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  • Clipboard: Copy image, get path back when pasting in file input.

    - by disown
    Hi All. First question here on superuser. I sometimes get ad-hoc bug reports from customers, which I need to transfer to our online bug tracker. Works fine for text, but pictures are tedious. I'm looking for a solution to copy-paste images from documents (like excel sheets) in a way that if you paste an image to a file input (or text input) on a html page, the file will automatically be written to disk (tmp dir), and the path written to the file input field. This question is related to Directly paste clipboard image into gmail message, but I would like to ask if there is a solution using a local program only. I'm interested in solutions for all OS's.

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  • where does windows vista hide the path environment variable?

    - by Bec
    i think that's what i need? i'm not sure i'm trying to run a command line program (BLAST, from NCBI) but it won't recognise the commands (blastall, formatdb, etc.) so i think i need to add the folder the bin is in to the path environment variable? i think that's what i need to do? i think that's what it's called? I think i've been shown this a few times, but i don't need to do it often, so i keep forgetting.

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  • WPF unity Activation error occured while trying to get instance of type

    - by Traci
    I am getting the following error when trying to Initialise the Module using Unity and Prism. The DLL is found by return new DirectoryModuleCatalog() { ModulePath = @".\Modules" }; The dll is found and the Name is Found #region Constructors public AdminModule( IUnityContainer container, IScreenFactoryRegistry screenFactoryRegistry, IEventAggregator eventAggregator, IBusyService busyService ) : base(container, screenFactoryRegistry) { this.EventAggregator = eventAggregator; this.BusyService = busyService; } #endregion #region Properties protected IEventAggregator EventAggregator { get; set; } protected IBusyService BusyService { get; set; } #endregion public override void Initialize() { base.Initialize(); } #region Register Screen Factories protected override void RegisterScreenFactories() { this.ScreenFactoryRegistry.Register(ScreenKeyType.ApplicationAdmin, typeof(AdminScreenFactory)); } #endregion #region Register Views and Various Services protected override void RegisterViewsAndServices() { //View Models this.Container.RegisterType<IAdminViewModel, AdminViewModel>(); } #endregion the code that produces the error is: namespace Microsoft.Practices.Composite.Modularity protected virtual IModule CreateModule(string typeName) { Type moduleType = Type.GetType(typeName); if (moduleType == null) { throw new ModuleInitializeException(string.Format(CultureInfo.CurrentCulture, Properties.Resources.FailedToGetType, typeName)); } return (IModule)this.serviceLocator.GetInstance(moduleType); <-- Error Here } Can Anyone Help Me Error Log Below: General Information Additional Info: ExceptionManager.MachineName: xxxxx ExceptionManager.TimeStamp: 22/02/2010 10:16:55 AM ExceptionManager.FullName: Microsoft.ApplicationBlocks.ExceptionManagement, Version=1.0.3591.32238, Culture=neutral, PublicKeyToken=null ExceptionManager.AppDomainName: Infinity.vshost.exe ExceptionManager.ThreadIdentity: ExceptionManager.WindowsIdentity: xxxxx 1) Exception Information Exception Type: Microsoft.Practices.Composite.Modularity.ModuleInitializeException ModuleName: AdminModule Message: An exception occurred while initializing module 'AdminModule'. - The exception message was: Activation error occured while trying to get instance of type AdminModule, key "" Check the InnerException property of the exception for more information. If the exception occurred while creating an object in a DI container, you can exception.GetRootException() to help locate the root cause of the problem. Data: System.Collections.ListDictionaryInternal TargetSite: Void HandleModuleInitializationError(Microsoft.Practices.Composite.Modularity.ModuleInfo, System.String, System.Exception) HelpLink: NULL Source: Microsoft.Practices.Composite StackTrace Information at Microsoft.Practices.Composite.Modularity.ModuleInitializer.HandleModuleInitializationError(ModuleInfo moduleInfo, String assemblyName, Exception exception) at Microsoft.Practices.Composite.Modularity.ModuleInitializer.Initialize(ModuleInfo moduleInfo) at Microsoft.Practices.Composite.Modularity.ModuleManager.InitializeModule(ModuleInfo moduleInfo) at Microsoft.Practices.Composite.Modularity.ModuleManager.LoadModulesThatAreReadyForLoad() at Microsoft.Practices.Composite.Modularity.ModuleManager.OnModuleTypeLoaded(ModuleInfo typeLoadedModuleInfo, Exception error) at Microsoft.Practices.Composite.Modularity.FileModuleTypeLoader.BeginLoadModuleType(ModuleInfo moduleInfo, ModuleTypeLoadedCallback callback) at Microsoft.Practices.Composite.Modularity.ModuleManager.BeginRetrievingModule(ModuleInfo moduleInfo) at Microsoft.Practices.Composite.Modularity.ModuleManager.LoadModuleTypes(IEnumerable`1 moduleInfos) at Microsoft.Practices.Composite.Modularity.ModuleManager.LoadModulesWhenAvailable() at Microsoft.Practices.Composite.Modularity.ModuleManager.Run() at Microsoft.Practices.Composite.UnityExtensions.UnityBootstrapper.InitializeModules() at Infinity.Bootstrapper.InitializeModules() in D:\Projects\dotNet\Infinity\source\Inifinty\Infinity\Application Modules\BootStrapper.cs:line 75 at Microsoft.Practices.Composite.UnityExtensions.UnityBootstrapper.Run(Boolean runWithDefaultConfiguration) at Microsoft.Practices.Composite.UnityExtensions.UnityBootstrapper.Run() at Infinity.App.Application_Startup(Object sender, StartupEventArgs e) in D:\Projects\dotNet\Infinity\source\Inifinty\Infinity\App.xaml.cs:line 37 at System.Windows.Application.OnStartup(StartupEventArgs e) at System.Windows.Application.<.ctorb__0(Object unused) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) 2) Exception Information Exception Type: Microsoft.Practices.ServiceLocation.ActivationException Message: Activation error occured while trying to get instance of type AdminModule, key "" Data: System.Collections.ListDictionaryInternal TargetSite: System.Object GetInstance(System.Type, System.String) HelpLink: NULL Source: Microsoft.Practices.ServiceLocation StackTrace Information at Microsoft.Practices.ServiceLocation.ServiceLocatorImplBase.GetInstance(Type serviceType, String key) at Microsoft.Practices.ServiceLocation.ServiceLocatorImplBase.GetInstance(Type serviceType) at Microsoft.Practices.Composite.Modularity.ModuleInitializer.CreateModule(String typeName) at Microsoft.Practices.Composite.Modularity.ModuleInitializer.Initialize(ModuleInfo moduleInfo) 3) Exception Information Exception Type: Microsoft.Practices.Unity.ResolutionFailedException TypeRequested: AdminModule NameRequested: NULL Message: Resolution of the dependency failed, type = "Infinity.Modules.Admin.AdminModule", name = "". Exception message is: The current build operation (build key Build Key[Infinity.Modules.Admin.AdminModule, null]) failed: The parameter screenFactoryRegistry could not be resolved when attempting to call constructor Infinity.Modules.Admin.AdminModule(Microsoft.Practices.Unity.IUnityContainer container, PhoenixIT.IScreenFactoryRegistry screenFactoryRegistry, Microsoft.Practices.Composite.Events.IEventAggregator eventAggregator, PhoenixIT.IBusyService busyService). (Strategy type BuildPlanStrategy, index 3) Data: System.Collections.ListDictionaryInternal TargetSite: System.Object DoBuildUp(System.Type, System.Object, System.String) HelpLink: NULL Source: Microsoft.Practices.Unity StackTrace Information at Microsoft.Practices.Unity.UnityContainer.DoBuildUp(Type t, Object existing, String name) at Microsoft.Practices.Unity.UnityContainer.DoBuildUp(Type t, String name) at Microsoft.Practices.Unity.UnityContainer.Resolve(Type t, String name) at Microsoft.Practices.Composite.UnityExtensions.UnityServiceLocatorAdapter.DoGetInstance(Type serviceType, String key) at Microsoft.Practices.ServiceLocation.ServiceLocatorImplBase.GetInstance(Type serviceType, String key) 4) Exception Information Exception Type: Microsoft.Practices.ObjectBuilder2.BuildFailedException ExecutingStrategyTypeName: BuildPlanStrategy ExecutingStrategyIndex: 3 BuildKey: Build Key[Infinity.Modules.Admin.AdminModule, null] Message: The current build operation (build key Build Key[Infinity.Modules.Admin.AdminModule, null]) failed: The parameter screenFactoryRegistry could not be resolved when attempting to call constructor Infinity.Modules.Admin.AdminModule(Microsoft.Practices.Unity.IUnityContainer container, PhoenixIT.IScreenFactoryRegistry screenFactoryRegistry, Microsoft.Practices.Composite.Events.IEventAggregator eventAggregator, PhoenixIT.IBusyService busyService). (Strategy type BuildPlanStrategy, index 3) Data: System.Collections.ListDictionaryInternal TargetSite: System.Object ExecuteBuildUp(Microsoft.Practices.ObjectBuilder2.IBuilderContext) HelpLink: NULL Source: Microsoft.Practices.ObjectBuilder2 StackTrace Information at Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context) at Microsoft.Practices.ObjectBuilder2.Builder.BuildUp(IReadWriteLocator locator, ILifetimeContainer lifetime, IPolicyList policies, IStrategyChain strategies, Object buildKey, Object existing) at Microsoft.Practices.Unity.UnityContainer.DoBuildUp(Type t, Object existing, String name) 5) Exception Information Exception Type: System.InvalidOperationException Message: The parameter screenFactoryRegistry could not be resolved when attempting to call constructor Infinity.Modules.Admin.AdminModule(Microsoft.Practices.Unity.IUnityContainer container, PhoenixIT.IScreenFactoryRegistry screenFactoryRegistry, Microsoft.Practices.Composite.Events.IEventAggregator eventAggregator, PhoenixIT.IBusyService busyService). Data: System.Collections.ListDictionaryInternal TargetSite: Void ThrowForResolutionFailed(System.Exception, System.String, System.String, Microsoft.Practices.ObjectBuilder2.IBuilderContext) HelpLink: NULL Source: Microsoft.Practices.ObjectBuilder2 StackTrace Information at Microsoft.Practices.ObjectBuilder2.DynamicMethodConstructorStrategy.ThrowForResolutionFailed(Exception inner, String parameterName, String constructorSignature, IBuilderContext context) at BuildUp_Infinity.Modules.Admin.AdminModule(IBuilderContext ) at Microsoft.Practices.ObjectBuilder2.DynamicMethodBuildPlan.BuildUp(IBuilderContext context) at Microsoft.Practices.ObjectBuilder2.BuildPlanStrategy.PreBuildUp(IBuilderContext context) at Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context) 6) Exception Information Exception Type: Microsoft.Practices.ObjectBuilder2.BuildFailedException ExecutingStrategyTypeName: BuildPlanStrategy ExecutingStrategyIndex: 3 BuildKey: Build Key[PhoenixIT.IScreenFactoryRegistry, null] Message: The current build operation (build key Build Key[PhoenixIT.IScreenFactoryRegistry, null]) failed: The current type, PhoenixIT.IScreenFactoryRegistry, is an interface and cannot be constructed. Are you missing a type mapping? (Strategy type BuildPlanStrategy, index 3) Data: System.Collections.ListDictionaryInternal TargetSite: System.Object ExecuteBuildUp(Microsoft.Practices.ObjectBuilder2.IBuilderContext) HelpLink: NULL Source: Microsoft.Practices.ObjectBuilder2 StackTrace Information at Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context) at Microsoft.Practices.Unity.ObjectBuilder.NamedTypeDependencyResolverPolicy.Resolve(IBuilderContext context) at BuildUp_Infinity.Modules.Admin.AdminModule(IBuilderContext ) 7) Exception Information Exception Type: System.InvalidOperationException Message: The current type, PhoenixIT.IScreenFactoryRegistry, is an interface and cannot be constructed. Are you missing a type mapping? Data: System.Collections.ListDictionaryInternal TargetSite: Void ThrowForAttemptingToConstructInterface(Microsoft.Practices.ObjectBuilder2.IBuilderContext) HelpLink: NULL Source: Microsoft.Practices.ObjectBuilder2 StackTrace Information at Microsoft.Practices.ObjectBuilder2.DynamicMethodConstructorStrategy.ThrowForAttemptingToConstructInterface(IBuilderContext context) at BuildUp_PhoenixIT.IScreenFactoryRegistry(IBuilderContext ) at Microsoft.Practices.ObjectBuilder2.DynamicMethodBuildPlan.BuildUp(IBuilderContext context) at Microsoft.Practices.ObjectBuilder2.BuildPlanStrategy.PreBuildUp(IBuilderContext context) at Microsoft.Practices.ObjectBuilder2.StrategyChain.ExecuteBuildUp(IBuilderContext context) For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

