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  • Daily tech links for .net and related technologies - Mar 26-28, 2010

    - by SanjeevAgarwal
    Daily tech links for .net and related technologies - Mar 26-28, 2010 Web Development Creating Rich View Components in ASP.NET MVC - manzurrashid Diagnosing ASP.NET MVC Problems - Brad Wilson Templated Helpers & Custom Model Binders in ASP.NET MVC 2 - gshackles The jQuery Templating Plugin and Why You Should Be Excited! - Chris Love Web Deployment Made Awesome: If You're Using XCopy, You're Doing It Wrong - Scott Hansleman Dynamic User Specific CSS Selection at Run Time - Misfit Geek Sending email...(read more)

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  • Failed to load viewstate.The control tree into which viewstate is being loaded...etc

    - by alaa9jo
    Two days ago,a colleague of mine tried to publish an asp.net website (which is built in VS2008 using framework 3.5) to our server,he configured everything in IIS (he made sure that the selected asp.net version is 2.0) and launched the website..at first it was working great but when he tried to click on a specific treeview...BOOM..: "Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request. For example, when adding controls dynamically, the controls added during a post-back must match the type and position of the controls added during the initial request." In that page there were these control: a TreeView and a Placeholder,when the user selects any node then it's controls will be created dynamically into that placeholder..for the first time it's working fine but when (s)he select another node then that issue appears. He called me to help him with this issue,for me this is the first time I see such an issue,scratch my head then I decided to eliminate the possibilities of this issue one by one,at the development machine it's working perfectly,he published the website at the local IIS and again..it's working perfectly,I took a copy of the website and published it into my laptop but no issues at all,so this is means that it's not an issue in the code. So there is something missing/wrong in our server [it has Windows Server 2003],we went to the server and checked on the web-config and the configurations on IIS...nothing wrong so far,so I decided to check if the framework 3.5 is installed or not and the answer: it wasn't installed Of course he assumed that it was installed and there was nothing to tell if it wasn't from the "ASP.Net version" in IIS because frameworks 3.0 and 3.5 will not be listed there [2.0 will be listed there instead],the only way to check if it was installed or not is to search for the framework in this path:[WINDOWS Folder]\Microsoft.NET\Framework or check if it was installed in Add or remove programs. The obvious solution for his case: We installed Framework 3.5 SP1 into our server,did a restart to the machine and it worked ! If anyone faced the same issue and solved it using the same solution or with a different one please post it here to share experience.

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  • Daily tech links for .net and related technologies - Mar 18-21, 2010

    - by SanjeevAgarwal
    Daily tech links for .net and related technologies - Mar 18-21, 2010 Web Development TDD kata for ASP.NET MVC controllers (part 2) -David Take Control Of Web Control ClientID Values in ASP.NET 4.0 - Scott Mitchell Inside the ASP.NET MVC Controller Factory - Dino Esposito Microsoft, jQuery, and Templating - stephen walther Cross Domain AJAX Request with YQL and jQuery - Jeffrey Way T4MVC Add-In to auto run template -Wayne Web Design Website Content Planning The Right Way - Kristin Wemmer Microsoft...(read more)

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  • Daily tech links for .net and related technologies - May 13-16, 2010

    - by SanjeevAgarwal
    Daily tech links for .net and related technologies - May 13-16, 2010 Web Development Integrating Twitter Into An ASP.NET Website Using OAuth - Scott Mitchell T4MVC Extensions for MVC Partials - Evan Building a Data Grid in ASP.NET MVC - Ali Bastani Introducing the MVC Music Store - MVC 2 Sample Application and Tutorial - Jon Galloway Announcing the RTM of MvcExtensions - kazimanzurrashid Optimizing Your Website For Speed Web Design Validation with the jQuery UI Tabs Widget - Chris Love A Brief History...(read more)

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  • I spy a Live Framework portal

