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• Can't log in a user in MVC!

  - by devlife

  I have been scratching my head on this for a while now but still can't get it. I'm trying to simply log in a user in an MVC2 application. I have tried everything that I know to try but still can't figure out what I'm doing wrong. Here are a few things that I have tried: FormsAuthentication.SetAuthCookie( emailAddress, rememberMe ); var cookie = FormsAuthentication.GetAuthCookie( emailAddress, rememberMe ); HttpContext.Response.Cookies.Add( cookie ); FormsAuthenticationTicket ticket = new FormsAuthenticationTicket( emailAddress, rememberMe, 15 ); FormsIdentity identity = new FormsIdentity( ticket ); GenericPrincipal principal = new GenericPrincipal(identity, new string[0]); HttpContext.User = principal; I'm not sure if any of this is the right thing to do (as it's not working). After setting HttpContext.User = principal then Request.IsAuthenticated == true. However, in Global.asax I have this: HttpCookie authenCookie = Context.Request.Cookies.Get( FormsAuthentication.FormsCookieName ); The only cookie that ever is available is the aspnet session cookie. Any ideas at all would be much appreciated!

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• Help with editing data in entity framework.

  - by Levelbit

  Title of this question is simple because there is no an easy explanation for what I'm trying to ask you. I hope you'll understand in the end :). I have to tables in my database: Company and Location (relationship:one to many) and corresponding entity sets. In my wpf application I have some datagrid which I want to fill with locations and to be able to edit every row in separate window as some form of details view (so I don't want to edit my data in datagrid). I did this by accessing Location entity from selected row and creating a new Location entity and then I copy properties from original entity to newly created. Something like cloning the object. After editing if I press OK changed data is copied to original object back, and if I press Cancel nothing happens. Of course, you probably thinking I could use NoTracking option and AttachAsModified method as was mentioned as solution in some earlier questions(see:http://stackoverflow.com/questions/803022/changing-entities-in-the-entityframework) by Alex James, but lets say I had some problems about that and I have my own reasons for doing this. Finally, because navigation property(Company) of my location entity is assigned to newly created location object(during cloning) from some reason in object context additional object as copy of object I want to edit from datagrid is created without my will(similar problem :http://blogs.msdn.com/alexj/archive/2009/12/02/tip-47-how-fix-up-can-make-it-hard-to-change-relationships.aspx). So, when I do ObjectContext.SaveChanges it inserts additional row of data into my database table Location, the same as the one i wanted to edit. I read about sth like this, but I don't quite understand why is that and how to block or override this. I hope I was clear as I could. Please, solutions or some other ideas.

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• Can someone describe the nested set model from a C#/LINQ perspective?

  - by Chad

  I know the nested set model doesn't pertain to the C# language or LINQ directly... it's what I'm using to develop my web app. For hierarchical data (categories with sub-categories in my case), I'm currently using something similar to the Adjacency List model. At the moment, I've only got 2 levels of categories, but I'd like to take it further and allow for n levels of categories using the nested set model. I'm not quite clear on how to use it in a C# context. Here's the article I'm reading on the nested set model. Though this article cleared up my confusion some, I still have a big ?? in my head: - Is inserting, updating or deleting categories tedious? It looks like the left and right numbers would require re-numbering... what would the LINQ queries look like for the following scenarios? Delete a child node (re-number all node's left/right values) Delete a parent node (what do you do with the orphans?) Move a child node to a different parent node (renumber again) If my understanding is correct, at all times the child node's left/right values will always be between the parent node's left/right values, am I correct? Seems easy enough, if only the categories were static... most likely I need to spend more time to get my head around the concept. Any help is greatly appreciated!

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• Cooperative/Non-preemptive threading avoiding threadlooks?

  - by Wayne

  Any creative ideas to avoid deadlocks on a yield or sleep with cooperative/non-preemptive multitasking without doing an O/S Thread.Sleep(10)? Typically the yield or sleep call will call back into the scheduler to run other tasks. But this can sometime produce deadlocks. Some background: This application has enormous need for speed and, so far, it's extremely fast as compared to other systems in the same industry. One of the speed techniques is cooperative/non-preemptive threading rather then the cost of a context switch from O/S threads. The high level design a priority manager which calls out to tasks depending on priority and processing time. Each task does one "iteration" of work and returns to wait its turn again in the priority queue. The tricky thing with non-preemptive threading is what to do when you want to a particular task to stop in the middle of work and wait for some other event from a different task before continuing. In this case, we have 3 tasks, A B and C where A is a controller that must synchronize the activity of B and C. First, A starts both B and C. Then B yields so C gets invoked. When C yields, A sees they are both inactive, decides it's time for B to run but not time for C yet. Well B is now stuck in a yield that has called C, so it can never run. Sincerely, Wayne

