO: Initialize to an appropriate value int expected = 10; // TODO: Initialize to an appropriate value int actual; actual = target.OnGetCustomerID(regNo); Assert.AreEqual(expected, actual); } The method which I call from DAL is: public int OnGetCustomerID(string regNo) { using (LINQDataAccess.EICDataClassesDataContext dataContext = new LINQDataAccess.EICDataClassesDataContext()) { IEnumerable<LINQDataAccess.GetCustomerIDResult> sProcCustomerIDResult = dataContext.GetCustomerID(regNo); int customerID = sProcCustomerIDResult.First().CustomerID; return customerID; } } So basically everything fails after it reaches the 1st line of DA layer method and when it tries to instantiate the LINQ data access class... I've spent around 10 hours trying to troubleshoot the problem but no result...I would really appreciate any help! UPDATE: Finally I've fixed this!!!!:) I dont know why but for some reasons in the app.config file the connection to my database was as follows: AttachDbFilename=|DataDirectory|\EICDatabase.MDF So what I did is I just changed the path and instead of |DataDirectory| I put the actual path where my MDF file sits,i.e C:\Users\1\Documents\Visual Studio 2008\Projects\EICWebSystem\EICWebSystem\App_Data\EICDatabase.mdf After I had done that it worked out!But still it's a bit not clear what was the problem...probably incorrect path to the database?My web.config of ASP.NET project contains the |DataDirectory|\EICDatabase.MDF path though..

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  • Using LinqExtender to make OData feed fails

    - by BurningIce
    A pretty simple question, has anyone here tried to make a OData feed based on a IQueryable created with LinqExtender? I have created a simple Linq-provider that supports Where, Select, OrderBy and Take and wanted to expose it as an OData Feed. I keep getting an error though, and the Exception is a NullReference with the following StackTrace at System.Data.Services.Serializers.Serializer.GetObjectKey(Object resource, IDataServiceProvider provider, String containerName) at System.Data.Services.Serializers.Serializer.GetUri(Object resource, IDataServiceProvider provider, ResourceContainer container, Uri absoluteServiceUri) at System.Data.Services.Serializers.SyndicationSerializer.WriteEntryElement(IExpandedResult expanded, Object element, Type expectedType, Uri absoluteUri, String relativeUri, SyndicationItem target) at System.Data.Services.Serializers.SyndicationSerializer.<DeferredFeedItems>d__0.MoveNext() at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteItems(XmlWriter writer, IEnumerable`1 items, Uri feedBaseUri) at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteFeedTo(XmlWriter writer, SyndicationFeed feed, Boolean isSourceFeed) at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteFeed(XmlWriter writer) at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteTo(XmlWriter writer) at System.Data.Services.Serializers.SyndicationSerializer.WriteTopLevelElements(IExpandedResult expanded, IEnumerator elements, Boolean hasMoved) at System.Data.Services.Serializers.Serializer.WriteRequest(IEnumerator queryResults, Boolean hasMoved) at System.Data.Services.ResponseBodyWriter.Write(Stream stream) I've kinda narrowed it down to a issue where LinqExtender wraps every returned object, so that my object actually inherits itself - thats at least how it looks like in the debugger. These two queries are basicly the same. The first is the legacy-api where the OrderBy and Select is regular Linq to Objects. The second query is a "real" linq-provider made with LinqExtender. var db = CalendarDataProvider.GetCalendarEntriesByDate(DateTime.Now, DateTime.Now.AddMonths(1), Guid.Empty) .OrderBy(o => o.Title) .Select(o => new ODataCalendarEntry(o)); var query = new ODataCalendarEntryQuery() .Where(o => o.Start > DateTime.Now && o.End < DateTime.Now.AddMonths(1)) .OrderBy(o => o.Title); When returning db for the OData feed everything is fine, but returning query throws a NullRefenceException. I've tried all kind of tricks and even tried to project all the data into a new object like this, but still the same error return query.Select(o => new ODataCalendarEntry { Title = o.Title, Start = o.Start, End = o.End, Name = o.Name });

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  • F# List SelectMany

    - by Tuomas Hietanen
    This is quite simple question but I didn't find an answer: Is there any Seq/List operation in F# to match the LINQ SelectMany? I know I can use System.Linq in F# if I want to. I know I can make a recursive method and use F# Computation Expressions (and make even more powerful things). But if I try to prove that F# List operations are more powerful than LINQ... .Where = List.filter .Select = List.map .Aggregate = List.fold ... In C# SelectMany usage syntax is pretty simple: var flattenedList = from i in items1 from j in items2 select ... Is there any easy direct match, List.flatten, List.bind or something like that? SelectMany has a couple of signatures, but the most complex one seems to be: IEnumerable<TResult> SelectMany<TSource, TCollection, TResult>( this IEnumerable<TSource> source, Func<TSource, IEnumerable<TCollection>> collectionSelector, Func<TSource, TCollection, TResult> resultSelector ); In F# terms this would be: ('a -> 'b list) -> ('a -> 'b -> 'c) -> 'a list -> 'c list

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  • How can I make this LinqToSQL query work? (SqlExecption)

    - by kversch
    The following code gives me an SqlException: OO theCourse = subject.Course; var students = dc.studentsCourses.Where(x = x.course == theCourse).Select(x = x.student); "Invalid object name 'dbo.studentsCourses'." I tried the following code instead but I also get an Exception. My original question was asked on Aardvark and can be read bellow: var allStudents = from s in dc.students select s; List thestudents = new List(); foreach (student s in allStudents) { if (s.courses.Contains(theCourse)) { thestudents.Add(s); } } I did a right click, "run custom tool" on my dbml and checked my names of my tables and entities. The project compiles but I get an Exception at runtime on this line: "if (s.courses.Contains(theCourse))" Any ideas? Original question on Aardvark: How do I do a LinqToSQL query that gives me this: I want to select all students that attended a certain lesson. The lesson is from a certain course. So select the course the lesson is from. Now select all the students that are following that course. There is a many-to-many relationship between the students and the courses table in my DB. I already extended my LINQ entities to be able to select student.Courses and course.Students using this method: http://www.codeproject.com/KB/linq/linq-to-sql-many-to-many.aspx

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  • How can I check if a user has written his username and password correctly?

