Search Results

Search found 4738 results on 190 pages for 'linq'.

Page 135/190 | < Previous Page | 131 132 133 134 135 136 137 138 139 140 141 142  | Next Page >

• MySql Connector/NET 6.7.4 GA has been released

  - by fernando

  MySQL Connector/Net 6.7.4, a new version of the all-managed .NET driver for MySQL has been released.  This is the GA, is feature complete. It is recommended for production environments.  It is appropriate for use with MySQL server versions 5.0-5.7.  It is now available in source and binary form from http://dev.mysql.com/downloads/connector/net/#downloads and mirror sites (note that not all mirror sites may be up to date at this point-if you can't find this version on some mirror, please try again later or choose another download site.) The 6.7 version of MySQL Connector/Net brings the following new features: -  WinRT Connector. -  Load Balancing support. -  Entity Framework 5.0 support. -  Memcached support for Innodb Memcached plugin. -  This version also splits the product in two: from now on, starting version 6.7, Connector/NET will include only the former Connector/NET ADO.NET driver, Entity Framework and ASP.NET providers (Core libraries of MySql.Data, MySql.Data.Entity & MySql.Web). While all the former product Visual Studio integration (Design support, Intellisense, Debugger) are available as part of MySql Windows Installer under the name "MySql for Visual Studio".  WinRT Connector  ------------------------------------------- Now you can write MySql data access apps in Windows Runtime (aka Store Apps) using the familiar API of Connector/NET for .NET.  Load Balancing Support  -------------------------------------------  Now you can setup a Replication or Cluster configuration in the backend, and Connector/NET will balance the load of queries among all servers making up the backend topology.  Entity Framework 5.0  -------------------------------------------  Connector/NET is now compatible with EF 5, including special features of EF 5 like spatial types.  Memcached  -------------------------------------------  Just setup Innodb memcached plugin and use Connector/NET new APIs to establish a client to MySql 5.6 server's memcached daemon.  Bug fixes included in this release: - Fix for Entity Framework when inserts data having Identity columns (Oracle bug #16494585). - Fix for Connector/NET cannot read data from a MySql table using UTF-16/UTF-32 (MySql bug #69169, Oracle bug #16776818). - Fix for Malformed query in Entity Framework when eager loading due to multiple projections (MySql bug #67183, Oracle bug #16872852). - Fix for database objects with 'dbo' prefix when using automatic migrations in Entity Framework 5.0 (Oracle bug #16909439). - Fix for bug IIS application pool reset worker process causes website to crash (Oracle bug #16909237, Mysql Bug #67665). - Fix for bug Error in LINQ to Entities query when using Distinct().Count() (MySql Bug #68513, Oracle bug #16950146). - Fix for occasionally return no data when socket connection is slow, interrupted or delayed (MySql bug #69039, Oracle bug #16950212). - Fix for ConstraintException when filling a datatable (MySql bug #65065, Oracle bug #16952323). - Fix for Data Provider is not found after uninstalling Mysql for visual studio (Oracle bug #16973456). - Fix for nested sql generated for LINQ to Entities query with Take and Order by (MySql bug #65723, Oracle bug #16973939). The documentation is available at http://dev.mysql.com/doc/refman/5.7/en/connector-net.html  Enjoy and thanks for the support!  --  Fernando Gonzalez Sanchez | Software Engineer |  Oracle MySQL Windows Experience Team, Connector/NET  Guadalajara | Jalisco | Mexico 

  Read the article

• 45 minutes to talk about C# [closed]

  - by Philip

  I have the opportunity to give a 45 minute talk on C# in the theory of programming languages class I'm taking. The college teaches Java almost exclusively, so that's what all the students are most familiar with. (There's a little C, assembly, Prolog and LISP as well.) I decide what to talk about. It seems to me the best approach is to focus on a few of the big, obvious differences between C# and Java. I don't intend it to be a recommendation to use C# -- there are reasons to use each, mostly because of their ecosystems. So I want to focus on C# as a language. I don't want to go too fast and end up listing a whole bunch of features without showing their usefulness. My current plan is this: Functions as first class objects. This is, in my opinion, one of the biggest differences between C# and Java. The professor briefly mentioned this notion and showed a LISP example, but many of the students have probably never used it. I can show real world examples where it's made my code more readable. Lambda expressions as concise syntax for anonymous functions. Obviously with examples to show how this is useful. The real hit-home examples will be at the end when it's combined with the rest. I don't see an advantage to first showing the old delegate syntax and then replacing it with lambdas -- most of us won't have ever seen delegates anyway so it would just be confusing. The yield keyword and how it's different from returning an array. I have the impression that a lot of C# developers aren't familiar with how to use this. It will likely be very foreign to Java developers. I have some examples from my own work where it was really useful, such as iterating over a tree traversal, or iterating over neighbors in a graph where the neighbors aren't stored in memory. In both cases, doing it in Java would likely mean returning a complete list -- with yield I can stop iterating if I find what I want early on, without using memory for superfluous lists or arrays. Extension methods as a way to write implementation on interfaces. We'll all be familiar with how interfaces don't allow method implementation, and how this leads to code duplication. I'll show a specific example of this and how the extension method can solve the problem. Demonstrate how the above can be combined by implementing some simple Linq methods and using them. Where, Select, First, maybe more depending on how much time is left. Ideas on which ones might 'hit home' the best? There are other things I could talk about such as generics, value types, properties and more. I haven't yet though of good ways to incorporate these. In the case of generics and value types, the advantages might not be obvious or as relevant. Properties are obviously useful, particularly since we're taught strict JavaBeans here, but I don't know if I could integrate it with the "path to Linq" discussion above without it feeling tacked on. So I'm looking for thoughts on how to talk about C#, and what to talk about. Even minor details. I'm sure there are more experienced C# developers than me here who have good insight about what's really important in the language, and what would miss the point.

