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• SQL SERVER – Concurrency Basics – Guest Post by Vinod Kumar

  - by pinaldave

  This guest post is by Vinod Kumar. Vinod Kumar has worked with SQL Server extensively since joining the industry over a decade ago. Working on various versions from SQL Server 7.0, Oracle 7.3 and other database technologies – he now works with the Microsoft Technology Center (MTC) as a Technology Architect. Let us read the blog post in Vinod’s own voice. Learning is always fun when it comes to SQL Server and learning the basics again can be more fun. I did write about Transaction Logs and recovery over my blogs and the concept of simplifying the basics is a challenge. In the real world we always see checks and queues for a process – say railway reservation, banks, customer supports etc there is a process of line and queue to facilitate everyone. Shorter the queue higher is the efficiency of system (a.k.a higher is the concurrency). Every database does implement this using checks like locking, blocking mechanisms and they implement the standards in a way to facilitate higher concurrency. In this post, let us talk about the topic of Concurrency and what are the various aspects that one needs to know about concurrency inside SQL Server. Let us learn the concepts as one-liners: Concurrency can be defined as the ability of multiple processes to access or change shared data at the same time. The greater the number of concurrent user processes that can be active without interfering with each other, the greater the concurrency of the database system. Concurrency is reduced when a process that is changing data prevents other processes from reading that data or when a process that is reading data prevents other processes from changing that data. Concurrency is also affected when multiple processes are attempting to change the same data simultaneously. Two approaches to managing concurrent data access: Optimistic Concurrency Model Pessimistic Concurrency Model Concurrency Models Pessimistic Concurrency Default behavior: acquire locks to block access to data that another process is using. Assumes that enough data modification operations are in the system that any given read operation is likely affected by a data modification made by another user (assumes conflicts will occur). Avoids conflicts by acquiring a lock on data being read so no other processes can modify that data. Also acquires locks on data being modified so no other processes can access the data for either reading or modifying. Readers block writer, writers block readers and writers. Optimistic Concurrency Assumes that there are sufficiently few conflicting data modification operations in the system that any single transaction is unlikely to modify data that another transaction is modifying. Default behavior of optimistic concurrency is to use row versioning to allow data readers to see the state of the data before the modification occurs. Older versions of the data are saved so a process reading data can see the data as it was when the process started reading and not affected by any changes being made to that data. Processes modifying the data is unaffected by processes reading the data because the reader is accessing a saved version of the data rows. Readers do not block writers and writers do not block readers, but, writers can and will block writers. Transaction Processing A transaction is the basic unit of work in SQL Server. Transaction consists of SQL commands that read and update the database but the update is not considered final until a COMMIT command is issued (at least for an explicit transaction: marked with a BEGIN TRAN and the end is marked by a COMMIT TRAN or ROLLBACK TRAN). Transactions must exhibit all the ACID properties of a transaction. ACID Properties Transaction processing must guarantee the consistency and recoverability of SQL Server databases. Ensures all transactions are performed as a single unit of work regardless of hardware or system failure. A – Atomicity C – Consistency I – Isolation D- Durability Atomicity: Each transaction is treated as all or nothing – it either commits or aborts. Consistency: ensures that a transaction won’t allow the system to arrive at an incorrect logical state – the data must always be logically correct.  Consistency is honored even in the event of a system failure. Isolation: separates concurrent transactions from the updates of other incomplete transactions. SQL Server accomplishes isolation among transactions by locking data or creating row versions. Durability: After a transaction commits, the durability property ensures that the effects of the transaction persist even if a system failure occurs. If a system failure occurs while a transaction is in progress, the transaction is completely undone, leaving no partial effects on data. Transaction Dependencies In addition to supporting all four ACID properties, a transaction might exhibit few other behaviors (known as dependency problems or consistency problems). Lost Updates: Occur when two processes read the same data and both manipulate the data, changing its value and then both try to update the original data to the new value. The second process might overwrite the first update completely. Dirty Reads: Occurs when a process reads uncommitted data. If one process has changed data but not yet committed the change, another process reading the data will read it in an inconsistent state. Non-repeatable Reads: A read is non-repeatable if a process might get different values when reading the same data in two reads within the same transaction. This can happen when another process changes the data in between the reads that the first process is doing. Phantoms: Occurs when membership in a set changes. It occurs if two SELECT operations using the same predicate in the same transaction return a different number of rows. Isolation Levels SQL Server supports 5 isolation levels that control the behavior of read operations. Read Uncommitted All behaviors except for lost updates are possible. Implemented by allowing the read operations to not take any locks, and because of this, it won’t be blocked by conflicting locks acquired by other processes. The process can read data that another process has modified but not yet committed. When using the read uncommitted isolation level and scanning an entire table, SQL Server can decide to do an allocation order scan (in page-number order) instead of a logical order scan (following page pointers). If another process doing concurrent operations changes data and move rows to a new location in the table, the allocation order scan can end up reading the same row twice. Also can happen if you have read a row before it is updated and then an update moves the row to a higher page number than your scan encounters later. Performing an allocation order scan under Read Uncommitted can cause you to miss a row completely – can happen when a row on a high page number that hasn’t been read yet is updated and moved to a lower page number that has already been read. Read Committed Two varieties of read committed isolation: optimistic and pessimistic (default). Ensures that a read never reads data that another application hasn’t committed. If another transaction is updating data and has exclusive locks on data, your transaction will have to wait for the locks to be released. Your transaction must put share locks on data that are visited, which means that data might be unavailable for others to use. A share lock doesn’t prevent others from reading but prevents them from updating. Read committed (snapshot) ensures that an operation never reads uncommitted data, but not by forcing other processes to wait. SQL Server generates a version of the changed row with its previous committed values. Data being changed is still locked but other processes can see the previous versions of the data as it was before the update operation began. Repeatable Read This is a Pessimistic isolation level. Ensures that if a transaction revisits data or a query is reissued the data doesn’t change. That is, issuing the same query twice within a transaction cannot pickup any changes to data values made by another user’s transaction because no changes can be made by other transactions. However, this does allow phantom rows to appear. Preventing non-repeatable read is a desirable safeguard but cost is that all shared locks in a transaction must be held until the completion of the transaction. Snapshot Snapshot Isolation (SI) is an optimistic isolation level. Allows for processes to read older versions of committed data if the current version is locked. Difference between snapshot and read committed has to do with how old the older versions have to be. It’s possible to have two transactions executing simultaneously that give us a result that is not possible in any serial execution. Serializable This is the strongest of the pessimistic isolation level. Adds to repeatable read isolation level by ensuring that if a query is reissued rows were not added in the interim, i.e, phantoms do not appear. Preventing phantoms is another desirable safeguard, but cost of this extra safeguard is similar to that of repeatable read – all shared locks in a transaction must be held until the transaction completes. In addition serializable isolation level requires that you lock data that has been read but also data that doesn’t exist. Ex: if a SELECT returned no rows, you want it to return no. rows when the query is reissued. This is implemented in SQL Server by a special kind of lock called the key-range lock. Key-range locks require that there be an index on the column that defines the range of values. If there is no index on the column, serializable isolation requires a table lock. Gets its name from the fact that running multiple serializable transactions at the same time is equivalent of running them one at a time. Now that we understand the basics of what concurrency is, the subsequent blog posts will try to bring out the basics around locking, blocking, deadlocks because they are the fundamental blocks that make concurrency possible. Now if you are with me – let us continue learning for SQL Server Locking Basics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Concurrency

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• Getting a Web Resource Url in non WebForms Applications