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• The "first past the post election" query problem

  - by MPelletier

  This problem may seem like school work, but it isn't. At best it is self-imposed school work. I encourage any teachers to take is as an example if they wish. "First past the post" elections are single-round, meaning that whoever gets the most votes win, no second rounds. Suppose a table for an election. CREATE TABLE ElectionResults ( DistrictHnd INTEGER NOT NULL, PartyHnd INTEGER NOT NULL, CandidateName VARCHAR2(100) NOT NULL, TotalVotes INTEGER NOT NULL, PRIMARY KEY DistrictHnd, PartyHnd); The table has two foreign keys: DistrictHnd points to a District table (lists all the different electoral districts) and PartyHnd points to a Party table (lists all the different political parties). I won't bother with other tables here, joining them is trivial. This is just a wee bit of context. The question: What SQL query will return a table listing the DistrictHnd, PartyHnd, CandidateName and TotalVotes of the winners (max votes) in each District? This does not suppose any particular database system. If you wish to stick to a particular implementation of SQL, go the way of SQLite and MySQL. If you can devise a better schema (or an easier one), that is acceptable too. Criteria: simplicity, portability to other databases.

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• DropDownListFor and relating my lambda to my ViewModel

  - by Daniel Harvey

  After googling for a while I'm still drawing a blank here. I'm trying to use a ViewModel to pull and provide a dictionary to a drop down list inside a strongly typed View: <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="Notebook.ViewModels.CorporationJoinViewModel" %> ... <%: Html.DropDownListFor(c => c.CorpDictionary.Keys, new SelectList(Model.CorpDictionary, "Value", "Key"))%> I'm getting the error CS1061: 'object' does not contain a definition for 'CorpDictionary' and no extension method 'CorpDictionary' accepting a first argument of type 'object' could be found and the relevant bit of my ViewModel public class CorporationJoinViewModel { DB _db = new DB(); // data context public Dictionary<int, string> CorpDictionary { get { Dictionary<int, string> corporations = new Dictionary<int, string>(); int x = 0; foreach (Corporation corp in _db.Corporations) { corporations.Add(x, corp.name); } return corporations; } } I'll admit i have a pretty magical understanding of how linq is finding my ViewModel object from that lambda, and the error message is making me think it's not. Is my problem the method I'm using to pass the data? What am I missing here?

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• Red5 Unable to Start Distribution.

  - by Iscariot

  I have installed subclipse, Ant, IvyDE, Red5 Plugin for eclipse, All of the Environmental variables are set and the necessary elements have been added to the path. I am attempting to create a Red5 Distribution by using eclipse, opening Build.xml right clicking dist [default] in the outline window and running as and selecting Ant Builder. Eclipse says that the build is Successful. I first stop the Red5 Service, and then I attempt to run the build I create in eclipse it fails, below are the errors that display in the command prompt. I was hoping someone else might have run into a similar issue before. Starting Red5 Red5 root: C:/Users/Admin/workspace/temp/red5_server/dist Configuation root: C:/Users/Admin/workspace/temp/red5_server/dist/conf Setting temp directory to C:\Users\Admin\AppData\localLow Exception in thread "main" java.lang.Error: Unresolved compilation problems: The import org.slf4j.bridge cannot be resolved The import org.springframework.context.support.FileSystemXmlApplicationC ontext cannot be resolved SLF4JBridgeHandler cannot be resolved FileSystemXmlApplicationContext cannot be resolved to a type FileSystemXmlApplicationContext cannot be resolved to a type at org.red5.server.Launcher.<init>(Launcher.java:25) at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstruct orAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingC onstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at java.lang.Class.newInstance0(Class.java:355) at java.lang.Class.newInstance(Class.java:308) at org.red5.server.Bootstrap.bootStrap(Bootstrap.java:132) at org.red5.server.Bootstrap.main(Bootstrap.java:50) Press any key to continue . . .