    - by jamiet
    Those that have followed my blogs for a while may know that I have a slightly banal interest in Windows Live and, more specifically, the Live Services developer platform'; if that doesn’t sound interesting to you then stop reading now. My interest mainly stems from the Live Mesh technology that was announced a couple of years ago and the data synchronisation platform API that underpins it; that platform is called the Live Framework or LiveFX for short. At the Professional Developer’s Conference (PDC) 2008 Microsoft made LiveFX available to the public as a Tech Preview and I spent some time learning to use it and also built a few test apps on it too. In August 2009 an announcement came that that tech preview was getting shut down: "At the Professional Developer Conference 2008, we gave the developer community access to the technical preview of the Live Framework. The Live Framework is core to our vision of providing you with a consistent programming interface. Now we are working to integrate existing services, controls and the Live Framework into the next release of Windows Live. Your feedback continues to help us build the best possible offerings for Windows Live users, for you and for your customers. " Since then news on LiveFX has disappeared save for a throwaway session at PDC09 and I was hoping that news was going to appear at this week’s MIX conference but nothing was forthcoming. Instead though today I stumbled upon an unannounced portal for future LiveFX applications on Microsoft’s Azure portal at http://live.azure.com. Check it out: I consider this to be very good news. This Azure portal was built after the LiveFX tech preview was decommissioned so seeing Live Services existing so prominently alongside Microsoft’s other cloud efforts like Windows Azure and SQL Azure vindicates my early investment in the platform and gives me hope that we’re going to see something get released very very soon. I believe that the potential uses for this platform are extremely compelling and I’m looking forward to trying some out in the near future. I am also expecting LiveFX to have a heavy dependency on the OData protocol that I talked about yesterday in my post OData.org updated - gives clues about future sql azure enhancements so you can tell where my interest in that stems from. In case you’re wondering the projects that you see listed above (Basic List Sample, JT-proj etc…) are projects that I built on the old Tech Preview platform so clearly that stuff has not gone for good which is also good news; not just because it means I’ll have access to the code I wrote before but I also assume it means that LiveFX won’t have changed much since its tech preview incarnation. I know there are other LiveFX buffs out there and hopefully this news reaches some of them. If you are one of them the please put a comment below and let me know your thoughts! @Jamiet Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • How to eager load sibling data using LINQ to SQL?

    - by Scott
    The goal is to issue the fewest queries to SQL Server using LINQ to SQL without using anonymous types. The return type for the method will need to be IList<Child1>. The relationships are as follows: Parent Child1 Child2 Grandchild1 Parent Child1 is a one-to-many relationship Child1 Grandchild1 is a one-to-n relationship (where n is zero to infinity) Parent Child2 is a one-to-n relationship (where n is zero to infinity) I am able to eager load the Parent, Child1 and Grandchild1 data resulting in one query to SQL Server. This query with load options eager loads all of the data, except the sibling data (Child2): DataLoadOptions loadOptions = new DataLoadOptions(); loadOptions.LoadWith<Child1>(o => o.GrandChild1List); loadOptions.LoadWith<Child1>(o => o.Parent); dataContext.LoadOptions = loadOptions; IQueryable<Child1> children = from child in dataContext.Child1 select child; I need to load the sibling data as well. One approach I have tried is splitting the query into two LINQ to SQL queries and merging the result sets together (not pretty), however upon accessing the sibling data it is lazy loaded anyway. Adding the sibling load option will issue a query to SQL Server for each Grandchild1 and Child2 record (which is exactly what I am trying to avoid): DataLoadOptions loadOptions = new DataLoadOptions(); loadOptions.LoadWith<Child1>(o => o.GrandChild1List); loadOptions.LoadWith<Child1>(o => o.Parent); loadOptions.LoadWith<Parent>(o => o.Child2List); dataContext.LoadOptions = loadOptions; IQueryable<Child1> children = from child in dataContext.Child1 select child; exec sp_executesql N'SELECT * FROM [dbo].[Child2] AS [t0] WHERE [t0].[ForeignKeyToParent] = @p0',N'@p0 int',@p0=1 exec sp_executesql N'SELECT * FROM [dbo].[Child2] AS [t0] WHERE [t0].[ForeignKeyToParent] = @p0',N'@p0 int',@p0=2 exec sp_executesql N'SELECT * FROM [dbo].[Child2] AS [t0] WHERE [t0].[ForeignKeyToParent] = @p0',N'@p0 int',@p0=3 exec sp_executesql N'SELECT * FROM [dbo].[Child2] AS [t0] WHERE [t0].[ForeignKeyToParent] = @p0',N'@p0 int',@p0=4 I've also written LINQ to SQL queries to join in all of the data in hopes that it would eager load the data, however when the LINQ to SQL EntitySet of Child2 or Grandchild1 are accessed it lazy loads the data. The reason for returning the IList<Child1> is to hydrate business objects. My thoughts are I am either: Approaching this problem the wrong way. Have the option of calling a stored procedure? My organization should not be using LINQ to SQL as an ORM? Any help is greatly appreciated. Thank you, -Scott