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  • How to extend WPF hit testing zone for a Path object.

    - by user275587
    Wpf hit testing is pretty good but the only method I found to extend the hit zone is to put a transparent padding area around your object. I can't find any method to add a transparent area arround a Path object. The path is very thin and I would like to enable hit testing if the user clicks near the path. I can't find any method to extend the path object with a transparent area like the image below : I tried to used a partially transparent stroke brush but I ran into the problem described here : http://stackoverflow.com/questions/1412833/how-can-i-draw-a-soft-line-in-wpf-presumably-using-a-lineargradientbrush I also tried to put an adorner over my line but because of WPF anti-aliasing algorithms, the position is way off when I zoom in my canvas and interfere with other objects hit-testing in a bad way. Any suggestion to extend the hit testing zone would be highly appreciated. Thanks, Kumar

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  • Shortest-path algorithms which use a space-time tradeoff?

    - by Chris Mounce
    I need to find shortest paths in an unweighted, undirected graph. There are algorithms which can find a shortest path between two nodes, but this can take time. There are also algorithms for computing shortest paths for all pairs of nodes in the graph, but storing such a lookup table would take lots of disk space. What I'm wondering: Is there an algorithm which offers a space-time tradeoff that's somewhere between these two extremes? In other words, is there a way to speed up a shortest-path search, while using less disk space than would be occupied by an all-pairs shortest-path table? I know there are ways to efficiently store lookup tables for this problem, and I already have a couple of ideas for speeding up shortest-path searches using precomputed data. But I don't want to reinvent the wheel if there's already some established algorithm that solves this problem.

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  • Eclipse CDT -- How to map Linux path's to Windows paths?

    - by SiegeX
    We have a C-code project written for a Linux environment but we also want the ability to view and edit the code on Eclipse for Windows and have the headers be resolved. The problem we are facing is that a lot of the headers are included with absolute paths in the Linux format such as: #include /path/to/custom/header.h What I would like to be able to do is have Eclipse CDT map /path/to/custom/ to C:\path\to\custom. Is this possible?

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  • To read the hyperlink path of a text from Excel file via JAVA?

    - by Guru
    I have done upto reading text (String) from Excel file i could leverage the same into my JAVA. But now i have an other querry. Supposing if the text in excel is a hyperlink i need the link path of that text. Say: "hyperlink text" path manually mapped to say ("C:\Folder\iamge.jpg") I want this path in java. Can any one help me with this!

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  • How can I get the path separator in Perl?

    - by ram
    In case of Java, we can get the path separator using System.getProperty("path.separator"); Is there a similar way in Perl? All I want to do is to find a dir, immediate sub directory. Say I am being given two arguments $a and $b; I am splitting the first one based on the path separator and joining it again except the last fragment and comparing with the second argument. The problem is my code has to be generic and for that I need to know whats the system dependent path separator is?

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  • What does a leading "\??\" on a windows path mean?

    - by kdt
    When using GetModuleFileNameEx to query the image path of a running process, some processes have an image path that starts with "\??\". For example, while most processes start "C:\WINDOWS", some processes start "\??\C:\WINDOWS". What does the leading \??\ mean on a windows path?

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  • How to condense a path in C++ using Boost?

