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• Does performance even matter anymore? [closed]

  - by Jeff Dahmer

  The performance differences between C/C++ and C# are astounding. An ASP.NET page loads in 1/8 the time that a PHP script does haha.... WPF, aka " The Future ", (you know it will be, all the companies are gonna want cool looking desktop apps, don't kid yourself.) And it has huge performance hits just to start up. We've let Microsoft make us as developers lazy! Why do I hate this, it's such a good thing? Are we at a point in time where the majority of computers can handle this kinda crap? I remember when performance used to matter. Anyways, I'm writing a .NET library and ever since I found out LINQ is slower than traditional delegates which is slower than the normal procedural code... well it's a guilty evil I feel for every LINQ query I write, because they are so beautiful. Am I just too much of a performance stickler? Or just too big of a nerd?

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• Databind Parent/Child relation with Mysql

  - by e2k

  What is the best way to databind parent/child relations? Lets say I have two simple objects: Parent with the following properties, ParentId, Name and Childs and Child with the following properties, ChildId, Name and Parent. I want to write a repository using MySql for this but is failing when I bind both Childs and Parent properties, I have only been able to bind either the Childs property of parent or the Parent property och Child or else I would get a infinite loop. Thinking of it the preferable solution would be to only bind this properties when requested. If I use Linq to sql i would be able to write Parent.Childs[0].Parent.Name but how should I accomplish this with my own repository and with MySql, could anyone point me in the right direction? Looking at the Linq 2 sql generated classes they use EntitySet<Child and EntityRef<Parent could this be used with Mysql? I had a thought of using my IChildRepository in the Parent object and let the Public IEnumerable Childs databind the childs but it seems not right? Best regards E2k

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• nHibernate session - Using repository pattern in Web, windows, wcf etc...

  - by alex

  I recently posted a question which was answered by Bryan Watts, regarding generic repository for nHibernate. I'm trying to design my data access to allow various facets - from ASP.net, WCF and Windows Forms / Windows services. I'm a bit confused re: session management etc.. How would I handle this? I've been checking out code such as: http://membranecms.googlecode.com/svn/ and questions such as: http://stackoverflow.com/questions/1207833/nhibernate-linq-session-management But what do i do if i don't just do things in a web based environment..? Do i need to create different repositories for each client? Or do i pass in the ISession into the (for example) UserRepository constructor..? ... as a side note I'm using nHibernate.Linq Also using fluent nHibernate to config my mapping

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• Problem using System.Xml in unit test in MonoDevelop (MonoTouch)

  - by hambonious

  I'm new to the MonoDevelop and MonoTouch environment so hopefully I'm just missing something easy here. When I have a unit test that requires the System.Xml or System.Xml.Linq namespaces, I get the following error when I run the test: System.IO.FileNotFoundException : Could not load file or assembly 'System.Xml.Linq, Version=2.0.5.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. Things I've verified: I have the proper usings in the test. The project builds with no problems. Using these namespaces work fine when I run the app in the emulator. I've written a very simple unit test to prove that unit testing works at all (and it does). I'm a test driven kinda guy so I can't wait to get this working so I can progress with my app. Thanks in advance.

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• Target .Net Framework 4 in t4 templates

  - by HeavyWave

  We have a template that goes like this <#@ template language="C#v3.5" #> <#@ assembly name="System.dll" #> <#@ assembly name="System.Core.dll" #> <#@ assembly name="System.Data.Linq.dll" #> It compiles and runs on .Net 3.5, but after we have switched to .Net 4 the template has stopped working, so I've tried using answer from here, but I get errors like this Error 99 Compiling transformation: Metadata file 'System.Data.Linq.dll' could not be found How do I correctly modify the template to run on .Net Framework 4?

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• .NET Database Apps: Your Preferred Setup

  - by mdvaldosta

  I'm struggling to settle into a pattern for developing typical database driven apps in C# and Visual Studio. There are so many ways to set them up, using drag/drop datasets and adapters or writing the queries manually in ADO.NET or Linq to SQL, Linq to Entities, to bind or not to data bind etc etc. Where to store the connection string, in app.config or in a method or both etc etc. So many tutorials and all of them are different. Everytime I write something I start hating the way it looks and works, so I scrap it and start over. It's getting a bit tedious. Maybe it's alittle of the OCD in me. Would any of you professional developers out there share your method of setting up and structuring your database logic and maybe some sample code? It's really how to go about organizing the code and the method(s) of interacting with SQL that I'm trying to get into a routine with, one that works and won't get me laughed at by someone reviewing it.

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• What is the motivation behind "Use Extension Methods Sparingly?"