    - by Sergio Tapia
    I'm using a Linq-to-SQL class called Scans.dbml. In that class I've dragged a table called Users (username, password, role) onto the graphic area and now I can access User object via a UserRepository class: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Scanner.Classes { public class UserRepository { private ScansDataContext db = new ScansDataContext(); public User getUser(string username) { return db.Users.SingleOrDefault(x => x.username == username); } public bool exists(string username) { } } } Now in my Login form, I want to use this Linq-to-SQL goodness to do all the data related activities. UserRepository users = new UserRepository(); private void btnLogin_Click(object sender, EventArgs e) { loginToSystem(); } private void loginToSystem() { if (users.getUser(txtUsername.Text)) { } //If txtUsername exists && User.password == Salt(txtPassword) //then Show.MainForm() with User.accountType in constructor to set permissions. } I need help with verifying that a user exists && that that users.password is equal to SALT(txtpassword.text). Any guidance please?

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  • Dynamically Run IQueryable Method

    - by Micah
    Hi! I'm trying to run the Count() function of a Linq statement in an overriden Gridview function. Basically, I want to be able to assign a linq query to a gridview, and on the OnDataBound(e) event in my new extended gridview have it retrieve the count, using the IQueryable. This is where I'm at so far: protected override void OnDataBound(EventArgs e) { IEnumerable _data = null; if (this.DataSource is IQueryable) { _data = (IQueryable)this.DataSource; } System.Type dataSourceType = _data.GetType(); System.Type dataItemType = typeof(object); if (dataSourceType.HasElementType) { dataItemType = dataSourceType.GetElementType(); } else if (dataSourceType.IsGenericType) { dataItemType = dataSourceType.GetGenericArguments()[0]; } else if (_data is IEnumerable) { IEnumerator dataEnumerator = _data.GetEnumerator(); if (dataEnumerator.MoveNext() && dataEnumerator.Current != null) { dataItemType = dataEnumerator.Current.GetType(); } } Object o = Activator.CreateInstance(dataItemType); object[] objArray = new object[] { o }; RowCount = (int)dataSourceType.GetMethod("Count").Invoke(_data, objArray); Any ideas? I'm really new with working with IQueryables and Linq so I may be way off. How can I get my _data to allow me to run the Count function?

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  • How to start with entity framework and service oriented architecture?

    - by citronas
    At work I need to create a new web application, that will connection to an MySql Database. (So far I only have expercience with Linq-To-Sql classes and MSSQL Servers.) My superior tells me to use the entity framework (he probably refers to Linq-To-Entity) and provide everything as a service based architecture. Unfortunatly nobody at work has experience with that framework and with a real nice server oriented architecture. (till now no customer wanted to pay for architecture that he can't see. This speficic project I'm leading will be long-term, meaning multiple years, so it would be best to design it the way, that multiple targetting plattforms like asp.net, c# wpf, ... could use it) For now, the main target plattform is ASP.net So I do have the following questions: 1) Where can I read best what's really behind service oriented architecture (but for now beginner tutorials work fine as well) and how to do it in best practise? 2) So far I can't seem a real difference between Linq-To-Sql classes and the information I've google so far on the 'entity framework'. So, whats the difference? Where do I find nice tutorials for it. 3) Is there any difference in the entity framework regarding the database server (MSSQL or MySQL). If not, does that mean that code snipperts I will stumble across will word database independent? 4) I do you Visual Studio 2010. Do I have to regard something specific?

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  • Populate JOIN into a list in one database query

    - by axio
    I am trying to get the records from the 'many' table of a one-to-many relationship and add them as a list to the relevant record from the 'one' table. I am also trying to do this in a single database request. Code derived from http://stackoverflow.com/questions/1580199/linq-to-sql-populate-join-result-into-a-list almost achieves the intended result, but makes one database request per entry in the 'one' table which is unacceptable. That failing code is here: var res = from variable in _dc.GetTable<VARIABLE>() select new { x = variable, y = variable.VARIABLE_VALUEs }; However if I do a similar query but loop through all the results, then only a single database request is made. This code achieves all goals: var res = from variable in _dc.GetTable<VARIABLE>() select variable; List<GDO.Variable> output = new List<GDO.Variable>(); foreach (var v2 in res) { List<GDO.VariableValue> values = new List<GDO.VariableValue>(); foreach (var vv in v2.VARIABLE_VALUEs) { values.Add(VariableValue.EntityToGDO(vv)); } output.Add(EntityToGDO(v2)); output[output.Count - 1].VariableValues = values; } However the latter code is ugly as hell, and it really feels like something that should be do-able in a single linq query. So, how can this be done in a single linq query that makes only a single database query? In both cases the table is set to preload using the following code: _dc = _db.CreateLinqDataContext(); var loadOptions = new DataLoadOptions(); loadOptions.LoadWith<VARIABLE>(v => v.VARIABLE_VALUEs); _dc.LoadOptions = loadOptions; I am using .NET 3.5, and the database back-end was generated using SqlMetal.

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