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  • Shopping Cart Suggestions Needed

    - by Maen
    I am building a small web app for a pharmacy to keep track of sales and stocks, so in short, in one page, the pharmacist will enter a bar-code and the item is displayed, pharmacist enters quantity (price will be automatically calculated) then next item and next and so on, I haven't worked with such a problem before so I would appreciate any advices/tips on how to do it, what to use and wither its already done in some tidy neat way I can just import into my page. Am using ASP.net and VB.net, SQL 2008 and all express withing Visual Web Developer (also ExpresS)

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  • convert string to double

    - by James123
    I have string value in that I need to convert to double in VB.Net. Conditions are like below string = "12345.00232232" if condition is 3 (2 digits after decimal and comma) display = 12,345.00 if condition is 5 (5 digits after decimal and comma) display = 12,345.00232 If Condition is 7 ( 5 digits after decimal and no comma) display = 12345.00232 How can I do that in VB.Net?

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  • close jquery UI dialog when file download begins

    - by vanillaike
    I am using an ASP.Net MVC site that has a link to an ASP.Net WebForms page that performs the actual download. I would like my jquery ui dialog to close when the download starts. Is there a javascript/jquery event that I can use to accomplish this? I found an example with exactly what I want to do here, but since I'm using MVC instead of WebForms I can't seem to get it to work.

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  • Binary serialization of datasets parameters in web services

    - by Someone
    In a system with both ends (client and server) in .NET, is it possible to use the binary serialization provided by the dataset class in ADO.NET 2.0 when the datasets are exposed as WebMethods parameters ? Is it ok to use something like the following just before the dataset is returned: someDataSet.RemotingFormat = SerializationFormat.Binary;

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  • Windows Media Service authentication issue

    - by George2
    Hello everyone, I am using Windows Server 2008 R2 with Windows Media Service. At the client side, I want to use Silverlight to play the media file. I am using VSTS 2008 + Silverlight 3 + ASP.Net + .Net 3.5. I want to know how to implement a custom authentication protocol (I have a custom user database, which contains user name and password. I want to enable logged-in user to be able to play through Silverlight)? thanks in advance, George

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  • Does a .cs file compile under a .vbproj?

    - by serhio
    Does a .cs(C#) file compile under a .vbproj(VB.NET project) ? (VS 2005, .NET 2) Say I have Animals.vbproj (namespace Animals) I have Wolf.vb, Tiger.vb, Cat.vb, and a Human.cs Could I use Animals.Human from a external AnimalsForm.vb form? Why?

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  • Deleteing cache upon submit

    - by user279521
    I have an asp.net web form (c#, .NET framework 3.5) that returns to itself after the user clicks the submit button. I think that some values of the form are cached (some controls in a "placeholder" are out of position... meaning they have moved slightly up or down on the web form). How can I delete the cache after user clicks submit, and ensure that the form reloads fresh, after submit?

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  • Microsoft Visual Studio Release History/Timelines/Milestones

    1975 – Bill Gates and Paul Allen write a version of Basic for Altair 8080 1982 – IBM releases BASCOM 1.0 (developed by Microsoft) 1983 – Microsoft Basic Compiler System v5.35 for MS-DOS release 1984 - Microsoft Basic Compiler System v5.36 release 1985 – Microsoft QuickBASIC 1.0 1986 – Microsoft QuickBASIC 1.01, 1.02, 2.00 1987 – Microsoft QuickBASIC 2.01, 3.00, 4.00 1987 – Microsoft BASIC 6.0 1988 – Microsoft QuickBASIC 4.00, 4.00b, 4.50 1989 – Microsoft BASIC Professional Development System 7.0 1990 - Microsoft BASIC Professional Development System 7.1 1991 – Microsoft Visual Basic released May 20-Windows World Convention –Atlanta 1992 – Microsoft Visual Basic 2.0 1993 – Microsoft Visual Basic 3.0 in Standard and Professional versions 1995 – Microsoft Visual Basic 4.0 released, supported the new Windows 95 1997 – Microsoft Visual Basic 5.0 – introduction of IntelliSense 1998 – Microsoft Visual Studio 6.0 that included Visual Basic 6.0 released (first VS) 2002 – Microsoft Visual Basic .NET 7.0 2002 – Visual Studio .NET 2003 – Microsoft Visual Basic .NET 7.1 2003 – Microsoft Visual Studio w/Intellisense 2003 – Visual Studio .NET 2004 – Announce Visual Studios 2005 – Code name Whidbey 2005 – Visual Studio 2005 release w/Extensibility 2005 – Visual Studio Express released 2006 - Expression Tool Set released - devs and designers work together 2006 – Visual Studio Team release – November 30th 2007 – Visual Studio 2008 (code name Orcas) ships November = Video Studio Shell 2010 - Visual Studios (code name Rosario) span.fullpost {display:none;}

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  • Part 14: Execute a PowerShell script

