Search Results

Search found 1238 results on 50 pages for 'ienumerable'.

Page 34/50 | < Previous Page | 30 31 32 33 34 35 36 37 38 39 40 41  | Next Page >

  • How to rewrite the following?(C#3.0)

    - by Newbie
    I am trying to write the following double sum_res = 0.0; double yhat = 0; double res = 0; int n = 0; for(int i=0;i<x.Count;i++) { yhat = inter + (slp*x[i]); res = yhat - y[i]; n++; } using lambda but somehow not able to get it work(compile time error) Enumerable.Range(0, x.Count).Select(i => { yhat = inter + (slp * x[i]); res = yhat - y[i]; sum_res += res * res; n++; }); Error: The type arguments for method 'System.Linq.Enumerable.Select(System.Collections.Generic.IEnumerable, System.Func)' cannot be inferred from the usage. Try specifying the type arguments explicitly. Help needed. Thanks

    Read the article

  • How to ignore an exception and continue processing a foreach loop?

    - by Barry Dysert
    I have a test program that is supposed to loop over all the files under C:. It dies when it hits the "Documents and Settings" folder. I'd like to ignore the error and keep looping over the remaining files. The problem is that the exception is thrown in the foreach, so putting a try/catch around the foreach will cause the loop to exit. And putting a try/catch after the foreach never fires (because the exception is thrown in the foreach). Is there any way to ignore the exception and continue processing the loop? Here's the code: static void Main(string[] args) { IEnumerable<string> files = Directory.EnumerateFiles(@"C:\", "*.*", SearchOption.AllDirectories); foreach (string file in files) // Exception occurs when evaluating "file" Console.WriteLine(file); }

    Read the article

  • dynamically build Intersect statement ASP.NET

    - by TDDG
    I would like to use the IEnumerable function Intersect() to combine a few list and get the similar integers from each list. The problem I'm faced with is that I don't know how many list I will need to compare. Here is an example: A{1,2,3,4} B{1,2,3} C{1,2} results = A.Intersect(B).Intersect(C) This works great, but the next time around I may have a D{1,2} next time I come across the function. I'd like to use the Intersect method, but I'm open to new ideas as well.

    Read the article

  • How does OfType<T>() Work?

    - by TheCloudlessSky
    How does OfType() Work? I read this link about what's going on but how exactly does the LINQ provider know how to get all objects matching the specified type. I know the IQueryable<T> "chains" up requests and then evaluates when GetEnumerator() is called (right?). Specifically I want to know how does the framework quickly do type comparison? I wrote a method in a .NET 2.0 project that went like this (since 2.0 doesn't support these kind of features): public IEnumerable<TResult> OfType<TResult>() where TResult : class { foreach (TItem item in this.InnerList) { TResult matchItem = item as TResult; if (matchItem != null) { yield return matchItem; } } } Is this the best implementation?

    Read the article

  • List.clear() followed by List.add() not working.

    - by Vincent
    I have the following C# Class/Function: class Hand { private List<Card> myCards = new List<Card>(); public void sortBySuitValue() { IEnumerable<Card> query = from s in myCards orderby (int)s.suit, (int)s.value select s; myCards = new List<Card>(); myCards.AddRange(query); } } On a card Game. This works fine, however, I had trouble at first, instead of using myCards = new List(); to 'reset' myCards, I would use myCards.clear(), however, once I called the clear function, I would not be able to call myCards.add() or myCards.addRange(). The count would stay at zero. Is my current approach good? Is using LINQ to sort my cards good/bad?

    Read the article

  • get look up a string given a func<T,object> param

    - by Sammy
    given this code namespace GridTests { public class Grid<T> { IEnumerable<T> DataSource { get; set; } IList<Column> Columns = new List<Column>(); class Column { public string DisplayText { get; set; } Func<T, object> Rowdata { get; set; } } } } I need to be able to loop through the columns collection and get the Rowdata's object value using the DisplayText. Thanks

    Read the article

  • Problem in populating a dictionary object using Enumerable.Range() (C#3.0)

    - by Newbie
    If I do for (int i = 0; i < appSettings.Count; i++) { string key = appSettings.Keys[i]; euFileDictionary.Add(key, appSettings[i]); } It is working fine. When I am trying the same thing using Enumerable.Range(0, appSettings.Count).Select(i => { string Key = appSettings.Keys[i]; string Value = appSettings[i]; euFileDictionary.Add(Key, Value); }).ToDictionary<string,string>(); I am getting a compile time error The type arguments for method 'System.Linq.Enumerable.Select(System.Collections.Generic.IEnumerable, System.Func)' cannot be inferred from the usage. Try specifying the type arguments explicitly. Any idea? Using C#3.0 Thanks

    Read the article

  • Search a List inside another with IQueryable

    - by ovini poornima
    public static IQueryable<Institution> WithFunds(this IQueryable<Institution> query, IEnumerable<Fund> allowedFunds) { return query. } I want to get the query to return all Institutions having any of the Fund given in 'allowedFunds' list in Institution.Funds. Please help. My class hierarchy goes like this. public partial class Institution { public int Id { get; set; } public virtual ICollection<Fund> Funds { get; set; } } public partial class Fund { public int Id { get; set; } public virtual Institution Institution { get; set; } }

    Read the article

  • DropDownList and ViewData

    - by Petko Xyz
    In my controller I have: Category x = new Category(1, "prva", 0); Category y = new Category(2, "vtora", 1); Category z = new Category(3, "treta", 1); List<Category> categories = new List<Category>(); categories.Add(x); categories.Add(y); categories.Add(z); ViewData["categories"] = categories; And in my view I have: <%= Html.DropDownList("categories")%> But I have an error: The ViewData item that has the key 'categories' is of type 'System.Collections.Generic.List`1[[Category, MvcApplication1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]' but must be of type 'IEnumerable'. Uggggghhh how to resolve this?