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• DataBinding the AJAX Control Toolkit's Rating Control

  - by Nevada

  I'm attempting to use the AJAX Control Toolkit's Rating control in a DataBinding scenario. I have a ReuseRating column in my database that is a tinyint. It can hold values 1 through 5. Every record in the table has the value set to 1 currently. If I do this in my ItemTemplate everything works fine. I get 1 star filled in on my rating control. <act:Rating ID="ReuseRatingRating" runat="server" CurrentRating='<%# Convert.ToInt16(Eval("ReuseRating")) %>' MaxRating="5" StarCssClass="ratingStar" WaitingStarCssClass="savedRatingStar" FilledStarCssClass="filledRatingStar" EmptyStarCssClass="emptyRatingStar" /> Now I want to DataBind this in my EditTemplate like so. <act:Rating ID="ReuseRatingRating" runat="server" CurrentRating='<%# Convert.ToInt16(Bind("ReuseRating")) %>' MaxRating="5" StarCssClass="ratingStar" WaitingStarCssClass="savedRatingStar" FilledStarCssClass="filledRatingStar" EmptyStarCssClass="emptyRatingStar" /> Note, that I changed my Eval to a Bind in the CurrentRating property. This throws the following error. CS0103: The name 'Bind' does not exist in the current context Can anyone help me out on this one? I've been knocking my head against the wall for a couple of hours now.

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• In Seam what's the difference between injected EntityManager and getEntityManager from EntityHome

  - by Navi

  I am testing a Seam application using the needle test API. In my code I am using the getEntityManager() method from EntityHome. When I run the unit tests against an in memory database I get the following exception: java.lang.IllegalStateException: No application context active at org.jboss.seam.Component.forName(Component.java:1945) at org.jboss.seam.Component.getInstance(Component.java:2005) at org.jboss.seam.Component.getInstance(Component.java:1983) at org.jboss.seam.Component.getInstance(Component.java:1977) at org.jboss.seam.Component.getInstance(Component.java:1972) at org.jboss.seam.framework.Controller.getComponentInstance(Controller.java:272) at org.jboss.seam.framework.PersistenceController.getPersistenceContext(PersistenceController.java:20) at org.jboss.seam.framework.EntityHome.getEntityManager(EntityHome.java:177) etc .. I can resolve some of these errors by injecting the EntityManager with @In EntityManager entityManager; Unfortunately the persist method of EntityHome also calls the getEntityManager. This means a lot of mocks or rewriting the code somehow. Is there any workaround and why is this exception thrown anyway? I am using Seam 2.2.0 GA by the way. There is nothing special about the components. They are generated by seam-gen. The test is performed with in memory database - I followed the examples in http://jbosscc-needle.sourceforge.net/jbosscc-needle/1.0/db-util.html.

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• How do you unit test a method containing a LINQ expression?

  - by Phil.Wheeler

  I'm struggling to get my head around how to accommodate a mocked method that only accepts a Linq expression as its argument. Specifically, the repository I'm using has a First() method that looks like this: public T First(Expression<Func<T, bool>> expression) { return All().Where(expression).FirstOrDefault(); } The difficulty I'm encountering is with my MSpec tests, where I'm (probably incorrectly) trying to mock that call: public abstract class with_userprofile_repository { protected static Mock<IRepository<UserProfile>> repository; Establish context = () => { repository = new Mock<IRepository<UserProfile>>(); repository.Setup<UserProfile>(x => x.First(up => up.OpenID == @"http://testuser.myopenid.com")).Returns(GetDummyUser()); }; protected static UserProfile GetDummyUser() { UserProfile p = new UserProfile(); p.OpenID = @"http://testuser.myopenid.com"; p.FirstName = "Joe"; p.LastLogin = DateTime.Now.Date.AddDays(-7); p.LastName = "Bloggs"; p.Email = "[email protected]"; return p; } } I run into trouble because it's not enjoying the Linq expression: System.NotSupportedException: Expression up = (up.OpenID = "http://testuser.myopenid.com") is not supported. So how does one test these sorts of scenarios?