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  • DevDays ‘00 The Netherlands day #2

    - by erwin21
    Day 2 of DevDays 2010 and again 5 interesting sessions at the World Forum in The Hague. The first session of the today in the big world forum theater was from Scott Hanselman, he gives a lap around .NET 4.0. In his way of presenting he talked about all kind of new features of .NET 4.0 like MEF, threading, parallel processing, changes and additions to the CLR and DLR, WPF and all new language features of .NET 4.0. After a small break it was ready for session 2 from Scott Allen about Tips, Tricks and Optimizations of LINQ. He talked about lazy and deferred executions, the difference between IQueryable and IEnumerable and the two flavors of LINQ syntax. The lunch was again very good prepared and delicious, but after that it was time for session 3 Web Vulnerabilities and Exploits from Alex Thissen. This was no normal session but more like a workshop, we decided what kind of subjects we discussed, the subjects where OWASP, XSS and other injections, validation, encoding. He gave some handy tips and tricks how to prevent such attacks. Session 4 was about the new features of C# 4.0 from Alex van Beek. He talked about Optional- en Named Parameters, Generic Co- en Contra Variance, Dynamic keyword and COM Interop features. He showed how to use them but also when not to use them. The last session of today and also the last session of DevDays 2010 was about WCF Best Practices from Gerben van Loon. He talked about 7 best practices that you must know when you are going to use WCF. With some quick demos he showed the problem and the solution for some common issues. It where two interesting days and next year i sure will be attending again.

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  • Entity Framework 4.0: Why Would One Use the Code Generated EntityObjects Over POCO Objects?

    - by senfo
    Aside from faster development time (Visual Studio 2010 beta 2 has no T4 templates for building POCO entity objects that I'm aware of), are there any advantages to using the traditional EntityObject entities that Entity Framework creates, by default? If Microsoft delivers a T4 template for building POCO objects, I'm trying to figure out why anybody would want to use the traditional method.

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  • Linq PredicateBuilder with conditional AND, OR and NOT filters.

    - by richeym
    We have a project using LINQ to SQL, for which I need to rewrite a couple of search pages to allow the client to select whether they wish to perform an and or an or search. I though about redoing the LINQ queries using PredicateBuilder and have got this working pretty well I think. I effectively have a class containing my predicates, e.g.: internal static Expression<Func<Job, bool>> Description(string term) { return p => p.Description.Contains(term); } To perform the search i'm doing this (some code omitted for brevity): public Expression<Func<Job, bool>> ToLinqExpression() { var predicates = new List<Expression<Func<Job, bool>>>(); // build up predicates here if (SearchType == SearchType.And) { query = PredicateBuilder.True<Job>(); } else { query = PredicateBuilder.False<Job>(); } foreach (var predicate in predicates) { if (SearchType == SearchType.And) { query = query.And(predicate); } else { query = query.Or(predicate); } } return query; } While i'm reasonably happy with this, I have two concerns: The if/else blocks that evaluate a SearchType property feel like they could be a potential code smell. The client is now insisting on being able to perform 'and not' / 'or not' searches. To address point 2, I think I could do this by simply rewriting my expressions, e.g.: internal static Expression<Func<Job, bool>> Description(string term, bool invert) { if (invert) { return p => !p.Description.Contains(term); } else { return p => p.Description.Contains(term); } } However this feels like a bit of a kludge, which usually means there's a better solution out there. Can anyone recommend how this could be improved? I'm aware of dynamic LINQ, but I don't really want to lose LINQ's strong typing.