    - by pdillon3
    Does Boost offer a simple way to condense a path such as /foo/bar/../bar or /foo/../. into the absolute path it refers to. /foo/bar/../bar -- /foo/bar /foo/../. -- / The goal is to combine base_path and rel_path with boost::filesystem::complete(rel_path, base_path) into a path into /foo/bar/with/no/dots. thanks

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  • HTML5 Input type=date Formatting Issues

    - by Rick Strahl
    One of the nice features in HTML5 is the abililty to specify a specific input type for HTML text input boxes. There a host of very useful input types available including email, number, date, datetime, month, number, range, search, tel, time, url and week. For a more complete list you can check out the MDN reference. Date input types also support automatic validation which can be useful in some scenarios but maybe can get in the way at other times. One of the more common input types, and one that can most benefit of a custom UI for selection is of course date input. Almost every application could use a decent date representation and HTML5's date input type seems to push into the right direction. It'd be nice if you could just say:<form action="DateTest.html"> <label for="FromDate">Enter a Date:</label> <input type="date" id="FromDate" name="FromDate" value="11/08/2012" class="date" /> <hr /> <input type="submit" id="btnSubmit" name="btnSubmit" value="Save Date" class="smallbutton" /> </form> but if you'd expect to just work, you're likely to be pretty disappointed. Problem #1: Browser Support For starters there's browser support. Out of the major browsers only the latest versions of WebKit and Opera based browsers seem to support date input. Neither FireFox, nor any version of Internet Explorer (including the new touch enabled IE10 in Windows RT) support input type=date. Browser support is an issue, but it would be OK if it wasn't for problem #2. Problem #2: Date Formatting If you look at my date input from before:<input type="date" id="FromDate" name="FromDate" value="11/08/2012" class="date" /> You can see that my date is formatted in local date format (ie. en-us). Now when I run this sadly the form that comes up in Chrome (and also iOS mobile browsers) comes up like this: Chrome isn't recognizing my local date string. Instead it's expecting my date format to be provided in ISO 8601 format which is: 2012-11-08 So if I change the date input field to:<input type="date" id="FromDate" name="FromDate" value="2012-10-08" class="date" /> I correctly get the date field filled in: Also when I pick a date with the DatePicker the date value is also returned is also set to the ISO date format. Yet notice how the date is still formatted to the local date time format (ie. en-US format). So if I pick a new date: and then save, the value field is set back to: 2012-11-15 using the ISO format. The same is true for Opera and iOS browsers and I suspect any other WebKit style browser and their date pickers. So to summarize input type=date: Expects ISO 8601 format dates to display intial values Sets selected date values to ISO 8601 Now what? This would sort of make sense, if all browsers supported input type=date. It'd be easy because you could just format dates appropriately when you set the date value into the control by applying the appropriate culture formatting (ie. .ToString("yyyy-MM-dd") ). .NET is actually smart enough to pick up the date on the other end for modelbinding when ISO 8601 is used. For other environments this might be a bit more tricky. input type=date is clearly the way to go forward. Date controls implemented in HTML are going the way of the dodo, given the intricacies of mobile platforms and scaling for both desktop and mobile. I've been using jQuery UI Datepicker for ages but once going to mobile, that's no longer an option as the control doesn't scale down well for mobile apps (at least not without major re-styling). It also makes a lot of sense for the browser to provide this functionality - creating a consistent date input experience across apps only makes sense, which is why I find it baffling that neither FireFox nor IE 10 deign it necessary to support date input natively. The problem is that a large number of even the latest and greatest browsers don't support this. So now you're stuck with not knowing what date format you have to serve since neither the local format, nor the ISO format works in all cases. For my current app I just broke down and used the ISO format and so I'll live with the non-local date format. <input type="date" id="ToDate" name="ToDate" value="2012-11-08" class="date"/> Here's what this looks like on Chrome: Here's what it looks like on my iPhone: Both Chrome and the phone do this the way it should be. For the phone especially this demonstrates why we'd want this - the built-in date picker there certainly beats manually trying to edit the date using finger gymnastics, and it's one of the easiest ways to pick a date I can think of (ie. easier to use than your typical date picker). Finally here's what the date looks like in FireFox: Certainly this is not the ideal date format, but it's clear enough I suppose. If users enter a date in local US format and that works as well (but won't work for other locales). It'll have to do. Over time one can only hope that other browsers will finally decide to implement this functionality natively to provide a unique experience. Until then, incomplete solutions it is. Related Posts Html 5 Input Types - How useful is this really going to be?© Rick Strahl, West Wind Technologies, 2005-2012Posted in HTML5  HTML   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • How to have multiple path separators in Bash

    - by binW
    I have few python scripts which were written by someone else in Windows. These scripts use double backslash as path separator but when run in Ubuntu they don't work because of this. I can change all \ to / and scripts will work but there are lot of scripts and its a lot of effort to change each \ to / So my question is: Is it possible to add \ as path separator in Ubuntu or only in Bash so that I dont have to modify these scripts?

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  • Path tables or real time searching for AI?

    - by SirYakalot
    What is the more common practice in commercial games; path lookup tables or real time searches? I've read that in many games path lookup tables are pre-calculated and baked into each map, so to speak, then steering behaviour is used to handle dynamic obstacles. or is it better practice to use optimised hierarchical A* searches? I understand the pro's and cons of each, I'm just curious as to what is most often used in the industry.

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  • Get location of "true" GVFS path from Nautilus

    - by user946850
    I mount my Samba shares through Nautilus. I know that, behind the scenes, the share is fuse-mounted and Nautilus somehow does the translation between smb:// URLs and the actual location in the file system. Is it possible to retrieve the "true" path in the file system for a GVFS-mounted share, for a directory or a file? How? This is related, but does not answer my question: How to copy the current path from Nautilus?

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  • Redirect root path on root domain to subdomain

    - by maknz
    Say there's a web application that runs on example.com, would there be a penalty for 301 redirecting the root of the domain (example.com/) to subdomain.example.com for purposes of hosting the marketing website for an application? Obviously we would expect subdomain.example.com to be what is ranked in the search engine, not example.com. We would want other paths on example.com like example.com/path/to/resource to index normally, and be unaffected by the 301 on the root path.

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  • Custom Validation - Dependent Drop Down Lists

    - by Holysmoke
    Hi, I've two columns in a sheet that are interdependent and I want to use validation, drop-down lists, on both as follows: Column A (TYPE) | Column B (Sub-TYPE) ------------------------------------------| TypeA, TypeB | If TypeA SubTypeA1, | ... TypeN | SubTypeA2 ... SubTypeAN | ------------------------------------------| Creating the column A drop down is trivial. How do I create the Column B drop down, that in turn depends on what was chosen in Column A? TIA

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  • Unable to cast transparent proxy to type &lt;type&gt;