    In the series the following parts have been published Part 1: Introduction Part 2: Add arguments and variables Part 3: Use more complex arguments Part 4: Create your own activity Part 5: Increase AssemblyVersion Part 6: Use custom type for an argument Part 7: How is the custom assembly found Part 8: Send information to the build log Part 9: Impersonate activities (run under other credentials) Part 10: Include Version Number in the Build Number Part 11: Speed up opening my build process template Part 12: How to debug my custom activities Part 13: Get control over the Build Output Part 14: Execute a PowerShell script Part 15: Fail a build based on the exit code of a console application With PowerShell you can add powerful scripting to your build to for example execute a deployment. If you want more information on PowerShell, please refer to http://technet.microsoft.com/en-us/library/aa973757.aspx For this example we will create a simple PowerShell script that prints “Hello world!”. To create the script, create a new text file and name it “HelloWorld.ps1”. Add to the contents of the script: Write-Host “Hello World!” To test the script do the following: Open the command prompt To run the script you must change the execution policy. To do this execute in the command prompt: powershell set-executionpolicy remotesigned Now go to the directory where you have saved the PowerShell script Execute the following command powershell .\HelloWorld.ps1 In this example I use a relative path, but when the path to the PowerShell script contains spaces, you need to change the syntax to powershell "& '<full path to script>' " for example: powershell "& ‘C:\sources\Build Customization\SolutionToBuild\PowerShell Scripts\HellloWorld.ps1’ " In this blog post, I create a new solution and that solution includes also this PowerShell script. I want to create an argument on the Build Process Template that holds the path to the PowerShell script. In the Build Process Template I will add an InvokeProcess activity to execute the PowerShell command. This InvokeProcess activity needs the location of the script as an argument for the PowerShell command. Since you don’t know the full path at the build server of this script, you can either specify in the argument the relative path of the script, but it is hard to find out what the relative path is. I prefer to specify the location of the script in source control and then convert that server path to a local path. To do this conversion you can use the ConvertWorkspaceItem activity. So to complete the task, open the Build Process Template CustomTemplate.xaml that we created in earlier parts, follow the following steps Add a new argument called “DeploymentScript” and set the appropriate settings in the metadata. See Part 2: Add arguments and variables  for more information. Scroll down beneath the TryCatch activity called “Try Compile, Test, and Associate Changesets and Work Items” Add a new If activity and set the condition to "Not String.IsNullOrEmpty(DeploymentScript)" to ensure it will only run when the argument is passed. Add in the Then branch of the If activity a new Sequence activity and rename it to “Start deployment” Click on the activity and add a new variable called DeploymentScriptFilename (scoped to the “Start deployment” Sequence Add a ConvertWorkspaceItem activity on the “Start deployment” Sequence Add a InvokeProcess activity beneath the ConvertWorkspaceItem activity in the “Start deployment” Sequence Click on the ConvertWorkspaceItem activity and change the properties DisplayName = Convert deployment script filename Input = DeploymentScript Result = DeploymentScriptFilename Workspace = Workspace Click on the InvokeProcess activity and change the properties Arguments = String.Format(" ""& '{0}' "" ", DeploymentScriptFilename) DisplayName = Execute deployment script FileName = "PowerShell" To see results from the powershell command drop a WriteBuildMessage activity on the "Handle Standard Output" and pass the stdOutput variable to the Message property. Do the same for a WriteBuildError activity on the "Handle Error Output" To publish it, check in the Build Process Template This leads to the following result We now go to the build definition that depends on the template and set the path of the deployment script to the server path to the HelloWorld.ps1. (If you want to see the result of the PowerShell script, change the Logging verbosity to Detailed or Diagnostic). Save and run the build. A lot of the deployment scripts you have will have some kind of arguments (like username / password or environment variables) that you want to define in the Build Definition. To make the PowerShell configurable, you can follow the following steps. Create a new script and give it the name "HelloWho.ps1". In the contents of the file add the following lines: param (         $person     ) $message = [System.String]::Format(“Hello {0}!", $person) Write-Host $message When you now run the script on the command prompt, you will see the following So lets change the Build Process Template to accept one parameter for the deployment script. You can of course make it configurable to add a for-loop that reads through a collection of parameters but that is out of scope of this blog post. Add a new Argument called DeploymentScriptParameter In the InvokeProcess activity where the PowerShell command is executed, modify the Arguments property to String.Format(" ""& '{0}' '{1}' "" ", DeploymentScriptFilename, DeploymentScriptParameter) Check in the Build Process Template Now modify the build definition and set the Parameter of the deployment to any value and run the build. You can download the full solution at BuildProcess.zip. It will include the sources of every part and will continue to evolve.