  Read the article

• Stepping outside Visual Studio IDE [Part 2 of 2] with Mono 2.6.4

  - by mbcrump

  Continuing part 2 of my Stepping outside the Visual Studio IDE, is the open-source Mono Project. Mono is a software platform designed to allow developers to easily create cross platform applications. Sponsored by Novell (http://www.novell.com/), Mono is an open source implementation of Microsoft's .NET Framework based on the ECMA standards for C# and the Common Language Runtime. A growing family of solutions and an active and enthusiastic contributing community is helping position Mono to become the leading choice for development of Linux applications. So, to clarify. You can use Mono to develop .NET applications that will run on Linux, Windows or Mac. It’s basically a IDE that has roots in Linux. Let’s first look at the compatibility: Compatibility If you already have an application written in .Net, you can scan your application with the Mono Migration Analyzer (MoMA) to determine if your application uses anything not supported by Mono. The current release version of Mono is 2.6. (Released December 2009) The easiest way to describe what Mono currently supports is: Everything in .NET 3.5 except WPF and WF, limited WCF. Here is a slightly more detailed view, by .NET framework version: Implemented C# 3.0 System.Core LINQ ASP.Net 3.5 ASP.Net MVC C# 2.0 (generics) Core Libraries 2.0: mscorlib, System, System.Xml ASP.Net 2.0 - except WebParts ADO.Net 2.0 Winforms/System.Drawing 2.0 - does not support right-to-left C# 1.0 Core Libraries 1.1: mscorlib, System, System.Xml ASP.Net 1.1 ADO.Net 1.1 Winforms/System.Drawing 1.1 Partially Implemented LINQ to SQL - Mostly done, but a few features missing WCF - silverlight 2.0 subset completed Not Implemented WPF - no plans to implement WF - Will implement WF 4 instead on future versions of Mono. System.Management - does not map to Linux System.EnterpriseServices - deprecated Links to documentation. The Official Mono FAQ’s Links to binaries. Mono IDE Latest Version is 2.6.4 That's it, nothing more is required except to compile and run .net code in Linux. Installation After landing on the mono project home page, you can select which platform you want to download. I typically pick the Virtual PC image since I spend all of my day using Windows 7. Go ahead and pick whatever version is best for you. The Virtual PC image comes with Suse Linux. Once the image is launch, you will see the following: I’m not going to go through each option but its best to start with “Start Here” icon. It will provide you with information on new projects or existing VS projects. After you get Mono installed, it's probably a good idea to run a quick Hello World program to make sure everything is setup properly. This allows you to know that your Mono is working before you try writing or running a more complex application. To write a "Hello World" program follow these steps: Start Mono Development Environment. Create a new Project: File->New->Solution Select "Console Project" in the category list. Enter a project name into the Project name field, for example, "HW Project". Click "Forward" Click “Packaging” then OK. You should have a screen very simular to a VS Console App. Click the "Run" button in the toolbar (Ctrl-F5). Look in the Application Output and you should have the “Hello World!” Your screen should look like the screen below. That should do it for a simple console app in mono. To test out an ASP.NET application, simply copy your code to a new directory in /srv/www/htdocs, then visit the following URL: http://localhost/directoryname/page.aspx where directoryname is the directory where you deployed your application and page.aspx is the initial page for your software. Databases You can continue to use SQL server database or use MySQL, Postgress, Sybase, Oracle, IBM’s DB2 or SQLite db. Conclusion I hope this brief look at the Mono IDE helps someone get acquainted with development outside of VS. As always, I welcome any suggestions or comments.

  Read the article

• Scenarios for Throwing Exceptions

  - by Joe Mayo

  I recently came across a situation where someone had an opinion that differed from mine of when an exception should be thrown. This particular case was an issue opened on LINQ to Twitter for an Exception on EndSession.  The premise of the issue was that the poster didn’t feel an exception should be raised, regardless of authentication status.  As first, this sounded like a valid point.  However, I went back to review my code and decided not to make any changes. Here's my rationale: 1. The exception doesn’t occur if the user is authenticated when EndAccountSession is called. 2. The exception does occur if the user is not authenticated when EndAccountSession is called. 3. The exception represents the fact that EndAccountSession is not able to fulfill its intended purpose - to end the session.  If a session never existed, then it would not be possible to perform the requested action.  Therefore, an exception is appropriate. To help illustrate how to handle this situation, I've modified the following code in Program.cs in the LinqToTwitterDemo project to illustrate the situation: static void EndSession(ITwitterAuthorizer auth) { using (var twitterCtx = new TwitterContext(auth, "https://api.twitter.com/1/", "https://search.twitter.com/")) { try { //Log twitterCtx.Log = Console.Out; var status = twitterCtx.EndAccountSession(); Console.WriteLine("Request: {0}, Error: {1}" , status.Request , status.Error); } catch (TwitterQueryException tqe) { var webEx = tqe.InnerException as WebException; if (webEx != null) { var webResp = webEx.Response as HttpWebResponse; if (webResp != null && webResp.StatusCode == HttpStatusCode.Unauthorized) Console.WriteLine("Twitter didn't recognize you as having been logged in. Therefore, your request to end session is illogical.\n"); } var status = tqe.Response; Console.WriteLine("Request: {0}, Error: {1}" , status.Request , status.Error); } } } As expected, LINQ to Twitter wraps the exception in a TwitterQueryException as the InnerException.  The TwitterQueryException serves a very useful purpose through it's Response property.  Notice in the example above that the response has Request and Error proprieties.  These properties correspond to the information that Twitter returns as part of it's response payload.  This is often useful while debugging to help you understand why Twitter was unable to perform the  requested action.  Other times, it's cryptic, but that's another story.  At least you have some way of knowing in your code how to anticipate and handle these situations, along with having extra information to debug with. To sum things up, there are two points to make: when and why an exception should be raised and when to wrap and re-throw an exception in a custom exception type. I felt it was necessary to allow the exception to be raised because the called method was unable to perform the task it was designed for.  I also felt that it is inappropriate for a general library to do anything with exceptions because that could potentially hide a problem from the caller.  A related point is that it should be the exclusive decision of the application that uses the library on what to do with an exception.  Another aspect of this situation is that I wrapped the exception in a custom exception and re-threw.  This is a tough call because I don’t want to hide any stack trace information.  However, the need to make the exception more meaningful by including vital information returned from Twitter swayed me in the direction to design an interface that was as helpful as possible to library consumers.  As shown in the code above, you can dig into the exception and pull out a lot of good information, such as the fact that the underlying HTTP response was a 401 Unauthorized.  In all, trade-offs are seldom perfect for all cases, but combining the fact that the method was unable to perform its intended function, this is a library, and the extra information can be more helpful, it seemed to be the better design. @JoeMayo

  Read the article

• With a little effort you can &ldquo;SEMI&rdquo;-protect your C# assemblies with obfuscation.