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  • SIMPLE PHP MVC Framework!

    - by Allen
    I need a simple and basic MVC example to get me started. I dont want to use any of the available packaged frameworks. I am in need of a simple example of a simple PHP MVC framework that would allow, at most, the basic creation of a simple multi-page site. I am asking for a simple example because I learn best from simple real world examples. Big popular frameworks (such as code ignighter) are to much for me to even try to understand and any other "simple" example I have found are not well explained or seem a little sketchy in general. I should add that most examples of simple MVC frameworks I see use mod_rewrite (for URL routing) or some other Apache-only method. I run PHP on IIS. I need to be able to understand a basic MVC framework, so that I could develop my own that would allow me to easily extend functionality with classes. I am at the point where I understand basic design patterns and MVC pretty well. I understand them in theory, but when it comes down to actually building a real world, simple, well designed MVC framework in PHP, i'm stuck. I would really appreciate some help! Edit: I just want to note that I am looking for a simple example that an experienced programmer could whip up in under an hour. I mean simple as in bare bones simple. I dont want to use any huge frameworks, I am trying to roll my own. I need a decent SIMPLE example to get me going.

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  • How do I use Linq-to-sql to iterate db records?

    - by Seth Spearman
    I asked on SO a few days ago what was the simplest quickest way to build a wrapper around a recently completed database. I took the advice and used sqlmetal to build linq classes around my database design. Now I am having two problems. One, I don't know LINQ. And, two, I have been shocked to realize how hard it is to learn. I have a book on LINQ (Linq In Action by Manning) and it has helped some but at the end of the day it is going to take me a couple of weeks to get traction and I need to make some progress on my project today. So, I am looking for some help getting started. Click HERE To see my simple database schema. Click HERE to see the vb class that was generated for the schema. My needs are simple. I have a console app. The main table is the SupplyModel table. Most of the other tables are child tables of the SupplyModel table. I want to iterate through each of Supply Model records. I want to grab the data for a supply model and then DoStuff with the data. And I also need to iterate through the child records, for each supply model, for example the NumberedInventories and DoStuff with that as well. I need help doing this in VB rather than C# if possible. I am not looking for the whole solution...if you can supply a couple of code-snippets to get me on my way that would be great. Thanks for your help. Seth

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  • Getting the first result from a LINQ query - why does ElementAt<T>(0) fails when First<T>() succeeds

    - by Mr Roys
    I have a method AddStudent() which looks for a student with the same name and returns an existing student from the database if there is a student with the same name, otherwise it creates a new student and adds it to the database. I'm curious why se = students.First<StudentEntity>(); succeeds when se = students.ElementAt<StudentEntity>(0); fails when I try to get the first result from the LINQ query. Aren't the two methods the same? The full code for the method is shown below. public Student AddStudent(string name) { using (SchoolEntities db = new SchoolEntities()) { // find student with same name via LINQ var students = from s in db.StudentEntitySet where s.name == name select s; StudentEntity se = default(StudentEntity); // if student with the same name is already present, return // that student if (students.Count<StudentEntity>() > 0) { // if i use ElementAt, if fails with a "LINQ to Entities does not // recognize the method 'StudentEntity ElementAt[StudentEntity] // (System.Linq.IQueryable`1[StudentEntity], Int32)' method, // and this method cannot be translated into a store expression.", // but not when I use First. Why? // se = students.ElementAt<StudentEntity>(0); se = students.First<StudentEntity>(); } else { // passing 0 for first parameter (id) since it's represented by // a BigInt IDENTITY field in the database so any value // doesn't matter. se = StudentEntity.CreateStudentEntity(0, name); db.AddToStudentEntitySet(se); db.SaveChanges(); } // create a Student object from the Entity object return new Student(se); } } Thanks!