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  • dotnet Cologne 2011 : Anmeldung ab 14. März

    - by WeigeltRo
    Am 6.5.2011 findet in Köln die dotnet Cologne 2011 statt, eine von der .NET User Group Köln und der von mir geleiteten Gruppe Bonn-to-Code.Net gemeinsam organisierte Community-Konferenz rund um .NET. Die “dotnet Cologne” hat sich mittlerweile als die große .NET Community- Konferenz in Deutschland etabliert. So war die letztjährige dotnet Cologne 2010 mit 300 Teilnehmern bereits einen Monat im Voraus ausgebucht. Und heise online schrieb: “Inzwischen besitzt die dotnet Cologne ein weites Einzugsgebiet. Die Teilnehmer kommen nicht mehr ausschließlich aus dem Kölner Umfeld, sondern aus allen Teilen Deutschlands [...] Die gute Qualität des Vorjahres in Verbindung mit einem geringen Preis hat sich schnell herumgesprochen, sodass Teilnehmer aus Bayern oder Thüringen keine Ausnahme waren.” Auch in diesem Jahr erwartet die Teilnehmer ein ganzer Tag voll mit Themen rund um .NET. Auf der Website http://www.dotnet-cologne.de sind dazu jetzt die ersten Vorträge, Sprecher sowie Infos zur Anmeldung veröffentlicht. Die Anmeldung ist ab Montag, den 14.3.2011 um 14:00 freigeschaltet. Es empfiehlt sich, schnell zu handeln, denn für die 100 ersten Teilnehmer gilt der “Super-Early Bird” Preis von nur 25,- Euro; diese Plätze waren letztes Jahr in Nullkommanix weg. Die Teilnehmer 101 – 200 zahlen den “Early Bird” Preis von 40,- Euro, ab Platz 201 gilt der “Normalpreis” von 55,- Euro. Aber egal ob “Super-Early”, “Early” oder “Normal”: 25 Vorträge auf 5 Tracks, gehalten von bekannten Namen der .NET Community, dazu den ganzen Tag über Verpflegung und Getränke – das ist zu diesem Preis ein sehr attraktives Angebot. Wir haben damit eine Konferenz organisiert, die wir selbst gerne besuchen würden. Ganz im Sinne “von Entwicklern, für Entwickler”. Was ist neu? Das Feedback vom letzten Jahr war sehr positiv, den Leuten hat’s einfach gut gefallen. Gleichwohl haben wir Feedback-Bögen, Blog-Einträge und Tweets sehr aufmerksam ausgewertet und bei der Organisation berücksichtigt: Der neue Veranstaltungsort, das Komed im Mediapark Köln, ist zentral gelegen und verfügt über günstige Parkmöglichkeiten Die Räumlichkeiten bieten mehr Platz für Teilnehmer, Sponsoren und natürlich auch das Mittagessen Wir haben dieses Jahr einige etwas speziellere Vorträge auf Level 300 und 400 im Programm, um neben fundierten Einführungen in Themengebiete auch “Deep Dives” für Experten anbieten zu können. Längere Pausen zwischen den Vorträgen ermöglichen es den Teilnehmern besser, nach den Vorträgen mit den Sprechern verbleibende Fragen zu klären, sich an den Sponsorenständen Infos zu holen oder einfach Kontakte mit Gleichgesinnten zu knüpfen. Was das Fördern der Kommunikation unter den Teilnehmern angeht, haben wir schon die eine oder andere Idee im Kopf. Aber einiges davon hängt nicht zuletzt von finanziellen Faktoren ab – und damit sind wir schon beim Thema: Es gibt noch Sponsoring-Möglichkeiten! Die dotnet Cologne 2011 ist die Gelegenheit, Produkte vorzustellen, neue Mitarbeiter zu suchen oder generell den Namen einer Firma bei den richtigen Leuten zu platzieren. Nicht ohne Grund unterstützen uns viele Sponsoren dieses Jahr zum wiederholten Mal. Vom Software-Sponsor für die Verlosung bis hin zum Aussteller vor Ort – es gibt vielfältige Möglichkeiten und wir schicken auf Anfrage gerne unsere Sponsoreninfos zu.

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  • Customize Team Build 2010 – Part 16: Specify the relative reference path