    Read the article

  • What is wrong with the below statement(C#3.0 / Lambda)

    - by Newbie
    what is wrong in the below Enumerable.Range(0, objEntityCode.Count - 1).Select(i => { options.Attributes[i] = new EntityCodeKey { EntityCode = objEntityCode[i].EntityCodes , OrganizationCode = Constants.ORGANIZATION_CODE }; }) .ToArray(); Throwing error The type arguments for method 'System.Linq.Enumerable.Select(System.Collections.Generic.IEnumerable, System.Func)' cannot be inferred from the usage. Try specifying the type arguments explicitly. But this works Enumerable.Range(0, objEntityCode.Count - 1).ToList().ForEach(i => { options.Attributes[i] = new EntityCodeKey { EntityCode = objEntityCode[i].EntityCodes , OrganizationCode = Constants.ORGANIZATION_CODE }; } ); Using C#3.0. Purpose: I am learning LINQ / LAMBDA and trying to do the same program in different way. Thanks.

    Read the article

  • Get all Methods with a given return type

    - by Aren B
    Is this code wrong? It's just not returning anything: public IEnumerable<string> GetMethodsOfReturnType(Type cls, Type ret) { var methods = cls.GetMethods(BindingFlags.NonPublic); var retMethods = methods.Where(m => m.ReturnType.IsSubclassOf(ret)) .Select(m => m.Name); return retMethods; } It's returning an empty enumerator. Note: I'm calling it on a ASP.NET MVC Controller looking for ActionResults GetMethodsOfReturnType(typeof(ProductsController), typeof(ActionResult));

    Read the article

  • How do I select the item with the highest value using LINQ?

    - by mafutrct
    Imagine you got a class like this: class Foo { string key; int value; } How would you select the Foo with the highest value from an IEnumeralbe<Foo>? A basic problem is to keep the number of iterations low (i.e. at 1), but that affects readability. After all, the best I could find was something along the lines of this: IEnumerable<Foo> list; Foo max = list.Aggregate ((l, r) => l.value > r.value ? l : r); Can you think of a more better way?

    Read the article

  • ASP.NET Web API - Screencast series Part 2: Getting Data

    - by Jon Galloway
    We're continuing a six part series on ASP.NET Web API that accompanies the getting started screencast series. This is an introductory screencast series that walks through from File / New Project to some more advanced scenarios like Custom Validation and Authorization. The screencast videos are all short (3-5 minutes) and the sample code for the series is both available for download and browsable online. I did the screencasts, but the samples were written by the ASP.NET Web API team. In Part 1 we looked at what ASP.NET Web API is, why you'd care, did the File / New Project thing, and did some basic HTTP testing using browser F12 developer tools. This second screencast starts to build out the Comments example - a JSON API that's accessed via jQuery. This sample uses a simple in-memory repository. At this early stage, the GET /api/values/ just returns an IEnumerable<Comment>. In part 4 we'll add on paging and filtering, and it gets more interesting.   The get by id (e.g. GET /api/values/5) case is a little more interesting. The method just returns a Comment if the Comment ID is valid, but if it's not found we throw an HttpResponseException with the correct HTTP status code (HTTP 404 Not Found). This is an important thing to get - HTTP defines common response status codes, so there's no need to implement any custom messaging here - we tell the requestor that the resource the requested wasn't there.  public Comment GetComment(int id) { Comment comment; if (!repository.TryGet(id, out comment)) throw new HttpResponseException(HttpStatusCode.NotFound); return comment; } This is great because it's standard, and any client should know how to handle it. There's no need to invent custom messaging here, and we can talk to any client that understands HTTP - not just jQuery, and not just browsers. But it's crazy easy to consume an HTTP API that returns JSON via jQuery. The example uses Knockout to bind the JSON values to HTML elements, but the thing to notice is that calling into this /api/coments is really simple, and the return from the $.get() method is just JSON data, which is really easy to work with in JavaScript (since JSON stands for JavaScript Object Notation and is the native serialization format in Javascript). $(function() { $("#getComments").click(function () { // We're using a Knockout model. This clears out the existing comments. viewModel.comments([]); $.get('/api/comments', function (data) { // Update the Knockout model (and thus the UI) with the comments received back // from the Web API call. viewModel.comments(data); }); }); }); That's it! Easy, huh? In Part 3, we'll start modifying data on the server using POST and DELETE.