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  • Use LINQ, to Sort and Filter items in a List<ReturnItem> collection, based on the values within a Li

    - by Daniel McPherson
    This is tricky to explain. We have a DataTable that contains a user configurable selection of columns, which are not known at compile time. Every column in the DataTable is of type String. We need to convert this DataTable into a strongly typed Collection of "ReturnItem" objects so that we can then sort and filter using LINQ for use in our application. We have made some progress as follows: We started with the basic DataTable. We then process the DataTable, creating a new "ReturnItem" object for each row This "ReturnItem" object has just two properties: ID ( string ) and Columns( List(object) ). The properties collection contains one entry for each column, representing a single DataRow. Each property is made Strongly Typed (int, string, datetime, etc). For example it would add a new "DateTime" object to the "ReturnItem" Columns List containing the value of the "Created" Datatable Column. The result is a List(ReturnItem) that we would then like to be able to Sort and Filter using LINQ based on the value in one of the properties, for example, sort on "Created" date. We have been using the LINQ Dynamic Query Library, which gets us so far, but it doesn't look like the way forward because we are using it over a List Collection of objects. Basically, my question boils down to: How can I use LINQ, to Sort and Filter items in a List(ReturnItem) collection, based on the values within a List(object) property which is part of the ReturnItem class?

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  • How to use different providers for Linq to entities?

    - by Anders Svensson
    I'm trying to familiarize myself a bit more with database programming, and I'm looking at different ways of creating a data access layer for applications. I've tried out a few ways but there is such a jungle of different database technologies that I don't know what to learn. For instance I've tried using datasets with tableadapters. Using that I am able to switch data provider rather easily (by programming against the interfaces such as IDbConnection). This is one thing I would want to achieve. But I also know everyone's talking about LINQ, and I'm trying to get to know that a bit better too. So I have tried using Linq to Sql classes as the data access layer as well, but apparently this is not provider independent (works only for SQL Server). So then I read about the Entity Framework (which just as Linq to SQL apparently has gotten its share of bashing already...). It's supposed to be provider independent everybody says, but how? I tried out a tutorial to create an entity data model, but the only providers to choose from were SQL Server/Express. Just for learning purposes, I would like to know how to use the entity framework with MS Access/OleDb. Also, I would appreciate some input on what is the preferred database technology for data access. Is it LINQ still after all the bashing, or should you just use datasets because they are provider independent? Any pointers for what to learn would be great, because it's just too much to learn it all if I'm not going to use it in the end...!

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  • LINQ to SQL exception: System.OutOfMemoryException

    - by Adam
    Not sure why I keep getting an OutOfMemory exception. I'm using ASP.NET MVC with LINQ to SQL. Here's some of the stack trace: [OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.] System.Runtime.CompilerServices.RuntimeHelpers._CompileMethod(IntPtr method) +0 System.Reflection.Emit.DynamicMethod.CreateDelegate(Type delegateType) +7652553 System.Data.Linq.SqlClient.ObjectReaderCompiler.Compile(SqlExpression expression, Type elementType) +442 System.Data.Linq.SqlClient.SqlProvider.GetReaderFactory(SqlNode node, Type elemType) +100 System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) +253 System.Data.Linq.Table1.System.Linq.IQueryProvider.Execute(Expression expression) +49 System.Linq.Queryable.Single(IQueryable1 source, Expression`1 predicate) +301 WorkGrabber.Web.Models.WorkGrabberDataContext.GetJob(Int32 id) +233 WorkGrabber.Web.Controllers.BidsController.New(Int32 jobId) +19

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  • What's the next big thing after LINQ?