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• Aliasing Resources (WPF)

  - by Noldorin

  I am trying to alias a resource in XAML, as follows: <UserControl.Resources> <StaticResourceExtension x:Key="newName" ResourceKey="oldName"/> </UserControl.Resources> oldName simply refers to a resource of type Image, defined in App.xaml. As far as I understand, this is the correct way to do this, and should work fine. However, the XAML code gives me the superbly unhelpful error: "The application XAML file failed to load. Fix errors in the application XAML before opening other XAML files." This appears when I hover over the StaticResourceExtension line in the code (which has a squiggly underline). Several other errors are generated in the actual Error List, but seem to be fairly irrelevant and nonsenical (such messages as "The name 'InitializeComponent' does not exist in the current context"), as they all disappear when the line is removed. I'm completely stumped here. Why is WPF complaining about this code? Any ideas as to a resolution please? Note: I'm using WPF in .NET 3.5 SP1. Update 1: I should clairfy that I do receive compiler errors (the aforementioned messages in the Error List), so it's not just a designer problem. Update 2: Here's the relevant code in full... In App.xaml (under Application.Resource): <Image x:Key="bulletArrowUp" Source="Images/Icons/bullet_arrow_up.png" Stretch="None"/> <Image x:Key="bulletArrowDown" Source="Images/Icons/bullet_arrow_down.png" Stretch="None"/> And in MyUserControl.xaml (under UserControl.Resources): <StaticResourceExtension x:Key="columnHeaderSortUpImage" ResourceKey="bulletArrowUp"/> <StaticResourceExtension x:Key="columnHeaderSortDownImage" ResourceKey="bulletArrowDown"/> These are the lines that generate the errors, of course.

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• Informational messages returned with WCF involved

  - by DT

  This question is about “informational messages” and having them flow from a “back end” to a “front end” in a consistent manner. The quick question is “how do you do it”? Background: Web application using WCF to call back end services. In the back end service a “message” may occur. Now, the reason for this “message” may be a number of reasons, but for this discussion let’s assume that a piece of data was looked at and it was determined that the caller should be given back some information regarding it. This “informational” message may occur during a save and also may occur during retrieval of information. Again, the message is not what is important here, but the fact that there is some informational messages to give back under a number of different scenarios. From a team perspective we all want to return these “messages” in a standard way all of the time. Now, in the past this “standard way” has been done different ways by different people. Here are some possibilities: 1) Every operation has a “ref” parameter at the end that contains these messages 2) Every method returns these messages… however, this only kind of works for “Save” methods as one would think that “Retrieve” methods should return actual data and not messages 3) Some approach using the call context so as to not "pollute" all message signatures with something; however, with WCF in the picture this complicates things. That is, going back to the messages go on a header? Question: Back to my question then… how are others returning “messages” such as what was described above back through tiers of an application, over WCF and back to the caller?

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• Namespace Problem

  - by Tarik

  Hello, Normally we all do use using System.Linq; and using System.Data.Linq; for example on the code-behind and expect we can reach the members of these namespaces from Source Code like <%= Something.First()%> but when I wrote it, asp.net said it couldn't find First() in the context and I had to add <%@ Import Namespace="System.Linq" which looked very weird to me but it worked out. Since they are targeting at the same class why they both need separate namespace importing. Code-behind : using System; using System.Data.Linq; using System.Linq; using System.Text namespace Something { class Items : System.Web.UI { //... } } but also I need to add the same Linq namespace on the Html Source part <%@Import Namespace="System.Linq"%> Do I know something wrong or this is some kind of bug in asp.net. I thought when the page is compiling, asp.net combines these two classes and converts html source code into cs class and indicates the control in Control c= new Control(); hierarchy. Thanks in advance.

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• Entity framework entity class mapping with plain .net class

  - by Elan

  I have following in entity framework Table - Country Fields List item Country_ID Dialing_Code ISO_Alpha2 ISO_Alpha3 ISO_Full I would like to map only selected fields from this entity model to my domain class. My domain model class is public class DomainCountry { public int Country_ID { get; set; } public string Dialing_Code { get; set; } public string ISO_3166_1_Alpha_2 { get; set; } } The following will work however insert or update is not possible. In order to get insert or update we need to use ObjectSet< but it will not support in my case. IQueryable<DomainCountry> countries = context.Countries.Select( c => new DomainCountry { Country_ID = c.Country_Id, Dialing_Code = c.Dialing_Code, ISO_3166_1_Alpha_2 = c.ISO_3166_1_Alpha_2 }); It will be really fantastic could someone provide a nice solution for this. Ideally it will be kind of proxy class which will support all the futures however highly customizable i.e. only the columns we want to expose to the outer world

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• NHibernate + Remoting = ReflectionPermission Exception