  - by Rick Strahl

  WebResources in ASP.NET are pretty useful feature. WebResources are resources that are embedded into a .NET assembly and can be loaded from the assembly via a special resource URL. WebForms includes a method on the ClientScriptManager (Page.ClientScript) and the ScriptManager object to retrieve URLs to these resources. For example you can do: ClientScript.GetWebResourceUrl(typeof(ControlResources), ControlResources.JQUERY_SCRIPT_RESOURCE); GetWebResourceUrl requires a type (which is used for the assembly lookup in which to find the resource) and the resource id to lookup. GetWebResourceUrl() then returns a nasty old long URL like this: WebResource.axd?d=-b6oWzgbpGb8uTaHDrCMv59VSmGhilZP5_T_B8anpGx7X-PmW_1eu1KoHDvox-XHqA1EEb-Tl2YAP3bBeebGN65tv-7-yAimtG4ZnoWH633pExpJor8Qp1aKbk-KQWSoNfRC7rQJHXVP4tC0reYzVw2&t=634533278261362212 While lately excessive resource usage has been frowned upon especially by MVC developers who tend to opt for content distributed as files, I still think that Web Resources have their place even in non-WebForms applications. Also if you have existing assemblies that include resources like scripts and common image links it sure would be nice to access them from non-WebForms pages like MVC views or even in plain old Razor Web Pages. Where's my Page object Dude? Unfortunately natively ASP.NET doesn't have a mechanism for retrieving WebResource Urls outside of the WebForms engine. It's a feature that's specifically baked into WebForms and that relies specifically on the Page HttpHandler implementation. Both Page.ClientScript (obviously) and ScriptManager rely on a hosting Page object in order to work and the various methods off these objects require control instances passed. The reason for this is that the script managers can inject scripts and links into Page content (think RegisterXXXX methods) and for that a Page instance is required. However, for many other methods - like GetWebResourceUrl() - that simply return resources or resource links the Page reference is really irrelevant. While there's a separate ClientScriptManager class, it's marked as sealed and doesn't have any public constructors so you can't create your own instance (without Reflection). Even if it did the internal constructor it does have requires a Page reference. No good… So, can we get access to a WebResourceUrl generically without running in a WebForms Page instance? We just have to create a Page instance ourselves and use it internally. There's nothing intrinsic about the use of the Page class in ClientScript, at least for retrieving resources and resource Urls so it's easy to create an instance of a Page for example in a static method. For our needs of retrieving ResourceUrls or even actually retrieving script resources we can use a canned, non-configured Page instance we create on our own. The following works just fine: public static string GetWebResourceUrl(Type type, string resource ) { Page page = new Page(); return page.ClientScript.GetWebResourceUrl(type, resource); } A slight optimization for this might be to cache the created Page instance. Page tends to be a pretty heavy object to create each time a URL is required so you might want to cache the instance: public class WebUtils { private static Page CachedPage { get { if (_CachedPage == null) _CachedPage = new Page(); return _CachedPage; } } private static Page _CachedPage; public static string GetWebResourceUrl(Type type, string resource) { return CachedPage.ClientScript.GetWebResourceUrl(type, resource); } } You can now use GetWebResourceUrl in a Razor page like this: <!DOCTYPE html> <html <head> <script src="@WebUtils.GetWebResourceUrl(typeof(ControlResources),ControlResources.JQUERY_SCRIPT_RESOURCE)"> </script> </head> <body> <div class="errordisplay"> <img src="@WebUtils.GetWebResourceUrl(typeof(ControlResources),ControlResources.WARNING_ICON_RESOURCE)" /> This is only a Test! </div> </body> </html> And voila - there you have WebResources served from a non-Page based application. WebResources may be a on the way out, but legacy apps have them embedded and for some situations, like fallback scripts and some common image resources I still like to use them. Being able to use them from non-WebForms applications should have been built into the core ASP.NETplatform IMHO, but seeing that it's not this workaround is easy enough to implement.© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  MVC   Tweet (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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• Rendering ASP.NET MVC Razor Views outside of MVC revisited

  - by Rick Strahl

  Last year I posted a detailed article on how to render Razor Views to string both inside of ASP.NET MVC and outside of it. In that article I showed several different approaches to capture the rendering output. The first and easiest is to use an existing MVC Controller Context to render a view by simply passing the controller context which is fairly trivial and I demonstrated a simple ViewRenderer class that simplified the process down to a couple lines of code. However, if no Controller Context is available the process is not quite as straight forward and I referenced an old, much more complex example that uses my RazorHosting library, which is a custom self-contained implementation of the Razor templating engine that can be hosted completely outside of ASP.NET. While it works inside of ASP.NET, it’s an awkward solution when running inside of ASP.NET, because it requires a bit of setup to run efficiently.Well, it turns out that I missed something in the original article, namely that it is possible to create a ControllerContext, if you have a controller instance, even if MVC didn’t create that instance. Creating a Controller Instance outside of MVCThe trick to make this work is to create an MVC Controller instance – any Controller instance – and then configure a ControllerContext through that instance. As long as an HttpContext.Current is available it’s possible to create a fully functional controller context as Razor can get all the necessary context information from the HttpContextWrapper().The key to make this work is the following method:/// <summary> /// Creates an instance of an MVC controller from scratch /// when no existing ControllerContext is present /// </summary> /// <typeparam name="T">Type of the controller to create</typeparam> /// <returns>Controller Context for T</returns> /// <exception cref="InvalidOperationException">thrown if HttpContext not available</exception> public static T CreateController<T>(RouteData routeData = null) where T : Controller, new() { // create a disconnected controller instance T controller = new T(); // get context wrapper from HttpContext if available HttpContextBase wrapper = null; if (HttpContext.Current != null) wrapper = new HttpContextWrapper(System.Web.HttpContext.Current); else throw new InvalidOperationException( "Can't create Controller Context if no active HttpContext instance is available."); if (routeData == null) routeData = new RouteData(); // add the controller routing if not existing if (!routeData.Values.ContainsKey("controller") && !routeData.Values.ContainsKey("Controller")) routeData.Values.Add("controller", controller.GetType().Name .ToLower() .Replace("controller", "")); controller.ControllerContext = new ControllerContext(wrapper, routeData, controller); return controller; }This method creates an instance of a Controller class from an existing HttpContext which means this code should work from anywhere within ASP.NET to create a controller instance that’s ready to be rendered. This means you can use this from within an Application_Error handler as I needed to or even from within a WebAPI controller as long as it’s running inside of ASP.NET (ie. not self-hosted). Nice.So using the ViewRenderer class from the previous article I can now very easily render an MVC view outside of the context of MVC. Here’s what I ended up in my Application’s custom error HttpModule: protected override void OnDisplayError(WebErrorHandler errorHandler, ErrorViewModel model) { var Response = HttpContext.Current.Response; Response.ContentType = "text/html"; Response.StatusCode = errorHandler.OriginalHttpStatusCode; var context = ViewRenderer.CreateController<ErrorController>().ControllerContext; var renderer = new ViewRenderer(context); string html = renderer.RenderView("~/Views/Shared/GenericError.cshtml", model); Response.Write(html); }That’s pretty sweet, because it’s now possible to use ViewRenderer just about anywhere in any ASP.NET application, not only inside of controller code. This also allows the constructor for the ViewRenderer from the last article to work without a controller context parameter, using a generic view as a base for the controller context when not passed:public ViewRenderer(ControllerContext controllerContext = null) { // Create a known controller from HttpContext if no context is passed if (controllerContext == null) { if (HttpContext.Current != null) controllerContext = CreateController<ErrorController>().ControllerContext; else throw new InvalidOperationException( "ViewRenderer must run in the context of an ASP.NET " + "Application and requires HttpContext.Current to be present."); } Context = controllerContext; }In this case I use the ErrorController class which is a generic controller instance that exists in the same assembly as my ViewRenderer class and that works just fine since ‘generically’ rendered views tend to not rely on anything from the controller other than the model which is explicitly passed.While these days most of my apps use MVC I do still have a number of generic pieces in most of these applications where Razor comes in handy. This includes modules like the above, which when they error often need to display error output. In other cases I need to generate string template output for emailing or logging data to disk. Being able to render simply render an arbitrary View to and pass in a model makes this super nice and easy at least within the context of an ASP.NET application!You can check out the updated ViewRenderer class below to render your ‘generic views’ from anywhere within your ASP.NET applications. Hope some of you find this useful.ResourcesViewRenderer Class in Westwind.Web.Mvc Library (Github)Original ViewRenderer ArticleRazor Hosting Library (GitHub)Original Razor Hosting Article© Rick Strahl, West Wind Technologies, 2005-2013Posted in ASP.NET  MVC   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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• Announcing ASP.NET MVC 3 (Release Candidate 2)