    Read the article

  • ASP.NET MVC localization DisplayNameAttribute alternatives: a better way

    - by Brian Schroer
    In my last post, I talked bout creating a custom class inheriting from System.ComponentModel.DisplayNameAttribute to retrieve display names from resource files: [LocalizedDisplayName("RememberMe")] public bool RememberMe { get; set; } That’s a lot of work to put an attribute on all of my model properties though. It would be nice if I could intercept the ASP.NET MVC code that analyzes the model metadata to retrieve display names to make it automatically get localized text from my resource files. That way, I could just set up resource file entries where the keys are the property names, and not have to put attributes on all of my properties. That’s done by creating a custom class inheriting from System.Web.Mvc.DataAnnotationsModelMetadataProvider: 1: public class LocalizedDataAnnotationsModelMetadataProvider : 2: DataAnnotationsModelMetadataProvider 3: { 4: protected override ModelMetadata CreateMetadata( 5: IEnumerable<Attribute> attributes, 6: Type containerType, 7: Func<object> modelAccessor, 8: Type modelType, 9: string propertyName) 10: { 11: var meta = base.CreateMetadata 12: (attributes, containerType, modelAccessor, modelType, propertyName); 13:   14: if (string.IsNullOrEmpty(propertyName)) 15: return meta; 16:   17: if (meta.DisplayName == null) 18: GetLocalizedDisplayName(meta, propertyName); 19:   20: if (string.IsNullOrEmpty(meta.DisplayName)) 21: meta.DisplayName = string.Format("[[{0}]]", propertyName); 22:   23: return meta; 24: } 25:   26: private static void GetLocalizedDisplayName(ModelMetadata meta, string propertyName) 27: { 28: ResourceManager resourceManager = MyResource.ResourceManager; 29: CultureInfo culture = Thread.CurrentThread.CurrentUICulture; 30:   31: meta.DisplayName = resourceManager.GetString(propertyName, culture); 32: } 33: } Line 11 calls the base CreateMetadata method. Line 17 checks whether the metadata DisplayName property has already been populated by a DisplayNameAttribute (or my LocalizedDisplayNameAttribute). If so, it respects that and doesn’t use my custom localized text lookup. The GetLocalizedDisplayName method checks for the property name as a resource file key. If found, it uses the localized text from the resource files. If the key is not found in the resource file, as with my LocalizedDisplayNameAttribute, I return a formatted string containing the property name (e.g. “[[RememberMe]]”) so I can tell by looking at my web pages which resource keys I haven’t defined yet. It’s hooked up with this code in the Application_Start method of Global.asax: ModelMetadataProviders.Current = new LocalizedDataAnnotationsModelMetadataProvider();

    Read the article

  • StreamInsight and Reactive Framework Challenge

    In his blogpost Roman from the StreamInsight team asked if we could create a Reactive Framework version of what he had done in the post using StreamInsight.  For those who don’t know, the Reactive Framework or Rx to its friends is a library for composing asynchronous and event-based programs using observable collections in the .Net framework.  Yes, there is some overlap between StreamInsight and the Reactive Extensions but StreamInsight has more flexibility and power in its temporal algebra (Windowing, Alteration of event headers) Well here are two alternate ways of doing what Roman did. The first example is a mix of StreamInsight and Rx var rnd = new Random(); var RandomValue = 0; var interval = Observable.Interval(TimeSpan.FromMilliseconds((Int32)rnd.Next(500,3000))) .Select(i => { RandomValue = rnd.Next(300); return RandomValue; }); Server s = Server.Create("Default"); Microsoft.ComplexEventProcessing.Application a = s.CreateApplication("Rx SI Mischung"); var inputStream = interval.ToPointStream(a, evt => PointEvent.CreateInsert( System.DateTime.Now.ToLocalTime(), new { RandomValue = evt}), AdvanceTimeSettings.IncreasingStartTime, "Rx Sample"); var r = from evt in inputStream select new { runningVal = evt.RandomValue }; foreach (var x in r.ToPointEnumerable().Where(e => e.EventKind != EventKind.Cti)) { Console.WriteLine(x.Payload.ToString()); } This next version though uses the Reactive Extensions Only   var rnd = new Random(); var RandomValue = 0; Observable.Interval(TimeSpan.FromMilliseconds((Int32)rnd.Next(500, 3000))) .Select(i => { RandomValue = rnd.Next(300); return RandomValue; }).Subscribe(Console.WriteLine, () => Console.WriteLine("Completed")); Console.ReadKey();   These are very simple examples but both technologies allow us to do a lot more.  The ICEPObservable() design pattern was reintroduced in StreamInsight 1.1 and the more I use it the more I like it.  It is a very useful pattern when wanting to show StreamInsight samples as is the IEnumerable() pattern.