    In the series the following parts have been published Part 1: Introduction Part 2: Add arguments and variables Part 3: Use more complex arguments Part 4: Create your own activity Part 5: Increase AssemblyVersion Part 6: Use custom type for an argument Part 7: How is the custom assembly found Part 8: Send information to the build log Part 9: Impersonate activities (run under other credentials) Part 10: Include Version Number in the Build Number Part 11: Speed up opening my build process template Part 12: How to debug my custom activities Part 13: Get control over the Build Output Part 14: Execute a PowerShell script Part 15: Fail a build based on the exit code of a console application Part 16: Specify the relative reference path As I have already blogged about, it is not intuitive how to specify the paths where the build server has to look for references that are stored in Source Control. It is a common practice to store 3rd party libraries in Source Control, so they are available to everyone, everyone uses the same version of the libraries and updating a library can be done centrally. In Team Build 2010 these paths are specified as a parameter for MSBuild. What we will do in this post is building the values for this parameter based on the values in an argument. You are now pretty aware how to customize the build template, so let’s do the modifications in another way. Instead of opening the xaml file in the workflow designer, we open it in the XML editor. You can open it in the XML Editor by either selecting the Open with menu (see the context menu), or by choosing the View code option. To add this functionality we need to: Specify a new argument Add the argument to the metadata Build the absolute paths for the references and add these paths to the MSBuild arguments 1. Specify a new argument Locate at the top of the document the Members (which are the arguments) of the XAML and add the following line <x:Property Name="ReferencePaths" Type="InArgument(s:String[])" /> 2. Add the argument to the metadata Then locate the line <mtbw:ProcessParameterMetadataCollection> and paste the following line <mtbw:ProcessParameterMetadata Category="Misc" Description="The list of reference paths, relative to the root path in the Workspace mapping." DisplayName="Reference paths" ParameterName="ReferencePaths" /> 3. Build the absolute paths for the references and add these paths to the MSBuild arguments Now locate the place where the assignments are done to the variables used in the agent. And add the following lines after the last Assign activity         <Sequence DisplayName="Initialize ReferencePath" sap:VirtualizedContainerService.HintSize="464,428">           <Sequence.Variables>             <Variable x:TypeArguments="x:String" Name="ReferencePathsArgument">               <Variable.Default>                 <Literal x:TypeArguments="x:String" Value="" />               </Variable.Default>             </Variable>           </Sequence.Variables>           <sap:WorkflowViewStateService.ViewState>             <scg:Dictionary x:TypeArguments="x:String, x:Object">               <x:Boolean x:Key="IsExpanded">True</x:Boolean>             </scg:Dictionary>           </sap:WorkflowViewStateService.ViewState>           <ForEach x:TypeArguments="x:String" DisplayName="Iterate through the paths" sap:VirtualizedContainerService.HintSize="287,206" mtbwt:BuildTrackingParticipant.Importance="Low" Values="[ReferencePaths]">             <ActivityAction x:TypeArguments="x:String">               <ActivityAction.Argument>                 <DelegateInArgument x:TypeArguments="x:String" Name="path" />               </ActivityAction.Argument>               <Assign x:TypeArguments="x:String" DisplayName="Build ReferencePath argument" sap:VirtualizedContainerService.HintSize="257,100" mtbwt:BuildTrackingParticipant.Importance="Low"  To="[ReferencePathsArgument]" Value="[If(String.IsNullOrEmpty(ReferencePathsArgument), &quot;&quot;, ReferencePathsArgument + &quot;;&quot;) + IO.Path.Combine(SourcesDirectory, path)]" />             </ActivityAction>           </ForEach>           <Assign DisplayName="Append the reference paths to the MSBuild Arguments" sap:VirtualizedContainerService.HintSize="287,58">             <Assign.To>               <OutArgument x:TypeArguments="x:String">[MSBuildArguments]</OutArgument>             </Assign.To>             <Assign.Value>               <InArgument x:TypeArguments="x:String">[String.Format("{0} /p:ReferencePath=""{1}""", MSBuildArguments, ReferencePathsArgument)]</InArgument>             </Assign.Value>           </Assign>         </Sequence> Now you can use the template to specify the paths relative to SourcesDirectory. You can download the full solution at BuildProcess.zip. It will include the sources of every part and will continue to evolve.

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  • Dynamic meta description and keyword tags for your MasterPages

    - by Aamir Hasan
     Today we're going to look at a technique for dynamically inserting meta tags into your master pages. By taking control of the head tag and inserting your own HtmlMeta you can easily customise these tags.Might have noticed that when you create a new master page in visual studio your <head> tag gets decorated with a runat="server" attribute.Asp.net doesn't add this kind of decoration to any other html tags (although you are free to add it if you want). So what makes the head tag special?By adding the runat="server" you're giving actually converting the control into a HtmlHead control. That doesn't particularly matter for this tutorial other than to note that given a reference to the head control you get all the extras that come with asp.net controls such as access to its controls collection.The HtmlMeta control lets us wrap up <meta> tags via asp.net code. To add a meta description we need to create an instance, set the name property, the content property, and then add it to the head: asp.net using (C#)protected void Page_Init(object sender, EventArgs e){  // Add meta description tag  HtmlMeta metaDescription = new HtmlMeta();  metaDescription.Name = "Description";  metaDescription.Content = "Short, unique and keywords rich page description.";  Page.Header.Controls.Add(metaDescription);   // Add meta keywords tag  HtmlMeta metaKeywords = new HtmlMeta();  metaKeywords.Name = "Keywords";  metaKeywords.Content = "selected,page,keywords";  Page.Header.Controls.Add(metaKeywords);}asp.net ( VB.NET )Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init  ' Add meta description tag  Dim metaDescription As HtmlMeta = New HtmlMeta()  metaDescription.Name = "Description"  metaDescription.Content = "Short, unique and keywords rich page description."  Page.Header.Controls.Add(metaDescription)   ' Add meta keywords tag  Dim metaKeywords As HtmlMeta = New HtmlMeta()  metaKeywords.Name = "Keywords"  metaKeywords.Content = "selected,page,keywords"  Page.Header.Controls.Add(metaKeywords)End Sub