    - by Rick Strahl
    This is not the first time I've run into this wonderful error while creating new AppDomains in .NET and then trying to load types and access them across App Domains. In almost all cases the problem I've run into with this error the problem comes from the two AppDomains involved loading different copies of the same type. Unless the types match exactly and come exactly from the same assembly the typecast will fail. The most common scenario is that the types are loaded from different assemblies - as unlikely as that sounds. An Example of Failure To give some context, I'm working on some old code in Html Help Builder that creates a new AppDomain in order to parse assembly information for documentation purposes. I create a new AppDomain in order to load up an assembly process it and then immediately unload it along with the AppDomain. The AppDomain allows for unloading that otherwise wouldn't be possible as well as isolating my code from the assembly that's being loaded. The process to accomplish this is fairly established and I use it for lots of applications that use add-in like functionality - basically anywhere where code needs to be isolated and have the ability to be unloaded. My pattern for this is: Create a new AppDomain Load a Factory Class into the AppDomain Use the Factory Class to load additional types from the remote domain Here's the relevant code from my TypeParserFactory that creates a domain and then loads a specific type - TypeParser - that is accessed cross-AppDomain in the parent domain:public class TypeParserFactory : System.MarshalByRefObject,IDisposable { …/// <summary> /// TypeParser Factory method that loads the TypeParser /// object into a new AppDomain so it can be unloaded. /// Creates AppDomain and creates type. /// </summary> /// <returns></returns> public TypeParser CreateTypeParser() { if (!CreateAppDomain(null)) return null; /// Create the instance inside of the new AppDomain /// Note: remote domain uses local EXE's AppBasePath!!! TypeParser parser = null; try { Assembly assembly = Assembly.GetExecutingAssembly(); string assemblyPath = Assembly.GetExecutingAssembly().Location; parser = (TypeParser) this.LocalAppDomain.CreateInstanceFrom(assemblyPath, typeof(TypeParser).FullName).Unwrap(); } catch (Exception ex) { this.ErrorMessage = ex.GetBaseException().Message; return null; } return parser; } private bool CreateAppDomain(string lcAppDomain) { if (lcAppDomain == null) lcAppDomain = "wwReflection" + Guid.NewGuid().ToString().GetHashCode().ToString("x"); AppDomainSetup setup = new AppDomainSetup(); // *** Point at current directory setup.ApplicationBase = AppDomain.CurrentDomain.BaseDirectory; //setup.PrivateBinPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "bin"); this.LocalAppDomain = AppDomain.CreateDomain(lcAppDomain,null,setup); // Need a custom resolver so we can load assembly from non current path AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(CurrentDomain_AssemblyResolve); return true; } …} Note that the classes must be either [Serializable] (by value) or inherit from MarshalByRefObject in order to be accessible remotely. Here I need to call methods on the remote object so all classes are MarshalByRefObject. The specific problem code is the loading up a new type which points at an assembly that visible both in the current domain and the remote domain and then instantiates a type from it. This is the code in question:Assembly assembly = Assembly.GetExecutingAssembly(); string assemblyPath = Assembly.GetExecutingAssembly().Location; parser = (TypeParser) this.LocalAppDomain.CreateInstanceFrom(assemblyPath, typeof(TypeParser).FullName).Unwrap(); The last line of code is what blows up with the Unable to cast transparent proxy to type <type> error. Without the cast the code actually returns a TransparentProxy instance, but the cast is what blows up. In other words I AM in fact getting a TypeParser instance back but it can't be cast to the TypeParser type that is loaded in the current AppDomain. Finding the Problem To see what's going on I tried using the .NET 4.0 dynamic type on the result and lo and behold it worked with dynamic - the value returned is actually a TypeParser instance: Assembly assembly = Assembly.GetExecutingAssembly(); string assemblyPath = Assembly.GetExecutingAssembly().Location; object objparser = this.LocalAppDomain.CreateInstanceFrom(assemblyPath, typeof(TypeParser).FullName).Unwrap(); // dynamic works dynamic dynParser = objparser; string info = dynParser.GetVersionInfo(); // method call works // casting fails parser = (TypeParser)objparser; So clearly a TypeParser type is coming back, but nevertheless it's not the right one. Hmmm… mysterious.Another couple of tries reveal the problem however:// works dynamic dynParser = objparser; string info = dynParser.GetVersionInfo(); // method call works // c:\wwapps\wwhelp\wwReflection20.dll (Current Execution Folder) string info3 = typeof(TypeParser).Assembly.CodeBase; // c:\program files\vfp9\wwReflection20.dll (my COM client EXE's folder) string info4 = dynParser.GetType().Assembly.CodeBase; // fails parser = (TypeParser)objparser; As you can see the second value is coming from a totally different assembly. Note that this is even though I EXPLICITLY SPECIFIED an assembly path to load the assembly from! Instead .NET decided to load the assembly from the original ApplicationBase folder. Ouch! How I actually tracked this down was a little more tedious: I added a method like this to both the factory and the instance types and then compared notes:public string GetVersionInfo() { return ".NET Version: " + Environment.Version.ToString() + "\r\n" + "wwReflection Assembly: " + typeof(TypeParserFactory).Assembly.CodeBase.Replace("file:///", "").Replace("/", "\\") + "\r\n" + "Assembly Cur Dir: " + Directory.GetCurrentDirectory() + "\r\n" + "ApplicationBase: " + AppDomain.CurrentDomain.SetupInformation.ApplicationBase + "\r\n" + "App Domain: " + AppDomain.CurrentDomain.FriendlyName + "\r\n"; } For the factory I got: .NET Version: 4.0.30319.239wwReflection Assembly: c:\wwapps\wwhelp\bin\wwreflection20.dllAssembly Cur Dir: c:\wwapps\wwhelpApplicationBase: C:\Programs\vfp9\App Domain: wwReflection534cfa1f For the instance type I got: .NET Version: 4.0.30319.239wwReflection Assembly: C:\\Programs\\vfp9\wwreflection20.dllAssembly Cur Dir: c:\\wwapps\\wwhelpApplicationBase: C:\\Programs\\vfp9\App Domain: wwDotNetBridge_56006605 which clearly shows the problem. You can see that both are loading from different appDomains but the each is loading the assembly from a different location. Probably a better solution yet (for ANY kind of assembly loading problem) is to use the .NET Fusion Log Viewer to trace assembly loads.The Fusion viewer will show a load trace for each assembly loaded and where it's looking to find it. Here's what the viewer looks like: The last trace above that I found for the second wwReflection20 load (the one that is wonky) looks like this:*** Assembly Binder Log Entry (1/13/2012 @ 3:06:49 AM) *** The operation was successful. Bind result: hr = 0x0. The operation completed successfully. Assembly manager loaded from: C:\Windows\Microsoft.NET\Framework\V4.0.30319\clr.dll Running under executable c:\programs\vfp9\vfp9.exe --- A detailed error log follows. === Pre-bind state information === LOG: User = Ras\ricks LOG: DisplayName = wwReflection20, Version=4.61.0.0, Culture=neutral, PublicKeyToken=null (Fully-specified) LOG: Appbase = file:///C:/Programs/vfp9/ LOG: Initial PrivatePath = NULL LOG: Dynamic Base = NULL LOG: Cache Base = NULL LOG: AppName = vfp9.exe Calling assembly : (Unknown). === LOG: This bind starts in default load context. LOG: Using application configuration file: C:\Programs\vfp9\vfp9.exe.Config LOG: Using host configuration file: LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\V4.0.30319\config\machine.config. LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind). LOG: Attempting download of new URL file:///C:/Programs/vfp9/wwReflection20.DLL. LOG: Assembly download was successful. Attempting setup of file: C:\Programs\vfp9\wwReflection20.dll LOG: Entering run-from-source setup phase. LOG: Assembly Name is: wwReflection20, Version=4.61.0.0, Culture=neutral, PublicKeyToken=null LOG: Binding succeeds. Returns assembly from C:\Programs\vfp9\wwReflection20.dll. LOG: Assembly is loaded in default load context. WRN: The same assembly was loaded into multiple contexts of an application domain: WRN: Context: Default | Domain ID: 2 | Assembly Name: wwReflection20, Version=4.61.0.0, Culture=neutral, PublicKeyToken=null WRN: Context: LoadFrom | Domain ID: 2 | Assembly Name: wwReflection20, Version=4.61.0.0, Culture=neutral, PublicKeyToken=null WRN: This might lead to runtime failures. WRN: It is recommended to inspect your application on whether this is intentional or not. WRN: See whitepaper http://go.microsoft.com/fwlink/?LinkId=109270 for more information and common solutions to this issue. Notice that the fusion log clearly shows that the .NET loader makes no attempt to even load the assembly from the path I explicitly specified. Remember your Assembly Locations As mentioned earlier all failures I've seen like this ultimately resulted from different versions of the same type being available in the two AppDomains. At first sight that seems ridiculous - how could the types be different and why would you have multiple assemblies - but there are actually a number of scenarios where it's quite possible to have multiple copies of the same assembly floating around in multiple places. If you're hosting different environments (like hosting the Razor Engine, or ASP.NET Runtime for example) it's common to create a private BIN folder and it's important to make sure that there's no overlap of assemblies. In my case of Html Help Builder the problem started because I'm using COM interop to access the .NET assembly and the above code. COM Interop has very specific requirements on where assemblies can be found and because I was mucking around with the loader code today, I ended up moving assemblies around to a new location for explicit loading. The explicit load works in the main AppDomain, but failed in the remote domain as I showed. The solution here was simple enough: Delete the extraneous assembly which was left around by accident. Not a common problem, but one that when it bites is pretty nasty to figure out because it seems so unlikely that types wouldn't match. I know I've run into this a few times and writing this down hopefully will make me remember in the future rather than poking around again for an hour trying to debug the issue as I did today. Hopefully it'll save some of you some time as well in the future.© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET  COM   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • C#/.NET Little Wonders: Constraining Generics with Where Clause