    Read the article

  • Delegate performance of Roslyn Sept 2012 CTP is impressive

    - by dotneteer
    I wanted to dynamically compile some delegates using Roslyn. I came across this article by Piotr Sowa. The article shows that the delegate compiled with Roslyn CTP was not very fast. Since the article was written using the Roslyn June 2012, I decided to give Sept 2012 CTP a try. There are significant changes in Roslyn Sept 2012 CTP in both C# syntax supported as well as API. I found Anoop Madhisidanan’s article that has an example of the new API. With that, I was able to put together a comparison. In my test, the Roslyn compiled delegate is as fast as C# (VS 2012) compiled delegate. See the source code below and give it a try. using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Diagnostics; using Roslyn.Compilers; using Roslyn.Scripting.CSharp; using Roslyn.Scripting; namespace RoslynTest { class Program { public Func del; static void Main(string[] args) { Stopwatch stopWatch = new Stopwatch(); Program p = new Program(); p.SetupDel(); //Comment out this line and uncomment the next line to compare //p.SetupScript(); stopWatch.Start(); int result = DoWork(p.del); stopWatch.Stop(); Console.WriteLine(result); Console.WriteLine("Time elapsed {0}", stopWatch.ElapsedMilliseconds); Console.Read(); } private void SetupDel() { del = (s, i) => ++s; } private void SetupScript() { //Create the script engine //Script engine constructor parameters go changed var engine=new ScriptEngine(); //Let us use engine's Addreference for adding the required //assemblies new[] { typeof (Console).Assembly, typeof (Program).Assembly, typeof (IEnumerable<>).Assembly, typeof (IQueryable).Assembly }.ToList().ForEach(asm => engine.AddReference(asm)); new[] { "System", "System.Linq", "System.Collections", "System.Collections.Generic" }.ToList().ForEach(ns=>engine.ImportNamespace(ns)); //Now, you need to create a session using engine's CreateSession method, //which can be seeded with a host object var session = engine.CreateSession(); var submission = session.CompileSubmission>("new Func((s, i) => ++s)"); del = submission.Execute(); //- See more at: http://www.amazedsaint.com/2012/09/roslyn-september-ctp-2012-overview-api.html#sthash.1VutrWiW.dpuf } private static int DoWork(Func del) { int result = Enumerable.Range(1, 1000000).Aggregate(del); return result; } } }  Since Roslyn Sept 2012 CTP is already over a year old, I cannot wait to see a new version coming out.

    Read the article

  • Caching no .NET Framework 4.0

    - by anobre
    Olá pessoal, como estão? Hoje vou apresentar uma mudança interessante sobre caching, em comparação com versões anteriores. Introdução A versão 4.0 da plataforma .NET trouxe uma mudança estrutural esperada para os recursos de Cache. Nas versão 3.5 (até SP1), a plataforma fornecia uma implementação do Cache através do namespace System.Web.Caching. Nas versões anteriores o cache estava disponível no namespace System.Web, o que criada uma dependência com as classes do ASP.NET. Neste novo framework, o namespace System.Runtime.Caching reúne toda a API necessária para criar todas as tarefas comuns ao ASP.NET Caching de versões anteriores. System.Runtime.Caching e MemoryCache Tudo que precisamos para trabalhar com cache, em aplicações Web ou não, está reunido no namespace System.Runtime.Caching. A unidade básica de trabalho é a classe abstrata ObjectCache, que fornece a base para criar implementações customizadas de cache. E como é de se esperar, a classe MemoryCache é a implementação da classe abstrata ObjectCache para armazenamento das informações em memória. public class MemoryCache : ObjectCache, IEnumerable, IDisposable A utilização do cache é muito simples, bem parecida com o modelo anterior: ObjectCache cache = MemoryCache.Default; string fileContents = cache["filecontents"] as string; if (fileContents == null) { CacheItemPolicy policy = new CacheItemPolicy(); List<string> filePaths = new List<string>(); filePaths.Add("c:\\cache\\example.txt"); policy.ChangeMonitors.Add(new HostFileChangeMonitor(filePaths)); // Fetch the file contents. fileContents = File.ReadAllText("c:\\cache\\example.txt"); cache.Set("filecontents", fileContents, policy); } Label1.Text = fileContents; Extendendo o Cache É possível customizar todo mecanismo de cache através de várias abordagens. ScottGu escreveu sobre isto, que você pode acessar através deste link. Conclusão Algo muito esperado em versões anteriores, finalmente o cache está disponível sem criar relacionamento com assemblies exclusivamente Web. Perfeito para quem desenvolve outros tipos de aplicação, usufruindo deste recurso sem carregar código desnecessário. Abraços!

    Read the article

  • Unification of TPL TaskScheduler and RX IScheduler

    - by JoshReuben
    using System; using System.Collections.Generic; using System.Reactive.Concurrency; using System.Security; using System.Threading; using System.Threading.Tasks; using System.Windows.Threading; namespace TPLRXSchedulerIntegration { public class MyScheduler :TaskScheduler, IScheduler     { private readonly Dispatcher _dispatcher; private readonly DispatcherScheduler _rxDispatcherScheduler; //private readonly TaskScheduler _tplDispatcherScheduler; private readonly SynchronizationContext _synchronizationContext; public MyScheduler(Dispatcher dispatcher)         {             _dispatcher = dispatcher;             _rxDispatcherScheduler = new DispatcherScheduler(dispatcher); //_tplDispatcherScheduler = FromCurrentSynchronizationContext();             _synchronizationContext = SynchronizationContext.Current;         }         #region RX public DateTimeOffset Now         { get { return _rxDispatcherScheduler.Now; }         } public IDisposable Schedule<TState>(TState state, DateTimeOffset dueTime, Func<IScheduler, TState, IDisposable> action)         { return _rxDispatcherScheduler.Schedule(state, dueTime, action);         } public IDisposable Schedule<TState>(TState state, TimeSpan dueTime, Func<IScheduler, TState, IDisposable> action)         { return _rxDispatcherScheduler.Schedule(state, dueTime, action);         } public IDisposable Schedule<TState>(TState state, Func<IScheduler, TState, IDisposable> action)         { return _rxDispatcherScheduler.Schedule(state, action);         }         #endregion         #region TPL /// Simply posts the tasks to be executed on the associated SynchronizationContext         [SecurityCritical] protected override void QueueTask(Task task)         {             _dispatcher.BeginInvoke((Action)(() => TryExecuteTask(task))); //TryExecuteTaskInline(task,false); //task.Start(_tplDispatcherScheduler); //m_synchronizationContext.Post(s_postCallback, (object)task);         } /// The task will be executed inline only if the call happens within the associated SynchronizationContext         [SecurityCritical] protected override bool TryExecuteTaskInline(Task task, bool taskWasPreviouslyQueued)         { if (SynchronizationContext.Current != _synchronizationContext)             { SynchronizationContext.SetSynchronizationContext(_synchronizationContext);             } return TryExecuteTask(task);         } // not implemented         [SecurityCritical] protected override IEnumerable<Task> GetScheduledTasks()         { return null;         } /// Implementes the MaximumConcurrencyLevel property for this scheduler class. /// By default it returns 1, because a <see cref="T:System.Threading.SynchronizationContext"/> based /// scheduler only supports execution on a single thread. public override Int32 MaximumConcurrencyLevel         { get             { return 1;             }         } //// preallocated SendOrPostCallback delegate //private static SendOrPostCallback s_postCallback = new SendOrPostCallback(PostCallback); //// this is where the actual task invocation occures //private static void PostCallback(object obj) //{ //    Task task = (Task) obj; //    // calling ExecuteEntry with double execute check enabled because a user implemented SynchronizationContext could be buggy //    task.ExecuteEntry(true); //}         #endregion     } }     What Design Pattern did I use here?