  - by ScottGu

  Earlier today the ASP.NET team shipped the final release candidate (RC2) for ASP.NET MVC 3.  You can download and install it here. Almost there… Today’s RC2 release is the near-final release of ASP.NET MVC 3, and is a true “release candidate” in that we are hoping to not make any more code changes with it.  We are publishing it today so that people can do final testing with it, let us know if they find any last minute “showstoppers”, and start updating their apps to use it.  We will officially ship the final ASP.NET MVC 3 “RTM” build in January. Works with both VS 2010 and VS 2010 SP1 Beta Today’s ASP.NET MVC 3 RC2 release works with both the shipping version of Visual Studio 2010 / Visual Web Developer 2010 Express, as well as the newly released VS 2010 SP1 Beta.  This means that you do not need to install VS 2010 SP1 (or the SP1 beta) in order to use ASP.NET MVC 3.  It works just fine with the shipping Visual Studio 2010.  I’ll do a blog post next week, though, about some of the nice additional feature goodies that come with VS 2010 SP1 (including IIS Express and SQL CE support within VS) which make the dev experience for both ASP.NET Web Forms and ASP.NET MVC even better. Bugs and Perf Fixes Today’s ASP.NET MVC 3 RC2 build contains many bug fixes and performance optimizations.  Our latest performance tests indicate that ASP.NET MVC 3 is now faster than ASP.NET MVC 2, and that existing ASP.NET MVC applications will experience a slight performance increase when updated to run using ASP.NET MVC 3. Final Tweaks and Fit-N-Finish In addition to bug fixes and performance optimizations, today’s RC2 build contains a number of last-minute feature tweaks and “fit-n-finish” changes for the new ASP.NET MVC 3 features.  The feedback and suggestions we’ve received during the public previews has been invaluable in guiding these final tweaks, and we really appreciate people’s support in sending this feedback our way.  Below is a short-list of some of the feature changes/tweaks made between last month’s ASP.NET MVC 3 RC release and today’s ASP.NET MVC 3 RC2 release: jQuery updates and addition of jQuery UI The default ASP.NET MVC 3 project templates have been updated to include jQuery 1.4.4 and jQuery Validation 1.7.  We are also excited to announce today that we are including jQuery UI within our default ASP.NET project templates going forward.  jQuery UI provides a powerful set of additional UI widgets and capabilities.  It will be added by default to your project’s \scripts folder when you create new ASP.NET MVC 3 projects. Improved View Scaffolding The T4 templates used for scaffolding views with the Add-View dialog now generates views that use Html.EditorFor instead of helpers such as Html.TextBoxFor. This change enables you to optionally annotate models with metadata (using data annotation attributes) to better customize the output of your UI at runtime. The Add View scaffolding also supports improved detection and usage of primary key information on models (including support for naming conventions like ID, ProductID, etc).  For example: the Add View dialog box uses this information to ensure that the primary key value is not scaffold as an editable form field, and that links between views are auto-generated correctly with primary key information. The default Edit and Create templates also now include references to the jQuery scripts needed for client validation.  Scaffold form views now support client-side validation by default (no extra steps required).  Client-side validation with ASP.NET MVC 3 is also done using an unobtrusive javascript approach – making pages fast and clean. [ControllerSessionState] –> [SessionState] ASP.NET MVC 3 adds support for session-less controllers.  With the initial RC you used a [ControllerSessionState] attribute to specify this.  We shortened this in RC2 to just be [SessionState]: Note that in addition to turning off session state, you can also set it to be read-only (which is useful for webfarm scenarios where you are reading but not updating session state on a particular request). [SkipRequestValidation] –> [AllowHtml] ASP.NET MVC includes built-in support to protect against HTML and Cross-Site Script Injection Attacks, and will throw an error by default if someone tries to post HTML content as input.  Developers need to explicitly indicate that this is allowed (and that they’ve hopefully built their app to securely support it) in order to enable it. With ASP.NET MVC 3, we are also now supporting a new attribute that you can apply to properties of models/viewmodels to indicate that HTML input is enabled, which enables much more granular protection in a DRY way.  In last month’s RC release this attribute was named [SkipRequestValidation].  With RC2 we renamed it to [AllowHtml] to make it more intuitive: Setting the above [AllowHtml] attribute on a model/viewmodel will cause ASP.NET MVC 3 to turn off HTML injection protection when model binding just that property. Html.Raw() helper method The new Razor view engine introduced with ASP.NET MVC 3 automatically HTML encodes output by default.  This helps provide an additional level of protection against HTML and Script injection attacks. With RC2 we are adding a Html.Raw() helper method that you can use to explicitly indicate that you do not want to HTML encode your output, and instead want to render the content “as-is”: ViewModel/View –> ViewBag ASP.NET MVC has (since V1) supported a ViewData[] dictionary within Controllers and Views that enables developers to pass information from a Controller to a View in a late-bound way.  This approach can be used instead of, or in combination with, a strongly-typed model class.  The below code demonstrates a common use case – where a strongly typed Product model is passed to the view in addition to two late-bound variables via the ViewData[] dictionary: With ASP.NET MVC 3 we are introducing a new API that takes advantage of the dynamic type support within .NET 4 to set/retrieve these values.  It allows you to use standard “dot” notation to specify any number of additional variables to be passed, and does not require that you create a strongly-typed class to do so.  With earlier previews of ASP.NET MVC 3 we exposed this API using a dynamic property called “ViewModel” on the Controller base class, and with a dynamic property called “View” within view templates.  A lot of people found the fact that there were two different names confusing, and several also said that using the name ViewModel was confusing in this context – since often you create strongly-typed ViewModel classes in ASP.NET MVC, and they do not use this API.  With RC2 we are exposing a dynamic property that has the same name – ViewBag – within both Controllers and Views.  It is a dynamic collection that allows you to pass additional bits of data from your controller to your view template to help generate a response.  Below is an example of how we could use it to pass a time-stamp message as well as a list of all categories to our view template: Below is an example of how our view template (which is strongly-typed to expect a Product class as its model) can use the two extra bits of information we passed in our ViewBag to generate the response.  In particular, notice how we are using the list of categories passed in the dynamic ViewBag collection to generate a dropdownlist of friendly category names to help set the CategoryID property of our Product object.  The above Controller/View combination will then generate an HTML response like below.    Output Caching Improvements ASP.NET MVC 3’s output caching system no longer requires you to specify a VaryByParam property when declaring an [OutputCache] attribute on a Controller action method.  MVC3 now automatically varies the output cached entries when you have explicit parameters on your action method – allowing you to cleanly enable output caching on actions using code like below: In addition to supporting full page output caching, ASP.NET MVC 3 also supports partial-page caching – which allows you to cache a region of output and re-use it across multiple requests or controllers.  The [OutputCache] behavior for partial-page caching was updated with RC2 so that sub-content cached entries are varied based on input parameters as opposed to the URL structure of the top-level request – which makes caching scenarios both easier and more powerful than the behavior in the previous RC. @model declaration does not add whitespace In earlier previews, the strongly-typed @model declaration at the top of a Razor view added a blank line to the rendered HTML output. This has been fixed so that the declaration does not introduce whitespace. Changed "Html.ValidationMessage" Method to Display the First Useful Error Message The behavior of the Html.ValidationMessage() helper was updated to show the first useful error message instead of simply displaying the first error. During model binding, the ModelState dictionary can be populated from multiple sources with error messages about the property, including from the model itself (if it implements IValidatableObject), from validation attributes applied to the property, and from exceptions thrown while the property is being accessed. When the Html.ValidationMessage() method displays a validation message, it now skips model-state entries that include an exception, because these are generally not intended for the end user. Instead, the method looks for the first validation message that is not associated with an exception and displays that message. If no such message is found, it defaults to a generic error message that is associated with the first exception. RemoteAttribute “Fields” -> “AdditionalFields” ASP.NET MVC 3 includes built-in remote validation support with its validation infrastructure.  This means that the client-side validation script library used by ASP.NET MVC 3 can automatically call back to controllers you expose on the server to determine whether an input element is indeed valid as the user is editing the form (allowing you to provide real-time validation updates). You can accomplish this by decorating a model/viewmodel property with a [Remote] attribute that specifies the controller/action that should be invoked to remotely validate it.  With the RC this attribute had a “Fields” property that could be used to specify additional input elements that should be sent from the client to the server to help with the validation logic.  To improve the clarity of what this property does we have renamed it to “AdditionalFields” with today’s RC2 release. ViewResult.Model and ViewResult.ViewBag Properties The ViewResult class now exposes both a “Model” and “ViewBag” property off of it.  This makes it easier to unit test Controllers that return views, and avoids you having to access the Model via the ViewResult.ViewData.Model property. Installation Notes You can download and install the ASP.NET MVC 3 RC2 build here.  It can be installed on top of the previous ASP.NET MVC 3 RC release (it should just replace the bits as part of its setup). The one component that will not be updated by the above setup (if you already have it installed) is the NuGet Package Manager.  If you already have NuGet installed, please go to the Visual Studio Extensions Manager (via the Tools –> Extensions menu option) and click on the “Updates” tab.  You should see NuGet listed there – please click the “Update” button next to it to have VS update the extension to today’s release. If you do not have NuGet installed (and did not install the ASP.NET MVC RC build), then NuGet will be installed as part of your ASP.NET MVC 3 setup, and you do not need to take any additional steps to make it work. Summary We are really close to the final ASP.NET MVC 3 release, and will deliver the final “RTM” build of it next month.  It has been only a little over 7 months since ASP.NET MVC 2 shipped, and I’m pretty amazed by the huge number of new features, improvements, and refinements that the team has been able to add with this release (Razor, Unobtrusive JavaScript, NuGet, Dependency Injection, Output Caching, and a lot, lot more).  I’ll be doing a number of blog posts over the next few weeks talking about many of them in more depth. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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• Move Files from a Failing PC with an Ubuntu Live CD