  - by Pedro

  Hi all, We are dealing with a problem when using NHibernate with Remoting in a machine with full trust enviroment (actually that's our dev machine). The problem happens when whe try to send as a parameter an object previously retrieved from the server, that contains a NHibernate Proxy in one of the properties (a lazy one). As we are in the dev machine, there's no restriction in the trust level of the web app (it's set to Full) and, as a plus, we've configured NHibernate's and Castle's assemblies to full trust in CAS (even thinking that it'd not be necessary as the remoting app in IIS has the full trust level). Does anyone have any idea of what can be causing this exception? Stack trace below. InnerException: System.Security.SecurityException Message="Falha na solicitação da permissão de tipo 'System.Security.Permissions.ReflectionPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'." Source="mscorlib" GrantedSet="" PermissionState="<IPermission class=\"System.Security.Permissions.ReflectionPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089\"\r\nversion=\"1\"\r\nFlags=\"ReflectionEmit\"/>\r\n" RefusedSet="" Url="" StackTrace: em System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet) em System.Security.CodeAccessPermission.Demand() em System.Reflection.Emit.AssemblyBuilder.DefineDynamicModuleInternalNoLock(String name, Boolean emitSymbolInfo, StackCrawlMark& stackMark) em System.Reflection.Emit.AssemblyBuilder.DefineDynamicModuleInternal(String name, Boolean emitSymbolInfo, StackCrawlMark& stackMark) em System.Reflection.Emit.AssemblyBuilder.DefineDynamicModule(String name, Boolean emitSymbolInfo) em Castle.DynamicProxy.ModuleScope.CreateModule(Boolean signStrongName) em Castle.DynamicProxy.ModuleScope.ObtainDynamicModuleWithWeakName() em Castle.DynamicProxy.ModuleScope.ObtainDynamicModule(Boolean isStrongNamed) em Castle.DynamicProxy.Generators.Emitters.ClassEmitter.CreateTypeBuilder(ModuleScope modulescope, String name, Type baseType, Type[] interfaces, TypeAttributes flags, Boolean forceUnsigned) em Castle.DynamicProxy.Generators.Emitters.ClassEmitter..ctor(ModuleScope modulescope, String name, Type baseType, Type[] interfaces, TypeAttributes flags, Boolean forceUnsigned) em Castle.DynamicProxy.Generators.Emitters.ClassEmitter..ctor(ModuleScope modulescope, String name, Type baseType, Type[] interfaces, TypeAttributes flags) em Castle.DynamicProxy.Generators.Emitters.ClassEmitter..ctor(ModuleScope modulescope, String name, Type baseType, Type[] interfaces) em Castle.DynamicProxy.Generators.BaseProxyGenerator.BuildClassEmitter(String typeName, Type parentType, Type[] interfaces) em Castle.DynamicProxy.Generators.BaseProxyGenerator.BuildClassEmitter(String typeName, Type parentType, IList interfaceList) em Castle.DynamicProxy.Generators.ClassProxyGenerator.GenerateCode(Type[] interfaces, ProxyGenerationOptions options) em Castle.DynamicProxy.Serialization.ProxyObjectReference.RecreateClassProxy() em Castle.DynamicProxy.Serialization.ProxyObjectReference.RecreateProxy() em Castle.DynamicProxy.Serialization.ProxyObjectReference..ctor(SerializationInfo info, StreamingContext context) Thank you in advance.

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• Adding a guideline to the editor in Visual Studio

  - by xsl

  Introduction I've always been searching for a way to make Visual Studio draw a line after a certain amount of characters: Below is a guide to enable these so called guidelines for various versions of Visual Studio. Visual Studio 2010 Install Paul Harrington's Editor Guidelines extension. Open the registry at HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\10.0\Text Editor and add a new string called Guides with the value RGB(100,100,100), 80. The first part specifies the color, while the other one (80) is the column the line will be displayed. Or install the Guidelines UI extension, which will add entries to the editor's context menu for adding/removing the entries without needing to edit the registry directly. The current disadvantage of this method is that you can't specify the column directly. Visual Studio 2008 and Other Versions If you are using Visual Studio 2008 open the registry at HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\9.0\Text Editor and add a new string called Guides with the value RGB(100,100,100), 80. The first part specifies the color, while the other one (80) is the column the line will be displayed. The vertical line will appear, when you restart Visual Studio. This trick also works for various other version of Visual Studio, as long as you use the correct path: 2003: HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\7.1\Text Editor 2005: HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\8.0\Text Editor 2008: HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\9.0\Text Editor 2008 Express: HKEY_CURRENT_USER\Software\Microsoft\VCExpress\9.0\Text Editor This also works in SQL Server 2005 and probably other versions.