    Read the article

  • Using set operation in LINQ

    - by vik20000in
    There are many set operation that are required to be performed while working with any kind of data. This can be done very easily with the help of LINQ methods available for this functionality. Below are some of the examples of the set operation with LINQ. Finding distinct values in the set of data. We can use the distinct method to find out distinct values in a given list.     int[] factorsOf300 = { 2, 2, 3, 5, 5 };     var uniqueFactors = factorsOf300.Distinct(); We can also use the set operation of UNION with the help of UNION method in the LINQ. The Union method takes another collection as a parameter and returns the distinct union values in  both the list. Below is an example.     int[] numbersA = { 0, 2, 4, 5, 6, 8, 9 };    int[] numbersB = { 1, 3, 5, 7, 8 };    var uniqueNumbers = numbersA.Union(numbersB); We can also get the set operation of INTERSECT with the help of the INTERSECT method. Below is an example.     int[] numbersA = { 0, 2, 4, 5, 6, 8, 9 };     int[] numbersB = { 1, 3, 5, 7, 8 };         var commonNumbers = numbersA.Intersect(numbersB);  We can also find the difference between the 2 sets of data with the help of except method.      int[] numbersA = { 0, 2, 4, 5, 6, 8, 9 };     int[] numbersB = { 1, 3, 5, 7, 8 };         IEnumerable<int> aOnlyNumbers = numbersA.Except(numbersB);  Vikram

    Read the article

  • SSIS and StreamInsight Working Together.

    I have been thinking a lot recently about what it would be like to have StreamInsight and SSIS working together.  Well the CAT team have produced a paper on some of our options here. Here are some of my thoughts. There is of course a slight mismatch in their types of usage.  StreamInsight is an Event Stream processing engine capable of operating on new data in the sub second timeframe.  The engine allows you to do real time analytics and take decisions on events that have potentially only just happened.  SSIS on the other hand is a batch processing engine.  In general I do not like having to invoke the same package more than once every 90 seconds or so as it can start to get expensive.  Usually when doing batch processing we have an hour or longer of grace before we have to move data from A –> B. StreamInsight operates on streams of data.  Before anyone mentions it yes I know StreamInsight is equally adept at using the IEnumerable interface, but I would argue live streaming and real-time analytics is a primary goal of the product.  SSIS does not have an “Always On” button I do not like the idea of embedding StreamInsight inside SSIS using a transform particularly.  It means StreamInsight becomes a batch processing engine because it can only operate when the SSIS package is running and SSIS is in charge of when that happens. If I am to have StreamInsight within SSIS then I prefer to have StreamInsight on the adapters.  This way you can force the adapters to stay open and introduce events into your Pipeline.   SSIS has a much richer set of transforms out of the box than StreamInsight.  Although “Always On” was not a design goal of SSIS I have used it like this and it works just fine. SSIS being called from within StreamInsight, now that excites me.  see below   For a while now I have been thinking what it would be like to decouple the Data Flow task from the SSIS package and expose it as something with which you can interact.  Anything can instantiate this version of a DFT as it would expose one or more  input interfaces and one or more output interfaces.  I can imagine that this would be a big hit when moving to “The Cloud” as well.  I could see the Data Flow task maybe being hosted in Azure Appfabric or some such layer. StreamInsight would be able to take advantage of this as well.   I am interested to see where this goes and will be pressing for more meat around the subject when I visit Redmond soon.