  - by mbcrump

  This method will not protect your assemblies from a experienced hacker. Everyday we see new keygens, cracks, serials being released that contain ways around copy protection from small companies. This is a simple process that will make a lot of hackers quit because so many others use nothing. If you were a thief would you pick the house that has security signs and an alarm or one that has nothing? To so begin: Obfuscation is the concealment of meaning in communication, making it confusing and harder to interpret. Lets begin by looking at the cartoon below:     You are probably familiar with the term and probably ignored this like most programmers ignore user security. Today, I’m going to show you reflection and a way to obfuscate it. Please understand that I am aware of ways around this, but I believe some security is better than no security.  In this sample program below, the code appears exactly as it does in Visual Studio. When the program runs, you get either a true or false in a console window. Sample Program. using System; using System.Diagnostics; using System.Linq;   namespace ObfuscateMe {     class Program     {                static void Main(string[] args)         {               Console.WriteLine(IsProcessOpen("notepad")); //Returns a True or False depending if you have notepad running.             Console.ReadLine();         }             public static bool IsProcessOpen(string name)         {             return Process.GetProcesses().Any(clsProcess => clsProcess.ProcessName.Contains(name));         }     } }   Pretend, that this is a commercial application. The hacker will only have the executable and maybe a few config files, etc. After reviewing the executable, he can determine if it was produced in .NET by examing the file in ILDASM or Redgate’s Reflector. We are going to examine the file using RedGate’s Reflector. Upon launch, we simply drag/drop the exe over to the application. We have the following for the Main method:   and for the IsProcessOpen method:     Without any other knowledge as to how this works, the hacker could export the exe and get vs project build or copy this code in and our application would run. Using Reflector output. using System; using System.Diagnostics; using System.Linq;   namespace ObfuscateMe {     class Program     {                static void Main(string[] args)         {               Console.WriteLine(IsProcessOpen("notepad"));             Console.ReadLine();         }             public static bool IsProcessOpen(string name)         {             return Process.GetProcesses().Any<Process>(delegate(Process clsProcess)             {                 return clsProcess.ProcessName.Contains(name);             });         }       } } The code is not identical, but returns the same value. At this point, with a little bit of effort you could prevent the hacker from reverse engineering your code so quickly by using Eazfuscator.NET. Eazfuscator.NET is just one of many programs built for this. Visual Studio ships with a community version of Dotfoscutor. So download and load Eazfuscator.NET and drag/drop your exectuable/project into the window. It will work for a few minutes depending if you have a quad-core or not. After it finishes, open the executable in RedGate Reflector and you will get the following: Main After Obfuscation IsProcessOpen Method after obfuscation: As you can see with the jumbled characters, it is not as easy as the first example. I am aware of methods around this, but it takes more effort and unless the hacker is up for the challenge, they will just pick another program. This is also helpful if you are a consultant and make clients pay a yearly license fee. This would prevent the average software developer from jumping into your security routine after you have left. I hope this article helped someone. If you have any feedback, please leave it in the comments below.

  Read the article

• bulk insert and update with ADO.NET Entity Framework

  - by Keith Barrows

  I am writing a small application that does a lot of feed processing. I want to use LINQ EF for this as speed is not an issue, it is a single user app and, in the end, will only be used once a month. My questions revolves around the best way to do bulk inserts using LINQ EF. After parsing the incoming data stream I end up with a List of values. Since the end user may end up trying to import some duplicate data I would like to "clean" the data during insert rather than reading all the records, doing a for loop, rejecting records, then finally importing the remainder. This is what I am currently doing: DateTime minDate = dataTransferObject.Min(c => c.DoorOpen); DateTime maxDate = dataTransferObject.Max(c => c.DoorOpen); using (LabUseEntities myEntities = new LabUseEntities()) { var recCheck = myEntities.ImportDoorAccess.Where(a => a.DoorOpen >= minDate && a.DoorOpen <= maxDate).ToList(); if (recCheck.Count > 0) { foreach (ImportDoorAccess ida in recCheck) { DoorAudit da = dataTransferObject.Where(a => a.DoorOpen == ida.DoorOpen && a.CardNumber == ida.CardNumber).First(); if (da != null) da.DoInsert = false; } } ImportDoorAccess newIDA; foreach (DoorAudit newDoorAudit in dataTransferObject) { if (newDoorAudit.DoInsert) { newIDA = new ImportDoorAccess { CardNumber = newDoorAudit.CardNumber, Door = newDoorAudit.Door, DoorOpen = newDoorAudit.DoorOpen, Imported = newDoorAudit.Imported, RawData = newDoorAudit.RawData, UserName = newDoorAudit.UserName }; myEntities.AddToImportDoorAccess(newIDA); } } myEntities.SaveChanges(); } I am also getting this error: System.Data.UpdateException was unhandled Message="Unable to update the EntitySet 'ImportDoorAccess' because it has a DefiningQuery and no element exists in the element to support the current operation." Source="System.Data.SqlServerCe.Entity" What am I doing wrong? Any pointers are welcome.

  Read the article

• Hidden Features of C#?