  - by Trevor Bekolay

  You’ve loaded the Ubuntu Live CD to salvage files from a failing system, but where do you store the recovered files? We’ll show you how to store them on external drives, drives on the same PC, a Windows home network, and other locations. We’ve shown you how to recover data like a forensics expert, but you can’t store recovered files back on your failed hard drive! There are lots of ways to transfer the files you access from an Ubuntu Live CD to a place that a stable Windows machine can access them. We’ll go through several methods, starting each section from the Ubuntu desktop – if you don’t yet have an Ubuntu Live CD, follow our guide to creating a bootable USB flash drive, and then our instructions for booting into Ubuntu. If your BIOS doesn’t let you boot using a USB flash drive, don’t worry, we’ve got you covered! Use a Healthy Hard Drive If your computer has more than one hard drive, or your hard drive is healthy and you’re in Ubuntu for non-recovery reasons, then accessing your hard drive is easy as pie, even if the hard drive is formatted for Windows. To access a hard drive, it must first be mounted. To mount a healthy hard drive, you just have to select it from the Places menu at the top-left of the screen. You will have to identify your hard drive by its size. Clicking on the appropriate hard drive mounts it, and opens it in a file browser. You can now move files to this hard drive by drag-and-drop or copy-and-paste, both of which are done the same way they’re done in Windows. Once a hard drive, or other external storage device, is mounted, it will show up in the /media directory. To see a list of currently mounted storage devices, navigate to /media by clicking on File System in a File Browser window, and then double-clicking on the media folder. Right now, our media folder contains links to the hard drive, which Ubuntu has assigned a terribly uninformative label, and the PLoP Boot Manager CD that is currently in the CD-ROM drive. Connect a USB Hard Drive or Flash Drive An external USB hard drive gives you the advantage of portability, and is still large enough to store an entire hard disk dump, if need be. Flash drives are also very quick and easy to connect, though they are limited in how much they can store. When you plug a USB hard drive or flash drive in, Ubuntu should automatically detect it and mount it. It may even open it in a File Browser automatically. Since it’s been mounted, you will also see it show up on the desktop, and in the /media folder. Once it’s been mounted, you can access it and store files on it like you would any other folder in Ubuntu. If, for whatever reason, it doesn’t mount automatically, click on Places in the top-left of your screen and select your USB device. If it does not show up in the Places list, then you may need to format your USB drive. To properly remove the USB drive when you’re done moving files, right click on the desktop icon or the folder in /media and select Safely Remove Drive. If you’re not given that option, then Eject or Unmount will effectively do the same thing. Connect to a Windows PC on your Local Network If you have another PC or a laptop connected through the same router (wired or wireless) then you can transfer files over the network relatively quickly. To do this, we will share one or more folders from the machine booted up with the Ubuntu Live CD over the network, letting our Windows PC grab the files contained in that folder. As an example, we’re going to share a folder on the desktop called ToShare. Right-click on the folder you want to share, and click Sharing Options. A Folder Sharing window will pop up. Check the box labeled Share this folder. A window will pop up about the sharing service. Click the Install service button. Some files will be downloaded, and then installed. When they’re done installing, you’ll be appropriately notified. You will be prompted to restart your session. Don’t worry, this won’t actually log you out, so go ahead and press the Restart session button. The Folder Sharing window returns, with Share this folder now checked. Edit the Share name if you’d like, and add checkmarks in the two checkboxes below the text fields. Click Create Share. Nautilus will ask your permission to add some permissions to the folder you want to share. Allow it to Add the permissions automatically. The folder is now shared, as evidenced by the new arrows above the folder’s icon. At this point, you are done with the Ubuntu machine. Head to your Windows PC, and open up Windows Explorer. Click on Network in the list on the left, and you should see a machine called UBUNTU in the right pane. Note: This example is shown in Windows 7; the same steps should work for Windows XP and Vista, but we have not tested them. Double-click on UBUNTU, and you will see the folder you shared earlier! As well as any other folders you’ve shared from Ubuntu. Double click on the folder you want to access, and from there, you can move the files from the machine booted with Ubuntu to your Windows PC. Upload to an Online Service There are many services online that will allow you to upload files, either temporarily or permanently. As long as you aren’t transferring an entire hard drive, these services should allow you to transfer your important files from the Ubuntu environment to any other machine with Internet access. We recommend compressing the files that you want to move, both to save a little bit of bandwidth, and to save time clicking on files, as uploading a single file will be much less work than a ton of little files. To compress one or more files or folders, select them, and then right-click on one of the members of the group. Click Compress…. Give the compressed file a suitable name, and then select a compression format. We’re using .zip because we can open it anywhere, and the compression rate is acceptable. Click Create and the compressed file will show up in the location selected in the Compress window. Dropbox If you have a Dropbox account, then you can easily upload files from the Ubuntu environment to Dropbox. There is no explicit limit on the size of file that can be uploaded to Dropbox, though a free account begins with a total limit of 2 GB of files in total. Access your account through Firefox, which can be opened by clicking on the Firefox logo to the right of the System menu at the top of the screen. Once into your account, press the Upload button on top of the main file list. Because Flash is not installed in the Live CD environment, you will have to switch to the basic uploader. Click Browse…find your compressed file, and then click Upload file. Depending on the size of the file, this could take some time. However, once the file has been uploaded, it should show up on any computer connected through Dropbox in a matter of minutes. Google Docs Google Docs allows the upload of any type of file – making it an ideal place to upload files that we want to access from another computer. While your total allocation of space varies (mine is around 7.5 GB), there is a per-file maximum of 1 GB. Log into Google Docs, and click on the Upload button at the top left of the page. Click Select files to upload and select your compressed file. For safety’s sake, uncheck the checkbox concerning converting files to Google Docs format, and then click Start upload. Go Online – Through FTP If you have access to an FTP server – perhaps through your web hosting company, or you’ve set up an FTP server on a different machine – you can easily access the FTP server in Ubuntu and transfer files. Just make sure you don’t go over your quota if you have one. You will need to know the address of the FTP server, as well as the login information. Click on Places > Connect to Server… Choose the FTP (with login) Service type, and fill in your information. Adding a bookmark is optional, but recommended. You will be asked for your password. You can choose to remember it until you logout, or indefinitely. You can now browse your FTP server just like any other folder. Drop files into the FTP server and you can retrieve them from any computer with an Internet connection and an FTP client. Conclusion While at first the Ubuntu Live CD environment may seem claustrophobic, it has a wealth of options for connecting to peripheral devices, local computers, and machines on the Internet – and this article has only scratched the surface. Whatever the storage medium, Ubuntu’s got an interface for it! Similar Articles Productive Geek Tips Backup Your Windows Live Writer SettingsMove a Window Without Clicking the Titlebar in UbuntuRecover Deleted Files on an NTFS Hard Drive from a Ubuntu Live CDCreate a Bootable Ubuntu USB Flash Drive the Easy WayReset Your Ubuntu Password Easily from the Live CD TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Acronis Online Backup DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows Tech Fanboys Field Guide Check these Awesome Chrome Add-ons iFixit Offers Gadget Repair Manuals Online Vista style sidebar for Windows 7 Create Nice Charts With These Web Based Tools Track Daily Goals With 42Goals

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• Sublime text 2 syntax highlighter?

  - by BigSack

  I have coded my first custom syntax highlighter for sublime text 2, but i don't know how to install it. It is based on notepad++ highlighter found here https://70995658-a-62cb3a1a-s-sites.googlegroups.com/site/lohanplus/files/smali_npp.xml?attachauth=ANoY7criVTO9bDmIGrXwhZLQ_oagJzKKJTlbNDGRzMDVpFkO5i0N6hk_rWptvoQC1tBlNqcqFDD5NutD_2vHZx1J7hcRLyg1jruSjebHIeKdS9x0JCNrsRivgs6DWNhDSXSohkP1ZApXw0iQ0MgqcXjdp7CkJJ6pY_k5Orny9TfK8UWn_HKFsmPcpp967NMPtUnd--ad-BImtkEi-fox2tjs7zc5LabkDQ%3D%3D&attredirects=0&d=1 <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>fileTypes</key> <array> <string>smali</string> </array> <dict> <key>Word1</key> <string>add-double add-double/2addr add-float add-float/2addr add-int add-int/2addr add-int/lit16 add-int/lit8 add-long add-long/2addr aget aget-boolean aget-byte aget-char aget-object aget-short aget-wide and-int and-int/2addr and-int/lit16 and-int/lit8 and-long and-long/2addr aput aput-boolean aput-byte aput-char aput-object aput-short aput-wide array-length check-cast cmp-long cmpg-double cmpg-float cmpl-double cmpl-float const const-class const-string const-string-jumbo const-wide const-wide/16 const-wide/32 const-wide/high16 const/16 const/4 const/high16 div-double div-double/2addr div-float div-float/2addr div-int div-int/2addr div-int/lit16 div-int/lit8 div-long div-long/2addr double-to-float double-to-int double-to-long execute-inline fill-array-data filled-new-array filled-new-array/range float-to-double float-to-int float-to-long goto goto/16 goto/32 if-eq if-eqz if-ge if-gez if-gt if-gtz if-le if-lez if-lt if-ltz if-ne if-nez iget iget-boolean iget-byte iget-char iget-object iget-object-quick iget-quick iget-short iget-wide iget-wide-quick instance-of int-to-byte int-to-char int-to-double int-to-float int-to-long int-to-short invoke-direct invoke-direct-empty invoke-direct/range invoke-interface invoke-interface/range invoke-static invoke-static/range invoke-super invoke-super-quick invoke-super-quick/range invoke-super/range invoke-virtual invoke-virtual-quick invoke-virtual-quick/range invoke-virtual/range iput iput-boolean iput-byte iput-char iput-object iput-object-quick iput-quick iput-short iput-wide iput-wide-quick long-to-double long-to-float long-to-int monitor-enter monitor-exit move move-exception move-object move-object/16 move-object/from16 move-result move-result-object move-result-wide move-wide move-wide/16 move-wide/from16 move/16 move/from16 mul-double mul-double/2addr mul-float mul-float/2addr mul-int mul-int/2addr mul-int/lit8 mul-int/lit16 mul-long mul-long/2addr neg-double neg-float neg-int neg-long new-array new-instance nop not-int not-long or-int or-int/2addr or-int/lit16 or-int/lit8 or-long or-long/2addr rem-double rem-double/2addr rem-float rem-float/2addr rem-int rem-int/2addr rem-int/lit16 rem-int/lit8 rem-long rem-long/2addr return return-object return-void return-wide rsub-int rsub-int/lit8 sget sget-boolean sget-byte sget-char sget-object sget-short sget-wide shl-int shl-int/2addr shl-int/lit8 shl-long shl-long/2addr shr-int shr-int/2addr shr-int/lit8 shr-long shr-long/2addr sparse-switch sput sput-boolean sput-byte sput-char sput-object sput-short sput-wide sub-double sub-double/2addr sub-float sub-float/2addr sub-int sub-int/2addr sub-int/lit16 sub-int/lit8 sub-long sub-long/2addr throw throw-verification-error ushr-int ushr-int/2addr ushr-int/lit8 ushr-long ushr-long/2addr xor-int xor-int/2addr xor-int/lit16 xor-int/lit8 xor-long xor-long/2addr</string> </dict> <dict> <key>Word2</key> <string>v0 v1 v2 v3 v4 v5 v6 v7 v8 v9 v10 v11 v12 v13 v14 v15 v16 v17 v18 v19 v20 v21 v22 v23 v24 v25 v26 v27 v28 v29 v30 v31 v32 v33 v34 v35 v36 v37 v38 v39 v40 v41 v42 v43 v44 v45 v46 v47 v48 v49 v50 p0 p1 p2 p3 p4 p5 p6 p7 p8 p9 p10 p11 p12 p13 p14 p15 p16 p17 p18 p19 p20 p21 p22 p23 p24 p25 p26 p27 p28 p29 p30</string> </dict> <dict> <key>Word3</key> <string>array-data .catch .catchall .class .end .end\ local .enum .epilogue .field .implements .line .local .locals .parameter .prologue .registers .restart .restart\ local .source .subannotation .super</string> </dict> <dict> <key>Word4</key> <string>abstract bridge constructor declared-synchronized enum final interface native private protected public static strictfp synchronized synthetic system transient varargs volatile</string> </dict> <dict> <key>Word4</key> <string>(&quot;0)&quot;0</string> </dict> <dict> <key>Word5</key> <string>.method .annotation .sparse-switch .packed-switch</string> </dict> <dict> <key>word6</key> <string>.end\ method .end\ annotation .end\ sparse-switch .end\ packed-switch</string> </dict> <dict> <key>word7</key> <string>&quot; ( ) , ; { } &gt;</string> </dict> <key>uuid</key> <string>27798CC6-6B1D-11D9-B8FA-000D93589AF6</string> </dict> </plist>