    - by Leniel Macaferi
    I started using LINQ (Language Integrated Query) when it was still in beta, more specifically Microsoft .NET LINQ Preview (May 2006). Almost 4 years have passed and here we are using LINQ in a lot of projects for the most diverse tasks. I even wrote my final college project based on LINQ. You see how I like it. LINQ and more recently PLINQ (Parallel LINQ) give our jobs a great boost when it comes to more programming power and less lines of code leading us to more expressive and readable code. I keep thinking what could be the next big language improvement for C# after LINQ. I know there are some promissing language features coming as Code Contracts, etc, but nothing having the impact that LINQ had. What do you think could be the next big thing?

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  • 3 methods for adding a "Product" through Entity Framework. What's the difference?

    - by Kohan
    Reading this MSDN article titled "Working with ObjectSet (Entity Framework)" It shows two examples on how to add a Product.. one for 3.5 and another for 4.0. http://msdn.microsoft.com/en-us/library/ee473442.aspx Through my lack of knowledge I am possibly completely missing something here, but i never added a Product like this: //In .NET Framework 3.5 SP1, use the following code: (ObjectQuery) using (AdventureWorksEntities context = new AdventureWorksEntities()) { // Add the new object to the context. context.AddObject("Products", newProduct); } //New in .NET Framework 4, use the following code: (ObjectSet) using (AdventureWorksEntities context = new AdventureWorksEntities()) { // Add the new object to the context. context.Products.AddObject(newProduct); } I would not have done it either way and just used: // (My familiar way) using (AdventureWorksEntities context = new AdventureWorksEntities()) { // Add the new object to the context. context.AddToProducts(newProduct); } What's the difference between these three ways? Is "My way" just another way of using an ObjectQuery? Thanks, Kohan

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  • LINQ – TakeWhile and SkipWhile methods

    - by nmarun
    I happened to read about these methods on Vikram's blog and tried testing it. Somehow when I saw the output, things did not seem to add up right. I’m writing this blog to show the actual workings of these methods. Let’s take the same example as showing in Vikram’s blog and I’ll build around it. 1: int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 }; 2:  3: foreach(var number in numbers.TakeWhile(n => n < 7)) 4: { 5: Console.WriteLine(number); 6: } Now, the way I (incorrectly) read the upper bound condition in the foreach loop was: ‘Give me all numbers that pass the condition of n<7’. So I was expecting the answer to be: 5, 4, 1, 3, 2, 0. But when I run the application, I see only: 5, 4, 1,3. Turns out I was wrong (happens at least once a day). The documentation on the method says ‘Returns elements from a sequence as long as a specified condition is true. To show in code, my interpretation was the below code’: 1: foreach (var number in numbers) 2: { 3: if (number < 7) 4: { 5: Console.WriteLine(number); 6: } 7: } But the actual implementation is: 1: foreach(var number in numbers) 2: { 3: if(number < 7) 4: { 5: Console.WriteLine(number); 6: break; 7: } 8: } So there it is, another situation where one simple word makes a difference of a whole world. The SkipWhile method has been implemented in a similar way – ‘Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements’ and not ‘Bypasses elements in a sequence where a specified condition is true and then returns the remaining elements’. (Subtle.. very very subtle). It’s feels strange saying this, but hope very few require to read this article to understand these methods.