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• Why isn't my new object being seen? C#

  - by Dan

  I am getting ready to take a class at a college on C#. I have been reading up on it a lot and decided to start a fun project. Here is what my project consists of: Main Control Form Configuration Form Arduino Program.cs calls Configuration.cs at start. This is where pin modes for the Arduino are set and where a timer is set. When I set these values, they get sent to MainControl.cs. When I hit the "Save" button in Configuration.cs, a MainControl.cs object is created [[I am correct in that?]] All of those values that were sent by Configuration.cs had corresponding setters that set private static variables in MainControl.cs [[ I don't really know if that is the preferred way, I am most definetly open to any suggestion anyone has]] MainControl.cs uses its default constructor, and this constructor calls a method that creates an arduino object from one of the private variables (serialPort) [[ Using this Arduino class Firmata.NET ]] When the arduino object is created, I know (I guess I do) because the form takes a few seconds to come up (As opposed to not using serial port) My problem is this: I do not understand why nothing can see the object I have been very wordy, I apologize if I wasn't concise. Here is the code: public partial class CMainControl : Form { private static string serialPort; public CMainControl() { InitializeComponent(); createArduino(); updateConfig(); // Change label values to values set in configuration } private void createArduino() { Arduino arduino = new Arduino(serialPort); } In Configuration.cs, when I set the serial port through a combobox, the value is sent to MainControl.cs just fine. Here is the error I get: Error 1 The name 'arduino' does not exist in the current context C:\Programming\Visual Studio\Workhead Demo\Workhead Demo\CMainControl.cs 94 13 Workhead Demo Please let me know if anyone can help and/or offer pointers, and please let me know if I didn't post or format anything correctly. Thank you very much :)

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• Lightweight spinlocks built from GCC atomic operations?

  - by Thomas

  I'd like to minimize synchronization and write lock-free code when possible in a project of mine. When absolutely necessary I'd love to substitute light-weight spinlocks built from atomic operations for pthread and win32 mutex locks. My understanding is that these are system calls underneath and could cause a context switch (which may be unnecessary for very quick critical sections where simply spinning a few times would be preferable). The atomic operations I'm referring to are well documented here: http://gcc.gnu.org/onlinedocs/gcc-4.4.1/gcc/Atomic-Builtins.html Here is an example to illustrate what I'm talking about. Imagine a RB-tree with multiple readers and writers possible. RBTree::exists() is read-only and thread safe, RBTree::insert() would require exclusive access by a single writer (and no readers) to be safe. Some code: class IntSetTest { private: unsigned short lock; RBTree<int>* myset; public: // ... void add_number(int n) { // Aquire once locked==false (atomic) while (__sync_bool_compare_and_swap(&lock, 0, 0xffff) == false); // Perform a thread-unsafe operation on the set myset->insert(n); // Unlock (atomic) __sync_bool_compare_and_swap(&lock, 0xffff, 0); } bool check_number(int n) { // Increment once the lock is below 0xffff u16 savedlock = lock; while (savedlock == 0xffff || __sync_bool_compare_and_swap(&lock, savedlock, savedlock+1) == false) savedlock = lock; // Perform read-only operation bool exists = tree->exists(n); // Decrement savedlock = lock; while (__sync_bool_compare_and_swap(&lock, savedlock, savedlock-1) == false) savedlock = lock; return exists; } }; (lets assume it need not be exception-safe) Is this code indeed thread-safe? Are there any pros/cons to this idea? Any advice? Is the use of spinlocks like this a bad idea if the threads are not truly concurrent? Thanks in advance. ;)

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• Empty UIView with minimal drawRect: overhead

  - by Benjohn Barnes

  Hi, I have an application that has three nested views that are mechanically important, but have no visual elements: A vanila UIView that doesn't have any content of its own, and is simply used as a host for CALayers. A UIScrollView (that is queried for it's origin and used to position CALayers in 3d: I really only use this view to faithfully replicate the scroll view's "mechanics"), The scroll view's contents: a UIView subclass. It simply picks up touch events and passes them to a delegate - all that is important are its UIResponder machinery. The UIView hosting CALayers is a sibling of a UIImageView that is a background image over which the CALayers are drawn. I'd really like to ensure that none of these empty UIViews have any drawing or compositing overhead (in time, or storage) associated with them, or if that's not possible, to get this overhead as small as possible, and to understand it so that I can perhaps decide if I should try a different approach. In interface builder, I've set all of the views to not clear their context before drawing. I've not set them to be opaque though, because they definitely are not opaque - they are completely transparent. I've found that I need to give the scroll view contents a transparent clear colour (again in IB by setting the background colour's opacity to zero), and this suggests that it is being drawn, which I don't want. So, in short, I've not got much idea of what is and isn't getting drawn (anyone know of a tool like Quartz Debug for iPhone / simulator?), or how to go about stopping things from getting drawn. Advice would be very welcome! Thanks, Benjohn

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• VS 2008 designer and usercontrol.