  - by Robert Harvey

  I find them a very natural way to extend existing classes, especially when you just need to "spot-weld" some functionality onto an existing class. Microsoft says, "In general, we recommend that you implement extension methods sparingly and only when you have to." And yet extension methods form the foundation of Linq; in fact, Linq was the reason extension methods were created. Are there specific design criteria where using extension methods are perferred over inheritance or composition? Under what criteria are they discouraged?

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• Groupby in relationtable

  - by Dofs

  I am creating some tag functionality for a forum using linq2sql, and I have two tables [Tag] TagId TagName [ForumTagRelation] TagId ForumId I would like to retrieve, like SO, the most popular tags. I have tried to do this by: List<Tag> popularTags = db.Tags.Select(x => x.ForumTagRelations.GroupBy(y => y.TagId).OrderByDescending(z => z.Count())).Take(count).ToList(); But this just returns the following error: Error 1 Cannot implicitly convert type 'System.Collections.Generic.List<System.Linq.IOrderedEnumerable<System.Linq.IGrouping<System.Guid?,SampleWebsite.ForumTagRelation>>>' to 'System.Collections.Generic.IEnumerable<SampleWebsite.Tag>'. An explicit conversion exists (are you missing a cast?) The question is how I easily can return a list of tags which has the most counts in the ForumTagRelation table?

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• Accessing Textboxes in Repeater Control

  - by CccTrash

  All the ways I can think to do this seem very hackish. What is the right way to do this, or at least most common? I am retrieving a set of images from a LINQ-to-SQL query and databinding it and some other data to a repeater. I need to add a textbox to each item in the repeater that will let the user change the title of each image, very similar to Flickr. How do I access the textboxes in the repeater control and know which image that textbox belongs to? Here is what the repeater control would look like, with a submit button which would update all the image rows in Linq-to-SQL:

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• nested repeaters - how to sort

  - by Cristian Boariu

  Hi guys, I have a table: Category with some sort of categories category1 category2 category3 I have another table Subcategory which has a fk to Category. So, each category1 can have subcategoryB, subcategoryA, subcategoryZ. Well... i've made two repeaters. The first one is binded to a linq data source which takes the categories from the parent table. The children repeater is binded to that foreign key like: DataSource='<%# Eval("Subcategories_1s") %' So the result is: category1 subcategoryB subcategoryA subcategoryZ category2 etc. Well, the strange question is: how can i order the subcategories alphabetically? If i'd have binded the children repeater to a linq it would be easy. But in this case...?

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• Best architecture for accessing secondary database

  - by fearofawhackplanet

  I'm currently developing an app which will use a Linq to SQL (or possibly EF) data access layer. We already have a database which holds all our Contacts information, but there is currently no API around this. I need to interact with this DB from the new app to retrieve contact details. I can think of two ways I could do this - 1) Develop a suite of web services against the contacts database 2) Write a Linq to SQL (or EF) DAL and API against the contacts database I will probably be developing several further apps in the future which will also need access to the Contacts data. Which would generally be the prefered method? What are the points I need to consider? Am I even asking a sensible question, or am I missing something obvious?

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• Starting to construct a data access layer. Things to consider?

  - by Phil

  Our organisation uses inline sql. We have been tasked with providing a suitable data access layer and are weighing up the pro's and cons of which way to go... Datasets ADO.net Linq Entity framework Subsonic Other? Some tutorials and articles I have been using for reference: http://www.asp.net/(S(pdfrohu0ajmwt445fanvj2r3))/learn/data-access/tutorial-01-vb.aspx http://www.simple-talk.com/dotnet/.net-framework/designing-a-data-access-layer-in-linq-to-sql/ http://msdn.microsoft.com/en-us/magazine/cc188750.aspx http://msdn.microsoft.com/en-us/library/aa697427(VS.80).aspx http://www.subsonicproject.com/ I'm extremely torn, and finding it very difficult to make a decision on which way to go. Our site is a series of 2 internal portals and a public web site. We are using vs2008 sp1 and framework version 3.5. Please can you give me advise on what factors to consider and any pro's and cons you have faced with your data access layer. Thanks.

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• Silverlight datagrid don't show any data with anonymous query RIA services

  - by user289082

  Hi all! I have an anonymous linq query that I bind to a datagrid, when I debug it brings alright the data but it doesn't show in the datagrid, I suspect that the request to RIA services isn't completed before I bound it to the datagrid. I could use the LoadOperation<() Completed event. But it only works with Defined Entities so how can I do that? For reference here is the last post: http://stackoverflow.com/questions/2403903/linq-query-null-reference-exception Here is the query: var bPermisos = from b in ruc.Permisos where b.IdUsuario == SelCu.Id select new { Id=b.Id, IdUsuario=b.IdUsuario, IdPerfil=b.IdPerfil, Estatus=b.Estatus, Perfil=b.Cat_Perfil.Nombre, Sis=b.Cat_Perfil.Cat_Sistema.Nombre }; I'm a totally newbie sorry if is a very simple question. Thanks!!