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  • Offre d’emploi – Job Offer - Montreal

    - by guybarrette
    I’m currently helping a client plan its management systems re-architecture and they are looking to hire a full time .NET developer.  It’s a small 70 people company located in the Old Montreal, you’ll be the sole dev there and you’ll use the latest technologies in re writing their core systems. Here’s the job offer in French: Concepteur de logiciel et programmeur-analyste .NET chevronné (poste permanent à temps plein) Employeur : Traductions Serge Bélair inc. Ville : Montreal QC TRSB, cabinet de traduction en croissance rapide regroupant à l’interne une des équipes de professionnels les plus compétentes et les plus diversifiées du secteur de la traduction au Canada, désire combler le poste de : Le concepteur de logiciel et programmeur-analyste .Net sera responsable de la conception, du développement complet et de l’implantation d’une solution clés en main personnalisée pour répondre aux besoins de l’entreprise. Il réalisera la conception, la programmation, la documentation, les tests, le dépannage et la maintenance du nouveau système de gestion des opérations de l’entreprise utilisant des bases de données et offrant une grande souplesse pour la production de rapports. S’il est nécessaire de faire appel à des fournisseurs ou à des consultants pour la réalisation du projet, il sera responsable de trouver les ressources requises, devra assurer les communications avec ces ressources et voir à l’exécution du travail. Il sera également appelé à mettre à jour et à maintenir les applications actuellement utilisées dans l’entreprise jusqu’à ce que l’application développée puisse être utilisée. Les principales tâches du concepteur et programmeur-analyste chevronné recherché seront les suivantes : Concevoir et développer un nouveau système de gestion des opérations en fonction des besoins d’exploitation de l’entreprise Trouver les ressources externes et internes requises Assurer les communications et le suivi avec des fournisseurs externes (p. ex., programmeurs, analystes ou architectes) Assumer la responsabilité de la mise en place du nouveau système de gestion des opérations Résoudre les problèmes liés au nouveau système de gestion des opérations Assurer le soutien les soirs de semaine et la fin de semaine (au besoin), principalement avec des outils de travail à distance Maintenir la documentation du système de gestion des opérations à jour Exécuter d’autres tâches connexes Exigences Baccalauréat en informatique ou l’équivalent Au moins 5 années d’expérience pertinente 2 ans et plus d'expérience en programmation C# Excellente connaissance en programmation d’applications Web avec bases de données Excellente connaissance en méthodologie structurée de développement et des techniques de programmation itératives Habiletés à procéder à la récolte d’informations ainsi que la rédaction de documents d’analyse Spécialisations techniques Essentielle - Design et programmation orientée objet avec C#, ASP.NET, .NET Framework 3.5, AJAX Importante - Silverlight 3, WCF, LINQ, SQL Server, Team Foundation Server Atout - Entity Framework, MVC, jQuery, MySQL, QuickBooks, Suite d’outils Telerik Technologies utilisées C# 4.0, Visual Studio 2010, Team Foundation Server 2010, LINQ, ASP.NET, ASP.NET MVC, jQuery, WCF, Silverlight 4, SQL Server 2008, MySQL, QuickBooks, Suite d’outils Telerik Qualités recherchées Bilinguisme oral et écrit Sens élevé des responsabilités Autonomie Sens de l’initiative Volonté de dépassement Leadership et aptitudes à la prise de décisions Motivation élevée Minutie et souci du détail Bon sens de l’organisation Souplesse et bonne capacité d’adaptation au changement Une expérience antérieure du développement de logiciel avec flux de processus et modules de facturation, de l’établissement de ponts entre des bases de données de types différents (Quickbooks et SQL p. ex.) et des outils d’aide à la traduction serait un atout important. Excellentes conditions de travail : salaire et avantages sociaux très concurrentiels, milieu de travail stimulant dans un environnement agréable, dans le Vieux-Montréal. Faire parvenir votre CV et votre lettre de motivation à [email protected] TRSB 276, rue Saint-Jacques, bureau 900 Montréal (Québec) H2Y 1N3 L’usage du générique masculin a pour seul but d’alléger le texte et d’en faciliter la lecture. var addthis_pub="guybarrette";

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  • {smartassembly} Software for Code Obfuscation

    {smartassembly} is a tool for ensuring that the source code your commercial .NET application isn't visible to anyone with .NET Reflector. Matteo Slaviero, who writes for us about encryption in .NET, asked if he could write a review of {smartassembly} for Simple-Talk. Because we like the product too, and Red Gate Software had recently taken it over, we were happy to agree. span.fullpost {display:none;}

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  • C# 4.0: Covariance And Contravariance In Generics