  - by Serhat Özgel

  This came to my mind after I learned the following from this question: where T : struct We, C# developers, all know the basics of C#. I mean declarations, conditionals, loops, operators, etc. Some of us even mastered the stuff like Generics, anonymous types, lambdas, linq, ... But what are the most hidden features or tricks of C# that even C# fans, addicts, experts barely know? Here are the revealed features so far: Keywords yield by Michael Stum var by Michael Stum using() statement by kokos readonly by kokos as by Mike Stone as / is by Ed Swangren as / is (improved) by Rocketpants default by deathofrats global:: by pzycoman using() blocks by AlexCuse volatile by Jakub Šturc extern alias by Jakub Šturc Attributes DefaultValueAttribute by Michael Stum ObsoleteAttribute by DannySmurf DebuggerDisplayAttribute by Stu DebuggerBrowsable and DebuggerStepThrough by bdukes ThreadStaticAttribute by marxidad FlagsAttribute by Martin Clarke ConditionalAttribute by AndrewBurns Syntax ?? operator by kokos number flaggings by Nick Berardi where T:new by Lars Mæhlum implicit generics by Keith one-parameter lambdas by Keith auto properties by Keith namespace aliases by Keith verbatim string literals with @ by Patrick enum values by lfoust @variablenames by marxidad event operators by marxidad format string brackets by Portman property accessor accessibility modifiers by xanadont ternary operator (?:) by JasonS checked and unchecked operators by Binoj Antony implicit and explicit operators by Flory Language Features Nullable types by Brad Barker Currying by Brian Leahy anonymous types by Keith __makeref __reftype __refvalue by Judah Himango object initializers by lomaxx format strings by David in Dakota Extension Methods by marxidad partial methods by Jon Erickson preprocessor directives by John Asbeck DEBUG pre-processor directive by Robert Durgin operator overloading by SefBkn type inferrence by chakrit boolean operators taken to next level by Rob Gough pass value-type variable as interface without boxing by Roman Boiko programmatically determine declared variable type by Roman Boiko Static Constructors by Chris Easier-on-the-eyes / condensed ORM-mapping using LINQ by roosteronacid Visual Studio Features select block of text in editor by Himadri snippets by DannySmurf Framework TransactionScope by KiwiBastard DependantTransaction by KiwiBastard Nullable<T> by IainMH Mutex by Diago System.IO.Path by ageektrapped WeakReference by Juan Manuel Methods and Properties String.IsNullOrEmpty() method by KiwiBastard List.ForEach() method by KiwiBastard BeginInvoke(), EndInvoke() methods by Will Dean Nullable<T>.HasValue and Nullable<T>.Value properties by Rismo GetValueOrDefault method by John Sheehan Tips & Tricks nice method for event handlers by Andreas H.R. Nilsson uppercase comparisons by John access anonymous types without reflection by dp a quick way to lazily instantiate collection properties by Will JavaScript-like anonymous inline-functions by roosteronacid Other netmodules by kokos LINQBridge by Duncan Smart Parallel Extensions by Joel Coehoorn

  Read the article

• A list of Entity Framework providers for various databases

  - by Robert Koritnik

  Which providers are there and your experience using them I would like to know about all possible native .net Framework Entity Framework providers that are out there as well as their limitations compared to the default Linq2Entities (from MS for MS SQL). If there are more for the same database even better. Tell me and I'll be updating this post with this list. Feel free to add additional providers directly into this post or provide an answer and others (including me) will add it to the list. Entity Framework 1 Microsoft SQL Server Standard/Enterprise/Express Linq 2 Entities - Microsoft SQL Server connector DataDirect ADO.NET Data Providers Microsoft SQL Server CE (Compact Edition) Any provider? MySQL MySQL Connector (since version 6.0) - I've read about issues when using Skip(), Take() and Sort() in the same expression tree - everyone welcome to input their experience/knowledge regarding this. (NOTE: MySQL Connector/NET Visual Studio Integration is not supported in the Express Editions of Visual Studio, meaning you won't be able to view MySQL databases in the Database explorer window or add a MySQL data source via Visual Studio wizard dialog boxes. Some users may find that this limits their ability to use Entity Framework and MySQL within Visual Studio Express). Devart dotConnect for MySQL - similar issues to MySql's connector as I've read and both try to blame MS for it [these issues are supposed to be solved] SQLite Devart dotConnect for SQLite System.Data.SQLite PostgreSQL Devart dotConnect for PostgreSQL Npgsql Oracle Devart dotConnect for Oracle Sample Entity Framework Provider for Oracle - community effort project DataDirect ADO.NET Data Providers DB2 IBM Data Server Provider has EF support. Here are some limitations. DataDirect ADO.NET Data Providers Sybase Sybase iAnywhere DataDirect ADO.NET Data Providers Informix IBM Data Server Provider supports Informix Firebird ADO.NET Data Provider with EF support Provider Wrappers Tracing and Caching Providers for EF Entity Framework 4 (beta) Microsoft SQL Server Microsoft's Linq to Entities 4 - shipped with .net 4.0 and Visual Studio 2010; so far the only provider for EF4 MySQL Devart dotConnect for MySQL SQLite Devart dotConnect for SQLite PostgreSQL Devart dotConnect for PostgreSQL Oracle Devart dotConnect for Oracle

  Read the article

• Connecting to Oracle 10g from .NET

  - by Xinus

  I am trying to connect to oracle server located at some IP address but always get error as System.TypeInitializationException: The type initializer for 'Oracle.DataAccess.Client.OracleConnection' threw an exception. --- Oracle.DataAccess.Client.OracleException The provider is not compatible with the version of Oracle client at Oracle.DataAccess.Client.OracleInit.Initialize() at Oracle.DataAccess.Client.OracleConnection..cctor() --- End of inner exception stack trace --- at Oracle.DataAccess.Client.OracleConnection..ctor(String connectionString) at WebApplication1._Default.Page_Load(Object sender, EventArgs e) in C:\Users\Sunil\Documents\Visual Studio 2008\Projects\WebApplication1\WebApplication1\Default.aspx.cs:line 26 Here is a test file using System; using System.Collections; using System.Configuration; using System.Data; using System.Linq; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.HtmlControls; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Xml.Linq; using Oracle.DataAccess.Client; namespace WebApplication1 { public partial class _Default : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { try { string oradb = "Data Source=(DESCRIPTION=(ADDRESS_LIST=" + "(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.1.11)(PORT=1523)))" + "(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=ORCL)));" + "User Id=<user id>;Password=<some password>;"; OracleConnection conn = new OracleConnection(oradb); // C# conn.Open(); } catch (Exception ex){ Label1.Text = ex.ToString(); } } } } I have installed 10gR2 client and oracle 10gR2 provider for ASP.NET. Am I missing anything ?