    - by James Michael Hare
    Back when I was primarily a C++ developer, I loved C++ templates.  The power of writing very reusable generic classes brought the art of programming to a brand new level.  Unfortunately, when .NET 1.0 came about, they didn’t have a template equivalent.  With .NET 2.0 however, we finally got generics, which once again let us spread our wings and program more generically in the world of .NET However, C# generics behave in some ways very differently from their C++ template cousins.  There is a handy clause, however, that helps you navigate these waters to make your generics more powerful. The Problem – C# Assumes Lowest Common Denominator In C++, you can create a template and do nearly anything syntactically possible on the template parameter, and C++ will not check if the method/fields/operations invoked are valid until you declare a realization of the type.  Let me illustrate with a C++ example: 1: // compiles fine, C++ makes no assumptions as to T 2: template <typename T> 3: class ReverseComparer 4: { 5: public: 6: int Compare(const T& lhs, const T& rhs) 7: { 8: return rhs.CompareTo(lhs); 9: } 10: }; Notice that we are invoking a method CompareTo() off of template type T.  Because we don’t know at this point what type T is, C++ makes no assumptions and there are no errors. C++ tends to take the path of not checking the template type usage until the method is actually invoked with a specific type, which differs from the behavior of C#: 1: // this will NOT compile! C# assumes lowest common denominator. 2: public class ReverseComparer<T> 3: { 4: public int Compare(T lhs, T rhs) 5: { 6: return lhs.CompareTo(rhs); 7: } 8: } So why does C# give us a compiler error even when we don’t yet know what type T is?  This is because C# took a different path in how they made generics.  Unless you specify otherwise, for the purposes of the code inside the generic method, T is basically treated like an object (notice I didn’t say T is an object). That means that any operations, fields, methods, properties, etc that you attempt to use of type T must be available at the lowest common denominator type: object.  Now, while object has the broadest applicability, it also has the fewest specific.  So how do we allow our generic type placeholder to do things more than just what object can do? Solution: Constraint the Type With Where Clause So how do we get around this in C#?  The answer is to constrain the generic type placeholder with the where clause.  Basically, the where clause allows you to specify additional constraints on what the actual type used to fill the generic type placeholder must support. You might think that narrowing the scope of a generic means a weaker generic.  In reality, though it limits the number of types that can be used with the generic, it also gives the generic more power to deal with those types.  In effect these constraints says that if the type meets the given constraint, you can perform the activities that pertain to that constraint with the generic placeholders. Constraining Generic Type to Interface or Superclass One of the handiest where clause constraints is the ability to specify the type generic type must implement a certain interface or be inherited from a certain base class. For example, you can’t call CompareTo() in our first C# generic without constraints, but if we constrain T to IComparable<T>, we can: 1: public class ReverseComparer<T> 2: where T : IComparable<T> 3: { 4: public int Compare(T lhs, T rhs) 5: { 6: return lhs.CompareTo(rhs); 7: } 8: } Now that we’ve constrained T to an implementation of IComparable<T>, this means that our variables of generic type T may now call any members specified in IComparable<T> as well.  This means that the call to CompareTo() is now legal. If you constrain your type, also, you will get compiler warnings if you attempt to use a type that doesn’t meet the constraint.  This is much better than the syntax error you would get within C++ template code itself when you used a type not supported by a C++ template. Constraining Generic Type to Only Reference Types Sometimes, you want to assign an instance of a generic type to null, but you can’t do this without constraints, because you have no guarantee that the type used to realize the generic is not a value type, where null is meaningless. Well, we can fix this by specifying the class constraint in the where clause.  By declaring that a generic type must be a class, we are saying that it is a reference type, and this allows us to assign null to instances of that type: 1: public static class ObjectExtensions 2: { 3: public static TOut Maybe<TIn, TOut>(this TIn value, Func<TIn, TOut> accessor) 4: where TOut : class 5: where TIn : class 6: { 7: return (value != null) ? accessor(value) : null; 8: } 9: } In the example above, we want to be able to access a property off of a reference, and if that reference is null, pass the null on down the line.  To do this, both the input type and the output type must be reference types (yes, nullable value types could also be considered applicable at a logical level, but there’s not a direct constraint for those). Constraining Generic Type to only Value Types Similarly to constraining a generic type to be a reference type, you can also constrain a generic type to be a value type.  To do this you use the struct constraint which specifies that the generic type must be a value type (primitive, struct, enum, etc). Consider the following method, that will convert anything that is IConvertible (int, double, string, etc) to the value type you specify, or null if the instance is null. 1: public static T? ConvertToNullable<T>(IConvertible value) 2: where T : struct 3: { 4: T? result = null; 5:  6: if (value != null) 7: { 8: result = (T)Convert.ChangeType(value, typeof(T)); 9: } 10:  11: return result; 12: } Because T was constrained to be a value type, we can use T? (System.Nullable<T>) where we could not do this if T was a reference type. Constraining Generic Type to Require Default Constructor You can also constrain a type to require existence of a default constructor.  Because by default C# doesn’t know what constructors a generic type placeholder does or does not have available, it can’t typically allow you to call one.  That said, if you give it the new() constraint, it will mean that the type used to realize the generic type must have a default (no argument) constructor. Let’s assume you have a generic adapter class that, given some mappings, will adapt an item from type TFrom to type TTo.  Because it must create a new instance of type TTo in the process, we need to specify that TTo has a default constructor: 1: // Given a set of Action<TFrom,TTo> mappings will map TFrom to TTo 2: public class Adapter<TFrom, TTo> : IEnumerable<Action<TFrom, TTo>> 3: where TTo : class, new() 4: { 5: // The list of translations from TFrom to TTo 6: public List<Action<TFrom, TTo>> Translations { get; private set; } 7:  8: // Construct with empty translation and reverse translation sets. 9: public Adapter() 10: { 11: // did this instead of auto-properties to allow simple use of initializers 12: Translations = new List<Action<TFrom, TTo>>(); 13: } 14:  15: // Add a translator to the collection, useful for initializer list 16: public void Add(Action<TFrom, TTo> translation) 17: { 18: Translations.Add(translation); 19: } 20:  21: // Add a translator that first checks a predicate to determine if the translation 22: // should be performed, then translates if the predicate returns true 23: public void Add(Predicate<TFrom> conditional, Action<TFrom, TTo> translation) 24: { 25: Translations.Add((from, to) => 26: { 27: if (conditional(from)) 28: { 29: translation(from, to); 30: } 31: }); 32: } 33:  34: // Translates an object forward from TFrom object to TTo object. 35: public TTo Adapt(TFrom sourceObject) 36: { 37: var resultObject = new TTo(); 38:  39: // Process each translation 40: Translations.ForEach(t => t(sourceObject, resultObject)); 41:  42: return resultObject; 43: } 44:  45: // Returns an enumerator that iterates through the collection. 46: public IEnumerator<Action<TFrom, TTo>> GetEnumerator() 47: { 48: return Translations.GetEnumerator(); 49: } 50:  51: // Returns an enumerator that iterates through a collection. 52: IEnumerator IEnumerable.GetEnumerator() 53: { 54: return GetEnumerator(); 55: } 56: } Notice, however, you can’t specify any other constructor, you can only specify that the type has a default (no argument) constructor. Summary The where clause is an excellent tool that gives your .NET generics even more power to perform tasks higher than just the base "object level" behavior.  There are a few things you cannot specify with constraints (currently) though: Cannot specify the generic type must be an enum. Cannot specify the generic type must have a certain property or method without specifying a base class or interface – that is, you can’t say that the generic must have a Start() method. Cannot specify that the generic type allows arithmetic operations. Cannot specify that the generic type requires a specific non-default constructor. In addition, you cannot overload a template definition with different, opposing constraints.  For example you can’t define a Adapter<T> where T : struct and Adapter<T> where T : class.  Hopefully, in the future we will get some of these things to make the where clause even more useful, but until then what we have is extremely valuable in making our generics more user friendly and more powerful!   Technorati Tags: C#,.NET,Little Wonders,BlackRabbitCoder,where,generics