    Read the article

  • Using Query Classes With NHibernate

    - by Liam McLennan
    Even when using an ORM, such as NHibernate, the developer still has to decide how to perform queries. The simplest strategy is to get access to an ISession and directly perform a query whenever you need data. The problem is that doing so spreads query logic throughout the entire application – a clear violation of the Single Responsibility Principle. A more advanced strategy is to use Eric Evan’s Repository pattern, thus isolating all query logic within the repository classes. I prefer to use Query Classes. Every query needed by the application is represented by a query class, aka a specification. To perform a query I: Instantiate a new instance of the required query class, providing any data that it needs Pass the instantiated query class to an extension method on NHibernate’s ISession type. To query my database for all people over the age of sixteen looks like this: [Test] public void QueryBySpecification() { var canDriveSpecification = new PeopleOverAgeSpecification(16); var allPeopleOfDrivingAge = session.QueryBySpecification(canDriveSpecification); } To be able to query for people over a certain age I had to create a suitable query class: public class PeopleOverAgeSpecification : Specification<Person> { private readonly int age; public PeopleOverAgeSpecification(int age) { this.age = age; } public override IQueryable<Person> Reduce(IQueryable<Person> collection) { return collection.Where(person => person.Age > age); } public override IQueryable<Person> Sort(IQueryable<Person> collection) { return collection.OrderBy(person => person.Name); } } Finally, the extension method to add QueryBySpecification to ISession: public static class SessionExtensions { public static IEnumerable<T> QueryBySpecification<T>(this ISession session, Specification<T> specification) { return specification.Fetch( specification.Sort( specification.Reduce(session.Query<T>()) ) ); } } The inspiration for this style of data access came from Ayende’s post Do You Need a Framework?. I am sick of working through multiple layers of abstraction that don’t do anything. Have you ever seen code that required a service layer to call a method on a repository, that delegated to a common repository base class that wrapped and ORMs unit of work? I can achieve the same thing with NHibernate’s ISession and a single extension method. If you’re interested you can get the full Query Classes example source from Github.

    Read the article

  • LINQ to Twitter v2.1.09 Released

    - by Joe Mayo
    Originally posted on: http://geekswithblogs.net/WinAZ/archive/2013/10/15/linq-to-twitter-v2.1.09-released.aspxToday, I released LINQ to Twitter v2.1.09. Here are important new changes. Bug Fixes This is primarily a bug fix release. Most notably, there were authentication problems in WinRT apps. This is now fixed. New Features One new feature is the addition of ApplicationOnlyAuthentication for WinRT. It is fully async.  Here’s how it works: var auth = new WinRtApplicationOnlyAuthorizer { Credentials = new InMemoryCredentials { ConsumerKey = "", ConsumerSecret = "" } }; if (auth == null || !auth.IsAuthorized) { await auth.AuthorizeAsync(); } var twitterCtx = new TwitterContext(auth); (from search in twitterCtx.Search where search.Type == SearchType.Search && search.Query == SearchTextBox.Text select search) .MaterializedAsyncCallback( async response => await Dispatcher.RunAsync( CoreDispatcherPriority.Normal, async () => { Search searchResponse = response.State.Single(); string message = string.Format( "Search returned {0} statuses", searchResponse.Statuses.Count); await new MessageDialog(message, "Search Complete").ShowAsync(); })); It’s called the WinRtApplicationOnlyAuthorizer. You only need two tokens, ConsumerKey and ConsumerSecret, which come from your Twitter API application settings page. Note: You need a Twitter Application, which you can create at https://dev.twitter.com/. The MaterializedAsyncCallback materializes your query and handles the response. I put everything together in a lambda for demonstration purposes, but you can always replace the callback with a handler of type Action<TwitterAsyncResponse<IEnumerable<T>>>, where T is Search for this example. On the Horizon The next version of LINQ to Twitter is in development. I discussed it at LINQ to Twitter Async. This isn’t complete, but you can download the source code at the LINQ to Twitter site on CodePlex. I’ve competed all the spikes for what I thought would be the hard parts and now have prototypes of queries and commands working. This would be a good time to provide feedback if there are features in the current version that you think could be improved. The current driving forces for the next version will be async and PCL.   @JoeMayo

    Read the article

  • Flattening System.Web.UI ControlCollection

    - by evovision
    Hi,   Sometimes one may need to get a list of child controls inside specific container and don't care about the underlying hierarchy.   The result is beautifully achieved using this extension method:   using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;    public static class ControlCollectionExtensionMethods    {        public static IEnumerable<Control> FlattenedList(this ControlCollection controls)        {            foreach (Control ctrl in controls)            {                  // return parent control                   yield return ctrl;                              // and dive into child collection                   foreach (Control child in ctrl.Controls.FlattenedList())                         yield return child;            }        }    }   P.S.: don't forget about namespaces when using it in your code, if above class is wrapped into namespace, for example: Sample, the source code file with calling code must explicitly reference it: using Sample;