  Read the article

• EF4 querying from parent to grandchildren

  - by Hans Kesting

  I have a model withs Parents, Children and Grandchildren, in a many-to-many relationship. Using this article I created POCO classes that work fine, except for one thing I can't yet figure out. When I query the Parents or Children directly using LINQ, the SQL reflects the LINQ query (a .Count() executes a COUNT in the database and so on) - fine. The Parent class has a Children property, to access it's children. But (and now for the problem) this doesn't expose an IQueryable interface but an ICollection. So when I access the Children property on a particular parent all the Parent's Children are read. Even worse, when I access the Grandchildren (theParent.Children.SelectMany(child => child.GrandChildren).Count()) then for each and every child a separate request is issued to select all data of it's grandchildren. That's a lot of separate queries! Changing the type of the Children property from ICollection to IQueryable doesn't solve this. Apart from missing methods I need, like Add() and Remove(), EF just doesn't recognize the navigation property then. Are there correct ways (as in: low database interaction) of querying through children (and what are they)? Or is this just not possible?

  Read the article

• asp.net mvc custom model binder

  - by mike

  pleas help guys, my custom model binder which has been working perfectly has starting giving me errors details below An item with the same key has already been added. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.ArgumentException: An item with the same key has already been added. Source Error: Line 31: { Line 32: string key = bindingContext.ModelName; Line 33: var doc = base.BindModel(controllerContext, bindingContext) as Document; Line 34: Line 35: // DoBasicValidation(bindingContext, doc); Source File: C:\Users\Bich Vu\Documents\Visual Studio 2008\Projects\PitchPortal\PitchPortal.Web\Binders\DocumentModelBinder.cs Line: 33 Stack Trace: [ArgumentException: An item with the same key has already been added.] System.ThrowHelper.ThrowArgumentException(ExceptionResource resource) +51 System.Collections.Generic.Dictionary2.Insert(TKey key, TValue value, Boolean add) +7462172 System.Linq.Enumerable.ToDictionary(IEnumerable1 source, Func2 keySelector, Func2 elementSelector, IEqualityComparer1 comparer) +270 System.Linq.Enumerable.ToDictionary(IEnumerable1 source, Func2 keySelector, IEqualityComparer1 comparer) +102 System.Web.Mvc.ModelBindingContext.get_PropertyMetadata() +157 System.Web.Mvc.DefaultModelBinder.BindProperty(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor) +158 System.Web.Mvc.DefaultModelBinder.BindProperties(ControllerContext controllerContext, ModelBindingContext bindingContext) +90 System.Web.Mvc.DefaultModelBinder.BindComplexElementalModel(ControllerContext controllerContext, ModelBindingContext bindingContext, Object model) +50 System.Web.Mvc.DefaultModelBinder.BindComplexModel(ControllerContext controllerContext, ModelBindingContext bindingContext) +1048 System.Web.Mvc.DefaultModelBinder.BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) +280 PitchPortal.Web.Binders.documentModelBinder.BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) in C:\Users\Bich Vu\Documents\Visual Studio 2008\Projects\PitchPortal\PitchPortal.Web\Binders\DocumentModelBinder.cs:33 System.Web.Mvc.ControllerActionInvoker.GetParameterValue(ControllerContext controllerContext, ParameterDescriptor parameterDescriptor) +257 System.Web.Mvc.ControllerActionInvoker.GetParameterValues(ControllerContext controllerContext, ActionDescriptor actionDescriptor) +109 System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +314 System.Web.Mvc.Controller.ExecuteCore() +105 System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) +39 System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext) +7 System.Web.Mvc.<c_DisplayClass8.b_4() +34 System.Web.Mvc.Async.<c_DisplayClass1.b_0() +21 System.Web.Mvc.Async.<c_DisplayClass81.b_7(IAsyncResult _) +12 System.Web.Mvc.Async.WrappedAsyncResult1.End() +59 System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +44 System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +7 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +8677678 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155 any ideas guys? Thanks

  Read the article

• Castle Windsor using wrong component to satisfy a dependency

  - by Neil Barnwell

  I have the following component mapping in Windsor xml: <component id="dataSession.DbConnection" service="System.Data.IDbConnection, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" type="System.Data.SqlClient.SqlConnection, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" lifestyle="custom" customLifestyleType="MyCompany.Castle.PerOperationLifestyle.PerOperationLifestyleManager, MyCompany.Castle"> <parameters> <connectionString>server=(local);database=MyCompany;trusted_connection=true;application name=OperationScopeTest;</connectionString> </parameters> </component> <component id="dataSession.DataContext" service="System.Data.Linq.DataContext, System.Data.Linq, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" type="MyCompany.BusinessLogic.MyCompanyDataContext, MyCompany.BusinessLogic" lifestyle="custom" customLifestyleType="MyCompany.Castle.PerOperationLifestyle.PerOperationLifestyleManager, MyCompany.Castle"> <parameters> <connection>${dataSession.DbConnection}</connection> </parameters> </component> However, when I ask the container for a DataContext, it actually uses the constructor requiring a connection string, despite the ${dataSession.DbConnection} being an IDbConnection. Why is this, and how to I make Windsor use the correct constructor?

  Read the article

• Installed VS Express 2010 with .NET 4.0 and now .NET 3.5 setup project adds 15 dependencies

  - by Heckflosse_230

  Hi, I installed VS Express 2010 with .NET 4.0 and now a .NET 3.5 setup project in VS 2008 adds 15 dependencies (below), what is going on??? I did not change anything in the project in between installing VS 2010, VS 2008 is packagin the following files in the project: ==================== Packaging file 'Microsoft.Transactions.Bridge.dll'... Packaging file 'System.Core.dll'... Packaging file 'System.Data.DataSetExtensions.dll'... Packaging file 'System.Data.Entity.dll'... Packaging file 'System.Data.Linq.dll'... Packaging file 'System.Data.Services.Client.dll'... Packaging file 'System.Data.Services.Design.dll'... Packaging file 'System.IdentityModel.Selectors.dll'... Packaging file 'System.IdentityModel.dll'... Packaging file 'System.Runtime.Serialization.dll'... Packaging file 'System.ServiceModel.Web.dll'... Packaging file 'System.ServiceModel.dll'... Packaging file 'System.Web.Abstractions.dll'... Packaging file 'System.Web.Extensions.dll'... Packaging file 'System.Xml.Linq.dll'... ==================== I've uninstalled VS 2010 and .NET 4.0 but to no avail, same problem. Lesson learned: DON'T EXPERIMENT ON DEVELOPMENT MACHINE! Thanks, Chris