    - by Paulo Morgado
    C# 4.0 (and .NET 4.0) introduced covariance and contravariance to generic interfaces and delegates. But what is this variance thing? According to Wikipedia, in multilinear algebra and tensor analysis, covariance and contravariance describe how the quantitative description of certain geometrical or physical entities changes when passing from one coordinate system to another.(*) But what does this have to do with C# or .NET? In type theory, a the type T is greater (>) than type S if S is a subtype (derives from) T, which means that there is a quantitative description for types in a type hierarchy. So, how does covariance and contravariance apply to C# (and .NET) generic types? In C# (and .NET), variance applies to generic type parameters and not to the resulting generic type. A generic type parameter is: covariant if the ordering of the generic types follows the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. contravariant if the ordering of the generic types is reversed from the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. invariant if neither of the above apply. If this definition is applied to arrays, we can see that arrays have always been covariant because this is valid code: object[] objectArray = new string[] { "string 1", "string 2" }; objectArray[0] = "string 3"; objectArray[1] = new object(); However, when we try to run this code, the second assignment will throw an ArrayTypeMismatchException. Although the compiler was fooled into thinking this was valid code because an object is being assigned to an element of an array of object, at run time, there is always a type check to guarantee that the runtime type of the definition of the elements of the array is greater or equal to the instance being assigned to the element. In the above example, because the runtime type of the array is array of string, the first assignment of array elements is valid because string = string and the second is invalid because string = object. This leads to the conclusion that, although arrays have always been covariant, they are not safely covariant – code that compiles is not guaranteed to run without errors. In C#, the way to define that a generic type parameter as covariant is using the out generic modifier: public interface IEnumerable<out T> { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> { T Current { get; } bool MoveNext(); } Notice the convenient use the pre-existing out keyword. Besides the benefit of not having to remember a new hypothetic covariant keyword, out is easier to remember because it defines that the generic type parameter can only appear in output positions — read-only properties and method return values. In a similar way, the way to define a type parameter as contravariant is using the in generic modifier: public interface IComparer<in T> { int Compare(T x, T y); } Once again, the use of the pre-existing in keyword makes it easier to remember that the generic type parameter can only be used in input positions — write-only properties and method non ref and non out parameters. Because covariance and contravariance apply only to the generic type parameters, a generic type definition can have both covariant and contravariant generic type parameters in its definition: public delegate TResult Func<in T, out TResult>(T arg); A generic type parameter that is not marked covariant (out) or contravariant (in) is invariant. All the types in the .NET Framework where variance could be applied to its generic type parameters have been modified to take advantage of this new feature. In summary, the rules for variance in C# (and .NET) are: Variance in type parameters are restricted to generic interface and generic delegate types. A generic interface or generic delegate type can have both covariant and contravariant type parameters. Variance applies only to reference types; if you specify a value type for a variant type parameter, that type parameter is invariant for the resulting constructed type. Variance does not apply to delegate combination. That is, given two delegates of types Action<Derived> and Action<Base>, you cannot combine the second delegate with the first although the result would be type safe. Variance allows the second delegate to be assigned to a variable of type Action<Derived>, but delegates can combine only if their types match exactly. If you want to learn more about variance in C# (and .NET), you can always read: Covariance and Contravariance in Generics — MSDN Library Exact rules for variance validity — Eric Lippert Events get a little overhaul in C# 4, Afterward: Effective Events — Chris Burrows Note: Because variance is a feature of .NET 4.0 and not only of C# 4.0, all this also applies to Visual Basic 10.

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  • Windows 7 .NET 3.5.1 - 2.0 Slightly Corrupted, How to Repair?

    - by Quinxy von Besiex
    My Windows 7 included .NET installation (3.5 to 2.0) appears very slightly and particularly corrupted and I am trying to fix it without reinstalling Windows or trying to revert to backups. Everything was working and then my hard drive started corrupting a few files and checkdisk found bad clusters so I imaged the drive to a new one. As soon as I booted on the new drive everything worked except programs which call the System.Net.NetworkInformation methods within .NET 3.5 to 2.0 (like Ping() and IsNetworkAvailable()), which immediately crash the app in which the calls are (those calls in .NET 4.0 works fine). Those methods are found inside System.dll, and I assume call native methods which I believe are inside winnsi.dll or iphlpapi.dll or something else (I've not found this yet); I assume it calls native methods because the exception which causes the crash is Fatal Execution Engine Error which people mention is usually related to calling native methods and marshaling data between them. A huge clue about the culprit is likely found in the fact that when I launch the exact same crashing application through a code profiler (which executes the exe and captures stats on which methods took the longest) the app works fine, no crash at all! How could running it within the profiler work and running it outside not work? That seems the key to the mystery. I've used procmon to catch all the registry, filesystem, and network events from the crashing execution and the profiler-run successful execution and compared the two outputs but didn't learn much (I see the moment at which the non-profiled app crashes, but up until then they behave the same, loaded the same modules, ). The only big difference seems to be that at the moment before the app crash the profiler-executed code creates 4-6 new threads and the directly executed code only creates 1-2. I have diffed the files/directories which seemed most relevant (the .NET stuff under Windows and Program Files) pre- and post- disk trouble and seen no changes where I didn't expect any (no obvious file corruption). I have diffed the software and system registry hives pre- and post- disk trouble and seen no changes which seemed relevant. I have created a new user account and cleaned up any environment variables in case environment was related. No change. I did "sfc /scannow" and it found no integrity problems. I tried "ngen update" to regenerate pre-compiled code in case I missed something that might be damaged and nothing changed. I assume I need to repair my .NET installation but because Windows 7 included .NET 3.5 - 2.0 you can't just re-run a .NET installer to redo it. I do not have access to the Windows disks to try to re-install Windows over itself (the computer has a recovery partition but it is unusable); also the drive uses a whole-disk encryption solution and re-installing would be difficult. I absolutely do not want to start from scratch here and install a fresh Windows, reinstall dozens of software packages, try and remember dozens of development-related customizations/etc. Given all that... does anyone have any helpful advice? I need .NET 3.5 - 2.0 working as I am a developer and need to build and test against it. Thanks! Quinxy