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  • These are few objective type questions which i was not able to find the solution [closed]

    - by Tarun
    1. Which of the following advantages does System.Collections.IDictionaryEnumerator provide over System.Collections.IEnumerator? a. It adds properties for direct access to both the Key and the Value b. It is optimized to handle the structure of a Dictionary. c. It provides properties to determine if the Dictionary is enumerated in Key or Value order d. It provides reverse lookup methods to distinguish a Key from a specific Value 2. When Implementing System.EnterpriseServices.ServicedComponent derived classes, which of the following statements are true? a. Enabling object pooling requires an attribute on the class and the enabling of pooling in the COM+ catalog. b. Methods can be configured to automatically mark a transaction as complete by the use of attributes. c. You can configure authentication using the AuthenticationOption when the ActivationMode is set to Library. d. You can control the lifecycle policy of an individual instance using the SetLifetimeService method. 3. Which of the following are true regarding event declaration in the code below? class Sample { event MyEventHandlerType MyEvent; } a. MyEventHandlerType must be derived from System.EventHandler or System.EventHandler<TEventArgs> b. MyEventHandlerType must take two parameters, the first of the type Object, and the second of a class derived from System.EventArgs c. MyEventHandlerType may have a non-void return type d. If MyEventHandlerType is a generic type, event declaration must use a specialization of that type. e. MyEventHandlerType cannot be declared static 4. Which of the following statements apply to developing .NET code, using .NET utilities that are available with the SDK or Visual Studio? a. Developers can create assemblies directly from the MSIL Source Code. b. Developers can examine PE header information in an assembly. c. Developers can generate XML Schemas from class definitions contained within an assembly. d. Developers can strip all meta-data from managed assemblies. e. Developers can split an assembly into multiple assemblies. 5. Which of the following characteristics do classes in the System.Drawing namespace such as Brush,Font,Pen, and Icon share? a. They encapsulate native resource and must be properly Disposed to prevent potential exhausting of resources. b. They are all MarshalByRef derived classes, but functionality across AppDomains has specific limitations. c. You can inherit from these classes to provide enhanced or customized functionality 6. Which of the following are required to be true by objects which are going to be used as keys in a System.Collections.HashTable? a. They must handle case-sensitivity identically in both the GetHashCode() and Equals() methods. b. Key objects must be immutable for the duration they are used within a HashTable. c. Get HashCode() must be overridden to provide the same result, given the same parameters, regardless of reference equalityl unless the HashTable constructor is provided with an IEqualityComparer parameter. d. Each Element in a HashTable is stored as a Key/Value pair of the type System.Collections.DictionaryElement e. All of the above 7. Which of the following are true about Nullable types? a. A Nullable type is a reference type. b. A Nullable type is a structure. c. An implicit conversion exists from any non-nullable value type to a nullable form of that type. d. An implicit conversion exists from any nullable value type to a non-nullable form of that type. e. A predefined conversion from the nullable type S? to the nullable type T? exists if there is a predefined conversion from the non-nullable type S to the non-nullable type T 8. When using an automatic property, which of the following statements is true? a. The compiler generates a backing field that is completely inaccessible from the application code. b. The compiler generates a backing field that is a private instance member with a leading underscore that can be programmatically referenced. c. The compiler generates a backing field that is accessible via reflection d. The compiler generates a code that will store the information separately from the instance to ensure its security. 9. Which of the following does using Initializer Syntax with a collection as shown below require? CollectionClass numbers = new CollectionClass { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; a. The Collection Class must implement System.Collections.Generic.ICollection<T> b. The Collection Class must implement System.Collections.Generic.IList<T> c. Each of the Items in the Initializer List will be passed to the Add<T>(T item) method d. The items in the initializer will be treated as an IEnumerable<T> and passed to the collection constructor+K110 10. What impact will using implicitly typed local variables as in the following example have? var sample = "Hello World"; a. The actual type is determined at compilation time, and has no impact on the runtime b. The actual type is determined at runtime, and late binding takes effect c. The actual type is based on the native VARIANT concept, and no binding to a specific type takes place. d. "var" itself is a specific type defined by the framework, and no special binding takes place 11. Which of the following is not supported by remoting object types? a. well-known singleton b. well-known single call c. client activated d. context-agile 12. In which of the following ways do structs differ from classes? a. Structs can not implement interfaces b. Structs cannot inherit from a base struct c. Structs cannot have events interfaces d. Structs cannot have virtual methods 13. Which of the following is not an unboxing conversion? a. void Sample1(object o) { int i = (int)o; } b. void Sample1(ValueType vt) { int i = (int)vt; } c. enum E { Hello, World} void Sample1(System.Enum et) { E e = (E) et; } d. interface I { int Value { get; set; } } void Sample1(I vt) { int i = vt.Value; } e. class C { public int Value { get; set; } } void Sample1(C vt) { int i = vt.Value; } 14. Which of the following are characteristics of the System.Threading.Timer class? a. The method provided by the TimerCallback delegate will always be invoked on the thread which created the timer. b. The thread which creates the timer must have a message processing loop (i.e. be considered a UI thread) c. The class contains protection to prevent reentrancy to the method provided by the TimerCallback delegate d. You can receive notification of an instance being Disposed by calling an overload of the Dispose method. 15. What is the proper declaration of a method which will handle the following event? Class MyClass { public event EventHandler MyEvent; } a. public void A_MyEvent(object sender, MyArgs e) { } b. public void A_MyEvent(object sender, EventArgs e) { } c. public void A_MyEvent(MyArgs e) { } d. public void A_MyEvent(MyClass sender,EventArgs e) { } 16. Which of the following scenarios are applicable to Window Workflow Foundation? a. Document-centric workflows b. Human workflows c. User-interface page flows d. Builtin support for communications across multiple applications and/or platforms e. All of the above 17. When using an automatic property, which of the following statements is true? a. The compiler generates a backing field that is completely inaccessible from the application code. b. The compiler generates a backing field that is a private instance member with a leading underscore that can be programmatically referenced. c. The compiler generates a backing field that is accessible via reflection d. The compiler generates a code that will store the information separately from the instance to ensure its security. 18 While using the capabilities supplied by the System.Messaging classes, which of the following are true? a. Information must be explicitly converted to/from a byte stream before it uses the MessageQueue class b. Invoking the MessageQueue.Send member defaults to using the System.Messaging.XmlMessageFormatter to serialize the object. c. Objects must be XMLSerializable in order to be transferred over a MessageQueue instance. d. The first entry in a MessageQueue must be removed from the queue before the next entry can be accessed e. Entries removed from a MessageQueue within the scope of a transaction, will be pushed back into the front of the queue if the transaction fails. 19. Which of the following are true about declarative attributes? a. They must be inherited from the System.Attribute. b. Attributes are instantiated at the same time as instances of the class to which they are applied. c. Attribute classes may be restricted to be applied only to application element types. d. By default, a given attribute may be applied multiple times to the same application element. 20. When using version 3.5 of the framework in applications which emit a dynamic code, which of the following are true? a. A Partial trust code can not emit and execute a code b. A Partial trust application must have the SecurityCriticalAttribute attribute have called Assert ReflectionEmit permission c. The generated code no more permissions than the assembly which emitted it. d. It can be executed by calling System.Reflection.Emit.DynamicMethod( string name, Type returnType, Type[] parameterTypes ) without any special permissions Within Windows Workflow Foundation, Compensating Actions are used for: a. provide a means to rollback a failed transaction b. provide a means to undo a successfully committed transaction later c. provide a means to terminate an in process transaction d. achieve load balancing by adapting to the current activity 21. What is the proper declaration of a method which will handle the following event? Class MyClass { public event EventHandler MyEvent; } a. public void A_MyEvent(object sender, MyArgs e) { } b. public void A_MyEvent(object sender, EventArgs e) { } c. public void A_MyEvent(MyArgs e) { } d. public void A_MyEvent(MyClass sender,EventArgs e) { } 22. Which of the following controls allows the use of XSL to transform XML content into formatted content? a. System.Web.UI.WebControls.Xml b. System.Web.UI.WebControls.Xslt c. System.Web.UI.WebControls.Substitution d. System.Web.UI.WebControls.Transform 23. To which of the following do automatic properties refer? a. You declare (explicitly or implicitly) the accessibility of the property and get and set accessors, but do not provide any implementation or backing field b. You attribute a member field so that the compiler will generate get and set accessors c. The compiler creates properties for your class based on class level attributes d. They are properties which are automatically invoked as part of the object construction process 24. Which of the following are true about Nullable types? a. A Nullable type is a reference type. b. An implicit conversion exists from any non-nullable value type to a nullable form of that type. c. A predefined conversion from the nullable type S? to the nullable type T? exists if there is a predefined conversion from the non-nullable type S to the non-nullable type T 25. When using an automatic property, which of the following statements is true? a. The compiler generates a backing field that is completely inaccessible from the application code. b. The compiler generates a backing field that is accessible via reflection. c. The compiler generates a code that will store the information separately from the instance to ensure its security. 26. When using an implicitly typed array, which of the following is most appropriate? a. All elements in the initializer list must be of the same type. b. All elements in the initializer list must be implicitly convertible to a known type which is the actual type of at least one member in the initializer list c. All elements in the initializer list must be implicitly convertible to common type which is a base type of the items actually in the list 27. Which of the following is false about anonymous types? a. They can be derived from any reference type. b. Two anonymous types with the same named parameters in the same order declared in different classes have the same type. c. All properties of an anonymous type are read/write. 28. Which of the following are true about Extension methods. a. They can be declared either static or instance members b. They must be declared in the same assembly (but may be in different source files) c. Extension methods can be used to override existing instance methods d. Extension methods with the same signature for the same class may be declared in multiple namespaces without causing compilation errors