  Read the article

• Castle Windsor upgrade causes TypeLoadException for generic types

  - by Neil Barnwell

  I have the following mapping in my Castle Windsor xml file which has worked okay (unchanged) for some time: <component id="defaultBasicRepository" service="MyApp.Models.Repositories.IBasicRepository`1, MyApp.Models" type="MyApp.Models.Repositories.Linq.BasicRepository`1, MyApp.Models" lifestyle="perWebRequest"/> I got this from the Windsor documentation at http://www.castleproject.org/container/documentation/v1rc3/usersguide/genericssupport.html. Since I upgraded Windsor, I now get the following exception at runtime: Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.TypeLoadException: GenericArguments[0], 'T', on 'MyApp.Models.Repositories.Linq.BasicRepository`1[TEntity]' violates the constraint of type parameter 'TEntity'. Source Error: Line 44: public static void ConfigureIoC() Line 45: { Line 46: var windsor = new WindsorContainer("Windsor.xml"); Line 47: Line 48: ServiceLocator.SetLocatorProvider(() = new WindsorServiceLocator(windsor)); I'm using ASP.NET MVC 1.0, Visual Studio 2008 and Castle Windsor as downloaded from http://sourceforge.net/projects/castleproject/files/InversionOfControl/2.1/Castle-Windsor-2.1.1.zip/download Can anyone shed any light on this? I'm sure the upgrade of Castle Windsor is what caused it - it's been working well for ages.

  Read the article

• asp.net mvc custom model binder

  - by mike

  pleas help guys, my custom model binder which has been working perfectly has starting giving me errors details below An item with the same key has already been added. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.ArgumentException: An item with the same key has already been added. Source Error: Line 31: { Line 32: string key = bindingContext.ModelName; Line 33: var doc = base.BindModel(controllerContext, bindingContext) as Document; Line 34: Line 35: // DoBasicValidation(bindingContext, doc); Source File: C:\Users\Bich Vu\Documents\Visual Studio 2008\Projects\PitchPortal\PitchPortal.Web\Binders\DocumentModelBinder.cs Line: 33 Stack Trace: [ArgumentException: An item with the same key has already been added.] System.ThrowHelper.ThrowArgumentException(ExceptionResource resource) +51 System.Collections.Generic.Dictionary2.Insert(TKey key, TValue value, Boolean add) +7462172 System.Linq.Enumerable.ToDictionary(IEnumerable1 source, Func2 keySelector, Func2 elementSelector, IEqualityComparer1 comparer) +270 System.Linq.Enumerable.ToDictionary(IEnumerable1 source, Func2 keySelector, IEqualityComparer1 comparer) +102 System.Web.Mvc.ModelBindingContext.get_PropertyMetadata() +157 System.Web.Mvc.DefaultModelBinder.BindProperty(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor) +158 System.Web.Mvc.DefaultModelBinder.BindProperties(ControllerContext controllerContext, ModelBindingContext bindingContext) +90 System.Web.Mvc.DefaultModelBinder.BindComplexElementalModel(ControllerContext controllerContext, ModelBindingContext bindingContext, Object model) +50 System.Web.Mvc.DefaultModelBinder.BindComplexModel(ControllerContext controllerContext, ModelBindingContext bindingContext) +1048 System.Web.Mvc.DefaultModelBinder.BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) +280 PitchPortal.Web.Binders.documentModelBinder.BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) in C:\Users\Bich Vu\Documents\Visual Studio 2008\Projects\PitchPortal\PitchPortal.Web\Binders\DocumentModelBinder.cs:33 System.Web.Mvc.ControllerActionInvoker.GetParameterValue(ControllerContext controllerContext, ParameterDescriptor parameterDescriptor) +257 System.Web.Mvc.ControllerActionInvoker.GetParameterValues(ControllerContext controllerContext, ActionDescriptor actionDescriptor) +109 System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +314 System.Web.Mvc.Controller.ExecuteCore() +105 System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) +39 System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext) +7 System.Web.Mvc.<c_DisplayClass8.b_4() +34 System.Web.Mvc.Async.<c_DisplayClass1.b_0() +21 System.Web.Mvc.Async.<c__DisplayClass81.<BeginSynchronous>b__7(IAsyncResult _) +12 System.Web.Mvc.Async.WrappedAsyncResult1.End() +59 System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +44 System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +7 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +8677678 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155 any ideas guys? Thanks

  Read the article

• Looking for a .Net ORM

  - by SLaks

  I'm looking for a .Net 3.5 ORM framework with a rather unusual set of requirements: I need to create and alter tables at runtime with schemas defined by my end-users. (Obviously, that wouldn't be strongly-typed; I'm looking for something like a DataTable there) I also want regular strongly-typed partial classes for rows in non-dynamic tables, with custom validation and other logic. (Like normal ORMs) I want to load the entire database (or some entire tables) once, and keep it in memory throughout the life of the (WinForms) GUI. (I have a shared SQL Server with a relatively slow connection) I also want regular LINQ support (like LINQ-to-SQL) for ASP.Net on the shared server (which has a fast connection to SQL Server) In addition to SQL Server, I also want to be able to use a single-file database that would support XCopy deployment (without installing SQL CE on the end-user's machine). (Probably Access or SQLite) Finally, it has to be free (unless it's OpenAccess) I'll probably have to write it myself, as I don't think there is an existing ORM that meets these requirements. However, I don't want to re-invent the wheel if there is one, hence this question. I'm using VS2010, but I don't know when my webhost (LFC) will upgrade to .Net 4.0