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  • LINQ for SQL Developers and DBA’s

    - by AtulThakor
    Firstly I’d just like to thank the guys who organise the SQL Server User Group (Martin/Tony/Chris) and for giving me the opportunity to speak at the recent event. Sorry about the slides taking so long but here they are along with some extra information. Firstly the demo’s were all done using LINQPad 4.0 which can be downloaded here: http://www.linqpad.net/ There are 2 versions 3.5/4.0 With 3.5 you should be able to replicate the problem I showed where a query using a parameter which is X characters long would create a different execution plan to a query which uses a parameter which is Y characters long, otherwise I would just use 4.0 The sample database used is AdventureWorksLT2008 which can be downloaded from here: http://msftdbprodsamples.codeplex.com/releases/view/37109 The scripts have been named so that you can select the appropriate way to run them i.e.: C# expression / C#statement, each script can be run individually be highlighting the query and clicking the play symbol or hitting F5. Scripts and Slides: http://sqlblogcasts.com/blogs/atulthakor/An%20Introduction%20to%20LINQ.zip Please don't hesitate in sending any questions via email/twitter, I’ll try my best to answer your questions! Thanks, Atul

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  • Grouping data in LINQ with the help of group keyword

    - by vik20000in
    While working with any kind of advanced query grouping is a very important factor. Grouping helps in executing special function like sum, max average etc to be performed on certain groups of data inside the date result set. Grouping is done with the help of the Group method. Below is an example of the basic group functionality.     int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };         var numberGroups =         from num in numbers         group num by num % 5 into numGroup         select new { Remainder = numGroup.Key, Numbers = numGroup };  In the above example we have grouped the values based on the reminder left over when divided by 5. First we are grouping the values based on the reminder when divided by 5 into the numgroup variable.  numGroup.Key gives the value of the key on which the grouping has been applied. And the numGroup itself contains all the records that are contained in that group. Below is another example to explain the same. string[] words = { "blueberry", "abacus", "banana", "apple", "cheese" };         var wordGroups =         from num in words         group num by num[0] into grp         select new { FirstLetter = grp.Key, Words = grp }; In the above example we are grouping the value with the first character of the string (num[0]). Just like the order operator the group by clause also allows us to write our own logic for the Equal comparison (That means we can group Item by ignoring case also by writing out own implementation). For this we need to pass an object that implements the IEqualityComparer<string> interface. Below is an example. public class AnagramEqualityComparer : IEqualityComparer<string> {     public bool Equals(string x, string y) {         return getCanonicalString(x) == getCanonicalString(y);     }      public int GetHashCode(string obj) {         return getCanonicalString(obj).GetHashCode();     }         private string getCanonicalString(string word) {         char[] wordChars = word.ToCharArray();         Array.Sort<char>(wordChars);         return new string(wordChars);     } }  string[] anagrams = {"from   ", " salt", " earn", "  last   ", " near "}; var orderGroups = anagrams.GroupBy(w => w.Trim(), new AnagramEqualityComparer()); Vikram  

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  • Website development from scratch v/s web framework [duplicate]

    - by Ali
    This question already has an answer here: What should every programmer know about web development? 1 answer Do people develop websites from scratch when there are no particular requirements or they just pick up an existing web framework like Drupal, Joomla, WordPress, etc. The requirements are almost similar in most cases; if personal, it will be a blog or image gallery; if corporate, it will be information pages that can be updated dynamically along with news section. And similarly, there are other requirements which can be fulfilled by WordPress, Joomla or Drupal. So, Is it advisable to develop a website from scratch and why ? Update: to explain more as got commentt from @Raynos (thanks for comment and helping me clearify the question), the question is about: Should web sites be developed and designed fully from scratch? Should they be done by using framework like Spring, Zend, CakePHP? Should they be done using CMS like Joomla, WordPress, Drupal (people in east are using these as frameworks)?

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  • Where I can find SQL Generated by Entity framework?

    - by Jalpesh P. Vadgama
    Few days back I was optimizing the performance with Entity framework and Linq queries and I was using LinqPad and looking SQL generated by the Linq or entity framework queries. After some point of time I got the same question in mind that how I can find the SQL Statement generated by Entity framework?. After some struggling I have managed to found the way of finding SQL Statement so I thought it would be a great idea to write a post about  same and share my knowledge about that. So in this post I will explain how to find SQL statements generated Entity framework queries. Read More on dotnetjalps.com

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  • LINQ: Enhancing Distinct With The SelectorEqualityComparer