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  • Part 15: Fail a build based on the exit code of a console application

    In the series the following parts have been published Part 1: Introduction Part 2: Add arguments and variables Part 3: Use more complex arguments Part 4: Create your own activity Part 5: Increase AssemblyVersion Part 6: Use custom type for an argument Part 7: How is the custom assembly found Part 8: Send information to the build log Part 9: Impersonate activities (run under other credentials) Part 10: Include Version Number in the Build Number Part 11: Speed up opening my build process template Part 12: How to debug my custom activities Part 13: Get control over the Build Output Part 14: Execute a PowerShell script Part 15: Fail a build based on the exit code of a console application When you have a Console Application or a batch file that has errors, the exitcode is set to another value then 0. You would expect that the build would see this and report an error. This is not true however. First we setup the scenario. Add a ConsoleApplication project to your solution you are building. In the Main function set the ExitCode to 1     class Program    {        static void Main(string[] args)        {            Console.WriteLine("This is an error in the script.");            Environment.ExitCode = 1;        }    } Checkin the code. You can choose to include this Console Application in the build or you can decide to add the exe to source control Now modify the Build Process Template CustomTemplate.xaml Add an argument ErrornousScript Scroll down beneath the TryCatch activity called “Try Compile, Test, and Associate Changesets and Work Items” Add an Sequence activity to the template In the Sequence, add a ConvertWorkspaceItem and an InvokeProcess activity (see Part 14: Execute a PowerShell script  for more detailed steps) In the FileName property of the InvokeProcess use the ErrornousScript so the ConsoleApplication will be called. Modify the build definition and make sure that the ErrornousScript is executing the exe that is setting the ExitCode to 1. You have now setup a build definition that will execute the errornous Console Application. When you run it, you will see that the build succeeds. This is not what you want! To solve this, you can make use of the Result property on the InvokeProcess activity. So lets change our Build Process Template. Add the new variables (scoped to the sequence where you run the Console Application) called ExitCode (type = Int32) and ErrorMessage Click on the InvokeProcess activity and change the Result property to ExitCode In the Handle Standard Output of the InvokeProcess add a Sequence activity In the Sequence activity, add an Assign primitive. Set the following properties: To = ErrorMessage Value = If(Not String.IsNullOrEmpty(ErrorMessage), Environment.NewLine + ErrorMessage, "") + stdOutput And add the default BuildMessage to the sequence that outputs the stdOutput Add beneath the InvokeProcess activity and If activity with the condition ExitCode <> 0 In the Then section add a Throw activity and set the Exception property to New Exception(ErrorMessage) The complete workflow looks now like When you now check in the Build Process Template and run the build, you get the following result And that is exactly what we want.   You can download the full solution at BuildProcess.zip. It will include the sources of every part and will continue to evolve.

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  • Make it simple. Make it work.

    - by Sean Feldman
    In 2010 I had an experience to work for a business that had lots of challenges. One of those challenges was luck of technical architecture and business value recognition which translated in spending enormous amount of manpower and money on creating C++ solutions for desktop client w/o using .NET to minimize “footprint” (2#) of the client application in deployment environments. This was an awkward experience, considering that C++ custom code was created from scratch to make clients talk to .NET backend while simple having .NET as a dependency would cut time to market by at least 50% (and I’m downplaying the estimate). Regardless, recent Microsoft announcement about .NET vNext has reminded me that experience and how short sighted architecture at that company was. Investment made into making C++ client that cannot be maintained internally by team due to it’s specialization in .NET have created a situation where code to maintain will be more brutal over the time and  number of developers understanding it will be going and shrinking. Not only that. The ability to go cross-platform (#3) and performance achievement gained with native compilation (#1) would be an immediate pay back. Why am I saying all this? To make a simple point to myself and remind again – when working on a product that needs to get to the market, make it simple, make it work, and then see how technology is changing and how you can adopt. Simplicity will not let you down. But a complex solution will always do.