  Read the article

• Using NHibernate's HQL to make a query with multiple inner joins

  - by Abu Dhabi

  The problem here consists of translating a statement written in LINQ to SQL syntax into the equivalent for NHibernate. The LINQ to SQL code looks like so: var whatevervar = from threads in context.THREADs join threadposts in context.THREADPOSTs on threads.thread_id equals threadposts.thread_id join posts1 in context.POSTs on threadposts.post_id equals posts1.post_id join users in context.USERs on posts1.user_id equals users.user_id orderby posts1.post_time where threads.thread_id == int.Parse(id) select new { threads.thread_topic, posts1.post_time, users.user_display_name, users.user_signature, users.user_avatar, posts1.post_body, posts1.post_topic }; It's essentially trying to grab a list of posts within a given forum thread. The best I've been able to come up with (with the help of the helpful users of this site) for NHibernate is: var whatevervar = session.CreateQuery("select t.Thread_topic, p.Post_time, " + "u.User_display_name, u.User_signature, " + "u.User_avatar, p.Post_body, p.Post_topic " + "from THREADPOST tp " + "inner join tp.Thread_ as t " + "inner join tp.Post_ as p " + "inner join p.User_ as u " + "where tp.Thread_ = :what") .SetParameter<THREAD>("what", threadid) .SetResultTransformer(Transformers.AliasToBean(typeof(MyDTO))) .List<MyDTO>(); But that doesn't parse well, complaining that the aliases for the joined tables are null references. MyDTO is a custom type for the output: public class MyDTO { public string thread_topic { get; set; } public DateTime post_time { get; set; } public string user_display_name { get; set; } public string user_signature { get; set; } public string user_avatar { get; set; } public string post_topic { get; set; } public string post_body { get; set; } } I'm out of ideas, and while doing this by direct SQL query is possible, I'd like to do it properly, without defeating the purpose of using an ORM. Thanks in advance!

  Read the article

• General N-Tier Architecture Question

  - by whatispunk

  In an N-Tier app you're supposed to have a business logic layer and a data access layer. Is it bad to simply have two assemblies: BusinessLogicLayer.dll and DataAccessLayer.dll to handle all this logic? How do you actually represent these layers. It seems silly, the way I've seen it, to have a BusinessLogic class library containing classes like: CustomerBusinessLogic.cs, OrderBusinessLogic.cs, etc. each calling their appropriately named cousin in the DataAccessLayer class library, i.e. CustomerDataAccess.cs, OrderDataAccess.cs. I want to create a web app using MVP and it doesn't seem so cut and dry as this. There are lots of opinions about where the business logic is supposed to be put in MVP and I'm not sure I've found a really great answer yet. I want this project to be easily testable, and I am trying to adhere to TDD methodologies as best I can. I intend to use MSTest and Rhino Mocks for testing. I was thinking of something like the following for my architecture: I'd use LINQ-To-SQL to talk to the database. WCF services to define data contract interfaces for the business logic layer. Then use MVP with ASP.NET Forms for the UI/BLL. Now, this isn't the start of this project, most of the LINQ stuff is already done, so its stuck. The WCF service would replace the existing DataAccessLayer assembly and the UI/BLL would replace the BusinessLogicLayer assembly etc. This sort of makes sense in my head, but its getting really late. Anyone that's traveled down this path have any guidance? Good links? Warnings? Thanks!

  Read the article

• Newbie question about controllers in ASP.Net MVC.

  - by Sergio Tapia

  I'm following a tutorial on creating the NerdDinner using ASP.Net MVC. However, I'm using Visual Studio 2010 Ultimate edition and there was only MVC2 to choose from. So I've following the tutorial so far, and everything is really clicking and being really well explained, until this little hitch. The guide is asking me to create new methods on a Controller file like so: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; namespace NerdDinner.Controllers { public class DinnersController : Controller { public void Index(){ Response.Write("<h1>Coming Soon: Dinners</h1>"); } public void Details(int id) { Response.Write("<h1>Details DinnerID: " + id + "</h1>"); } } } However, when I created the Controllers file, Visual Studio created an Index method already, but it looks vastly different to what the tutorial shows. Maybe this is the new way to do things using MVC2? using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; namespace NerdDinner.Controllers { public class DinnersController : Controller { // // GET: /Dinners/ public ActionResult Index() { return View(); } } } My question is, how can I reproduce the Details and Index method (they're in MVC) to the MVC2 way? Is this even relevant? Thank you!

  Read the article

• Factory Pattern: Determining concrete factory class instantiation?

  - by Chris

  I'm trying to learn patterns and I'm stuck on determining how or where a Factory Pattern determines what class to instanciate. If I have a Application that calls the factory and sends it, say, an xml config file to determine what type of action to take, where does that logic for interpreting the config file happen? THE FACTORY using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace myNamespace { public abstract class SourceFactory { abstract public UploadSource getUploadSource(); } public class TextSourceFactory : SourceFactory { public override UploadSource getUploadSource() { return new TextUploadSource(); } } public class XmlSourceFacotry : SourceFactory { public override UploadSource getUploadSource() { return new XmlUploadSource(); } } public class SqlSourceFactory : SourceFactory { public override UploadSource getUploadSource() { return new SqlUploadSource(); } } } THE CLASSES using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace myNamespace { public abstract class UploadSource { abstract public void Execute(); } public class TextUploadSource : UploadSource { public override void Execute() { Console.WriteLine("You executed a text upload source"); } } public class XmlUploadSource : UploadSource { public override void Execute() { Console.WriteLine("You executed an XML upload source"); } } public class SqlUploadSource : UploadSource { public override void Execute() { Console.WriteLine("You executed a SQL upload source"); } } }

  Read the article

• csc.exe not found error

  - by pokrate

  I have installed a fresh copy of windows xp 2002 with SP2, and then VS.net 2008 enterprise edition. I am trying to build a simplest possible web application, and its not compiling giving error csc.exe not found. I googled a lot, and spot the problem in the following section in web.config : <system.codedom> <compilers> <compiler language="c#;cs;csharp" extension=".cs" warningLevel="4" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"> <providerOption name="CompilerVersion" value="v3.5"/> <providerOption name="WarnAsError" value="false"/> </compiler> <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" warningLevel="4" type="Microsoft.VisualBasic.VBCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"> <providerOption name="CompilerVersion" value="v3.5"/> <providerOption name="OptionInfer" value="true"/> <providerOption name="WarnAsError" value="false"/> </compiler> </compilers> </system.codedom> But if i remove the csharp compiler section , and then compile, it compiles fine with vb compiler section. And if I change the value from v3.5 to v2.0 in the of csharp section, then also it compiles fine. But then all my Linq Queries are not recognized by the compiler. But System.Linq and all classes present in it are accessible in the code. Please help in this weird behavior.