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• More XML Problems - Undeclared Entity 'nbsp'

  - by Gogster

  I'm getting the error: Line 49: xml = r.ReadToEnd(); Line 50: Line 51: System.Xml.Linq.XDocument xmlDoc = System.Xml.Linq.XDocument.Parse(xml); Line 52: Line 53: var query = from p in xmlDoc.Descendants("member") On my XML. When I run the code to generate the XML in an empty page, it runs without error, if I call the code within my webpage it throws this error. The only 'nbsp' on the page is a doctype declaration at the top of the XSLT: <!DOCTYPE xsl:stylesheet [ <!ENTITY nbsp "&#x00A0;"> ]> I'm at a loss as to where this error is coming from and I am looking for suggestions please! Thanks.

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• Please Find the error :

  - by jagdeep

  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; public partial class Expt : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void Bttnadd_Click(object sender, EventArgs e) { FileUpload1.SaveAs(MapPath("~/img//"+DateTime.Now.ToString()+FileUpload1.FileName)); } } Exception Details: System.Web.HttpException: ~/img//1/1/2011 1:47:52 PMWinter.jpg is not a valid virtual path.

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• Type or namespace name could not be found

  - by Pandiya Chendur

  I use this: public IQueryable<MaterialsView> FindAllMaterials() { var materials = from m in db.Materials join Mt in db.MeasurementTypes on m.MeasurementTypeId equals Mt.Id select new MaterialsView { MatId = m.Mat_Name, MesName = Mt.Name, MesType = m.Mat_Type }; return materials; } It gives me the following errors: The type or namespace name MaterialsView could not be found (are you missing a using directive or an assembly reference?) Cannot implicitly convert type System.Collections.Generic.IEnumerable<MaterialsView> to System.Linq.IQueryable<MaterialsView>. An explicit conversion exists (are you missing a cast?) The type arguments for method System.Linq.Enumerable.ToList<TSource>(System.Collections.Generic.IEnumerable<TSource>) cannot be inferred from the usage. Try specifying the type arguments explicitly. I have googled it and found this SO question but it doesn't help. What's wrong?

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• Dynamic Array Java program converted to C#

  - by Sef

  Hello, The folowing program was orignally in java. But i still get 1 error with the program in C#. (the eror is listed in comment in the 2nd block of code). using System; using System.Collections.Generic; using System.Linq; using System.Text; using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace DynArray { public class DynArrayTester { static void Main(string[] args) { DynArray da = new DynArray(5); for (int i = 1; i <= 7; i++) { da.setData(i, i); //da.put(0, 0); //da.put(6, 6); } Console.WriteLine(da); } }/*DynArrayTester*/ } using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace DynArray { public class DynArray { //toestand private int[] data; //gedrag public DynArray(int size) { data = new int[size]; } public int getData(int index) { return data[index - 1]; } private void expand(int size) { int[] tmp = data; data = new int[size]; for (int i = 0; i < tmp.Length; i++) { data[i] = tmp[i]; } }/*expand*/ public void setData(int index, int data) { if (0 < index) { if (index > this.data.length) // ***error, does not contain definition for "lenght" and no exetension method "lenght"*** expand(index); this.data[index - 1] = data; } } public override string ToString() { StringBuilder buf = new StringBuilder(); for (int i = 0; i < data.Length; i++) { buf.Append("[" + i + "]"); buf.Append(data[i]); buf.Append('\n'); } return buf.ToString(); } }/*DynArray*/ }

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• How can I push a string from one client connected to a WCF service to another connected as well?

  - by Sergio Tapia

  Here's what I have so far: IService: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.ServiceModel; namespace ServiceLibrary { [ServiceContract(SessionMode = SessionMode.Allowed, CallbackContract = typeof(IServiceCallback))] public interface IService { [OperationContract(IsOneWay = false, IsInitiating = true, IsTerminating = false)] void Join(string userName); } interface IServiceCallback { [OperationContract(IsOneWay = true)] void UserJoined(string senderName); } } Service: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.ServiceModel; namespace ServiceLibrary { [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession, ConcurrencyMode = ConcurrencyMode.Multiple)] public class Service:IService { IServiceCallback callback = null; public void Join(string userName) { callback = OperationContext.Current.GetCallbackChannel<IServiceCallback>(); } } } Just a simple string passed from one client to another.