    Read the article

  • MVC 2 Entity Framework View Model Insert

    - by cannibalcorpse
    This is driving me crazy. Hopefully my question makes sense... I'm using MVC 2 and Entity Framework 1 and am trying to insert a new record with two navigation properties. I have a SQL table, Categories, that has a lookup table CategoryTypes and another self-referencing lookup CategoryParent. EF makes two nav properties on my Category model, one called Parent and another called CategoryType, both instances of their respective models. On my view that creates the new Category, I have two dropdowns, one for the CategoryType and another for the ParentCategory. When I try and insert the new Category WITHOUT the ParentCategory, which allows nulls, everything is fine. As soon as I add the ParentCategory, the insert fails, and oddly (or so I think) complains about the CategoryType in the form of this error: 0 related 'CategoryTypes' were found. 1 'CategoryTypes' is expected. When I step through, I can verifiy that both ID properties coming in on the action method parameter are correct. I can also verify that when I go to the db to get the CategoryType and ParentCategory with the ID's, the records are being pulled fine. Yet it fails on SaveChanges(). All that I can see is that my CategoryParent dropdownlistfor in my view, is somehow causing the insert to bomb. Please see my comments in my httpPost Create action method. My view model looks like this: public class EditModel { public Category MainCategory { get; set; } public IEnumerable<CategoryType> CategoryTypesList { get; set; } public IEnumerable<Category> ParentCategoriesList { get; set; } } My Create action methods look like this: // GET: /Categories/Create public ActionResult Create() { return View(new EditModel() { CategoryTypesList = _db.CategoryTypeSet.ToList(), ParentCategoriesList = _db.CategorySet.ToList() }); } // POST: /Categories/Create [HttpPost] public ActionResult Create(Category mainCategory) { if (!ModelState.IsValid) return View(new EditModel() { MainCategory = mainCategory, CategoryTypesList = _db.CategoryTypeSet.ToList(), ParentCategoriesList = _db.CategorySet.ToList() }); mainCategory.CategoryType = _db.CategoryTypeSet.First(ct => ct.Id == mainCategory.CategoryType.Id); // This db call DOES get the correct Category, but fails on _db.SaveChanges(). // Oddly the error is related to CategoryTypes and not Category. // Entities in 'DbEntities.CategorySet' participate in the 'FK_Categories_CategoryTypes' relationship. // 0 related 'CategoryTypes' were found. 1 'CategoryTypes' is expected. //mainCategory.Parent = _db.CategorySet.First(c => c.Id == mainCategory.Parent.Id); // If I just use the literal ID of the same Category, // AND comment out the CategoryParent dropdownlistfor in the view, all is fine. mainCategory.Parent = _db.CategorySet.First(c => c.Id == 2); _db.AddToCategorySet(mainCategory); _db.SaveChanges(); return RedirectToAction("Index"); } Here is my Create form on the view : <% using (Html.BeginForm()) {%> <%= Html.ValidationSummary(true) %> <fieldset> <legend>Fields</legend> <div> <%= Html.LabelFor(model => model.MainCategory.Parent.Id) %> <%= Html.DropDownListFor(model => model.MainCategory.Parent.Id, new SelectList(Model.ParentCategoriesList, "Id", "Name")) %> <%= Html.ValidationMessageFor(model => model.MainCategory.Parent.Id) %> </div> <div> <%= Html.LabelFor(model => model.MainCategory.CategoryType.Id) %> <%= Html.DropDownListFor(model => model.MainCategory.CategoryType.Id, new SelectList(Model.CategoryTypesList, "Id", "Name"))%> <%= Html.ValidationMessageFor(model => model.MainCategory.CategoryType.Id)%> </div> <div> <%= Html.LabelFor(model => model.MainCategory.Name) %> <%= Html.TextBoxFor(model => model.MainCategory.Name)%> <%= Html.ValidationMessageFor(model => model.MainCategory.Name)%> </div> <div> <%= Html.LabelFor(model => model.MainCategory.Description)%> <%= Html.TextAreaFor(model => model.MainCategory.Description)%> <%= Html.ValidationMessageFor(model => model.MainCategory.Description)%> </div> <div> <%= Html.LabelFor(model => model.MainCategory.SeoName)%> <%= Html.TextBoxFor(model => model.MainCategory.SeoName, new { @class = "large" })%> <%= Html.ValidationMessageFor(model => model.MainCategory.SeoName)%> </div> <div> <%= Html.LabelFor(model => model.MainCategory.HasHomepage)%> <%= Html.CheckBoxFor(model => model.MainCategory.HasHomepage)%> <%= Html.ValidationMessageFor(model => model.MainCategory.HasHomepage)%> </div> <p><input type="submit" value="Create" /></p> </fieldset> <% } %> Maybe I've just been staying up too late playing with MVC 2? :) Please let me know if I'm not being clear enough.