  - by Ram

  Hello, I have created a custom data grid control. I dragged it on windows form and set its properties like column and all & ran the project. It built successfully and I am able to view the grid control on the form. Now if i try to view that form in designer, I am getting following error.. Object reference not set to an instance of an object. Instances of this error (1) 1. Hide Call Stack at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.GetMemberTargetObject(XmlElementData xmlElementData, String& member) at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.CreateAssignStatement(XmlElementData xmlElement) at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.XmlElementData.get_CodeDomElement() at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.EndElement(String prefix, String name, String urn) at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.Parse(XmlReader reader) at Microsoft.VisualStudio.Design.Serialization.CodeDom.XML.CodeDomXmlProcessor.ParseXml(String xmlStream, CodeStatementCollection statementCollection, String fileName, String methodName) at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomParser.OnMethodPopulateStatements(Object sender, EventArgs e) at System.CodeDom.CodeMemberMethod.get_Statements() at System.ComponentModel.Design.Serialization.TypeCodeDomSerializer.Deserialize(IDesignerSerializationManager manager, CodeTypeDeclaration declaration) at System.ComponentModel.Design.Serialization.CodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager manager) at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager serializationManager) at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.DeferredLoadHandler.Microsoft.VisualStudio.TextManager.Interop.IVsTextBufferDataEvents.OnLoadCompleted(Int32 fReload) If I ignore the exception, form appears blank with no sign of grid control on it. However I can see the code for the grid in the designer file. Any pointer on this would be a great help. I have customized grid for my custom requirements like I have added custom text box n all. I have defined 3 constructors public GridControl() public GridControl(IContainer container) protected GridControl(SerializationInfo info, StreamingContext context)

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• trying to draw scaled UIImage in custom view, but nothing's rendering

  - by Ben Collins

  I've created a custom view class and right now just want to draw an image scaled to fit the view, given a UIImage. I tried just drawing the UIImage.CGImage, but as others have attested to on this site (and in the docs), that renders the image upside down. So, at the suggestion of an answer I found to another question, I'm trying to draw it directly, but nothing is rendering in the view and I'm not sure why. Here's my drawing code: - (void)drawRect:(CGRect)rect { // Drawing code [super drawRect:rect]; if (self.originalImage) { [self drawImage]; } } - (void) drawImage { if (CGSizeEqualToSize(originalImage.size, self.frame.size) == NO) { CGFloat scaleFactor = 1.0; CGFloat scaledWidth = 0.0; CGFloat scaledHeight = 0.0; CGPoint thumbPoint = CGPointMake(0.0, 0.0); CGFloat widthFactor = self.frame.size.width / originalImage.size.width; CGFloat heightFactor = self.frame.size.height / originalImage.size.height; if (widthFactor < heightFactor) { scaleFactor = widthFactor; } else { scaleFactor = heightFactor; } scaledWidth = originalImage.size.width * scaleFactor; scaledHeight = originalImage.size.height * scaleFactor; if (widthFactor < heightFactor) { thumbPoint.y = (self.frame.size.height - scaledHeight) * 0.5; } else if (widthFactor > heightFactor) { thumbPoint.x = (self.frame.size.width - scaledWidth) * 0.5; } UIGraphicsBeginImageContext(self.frame.size); CGRect thumbRect = CGRectZero; thumbRect.origin = thumbPoint; thumbRect.size.width = scaledWidth; thumbRect.size.height = scaledHeight; [originalImage drawInRect:thumbRect]; self.scaledImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); } else { self.scaledImage = originalImage; } } My understanding (after studying this a bit) is that the UIGraphicsBeginImageContext function creates an offscreen for me to draw into, so now how do I render that context on top of the original one?