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• Display xml data in silverlight datagrid, vb.net

  - by Aishwarya

  I want to display an xml file data in silverlight datagrid. im using the below code but it doesnt work.Please help. My vb.net code: Imports System Imports System.Collections.Generic Imports System.Linq Imports System.Windows Imports System.Windows.Controls Imports System.Xml.Linq Namespace SilverlightApplication1 Public Partial Class Page Inherits UserControl Public Sub New() InitializeComponent() End Sub Private Sub Page_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs) DataGrid1.ItemsSource = GetPunchReport() End Sub Public Function GetStatusReport() As List(Of Table) Dim statusReport As New List(Of Table)() Dim doc As XElement = XElement.Load("Data/PunchReport.xml") report = (From row In doc.Elements() _ Select GetStatus(row)).ToList() Return statusReport End Function Private Function GetReport(ByVal row As XElement) As Table Dim s As New Table() s.JobID= row.Attribute("JobID").Value s.VenueName= row.Attribute("VenueName").Value) Return s End Function End Class End Namespace

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• Asp.net project is not recognising one of the folders in my class library.

  - by Rachel

  I am developing a project using Visual Studio 2008 in C#, I have added the class library within the project and set up the relevant references and used the relevant using statements. It seems to be a problem with just this one folder. can anyone help? this is the error message: Error 28 The type or namespace name 'Domain' does not exist in the namespace 'Forestry.SchoolLibrary' (are you missing an assembly reference?) C:\Projects\SchoolofForestry\trunk\Source\School\Account\Presenter\EditAccountPresenter.cs 26 40 School these are my using statements: using System; using System.Collections.Generic; using System.Configuration; using System.Linq; using System.Data.Linq; using System.Text; using System.Xml; using Forestry.SchoolLibrary.Core.Domain; using Forestry.SchoolLibrary.Properties;

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• Returning multiple datasets from a stored proc in VB

  - by Ryan Stephens

  I have an encrypted SQL Server stored proc that I run with (or the vb .net equivalent code of): declare @p4 nvarchar(100) set @p4=NULL declare @p5 bigint set @p5=NULL exec AA_PAY_BACS_EXPORT_RETRIEVE_S @PS_UserId=N'ADMN', @PS_Department=N'', @PS_PayFrequency=2, @PS_ErrorDescription=@p4 output select @p4, @p5 this returns 2 datasets and the output parameters for the results, the datasets are made up of various table joins etc, one holds the header record and one the detail records. I need to get the 2 datasets into a structure in VB .net (e.g. linq, sqldatareader, typed datasets) so that I can code with them, I don't know what tables any of this comes from and there are alot of them Whooopeee!!! I came close using Linq to SQL and IMultipleResults but got frustrated when I had to recode it every time I made a change to the designer file. My feelings are that there must be a simple way to do this, any ideas?

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• How can i sort DESC and ASC in list generic?

  - by Phsika

  How can I sort DESC and ASC in a generic list? With LINQ and without LINQ ? I'm using vs 2008. class Program { static void Main(string[] args) { List<int> li = new List<int>(); li.Add(456); li.Add(123); li.Add(12345667); li.Add(0); li.Add(1); li.Sort(); foreach (int item in li) { Console.WriteLine(item.ToString()+"\n"); } Console.ReadKey(); } }

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• Visual Studio stops debugging with no errors unexpectedly

  - by HeavyWave

  I am debugging a project and Visual Studio stops debugging and closes the program on the following line with no exceptions or error messages (I have enabled notifications for any thrown exceptions in options): var query = Session.Linq<RSS>() .Where(x => x.LastRetrieved <= date || x.LastRetrieved == null) .Where(x => x.Moderated); Where Session.Linq refers to LINQ2NHibernate. Anyway, the question is: what are the possible reasons for such behavior? Tested both on VS 2010 and 2008 - they behave identically just falling out of debugging.

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• Select n+1 problem

  - by Arnis L.

  Foo has Title. Bar references Foo. I have a collection with Bars. I need a collection with Foo.Title. If i have 10 bars in collection, i'll call db 10 times. bars.Select(x=x.Foo.Title) At the moment this (using NHibernate Linq and i don't want to drop it) retrieves Bar collection. var q = from b in Session.Linq<Bar>() where ... select b; I read what Ayende says about this. Another related question. A bit of documentation. And another related blog post. Maybe this can help? What about this? Maybe MultiQuery is what i need? :/ But i still can't 'compile' this in proper solution. How to avoid select n+1?

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• Best Data Access Methods for New Web Application

  - by user98454

  I'm building a new web application project and am confused by the numerous methods of performing data access. I'm backending on SQL and a bit confused whether to use LINQ to SQL or trtaditional ADO.net ? what are the advantages and disadvantages of using LINQ/SQL over ADO.net? If it is ADO.net,then what is the best way to retrieve data means either calling the stored procedures or directly calling the t-sql code? My question is what is cleanes and most effiecient and professional way of creating DAL for webapplication in asp.net? Thanks

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