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• .NET: Serializing object to a file from a 3rd party assembly

  - by MacGyver

  Below is a link that describes how to serialize an object. But it requires you implement from ISerializable for the object you are serializing. What I'd like to do is serialize an object that I did not define--an object based on a class in a 3rd party assembly (from a project reference) that is not implementing ISerializable. Is that possible? How can this be done? http://www.switchonthecode.com/tutorials/csharp-tutorial-serialize-objects-to-a-file Property (IWebDriver = interface type): private IWebDriver driver; Object Instance (FireFoxDriver is a class type): driver = new FirefoxDriver(firefoxProfile); ================ 3/21/2012 update after answer posted Why would this throw an error? It doesn't like this line: serializedObject.DriverInstance = (FirefoxDriver)driver; ... Error: Cannot implicitly convert type 'OpenQA.Selenium.IWebDriver' to 'OpenQA.Selenium.Firefox.FirefoxDriver'. An explicit conversion exists (are you missing a cast?) Here is the code: FirefoxDriverSerialized serializedObject = new FirefoxDriverSerialized(); Serializer serializer = new Serializer(); serializedObject = serializer.DeSerializeObject(@"C:\firefoxDriver.qa"); driver = serializedObject.DriverInstance; if (driver == null) { driver = new FirefoxDriver(firefoxProfile); serializedObject.DriverInstance = (FirefoxDriverSerialized)driver; serializer.SerializeObject(@"C:\firefoxDriver.qa", serializedObject); } Here are the two Serializer classes I built: public class Serializer { public Serializer() { } public void SerializeObject(string filename, FirefoxDriverSerialized objectToSerialize) { Stream stream = File.Open(filename, FileMode.Create); BinaryFormatter bFormatter = new BinaryFormatter(); bFormatter.Serialize(stream, objectToSerialize); stream.Close(); } public FirefoxDriverSerialized DeSerializeObject(string filename) { FirefoxDriverSerialized objectToSerialize; Stream stream = File.Open(filename, FileMode.Open); BinaryFormatter bFormatter = new BinaryFormatter(); objectToSerialize = (FirefoxDriverSerialized)bFormatter.Deserialize(stream); stream.Close(); return objectToSerialize; } } [Serializable()] public class FirefoxDriverSerialized : FirefoxDriver, ISerializable { private FirefoxDriver driverInstance; public FirefoxDriver DriverInstance { get { return this.driverInstance; } set { this.driverInstance = value; } } public FirefoxDriverSerialized() { } public FirefoxDriverSerialized(SerializationInfo info, StreamingContext ctxt) { this.driverInstance = (FirefoxDriver)info.GetValue("DriverInstance", typeof(FirefoxDriver)); } public void GetObjectData(SerializationInfo info, StreamingContext ctxt) { info.AddValue("DriverInstance", this.driverInstance); } } ================= 3/23/2012 update #2 - fixed serialization/de-serialization, but having another issue (might be relevant for new question) This fixed the calling code. Because we're deleting the *.qa file when we call the WebDriver.Quit() because that's when we chose to close the browser. This will kill off our cached driver as well. So if we start with a new browser window, we'll hit the catch block and create a new instance and save it to our *.qa file (in the serialized form). FirefoxDriverSerialized serializedObject = new FirefoxDriverSerialized(); Serializer serializer = new Serializer(); try { serializedObject = serializer.DeSerializeObject(@"C:\firefoxDriver.qa"); driver = serializedObject.DriverInstance; } catch { driver = new FirefoxDriver(firefoxProfile); serializedObject = new FirefoxDriverSerialized(); serializedObject.DriverInstance = (FirefoxDriver)driver; serializer.SerializeObject(@"C:\firefoxDriver.qa", serializedObject); } However, still getting this exception: Acu.QA.Main.Test_0055_GiftCertificate_UserCheckout: SetUp : System.Runtime.Serialization.SerializationException : Type 'OpenQA.Selenium.Firefox.FirefoxDriver' in Assembly 'WebDriver, Version=2.16.0.0, Culture=neutral, PublicKeyToken=1c2bd1631853048f' is not marked as serializable. TearDown : System.NullReferenceException : Object reference not set to an instance of an object. The 3rd line in this code block is throwing the exception: public void SerializeObject(string filename, FirefoxDriverSerialized objectToSerialize) { Stream stream = File.Open(filename, FileMode.Create); BinaryFormatter bFormatter = new BinaryFormatter(); bFormatter.Serialize(stream, objectToSerialize); // <=== this line stream.Close(); }

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• VLOOKUP in Excel, part 2: Using VLOOKUP without a database