    Read the article

  • ASP.NET MVC validation problem

    - by ile
    ArticleRepostitory.cs: using System; using System.Collections.Generic; using System.Linq; using System.Web; using CMS.Model; using System.Web.Mvc; namespace CMS.Models { public class ArticleDisplay { public ArticleDisplay() { } public int CategoryID { set; get; } public string CategoryTitle { set; get; } public int ArticleID { set; get; } public string ArticleTitle { set; get; } public DateTime ArticleDate; public string ArticleContent { set; get; } } public class ArticleRepository { private DB db = new DB(); // // Query Methods public IQueryable<ArticleDisplay> FindAllArticles() { var result = from category in db.ArticleCategories join article in db.Articles on category.CategoryID equals article.CategoryID select new ArticleDisplay { CategoryID = category.CategoryID, CategoryTitle = category.Title, ArticleID = article.ArticleID, ArticleTitle = article.Title, ArticleDate = article.Date, ArticleContent = article.Content }; return result; } public IQueryable<ArticleDisplay> FindTodayArticles() { var result = from category in db.ArticleCategories join article in db.Articles on category.CategoryID equals article.CategoryID where article.Date == DateTime.Today select new ArticleDisplay { CategoryID = category.CategoryID, CategoryTitle = category.Title, ArticleID = article.ArticleID, ArticleTitle = article.Title, ArticleDate = article.Date, ArticleContent = article.Content }; return result; } public Article GetArticle(int id) { return db.Articles.SingleOrDefault(d => d.ArticleID == id); } public IQueryable<ArticleDisplay> DetailsArticle(int id) { var result = from category in db.ArticleCategories join article in db.Articles on category.CategoryID equals article.CategoryID where id == article.ArticleID select new ArticleDisplay { CategoryID = category.CategoryID, CategoryTitle = category.Title, ArticleID = article.ArticleID, ArticleTitle = article.Title, ArticleDate = article.Date, ArticleContent = article.Content }; return result; } // // Insert/Delete Methods public void Add(Article article) { db.Articles.InsertOnSubmit(article); } public void Delete(Article article) { db.Articles.DeleteOnSubmit(article); } // // Persistence public void Save() { db.SubmitChanges(); } } } ArticleController.cs: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; using System.Web.Mvc.Ajax; using CMS.Models; using CMS.Model; namespace CMS.Controllers { public class ArticleController : Controller { ArticleRepository articleRepository = new ArticleRepository(); ArticleCategoryRepository articleCategoryRepository = new ArticleCategoryRepository(); // // GET: /Article/ public ActionResult Index() { var allArticles = articleRepository.FindAllArticles().ToList(); return View(allArticles); } // // GET: /Article/Details/5 public ActionResult Details(int id) { var article = articleRepository.DetailsArticle(id).Single(); if (article == null) return View("NotFound"); return View(article); } // // GET: /Article/Create public ActionResult Create() { ViewData["categories"] = new SelectList ( articleCategoryRepository.FindAllCategories().ToList(), "CategoryId", "Title" ); Article article = new Article() { Date = DateTime.Now, CategoryID = 1 }; return View(article); } // // POST: /Article/Create [AcceptVerbs(HttpVerbs.Post)] public ActionResult Create(Article article) { if (ModelState.IsValid) { try { // TODO: Add insert logic here articleRepository.Add(article); articleRepository.Save(); return RedirectToAction("Index"); } catch { return View(article); } } else { return View(article); } } // // GET: /Article/Edit/5 public ActionResult Edit(int id) { ViewData["categories"] = new SelectList ( articleCategoryRepository.FindAllCategories().ToList(), "CategoryId", "Title" ); var article = articleRepository.GetArticle(id); return View(article); } // // POST: /Article/Edit/5 [AcceptVerbs(HttpVerbs.Post)] public ActionResult Edit(int id, FormCollection collection) { Article article = articleRepository.GetArticle(id); try { // TODO: Add update logic here UpdateModel(article, collection.ToValueProvider()); articleRepository.Save(); return RedirectToAction("Details", new { id = article.ArticleID }); } catch { return View(article); } } // // HTTP GET: /Article/Delete/1 public ActionResult Delete(int id) { Article article = articleRepository.GetArticle(id); if (article == null) return View("NotFound"); else return View(article); } // // HTTP POST: /Article/Delete/1 [AcceptVerbs(HttpVerbs.Post)] public ActionResult Delete(int id, string confirmButton) { Article article = articleRepository.GetArticle(id); if (article == null) return View("NotFound"); articleRepository.Delete(article); articleRepository.Save(); return View("Deleted"); } } } View/Article/Create.aspx: <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<CMS.Model.Article>" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server"> Create </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <h2>Create</h2> <%= Html.ValidationSummary("Create was unsuccessful. Please correct the errors and try again.") %> <% using (Html.BeginForm()) {%> <fieldset> <legend>Fields</legend> <p> <label for="Title">Title:</label> <%= Html.TextBox("Title") %> <%= Html.ValidationMessage("Title", "*") %> </p> <p> <label for="Content">Content:</label> <%= Html.TextArea("Content", new { id = "Content" })%> <%= Html.ValidationMessage("Content", "*")%> </p> <p> <label for="Date">Date:</label> <%= Html.TextBox("Date") %> <%= Html.ValidationMessage("Date", "*") %> </p> <p> <label for="CategoryID">Category:</label> <%= Html.DropDownList("CategoryId", (IEnumerable<SelectListItem>)ViewData["categories"])%> </p> <p> <input type="submit" value="Create" /> </p> </fieldset> <% } %> <div> <%=Html.ActionLink("Back to List", "Index") %> </div> </asp:Content> If I remove DropDownList from .aspx file then validation (on date only because no other validation exists) works, but of course I can't create new article because one value is missing. If I leave dropdownlist and try to insert wrong date I get following error: System.InvalidOperationException: The ViewData item with the key 'CategoryId' is of type 'System.Int32' but needs to be of type 'IEnumerable'. If I enter correct date than the article is properly inserted. There's one other thing that's confusing me... For example, if I try manually add the categoyID: [AcceptVerbs(HttpVerbs.Post)] public ActionResult Create(Article article) { if (ModelState.IsValid) { try { // TODO: Add insert logic here // Manually add category value article.CategoryID = 1; articleRepository.Add(article); articleRepository.Save(); return RedirectToAction("Index"); } catch { return View(article); } } else { return View(article); } } ..I also get the above error. There's one other thing I noticed. If I add partial class Article, when returning to articleRepository.cs I get error that 'Article' is an ambiguous reference between 'CMS.Models.Article' and 'CMS.Model.Article' Any thoughts on this one?

    Read the article

< Previous Page | 30 31 32 33 34 35 36 37 38 39 40 41  | Next Page >