  Read the article

• Perform Grouping of Resultsets in Code, not on Database Level

  - by NinjaBomb

  Stackoverflowers, I have a resultset from a SQL query in the form of: Category Column2 Column3 A 2 3.50 A 3 2 B 3 2 B 1 5 ... I need to group the resultset based on the Category column and sum the values for Column2 and Column3. I have to do it in code because I cannot perform the grouping in the SQL query that gets the data due to the complexity of the query (long story). This grouped data will then be displayed in a table. I have it working for specific set of values in the Category column, but I would like a solution that would handle any possible values that appear in the Category column. I know there has to be a straightforward, efficient way to do it but I cannot wrap my head around it right now. How would you accomplish it? EDIT I have attempted to group the result in SQL using the exact same grouping query suggested by Thomas Levesque and both times our entire RDBMS crashed trying to process the query. I was under the impression that Linq was not available until .NET 3.5. This is a .NET 2.0 web application so I did not think it was an option. Am I wrong in thinking that? EDIT Starting a bounty because I believe this would be a good technique to have in the toolbox to use no matter where the different resultsets are coming from. I believe knowing the most concise way to group any 2 somewhat similar sets of data in code (without .NET LINQ) would be beneficial to more people than just me.

  Read the article

• Where and how to start on C# and .Net Framework ?

  - by Rachel

  Currently, I have been working as an PHP developer for approximately 1 year now and I want learn about C# and .Net Framework, I do not have any experience with .Net Framework and C# and also there is not firm basis as to why I am going for C# and .Net Framework vs Java or any other programming languages, this decision is mere on career point of view and job opportunities. So my question is about: Is my decision wise to go for C# and .Net Framework route after working for sometime as an PHP Developer ? What are the good resources which I can refer and learn from to get knowledge on C# and .NET Framework ? How should I go about learning on C# and .NET Framework ? What all technologies should I be learning OR have experience with to be considered as an C#/.Net Developer, I am mentioning some technologies, please add or suggest one, if am missing out any ? Technologies C#-THE LANGUAGE GUI APPLICATION DEVELOPMENT WINDOWS CONTROL LIBRARY DELEGATES DATA ACCESS WITH ADO.NET MULTI THREADING ASSEMBLIES WINDOWS SERVICES VB INTRODUCTION TO VISUAL STUDIO .NET WINDOWS CONTROL LIBRARY DATA ACCESS WITH ADO.NET ASP.NET WEB TECHNOLOGIES CONTROLS VALIDATION CONTROL STATE MANAGEMENT CACHING ASP.NET CONFIGURATION ADO.NET ASP.NET TRACING & SECURITY IN ASP.NET XMLPROGRAMMING WEB SERVICES CRYSTAL REPORTS SSRS (SQL Server Reporting Services) MS-Reports LINQ: NET Language-Integrated Query NET Language-Integrated Query LINQ to SQL: SQL Integration WCF: Windows Communication Foundation What Is Windows Communication Foundation? Fundamental Windows Communication Foundation Concepts Windows Communication Foundation Architecture WPF: Windows Presentation Foundation Getting Started (WPF) Application Development WPF Fundamentals What are your thoughts, suggestions on this and from Job and Market Perspective, what areas of C#/.Net Development should I put my focus on ? I know this is very subjective and long question but advice would be highly appeciated. Thanks.

  Read the article

• Use of var keyword in C#

  - by kronoz

  After discussion with colleagues regarding the use of the 'var' keyword in C# 3 I wondered what people's opinions were on the appropriate uses of type inference via var? For example I rather lazily used var in questionable circumstances, e.g.:- foreach(var item in someList) { // ... } // Type of 'item' not clear. var something = someObject.SomeProperty; // Type of 'something' not clear. var something = someMethod(); // Type of 'something' not clear. More legitimate uses of var are as follows:- var l = new List<string>(); // Obvious what l will be. var s = new SomeClass(); // Obvious what s will be. Interestingly LINQ seems to be a bit of a grey area, e.g.:- var results = from r in dataContext.SomeTable select r; // Not *entirely clear* what results will be here. It's clear what results will be in that it will be a type which implements IEnumerable, however it isn't entirely obvious in the same way a var declaring a new object is. It's even worse when it comes to LINQ to objects, e.g.:- var results = from item in someList where item != 3 select item; This is no better than the equivilent foreach(var item in someList) { // ... } equivilent. There is a real concern about type safety here - for example if we were to place the results of that query into an overloaded method that accepted IEnumerable<int> and IEnumerable<double> the caller might inadvertently pass in the wrong type. Edit - var does maintain strong typing but the question is really whether it's dangerous for the type to not be immediately apparent on definition, something which is magnified when overloads mean compiler errors might not be issued when you unintentionally pass the wrong type to a method. Related Question: http://stackoverflow.com/questions/633474/c-do-you-use-var

  Read the article

• NHibernate IQueryable Collection as Property of Root

  - by Khalid Abuhakmeh

  Hello and thank you for taking the time to read this. I have a root object that has a property that is a collection. For example : I have a Shelf object that has Books. // now public class Shelf { public ICollection<Book> Books {get; set;} } // want public class Shelf { public IQueryable<Book> Books {get;set;} } What I want to accomplish is to return a collection that is IQueryable so that I can run paging and filtering off of the collection directly from the the parent. var shelf = shelfRepository.Get(1); var filtered = from book in shelf.Books where book.Name == "The Great Gatsby" select book; I want to have that query executed specifically by NHibernate and not a get all to load a whole collection and then parse it in memory (which is what currently happens when I use ICollection). The reasoning behind this is that my collection could be huge, tens of thousands of records, and a get all query could bash my database. I would like to do this implicitly so that when NHibernate sees and IQueryable on my class it knows what to do. I have looked at NHibernates Linq provider and currently I am making the decision to take large collections and split them into their own repository so that I can make explicit calls for filtering and paging. Linq To SQL offers something similar to what I'm talking about.

  Read the article

< Previous Page | 131 132 133 134 135 136 137 138 139 140 141 142  | Next Page >