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  • Why won't my Windows 8 Command line update its path

    - by mawcsco
    I needed to add a new entry to my PATH variable. This is a common activity for me in my job, but I've recently started using Windows 8. I assumed the process would be similar to Windows 7, Vista, XP... Here's my sequence of events: Open System properties (Start- [type "Control Panel"] - Control Panel\System and Security\System - Advanced system settings - Environment Variables) Add the new path to beginning of my USER PATH variable (C:\dev\Java\apache-ant-1.8.4\bin;) Opened a command prompt (Start - [type "command prompt" enter] - [type "path" enter] My new path entry is not available (see attached image and vide). I Duplicated the exact same process on a Windows 7 machine and it worked. EDIT Windows 8 Environment Variables and Command Prompt video EDIT This is definitely not the behavior of Windows 7. Watch this video to see the behavior I expect working in Windows 7. http://youtu.be/95JXY5X0fII EDIT 5/31/2013 So, after much frustration, I wrote a small C# app to test the WM_SETTINGCHANGE event. This code receives the event in both Windows 7 and Windows 8. However, in Windows 8 on my system, I do not get the correct path; but, I do in Windows 7. This could not be reproduced in other Windows 8 systems. Here is the C# code. using System; using Microsoft.Win32; public sealed class App { static void Main() { SystemEvents.UserPreferenceChanging += new UserPreferenceChangingEventHandler(OnUserPreferenceChanging); Console.WriteLine("Waiting for system events."); Console.WriteLine("Press <Enter> to exit."); Console.ReadLine(); } static void OnUserPreferenceChanging(object sender, UserPreferenceChangingEventArgs e) { Console.WriteLine("The user preference is changing. Category={0}", e.Category); Console.WriteLine("path={0}", System.Environment.GetEnvironmentVariable("PATH")); } } OnUserPreferenceChanging is equivalent to WM_SETTINGCHANGE C# program running in Windows 7 (you can see the event come through and it picks up the correct path). C# program running in Windows 8 (you can see the event come through, but the wrong path). There is something about my environment that is precipitating this problem. However, is this a Windows 8 bug?

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  • 500 Metro Style WP7 Icons