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• Controlling ASP.NET output cache memory usage

  - by Josh Einstein

  I would like to use output caching with WCF Data Services and although there's nothing specifically built in to support caching, there is an OnStartProcessingRequest method that allows me to hook in and set the cacheability of the request using normal ASP.NET mechanisms. But I am worried about the worker process getting recycled due to excessive memory consumption if large responses are cached. Is there a way to specify an upper limit for the ASP.NET output cache so that if this limit is exceeded, items in the cache will be discarded? I've seen the caching configuration settings but I get the impression from the documentation that this is for explicit caching via the Cache object since there is a separate outputCacheSettings which has no memory-related attributes. Here's a code snippet from Scott Hanselman's post that shows how I'm setting the cacheability of the request. protected override void OnStartProcessingRequest(ProcessRequestArgs args) { base.OnStartProcessingRequest(args); //Cache for a minute based on querystring HttpContext context = HttpContext.Current; HttpCachePolicy c = HttpContext.Current.Response.Cache; c.SetCacheability(HttpCacheability.ServerAndPrivate); c.SetExpires(HttpContext.Current.Timestamp.AddSeconds(60)); c.VaryByHeaders["Accept"] = true; c.VaryByHeaders["Accept-Charset"] = true; c.VaryByHeaders["Accept-Encoding"] = true; c.VaryByParams["*"] = true; }

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• Why is the 'Named Domain Class' tool missing in the DSL Designer category in the toolbox ?

  - by Gishu

  I have the Domain-Specific development with VS DSL Tools book by Cook, Jones, et.all The book and various tutorials online mention a NamedDomainClass tool that should be present in the DSL Designer toolbox. I have installed VS 2010 beta 2 on Win XP - however this tool is missing in the toolbox. I've created a project using the Minimal project template as mentioned in the book. I have 12 tools showing up including the Domain Class tool. I've searched online and apparently no one else has this problem. Can someone confirm that it's missing in VS 2010 Beta 2? If not how can I get it to show up ? Is there any way in which I can add a Domain class instance and tweak it so that it becomes a Named Domain Class? The book mentions that there is some must-be-unique validation and serialization changes that are done by the NamedDomainClass tool. I've tried 'Choose Items' context menu on the DSL Designer category. These tools apparently are added dynamically ; do not show up in the lists on the dialog that comes up.

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• Handling dependencies with IoC that change within a single function call

  - by Jess

  We are trying to figure out how to setup Dependency Injection for situations where service classes can have different dependencies based on how they are used. In our specific case, we have a web app where 95% of the time the connection string is the same for the entire Request (this is a web application), but sometimes it can change. For example, we might have 2 classes with the following dependencies (simplified version - service actually has 4 dependencies): public LoginService (IUserRepository userRep) { } public UserRepository (IContext dbContext) { } In our IoC container, most of our dependencies are auto-wired except the Context for which I have something like this (not actual code, it's from memory ... this is StructureMap): x.ForRequestedType().Use() .WithCtorArg("connectionString").EqualTo(Session["ConnString"]); For 95% of our web application, this works perfectly. However, we have some admin-type functions that must operate across thousands of databases (one per client). Basically, we'd want to do this: public CreateUserList(IList<string> connStrings) { foreach (connString in connStrings) { //first create dependency graph using new connection string ???? //then call service method on new database _loginService.GetReportDataForAllUsers(); } } My question is: How do we create that new dependency graph for each time through the loop, while maintaining something that can easily be tested?

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• How to assign .net membership roles to individual database records

  - by mdresser

  I'm developing a system where we want to restrict the availability of information displayed to users based on their roles. e.g. I have a tabled called EventType (ID, EventTypeDescription) which contains the following records: 1, 'Basic Event' 2, 'Intermediate Event' 3, 'Admin Event' What I need to achieve is to filter the records returned based on the username (and hence role) of the logged-in user. e.g if an advanced user is logged in they will see all the event types, if the standard user is logged in they will only see the basic event type etc. Ideally id like to do this in a way which can be easily extended to other tables as necessary. So I'd like to avoid simply adding a 'Roles' field to each table where the data is user context sensitive. One idea I'm thinking of is to create some kind of permissions table like: PermissionsTable ( ID, Aspnet_RoleId, TableName, PrimaryKeyValue ) this has the drawback of using this is obviously having to use the table name to switch which table to join onto. Edit: In the absence of any better suggestions, I'm going to go with the last idea I mentioned, but instead of having a TableName field, I'm going to normalise the TableName out to it's own table as follows: TableNames ( ID, TableName ) UserPermissionsTable ( ID, Aspnet_UserId, TableID, PrimaryKeyValue )

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