  - by Mark Virtue

  In a recent article, we introduced the Excel function called VLOOKUP and explained how it could be used to retrieve information from a database into a cell in a local worksheet.  In that article we mentioned that there were two uses for VLOOKUP, and only one of them dealt with querying databases.  In this article, the second and final in the VLOOKUP series, we examine this other, lesser known use for the VLOOKUP function. If you haven’t already done so, please read the first VLOOKUP article – this article will assume that many of the concepts explained in that article are already known to the reader. When working with databases, VLOOKUP is passed a “unique identifier” that serves to identify which data record we wish to find in the database (e.g. a product code or customer ID).  This unique identifier must exist in the database, otherwise VLOOKUP returns us an error.  In this article, we will examine a way of using VLOOKUP where the identifier doesn’t need to exist in the database at all.  It’s almost as if VLOOKUP can adopt a “near enough is good enough” approach to returning the data we’re looking for.  In certain circumstances, this is exactly what we need. We will illustrate this article with a real-world example – that of calculating the commissions that are generated on a set of sales figures.  We will start with a very simple scenario, and then progressively make it more complex, until the only rational solution to the problem is to use VLOOKUP.  The initial scenario in our fictitious company works like this:  If a salesperson creates more than $30,000 worth of sales in a given year, the commission they earn on those sales is 30%.  Otherwise their commission is only 20%.  So far this is a pretty simple worksheet: To use this worksheet, the salesperson enters their sales figures in cell B1, and the formula in cell B2 calculates the correct commission rate they are entitled to receive, which is used in cell B3 to calculate the total commission that the salesperson is owed (which is a simple multiplication of B1 and B2). The cell B2 contains the only interesting part of this worksheet – the formula for deciding which commission rate to use: the one below the threshold of $30,000, or the one above the threshold.  This formula makes use of the Excel function called IF.  For those readers that are not familiar with IF, it works like this: IF(condition,value if true,value if false) Where the condition is an expression that evaluates to either true or false.  In the example above, the condition is the expression B1<B5, which can be read as “Is B1 less than B5?”, or, put another way, “Are the total sales less than the threshold”.  If the answer to this question is “yes” (true), then we use the value if true parameter of the function, namely B6 in this case – the commission rate if the sales total was below the threshold.  If the answer to the question is “no” (false), then we use the value if false parameter of the function, namely B7 in this case – the commission rate if the sales total was above the threshold. As you can see, using a sales total of $20,000 gives us a commission rate of 20% in cell B2.  If we enter a value of $40,000, we get a different commission rate: So our spreadsheet is working. Let’s make it more complex.  Let’s introduce a second threshold:  If the salesperson earns more than $40,000, then their commission rate increases to 40%: Easy enough to understand in the real world, but in cell B2 our formula is getting more complex.  If you look closely at the formula, you’ll see that the third parameter of the original IF function (the value if false) is now an entire IF function in its own right.  This is called a nested function (a function within a function).  It’s perfectly valid in Excel (it even works!), but it’s harder to read and understand. We’re not going to go into the nuts and bolts of how and why this works, nor will we examine the nuances of nested functions.  This is a tutorial on VLOOKUP, not on Excel in general. Anyway, it gets worse!  What about when we decide that if they earn more than $50,000 then they’re entitled to 50% commission, and if they earn more than $60,000 then they’re entitled to 60% commission? Now the formula in cell B2, while correct, has become virtually unreadable.  No-one should have to write formulae where the functions are nested four levels deep!  Surely there must be a simpler way? There certainly is.  VLOOKUP to the rescue! Let’s redesign the worksheet a bit.  We’ll keep all the same figures, but organize it in a new way, a more tabular way: Take a moment and verify for yourself that the new Rate Table works exactly the same as the series of thresholds above. Conceptually, what we’re about to do is use VLOOKUP to look up the salesperson’s sales total (from B1) in the rate table and return to us the corresponding commission rate.  Note that the salesperson may have indeed created sales that are not one of the five values in the rate table ($0, $30,000, $40,000, $50,000 or $60,000).  They may have created sales of $34,988.  It’s important to note that $34,988 does not appear in the rate table.  Let’s see if VLOOKUP can solve our problem anyway… We select cell B2 (the location we want to put our formula), and then insert the VLOOKUP function from the Formulas tab: The Function Arguments box for VLOOKUP appears.  We fill in the arguments (parameters) one by one, starting with the Lookup_value, which is, in this case, the sales total from cell B1.  We place the cursor in the Lookup_value field and then click once on cell B1: Next we need to specify to VLOOKUP what table to lookup this data in.  In this example, it’s the rate table, of course.  We place the cursor in the Table_array field, and then highlight the entire rate table – excluding the headings: Next we must specify which column in the table contains the information we want our formula to return to us.  In this case we want the commission rate, which is found in the second column in the table, so we therefore enter a 2 into the Col_index_num field: Finally we enter a value in the Range_lookup field. Important:  It is the use of this field that differentiates the two ways of using VLOOKUP.  To use VLOOKUP with a database, this final parameter, Range_lookup, must always be set to FALSE, but with this other use of VLOOKUP, we must either leave it blank or enter a value of TRUE.  When using VLOOKUP, it is vital that you make the correct choice for this final parameter. To be explicit, we will enter a value of true in the Range_lookup field.  It would also be fine to leave it blank, as this is the default value: We have completed all the parameters.  We now click the OK button, and Excel builds our VLOOKUP formula for us: If we experiment with a few different sales total amounts, we can satisfy ourselves that the formula is working. Conclusion In the “database” version of VLOOKUP, where the Range_lookup parameter is FALSE, the value passed in the first parameter (Lookup_value) must be present in the database.  In other words, we’re looking for an exact match. But in this other use of VLOOKUP, we are not necessarily looking for an exact match.  In this case, “near enough is good enough”.  But what do we mean by “near enough”?  Let’s use an example:  When searching for a commission rate on a sales total of $34,988, our VLOOKUP formula will return us a value of 30%, which is the correct answer.  Why did it choose the row in the table containing 30% ?  What, in fact, does “near enough” mean in this case?  Let’s be precise: When Range_lookup is set to TRUE (or omitted), VLOOKUP will look in column 1 and match the highest value that is not greater than the Lookup_value parameter. It’s also important to note that for this system to work, the table must be sorted in ascending order on column 1! If you would like to practice with VLOOKUP, the sample file illustrated in this article can be downloaded from here. Similar Articles Productive Geek Tips Using VLOOKUP in ExcelImport Microsoft Access Data Into ExcelImport an Access Database into ExcelCopy a Group of Cells in Excel 2007 to the Clipboard as an ImageShare Access Data with Excel in Office 2010 TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Quickly Schedule Meetings With NeedtoMeet Share Flickr Photos On Facebook Automatically Are You Blocked On Gtalk? Find out Discover Latest Android Apps On AppBrain The Ultimate Guide For YouTube Lovers Will it Blend? iPad Edition

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• A Closable jQuery Plug-in

  - by Rick Strahl

  In my client side development I deal a lot with content that pops over the main page. Be it data entry ‘windows’ or dialogs or simple pop up notes. In most cases this behavior goes with draggable windows, but sometimes it’s also useful to have closable behavior on static page content that the user can choose to hide or otherwise make invisible or fade out. Here’s a small jQuery plug-in that provides .closable() behavior to most elements by using either an image that is provided or – more appropriately by using a CSS class to define the picture box layout. /* * * Closable * * Makes selected DOM elements closable by making them * invisible when close icon is clicked * * Version 1.01 * @requires jQuery v1.3 or later * * Copyright (c) 2007-2010 Rick Strahl * http://www.west-wind.com/ * * Licensed under the MIT license: * http://www.opensource.org/licenses/mit-license.php Support CSS: .closebox { position: absolute; right: 4px; top: 4px; background-image: url(images/close.gif); background-repeat: no-repeat; width: 14px; height: 14px; cursor: pointer; opacity: 0.60; filter: alpha(opacity="80"); } .closebox:hover { opacity: 0.95; filter: alpha(opacity="100"); } Options: * handle Element to place closebox into (like say a header). Use if main element and closebox container are two different elements. * closeHandler Function called when the close box is clicked. Return true to close the box return false to keep it visible. * cssClass The CSS class to apply to the close box DIV or IMG tag. * imageUrl Allows you to specify an explicit IMG url that displays the close icon. If used bypasses CSS image styling. * fadeOut Optional provide fadeOut speed. Default no fade out occurs */ (function ($) { $.fn.closable = function (options) { var opt = { handle: null, closeHandler: null, cssClass: "closebox", imageUrl: null, fadeOut: null }; $.extend(opt, options); return this.each(function (i) { var el = $(this); var pos = el.css("position"); if (!pos || pos == "static") el.css("position", "relative"); var h = opt.handle ? $(opt.handle).css({ position: "relative" }) : el; var div = opt.imageUrl ? $("<img>").attr("src", opt.imageUrl).css("cursor", "pointer") : $("<div>"); div.addClass(opt.cssClass) .click(function (e) { if (opt.closeHandler) if (!opt.closeHandler.call(this, e)) return; if (opt.fadeOut) $(el).fadeOut(opt.fadeOut); else $(el).hide(); }); if (opt.imageUrl) div.css("background-image", "none"); h.append(div); }); } })(jQuery); The plugin can be applied against any selector that is a container (typically a div tag). The close image or close box is provided typically by way of a CssClass - .closebox by default – which supplies the image as part of the CSS styling. The default styling for the box looks something like this: .closebox { position: absolute; right: 4px; top: 4px; background-image: url(images/close.gif); background-repeat: no-repeat; width: 14px; height: 14px; cursor: pointer; opacity: 0.60; filter: alpha(opacity="80"); } .closebox:hover { opacity: 0.95; filter: alpha(opacity="100"); } Alternately you can also supply an image URL which overrides the background image in the style sheet. I use this plug-in mostly on pop up windows that can be closed, but it’s also quite handy for remove/delete behavior in list displays like this: you can find this sample here to look to play along: http://www.west-wind.com/WestwindWebToolkit/Samples/Ajax/AmazonBooks/BooksAdmin.aspx For closable windows it’s nice to have something reusable because in my client framework there are lots of different kinds of windows that can be created: Draggables, Modal Dialogs, HoverPanels etc. and they all use the client .closable plug-in to provide the closable operation in the same way with a few options. Plug-ins are great for this sort of thing because they can also be aggregated and so different components can pick and choose the behavior they want. The window here is a draggable, that’s closable and has shadow behavior and the server control can simply generate the appropriate plug-ins to apply to the main <div> tag: $().ready(function() { $('#ctl00_MainContent_panEditBook') .closable({ handle: $('#divEditBook_Header') }) .draggable({ dragDelay: 100, handle: '#divEditBook_Header' }) .shadow({ opacity: 0.25, offset: 6 }); }) The window is using the default .closebox style and has its handle set to the header bar (Book Information). The window is just closable to go away so no event handler is applied. Actually I cheated – the actual page’s .closable is a bit more ugly in the sample as it uses an image from a resources file: .closable({ imageUrl: '/WestWindWebToolkit/Samples/WebResource.axd?d=TooLongAndNastyToPrint', handle: $('#divEditBook_Header')}) so you can see how to apply a custom image, which in this case is generated by the server control wrapping the client DragPanel. More interesting maybe is to apply the .closable behavior to list scenarios. For example, each of the individual items in the list display also are .closable using this plug-in. Rather than having to define each item with Html for an image, event handler and link, when the client template is rendered the closable behavior is attached to the list. Here I’m using client-templating and the code that this is done with looks like this: function loadBooks() { showProgress(); // Clear the content $("#divBookListWrapper").empty(); var filter = $("#" + scriptVars.lstFiltersId).val(); Proxy.GetBooks(filter, function(books) { $(books).each(function(i) { updateBook(this); showProgress(true); }); }, onPageError); } function updateBook(book,highlight) { // try to retrieve the single item in the list by tag attribute id var item = $(".bookitem[tag=" +book.Pk +"]"); // grab and evaluate the template var html = parseTemplate(template, book); var newItem = $(html) .attr("tag", book.Pk.toString()) .click(function() { var pk = $(this).attr("tag"); editBook(this, parseInt(pk)); }) .closable({ closeHandler: function(e) { removeBook(this, e); }, imageUrl: "../../images/remove.gif" }); if (item.length > 0) item.after(newItem).remove(); else newItem.appendTo($("#divBookListWrapper")); if (highlight) { newItem .addClass("pulse") .effect("bounce", { distance: 15, times: 3 }, 400); setTimeout(function() { newItem.removeClass("pulse"); }, 1200); } } Here the closable behavior is applied to each of the items along with an event handler, which is nice and easy compared to having to embed the right HTML and click handling into each item in the list individually via markup. Ideally though (and these posts make me realize this often a little late) I probably should set up a custom cssClass to handle the rendering – maybe a CSS class called .removebox that only changes the image from the default box image. This example also hooks up an event handler that is fired in response to the close. In the list I need to know when the remove button is clicked so I can fire of a service call to the server to actually remove the item from the database. The handler code can also return false; to indicate that the window should not be closed optionally. Returning true will close the window. You can find more information about the .closable class behavior and options here: .closable Documentation Plug-ins make Server Control JavaScript much easier I find this plug-in immensely useful especial as part of server control code, because it simplifies the code that has to be generated server side tremendously. This is true of plug-ins in general which make it so much easier to create simple server code that only generates plug-in options, rather than full blocks of JavaScript code.  For example, here’s the relevant code from the DragPanel server control which generates the .closable() behavior: if (this.Closable && !string.IsNullOrEmpty(DragHandleID) ) { string imageUrl = this.CloseBoxImage; if (imageUrl == "WebResource" ) imageUrl = ScriptProxy.GetWebResourceUrl(this, this.GetType(), ControlResources.CLOSE_ICON_RESOURCE); StringBuilder closableOptions = new StringBuilder("imageUrl: '" + imageUrl + "'"); if (!string.IsNullOrEmpty(this.DragHandleID)) closableOptions.Append(",handle: $('#" + this.DragHandleID + "')"); if (!string.IsNullOrEmpty(this.ClientDialogHandler)) closableOptions.Append(",handler: " + this.ClientDialogHandler); if (this.FadeOnClose) closableOptions.Append(",fadeOut: 'slow'"); startupScript.Append(@" .closable({ " + closableOptions + "})"); } The same sort of block is then used for .draggable and .shadow which simply sets options. Compared to the code I used to have in pre-jQuery versions of my JavaScript toolkit this is a walk in the park. In those days there was a bunch of JS generation which was ugly to say the least. I know a lot of folks frown on using server controls, especially the UI is client centric as the example is. However, I do feel that server controls can greatly simplify the process of getting the right behavior attached more easily and with the help of IntelliSense. Often the script markup is easier is especially if you are dealing with complex, multiple plug-in associations that often express more easily with property values on a control. Regardless of whether server controls are your thing or not this plug-in can be useful in many scenarios. Even in simple client-only scenarios using a plug-in with a few simple parameters is nicer and more consistent than creating the HTML markup over and over again. I hope some of you find this even a small bit as useful as I have. Related Links Download jquery.closable West Wind Web Toolkit jQuery Plug-ins © Rick Strahl, West Wind Technologies, 2005-2010Posted in jQuery   ASP.NET  JavaScript  