    - by Bil Simser
    I was inspired by The Noun Project, a project that offers up “Metro-style” icons in SVG format. The project is licensed under a public domain license and while it’s a great project, all of the content is in SVG format. Jon Galloway has a great post (from 2007) talking about the differences between SVG and XAML so I highly recommend that for some background. I thought it would be helpful to the WPF/Windows Phone 7/Silverlight community to provide the content in alternative formats for use in your applications. The Goods I’ve put together a package of the 500 icons (502 actually) in PNG, XAML and the original SVG format along with a couple of sample projects so you can see them in action. There’s a WPF desktop app: And a Windows Phone 7 app: Building It To get all the content first I wrote up a quick program to suck the original SVG files. Luckily they’re all in a common path just named 1.SVG, 2.SVG, and so on. Easy sleazy to grab the contents. Once I had 500 SVG files I used the latest copy of XamlTune, an open source CodePlex project that has a command line conversion tool to convert the directory of SVG files into XAML (the tool also created a PNG file of each SVG so that’s just icing on the cake). Conversions The conversion from SVG to XAML isn’t 100%. While you can just drop the content into a WPF app, it doesn’t work that way for WP7. There are just some small adjustments I made to each format so you’ll have to do the same. Follow the information below or refer to the sample applications. As a sample, here’s an icon we want to use: Here’s the original SVG file: <svg version="1.0" id="Layer_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px" width="100px" height="94.616px" viewBox="0 0 100 94.616" enable-background="new 0 0 100 94.616" xml:space="preserve"> <path d="M25.076,15.639c4.324,0.009,7.824-3.488,7.82-7.82C32.9,3.512,29.4,0.012,25.076,0c-4.313,0.012-7.814,3.512-7.821,7.819 C17.262,12.15,20.763,15.648,25.076,15.639L25.076,15.639z"/> <path d="M4.593,43.388h6.861l4.137-15.135h1.716L13.22,43.388h24.318l-4.389-15.135h1.817l2.32,7.415 c1.08,3.131,3.852,3.851,6.003,1.162l8.375-10.142c2.651-3.42-2.104-7.021-4.844-4.035l-4.993,5.952 c0.007,0.095-0.96-3.278-0.96-3.278c-1.135-3.978-4.918-7.903-10.595-7.922H19.576c-5.071,0.019-9.043,4.434-9.888,7.214 L4.593,43.388L4.593,43.388z"/> <polygon points="56.206,22.753 56.206,7.163 49.192,7.163 49.192,22.753 56.206,22.753 "/> <path d="M79.87,15.738c4.332-0.014,7.831-3.516,7.82-7.82c0.011-4.332-3.488-7.833-7.82-7.82c-4.306-0.013-7.806,3.488-7.821,7.82 C72.064,12.222,75.564,15.725,79.87,15.738L79.87,15.738z"/> <path d="M89.759,89.556v-43.19h5.751V22.804c0.007-3.079-2.757-5.448-6.71-5.449H70.436c-3.65,0.001-4.539,1.186-5.551,2.168 L49.597,37.889c-3.098,3.848,2.428,8.333,5.55,4.743L69.88,25.226v64.43c-0.019,6.475,9.06,6.686,9.081,0.201v-36.58h1.765v36.379 C80.748,96.109,89.772,96.13,89.759,89.556L89.759,89.556z"/> <polygon points="100,54.035 100,45.155 0,45.155 0,54.035 100,54.035 "/> </svg> Here’s the XAML that XamlTune created. It can be used in any WPF app without any changes: <Canvas Name="Layer_1" Width="100" Height="94.616" ClipToBounds="True" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"> <Path Fill="#FF000000"> <Path.Data> <PathGeometry FillRule="Nonzero" Figures="M25.076,15.639C29.4,15.648 32.9,12.151 32.896,7.819 32.9,3.512 29.4,0.012 25.076,0 20.763,0.012 17.262,3.512 17.255,7.819 17.262,12.15 20.763,15.648 25.076,15.639L25.076,15.639z" /> </Path.Data> </Path> <Path Fill="#FF000000"> <Path.Data> <PathGeometry FillRule="Nonzero" Figures="M4.593,43.388L11.454,43.388 15.591,28.253 17.307,28.253 13.22,43.388 37.538,43.388 33.149,28.253 34.966,28.253 37.286,35.668C38.366,38.799,41.138,39.519,43.289,36.83L51.664,26.688C54.315,23.268,49.56,19.667,46.82,22.653L41.827,28.605C41.834,28.7 40.867,25.327 40.867,25.327 39.732,21.349 35.949,17.424 30.272,17.405L19.576,17.405C14.505,17.424,10.533,21.839,9.688,24.619L4.593,43.388 4.593,43.388z" /> </Path.Data> </Path> <Path Fill="#FF000000"> <Path.Data> <PathGeometry FillRule="Nonzero" Figures="M56.206,22.753L56.206,7.163 49.192,7.163 49.192,22.753 56.206,22.753z" /> </Path.Data> </Path> <Path Fill="#FF000000"> <Path.Data> <PathGeometry FillRule="Nonzero" Figures="M79.87,15.738C84.202,15.724 87.701,12.222 87.69,7.918 87.701,3.586 84.202,0.0849999999999991 79.87,0.097999999999999 75.564,0.084999999999999 72.064,3.586 72.049,7.918 72.064,12.222 75.564,15.725 79.87,15.738L79.87,15.738z" /> </Path.Data> </Path> <Path Fill="#FF000000"> <Path.Data> <PathGeometry FillRule="Nonzero" Figures="M89.759,89.556L89.759,46.366 95.51,46.366 95.51,22.804C95.517,19.725,92.753,17.356,88.8,17.355L70.436,17.355C66.786,17.356,65.897,18.541,64.885,19.523L49.597,37.889C46.499,41.737,52.025,46.222,55.147,42.632L69.88,25.226 69.88,89.656C69.861,96.131,78.94,96.342,78.961,89.857L78.961,53.277 80.726,53.277 80.726,89.656C80.748,96.109,89.772,96.13,89.759,89.556L89.759,89.556z" /> </Path.Data> </Path> <Path Fill="#FF000000"> <Path.Data> <PathGeometry FillRule="Nonzero" Figures="M100,54.035L100,45.155 0,45.155 0,54.035 100,54.035z" /> </Path.Data> </Path> </Canvas> The XAML works AS-IS in a WPF application but there are some changes I did to get it to work in a WP7 app. Here’s the modified XAML in a WP7 application: <Canvas Grid.Row="0" Grid.Column="0" Name="Icon_1" Width="100" Height="94.616"> <Path Fill="#FF000000" Data="M25.076,15.639C29.4,15.648 32.9,12.151 32.896,7.819 32.9,3.512 29.4,0.012 25.076,0 20.763,0.012 17.262,3.512 17.255,7.819 17.262,12.15 20.763,15.648 25.076,15.639L25.076,15.639z"> </Path> <Path Fill="#FF000000" Data="M4.593,43.388L11.454,43.388 15.591,28.253 17.307,28.253 13.22,43.388 37.538,43.388 33.149,28.253 34.966,28.253 37.286,35.668C38.366,38.799,41.138,39.519,43.289,36.83L51.664,26.688C54.315,23.268,49.56,19.667,46.82,22.653L41.827,28.605C41.834,28.7 40.867,25.327 40.867,25.327 39.732,21.349 35.949,17.424 30.272,17.405L19.576,17.405C14.505,17.424,10.533,21.839,9.688,24.619L4.593,43.388 4.593,43.388z"> </Path> <Path Fill="#FF000000" Data="M56.206,22.753L56.206,7.163 49.192,7.163 49.192,22.753 56.206,22.753z"> </Path> <Path Fill="#FF000000" Data="M79.87,15.738C84.202,15.724 87.701,12.222 87.69,7.918 87.701,3.586 84.202,0.0849999999999991 79.87,0.097999999999999 75.564,0.084999999999999 72.064,3.586 72.049,7.918 72.064,12.222 75.564,15.725 79.87,15.738L79.87,15.738z"> </Path> <Path Fill="#FF000000" Data="M89.759,89.556L89.759,46.366 95.51,46.366 95.51,22.804C95.517,19.725,92.753,17.356,88.8,17.355L70.436,17.355C66.786,17.356,65.897,18.541,64.885,19.523L49.597,37.889C46.499,41.737,52.025,46.222,55.147,42.632L69.88,25.226 69.88,89.656C69.861,96.131,78.94,96.342,78.961,89.857L78.961,53.277 80.726,53.277 80.726,89.656C80.748,96.109,89.772,96.13,89.759,89.556L89.759,89.556z"> </Path> <Path Fill="#FF000000" Data="M100,54.035L100,45.155 0,45.155 0,54.035 100,54.035z"> </Path> </Canvas> All I did was take the data portion and put it directly into a Data attribute on the Path. Note that while it does show up in the app (on the emulator or device) it wouldn’t show up in Visual Studio for me. Maybe some XAML guru out there can tell me why. You can just as easily use the PNG files in WP7 but if you want the crispness of vector graphics, go for the XAML version. Of course with XamlTune being open source you could always modify the output of that program to cater it to your app. If you do make a change that’s worthy please consider submitting a patch to the project so everyone can benefit. Hope this helps and happy programming! Resources and Links Sample Project and Icons XamlTune an open source project to convert SVG to XAML The Noun Project source of the original files Jon Galloways post on SVG and XAML StackOverflow question on converting SVG to XAML

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  • Entity Framework 4.0: Creating objects of correct type when using lazy loading

    - by DigiMortal
    In my posting about Entity Framework 4.0 and POCOs I introduced lazy loading in EF applications. EF uses proxy classes for lazy loading and this means we have new types in that come and go dynamically in runtime. We don’t have these types available when we write code but we cannot forget that EF may expect us to use dynamically generated types. In this posting I will give you simple hint how to use correct types in your code. The background of lazy loading and proxy classes As a first thing I will explain you in short what is proxy class. Business classes when designed correctly have no knowledge about their birth and death – they don’t know how they are created and they don’t know how their data is persisted. This is the responsibility of object runtime. When we use lazy loading we need a little bit different classes that know how to load data for properties when code accesses the property first time. As we cannot add this functionality to our business classes (they may be stored through more than one data access technology or by more than one Data Access Layer (DAL)) we create proxy classes that extend our business classes. If we have class called Product and product has lazy loaded property called Customer then we need proxy class, let’s say ProductProxy, that has same public signature as Product so we can use it INSTEAD OF product in our code. ProductProxy overrides Customer property. If customer is not asked then customer is null. But if we ask for Customer property then overridden property of ProductProxy loads it from database. This is how lazy loading works. Problem – two types for same thing As lazy loading may introduce dynamically generated proxy types we don’t know in our application code which type is returned. We cannot be sure that we have Product not ProductProxy returned. This leads us to the following question: how can we create Product of correct type if we don’t know the correct type? In EF solution is simple. Solution – use factory methods If you are using repositories and you are not using factories (imho it is pretty pointless with mapper) you can add factory methods to your EF based repositories. Take a look at this class. public class Event {     public int ID { get; set; }     public string Title { get; set; }     public string Location { get; set; }     public virtual Party Organizer { get; set; }     public DateTime Date { get; set; } } We have virtual member called Organizer. This property is virtual because we want to use lazy loading on this class so Organizer is loaded only when we ask it. EF provides us with method called CreateObject<T>(). CreateObject<T>() is member of ObjectContext class and it creates the object based on given type. In runtime proxy type for Event is created for us automatically and when we call CreateObject<T>() for Event it returns as object of Event proxy type. The factory method for events repository is as follows. public Event CreateEvent() {     var evt = _context.CreateObject<Event>();     return evt; } And we are done. Instead of creating factory classes we created factory methods that guarantee that created objects are of correct type. Conclusion Although lazy loading introduces some new objects we cannot use at design time because they live only in runtime we can write code without worrying about exact implementation type of object. This holds true until we have clean code and we don’t make any decisions based on object type. EF4.0 provides us with very simple factory method that create and return objects of correct type. All we had to do was adding factory methods to our repositories.

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