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  • Expando Object and dynamic property pattern

    - by Al.Net
    I have read about 'dynamic property pattern' of Martin Fowler in his site under the tag 1997 in which he used dictionary kind of stuff to achieve this pattern. And I have come across about Expando object in c# very recently. When I see its implementation, I am able to see IDictionary implemented. So Expando object uses dictionary to store dynamic properties and is it what, Martin Fowler already defined 15 years ago?

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  • dotnet Cologne 2013 – Vorträge gesucht!

    - by WeigeltRo
    Am 3. Mai 2013 findet im Mediapark Köln die dotnet Cologne 2013 statt. Damit die mittlerweile fünfte Ausgabe dieser Community-Konferenz wieder ein solcher Erfolg wie in den Vorjahren wird, suchen wir (Stefan Lange, Melanie Eibl, Albert Weinert und ich) Sprecher mit interessanten Vorträgen zu Technologien aus dem Microsoft-Umfeld. Dabei wünschen wir uns sowohl Einführungsvorträge in neue Themen als auch die eine oder andere “Level 400 Hardcore-Session” für Spezialisten. Für beides sind passende Räume im Komed vorhanden, das auch in diesem Jahr wieder Veranstaltungsort sein wird. Alle Infos zum Call for Papers gibt es hier. Über die dotnet Cologne Die dotnet Cologne, die 2009 zum ersten Mal stattfand, hat sich im Laufe der Jahre mit mittlerweile 350 Teilnehmern zur größten .NET Community-Konferenz in Deutschland entwickelt. Veranstaltet von den .NET User Groups Bonn-to-Code.Net und .net user group Köln, versteht sich die dotnet Cologne als Konferenz von Entwicklern für Entwickler.

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  • Bin packing part 6: Further improvements

    - by Hugo Kornelis
    In part 5 of my series on the bin packing problem, I presented a method that sits somewhere in between the true row-by-row iterative characteristics of the first three parts and the truly set-based approach of the fourth part. I did use iteration, but each pass through the loop would use a set-based statement to process a lot of rows at once. Since that statement is fairly complex, I am sure that a single execution of it is far from cheap – but the algorithm used is efficient enough that the entire...(read more)

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  • 302: this blog will be closed

    - by preishuber
    After nearly 7 years I will discontinue blogging on this site. My resources are limited. You can reach my German blog which is used to support my customers. Looking back to a long an interesting journey ASP.NET by ScottGu That was the reason to attend this site and support Microsoft as much as I can. For that I was honored as ASP.NET MVP- thanks again. Meet Scoot several times. Great guy! Forums I have left NNTP forums a few years ago and now Microsoft closed it- It was my idea ;-) AJAX Was the wrong way- JQuery won the game IIS7 That is really a great plattform and the IIS team rules. I am sad that is so silent around that topic. ASP.NET after 2.0 Is no longer my world. I love ASP.NET and ASP.NET Server controls. I hate the discussion about how to follow the holy rules of MVC. Microsoft have dropped the goal to bring ASP.NET to #1 and accepted PHP is it. Facebook & Twittering Microblogging takes over a part of the blogging business. Shorter faster cheaper- or as SteveB mentioned - do more with less. Google Google is taking over the web. I am using Bing every time as I can but Google have more options. Sorry Microsoft you will loose that game. Apple That is not the biggest problem of Microsoft. the Ixxx takes over a small part but big money of the market, but the customers are not strongly linked. New wave new hype- Game over Apple. Silverlight My new home. I can reuse a lot of my skills and love the possibilitys. Silverligth will passing WPF-and strike Flash Windows phone 7 Also my skills fit. I just will use it for fun. I am not really satisfied about what I have heard from MIX. Guys from Redmond, I am sad to say you have been the best Smartphone OS and lost everything. The ADO vNext Story That will be the next mystic point. WCF, REST, JSON, ATOM and now OData. Nothing about SQL commands. LINQ, ORM is also not the final solution for multilayered disconnected async scenarios. Personally I prefere the OData idea and dislike the Swiss Army Knife (German Eierlegende Wollmilchsau) WCF. I am still in INETA Speakers board and I am glad to come to your user group. In all other cases you can hire me over ppedv AG. Good by and have good live.

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  • Why is there no generic implementation of OrderedDictionary in .net?

    - by nonot1
    Why did Microsoft not provide generic implementation of OrderedDictionary? There are a few custom implementations I've seen, including: http://www.codeproject.com/KB/recipes/GenericOrderedDictionary.aspx But why did Microsoft not include it in the base .net library? Surely they had a reason for not building a generic.... but what is it? Prior to posting this message, I did see: http://stackoverflow.com/questions/2629027/no-generic-implementation-of-ordereddictionary But that just confirms that it does not exist. Not why it does not exist. Thanks

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