    - by Paulo Morgado
    On my last post, I introduced the PredicateEqualityComparer and a Distinct extension method that receives a predicate to internally create a PredicateEqualityComparer to filter elements. Using the predicate, greatly improves readability, conciseness and expressiveness of the queries, but it can be even better. Most of the times, we don’t want to provide a comparison method but just to extract the comaprison key for the elements. So, I developed a SelectorEqualityComparer that takes a method that extracts the key value for each element. Something like this: public class SelectorEqualityComparer<TSource, Tkey> : EqualityComparer<TSource> where Tkey : IEquatable<Tkey> { private Func<TSource, Tkey> selector; public SelectorEqualityComparer(Func<TSource, Tkey> selector) : base() { this.selector = selector; } public override bool Equals(TSource x, TSource y) { Tkey xKey = this.GetKey(x); Tkey yKey = this.GetKey(y); if (xKey != null) { return ((yKey != null) && xKey.Equals(yKey)); } return (yKey == null); } public override int GetHashCode(TSource obj) { Tkey key = this.GetKey(obj); return (key == null) ? 0 : key.GetHashCode(); } public override bool Equals(object obj) { SelectorEqualityComparer<TSource, Tkey> comparer = obj as SelectorEqualityComparer<TSource, Tkey>; return (comparer != null); } public override int GetHashCode() { return base.GetType().Name.GetHashCode(); } private Tkey GetKey(TSource obj) { return (obj == null) ? (Tkey)(object)null : this.selector(obj); } } Now I can write code like this: .Distinct(new SelectorEqualityComparer<Source, Key>(x => x.Field)) And, for improved readability, conciseness and expressiveness and support for anonymous types the corresponding Distinct extension method: public static IEnumerable<TSource> Distinct<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> selector) where TKey : IEquatable<TKey> { return source.Distinct(new SelectorEqualityComparer<TSource, TKey>(selector)); } And the query is now written like this: .Distinct(x => x.Field) For most usages, it’s simpler than using a predicate.

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  • SceneManagers as systems in entity system or as a core class used by a system?

    - by Hatoru Hansou
    It seems entity systems are really popular here. Links posted by other users convinced me of the power of such system and I decided to try it. (Well, that and my original code getting messy) In my project, I originally had a SceneManager class that maintained needed logic and structures to organize the scene (QuadTree, 2D game). Before rendering I call selectRect() and pass the x,y of the camera and the width and height of the screen and then obtain a minimized list containing only visible entities ordered from back to front. Now with Systems, originally in my first attempt my Render system required to get added all entities it should handle. This may sound like the correct approach but I realized this was not efficient. Trying to optimize It I reused the SceneManager class internally in the Renderer system, but then I realized I needed methods such as selectRect() in others systems too (AI principally) and make the SceneManager accessible globally again. Currently I converted SceneManager to a system, and ended up with the following interface (only relevant methods): /// Base system interface class System { public: virtual void tick (double delta_time) = 0; // (methods to add and remove entities) }; typedef std::vector<Entity*> EntitiesVector; /// Specialized system interface to allow query the scene class SceneManager: public System { public: virtual EntitiesVector& cull () = 0; /// Sets the entity to be used as the camera and replaces previous ones. virtual void setCamera (Entity* entity) = 0; }; class SceneRenderer // Not a system { vitual void render (EntitiesVector& entities) = 0; }; Also I could not guess how to convert renderers to systems. My game separates logic updates from screen updates, my main class have a tick() method and a render() method that may not be called the same times. In my first attempt renderers were systems but they was saved in a separated manager, updated only in render() and not in tick() like all other systems. I realized that was silly and simply created a SceneRenderer interface and give up about converting them to systems, but that may be for another question. Then... something does not feel right, isn't it? If I understood correctly a system should not depend on another or even count with another system exposing an specific interface. Each system should care only about its entities, or nodes (as optimization, so they have direct references to relevant components without having to constantly call the component() or getComponent() method of the entity).

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