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• CodePlex Daily Summary for Monday, March 29, 2010

  CodePlex Daily Summary for Monday, March 29, 2010New ProjectsBUtil: Backup toolcfDateTime: A library for conveniant dealing with date and time in code and UI.ComplexNetwork: Complex network is a network (graph) with non-trivial topological features—features that do not occur in simple networks such as lattices or random...Crash, Burn, Learn AI: Crash, Burn, Learn AI is a "social" AI that tries to learn a language. You provide it with words and it tries to speak.DashboardNET: Student project for Database Applications classDawf: Dual Audio Workflow: Dawf (Dual Audio Workflow) is a script for Sony Vegas Pro and PluralEyes. First, use PluralEyes to sync good audio from an external recorder (for ...EFDataPager: The EFDataPager is an Web User Control that provides Entity Framework data paging. This control enables your ListView, Datagrid or other data pres...GALOAP: GALOAP is a web framework for developing games with a purpose (or GWAP). A GWAP is a game played on a computer that serves some purpose for the peo...Modular CSharp Web Server: The Modular CSharp Web Server Is a small web server core that modules can be build to expand it.NHibernate Membership Provider: The NHMemberProvider is a complete .Net Membership Provider developed in C# and utilizing NHibernate for data persistence. NTP-VoIP Chat: NTP-VoIP chat is a sample VoIP based chat client (and server) developed for academic purposes at the Faculty of Electrical Engineering in Sarajevo....SharePoint Labs: SPLabs is a set of labs, either VB.NET or C#, focused on SharePoint technologies. Each lab is in itself a tutorial to learn a specific area of Shar...SharePoint Navigation Menu: Have a Web App with multiple site collections and need a common navigation menu? How about a SP Web Part that gives a consistent, easy to use, cen...Smebedor — greatest e-shop in the world: Smebedor - greatest e-shop in the worldStarksoft FTP and FTPS C# Client Library: Free, open source and easy to use .NET 2.0+ / Mono 2.x Component for connecting to FTP servers. Explicit and implicit SSL and TLS connections, dat...Sweet Office: The so Sweet Office built on the so sweet Silverlight.World Map WebPart: Display a world map and points several locations configured in the web part properties. The map is based on Google Maps and Live Maps.New ReleasesActivate Your Glutes: v1.0.2.0: An admin section has been added to the site and the log4net framework has been integrated. Minor tweak to registration to present a better date pic...ArkSwitch: ArkSwitch v1.1.4: Bugfix release, mainly for the new process mode.BatterySaver: Version 0.3: ChangeLog Add support for power change events in standby/hibernate (Issue) Add support for multiple configuration profiles (Issue) Added XSD for co...BUtil: BUtil 4.7: The initial releasecfDateTime: cfDateTime 0.1.1.3: This is the first public release of cfDateTime. Supported Features are: Base-implementation of the DateTimeSpan-type which is the logic-holder Im...Crash, Burn, Learn AI: Crash, Burn, Learn v0.1 Alpha: The first version of the AI. Got basic functionality but not everything works as it should so you're very welcome to test :)CycleMania Starter Kit EAP - ASP.NET 4 Problem - Design - Solution: Cyclemania 0.08.43: See Source Code tab for recent change history.Dawf: Dual Audio Workflow: Beta: Beta for DawfeCommerce by Onex Community Edition: Installer of eCommerce by Onex Community 1.0: Installer of eCommerce by Onex Community 1.0 Last changes: Added integration with Paypal Corrected of adding photos and attachments to products ...Encrypted Notes: Encrypted Notes 1.6.1: This is the latest version of Encrypted Notes (1.6.1), with bug fixes (mainly One-Time Pad). It has an installer - it will create a directory 'CPas...ExtAspNet: ExtAspNet v2.2.1: ExtAspNet v2.2.1 ExtAspNet is a set of professional Asp.net controls with native AJAX support and rich UI effect which aim at No JavaScript, No C...Load Test User Mock Toolkits: Open.LoadTest.User.Mock.Toolkits 1.0: 此版本为非正式版本，未对性能方面进行优化。而且框架正在重构调整中。miniTodo: mini Todo version 0.1: 超簡易TodoアプリMsmqJava: MsmqJava v1.2: MsmqJava v1.2 is an update of the Java/JNI wrapper for MSMQ. It is currently at v1.2.1.2. Last updated 28 March 2010. This version includes: ...N2 CMS: 2.0 beta2: Major Changes 2.0b-2.0b2 bugfixes prettified home interface analytics part icons for file types Major Changes 1.5-2.0b ASP.NET MVC 2 templat...New York Times Silverlight Kit: Version 1.0 for Windows Phone 7 Series: New York Times Silverlight Kit for Windows Phone 7 Series Release NotesDoes not include Articles or TimesTag APIsNHibernate Membership Provider: NHibernate Membership Provider 0.9b: This is the initial source code release of NHibernateProvider. I'm putting this up in beta for now, although it is currently being used in one of ...PowerShell ISE-Cream: PSISECream 0.1: So far, you must have downloaded the source code from this project and used the individual modules or scripts for different ISE addons. This projec...Prolog.NET: Prolog.NET 1.0 Beta 2: Installer includes: primary Prolog.NET assembly Prolog.NET Workbench Prolog.NET Scheduler sample application PrologTest console applicati...QuickStart Engine (3D Game Engine for XNA): QuickStart Engine v0.21: Main FeaturesClean engine architecture Makes it easy to make your own game using the engine. Messaging system allows you to communicate between s...S3Appender (Appender for Log4Net that Uses Amazon S3 For Storing Log Files): Stable Release 0.5: Download directly from source code http://s3appender.codeplex.com/SourceControl/changeset/view/43435SharePoint Labs: SPLab5001A-FRA-Level100: SPLab5001A-FRA-Level100 This SharePoint Lab will teach you how to increase your knowledge and use of CAML within Visual Studio. Lab Language : Fren...SharePoint Navigation Menu: spNavigationMenu 1.0: Inital release.Sweet Office: Simple drawing 0.0.1: A Visio-like simple drawing tool was built. Sweet Office is a Office-like tool set running on Silverlight.Switch Checker: v1.0.0.4 - Improved functionality: Added features: Add edit and delete options to right click switch list. Allow delete multiple switches from edit switches form. Allow copy MAC ...System.Common: System.Common Library: First release of System.Common.dlTeam 12 - Team FTW - Software Project: Quadrisauce Alpha Release: This is the first release of Quadrisauce!Visual Studio DSite: Math Wiz Quiz (Visual Basic 2008): A simple math quiz program, that test your knowledge of addition, subtraction and multiplication. This quiz is aimed for elementary kids, but you ...World Map WebPart: World Map Web Part v1.0: Display a world map and points several locations configured in the web part properties. The web part is using either Google Maps or Live Maps depen...WPF Dialogs: Version 0.2.0: 4 New Dialogs: NewFolderDialog / NewFolderDialog - Deutsch DeleteDialog / DeleteDialog - Deutsch] SaveDialog / SaveDialog- Deutsch RenamerDia...WPF Dialogs: Version 0.2.0 for .Net 3.5: The same new features like in the .Net 4 version Version 0.2.0ニコ生タイピング: Niconama Typing Ver. 10-03-28: ランキング 同順位の表示方法を変更 ランキング表示にスクロールバーを追加 切断ボタンを追加 スピードを5倍まで選択できるように変更 ニコ生の仕様変更に対応（運営コメント） デバッグ部分UI変更 NGワードを含む名前は登録できないように変更（含む場合、「名無し（NGコメ）...Most Popular ProjectsRawrWBFS ManagerASP.NET Ajax LibraryMicrosoft SQL Server Product Samples: DatabaseSilverlight ToolkitAJAX Control ToolkitLiveUpload to FacebookWindows Presentation Foundation (WPF)ASP.NETMicrosoft SQL Server Community & SamplesMost Active ProjectsRawrjQuery Library for SharePoint Web ServicesManaged Extensibility FrameworkLINQ to TwitterMicrosoft Biology FoundationBlogEngine.NETpatterns & practices: Composite WPF and SilverlightFarseer Physics EngineTable2ClassNB_Store - Free DotNetNuke Ecommerce Catalog Module

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• SQL SERVER – Weekly Series – Memory Lane – #003

  - by pinaldave

  Here is the list of curetted articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 This was the first year of my blogging and lots of new things I was learning as I go. I was indeed an infant in blogging a few years ago. However, as time passed by I have learned a lot. This year was year of experiments and new learning. 2007 Working as a full time DBA I often encoutered various errors and I started to learn how to avoid those error and document the same. ERROR Msg 5174 Each file size must be greater than or equal to 512 KB Whenever I see this error I wonder why someone is trying to attempt a database which is extremely small. Anyway, it does not matter what I think I keep on seeing this error often in industries. Anyway the solution of the error is equally interesting – just created larger database. Dilbert Humor This was very first encounter with database humor and I started to love it. It does not matter how many time we read this cartoon it does not get old. Generate Script with Data from Database – Database Publishing Wizard Generating schema script with data is one of the most frequently performed tasks among SQL Server Data Professionals. There are many ways to do the same. In the above article I demonstrated that how we can use the Database Publishing Wizard to accomplish the same. It was new to me at that time but I have not seen much of the adoption of the same still in the industry. Here is one of my videos where I demonstrate how we can generate data with schema. 2008 Delete Backup History – Cleanup Backup History Deleting backup history is important too but should be done carefully. If this is not carried out at regular interval there is good chance that MSDB will be filled up with all the old history. Every organization is different. Some would like to keep the history for 30 days and some for a year but there should be some limit. One should regularly archive the database backup history. South Asia MVP Open Days 2008 This was my very first year Microsoft MVP. I had Indeed big blast at the event and the fun was incredible. After this event I have attended many different MVP events but the fun and learning this particular event presented was amazing and just like me many others are not able to forget the same. Here are other links related to the event: South Asia MVP Open Day 2008 – Goa South Asia MVP Open Day 2008 – Goa – Day 1 South Asia MVP Open Day 2008 – Goa – Day 2 South Asia MVP Open Day 2008 – Goa – Day 3 2009 Enable or Disable Constraint  This is very simple script but I personally keep on forgetting it so I had blogged it. Till today, I keep on referencing this again and again as sometime a very little thing is hard to remember. Policy Based Management – Create, Evaluate and Fix Policies This article will cover the most spectacular feature of SQL 2008 – Policy-based management and how the configuration of SQL Server with policy-based management architecture can make a powerful difference. Policy based management is loaded with several advantages. It can help you implement various policies for reliable configuration of the system. It also provides additional administrative assistance to DBAs and helps them effortlessly manage various tasks of SQL Server across the enterprise. SQLPASS 2009 – My Very First SQPASS Experience Just Brilliant! I never had an experience such a thing in my life. SQL SQL and SQL – all around SQL! I am listing my own reasons here in order of importance to me. Networking with SQL fellows and experts Putting face to the name or avatar Learning and improving my SQL skills Understanding the structure of the largest SQL Server Professional Association Attending my favorite training sessions Since last time I have never missed a single time this event. This event is my favorite event and something keeps me going. Here are additional post related SQLPASS 2009. SQL PASS Summit, Seattle 2009 – Day 1 SQL PASS Summit, Seattle 2009 – Day 2 SQL PASS Summit, Seattle 2009 – Day 3 SQL PASS Summit, Seattle 2009 – Day 4 2010 Get All the Information of Database using sys.databases Even though we believe that we know everything about our database, we do not know a lot of things about our database. This little script enables us to know so many details about databases which we may not be familiar with. Run this on your server today and see how much you know your database. Reducing CXPACKET Wait Stats for High Transactional Database While engaging in a performance tuning consultation for a client, a situation occurred where they were facing a lot of CXPACKET Waits Stats. The client asked me if I could help them reduce this huge number of wait stats. I usually receive this kind of request from other client as well, but the important thing to understand is whether this question has any merits or benefits, or not. I discusses the same in this article – a bit long but insightful for sure. Error related to Database in Use There are so many database management operations in SQL Server which requires exclusive access to the database and it is not always possible to get it. When any database is online in SQL Server it either applications or system thread often accesses them. This means database can’t have exclusive access and the operations which required this access throws an error. There is very easy method to overcome this minor issue – a single line script can give you exclusive access to the database. Difference between DATETIME and DATETIME2 Developers have found the root reason of the problem when dealing with Date Functions – when data time values are converted (implicit or explicit) between different data types, which would lose some precision, so the result cannot match each other as expected. In this blog post I go over very interesting details and difference between DATETIME and DATETIME2 History of SQL Server Database Encryption I recently met Michael Coles and Rodeney Landrum the author of one of the kind book Expert SQL Server 2008 Encryption at SQLPASS in Seattle. During the conversation we ended up how Microsoft is evolving encryption technology. The same discussion lead to talking about history of encryption tools in SQL Server. Michale pointed me to page 18 of his book of encryption. He explicitly gave me permission to re-produce relevant part of history from his book. 2011 Functions FIRST_VALUE and LAST_VALUE with OVER clause and ORDER BY Some time an interesting feature and smart audience make a total difference in places. From last two days, I have been writing on SQL Server 2012 feature FIRST_VALUE and LAST_VALUE. I created a puzzle which was very interesting and got many people attempt to resolve it. It was based on following two articles: Introduction to FIRST_VALUE and LAST_VALUE Introduction to FIRST_VALUE and LAST_VALUE with OVER clause I even provided the hint about how one can solve this problem. The best part was many people solved the problem without using hints! Try your luck!  A Real Story of Book Getting ‘Out of Stock’ to A 25% Discount Story Available This is a great problem and everybody would love to have it. We had it and we loved it. Our book got out of stock in 48 hours of releasing and stocks were empty. We faced many issues and learned many valuable lessons. Some we were able to avoid in the future and some we are still facing it as those problems have no solutions. However, since that day – our books never gone out of stock. This inspiring learning story for us and I am confident that you will love to read it as well. Introduction to LEAD and LAG – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function LEAD() and LAG(). This function accesses data from a subsequent row (for lead) and previous row (for lag) in the same result set without the use of a self-join . It will be very difficult to explain this in words so I will attempt small example to explain you this function. I had a fantastic time writing this blog post and I am very confident when you read it, you will like the same. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Monitoring SQL Server Agent job run times

  - by okeofs

  Introduction A few months back, I was asked how long a particular nightly process took to run. It was a super question and the one thing that struck me was that there were a plethora of factors affecting the processing time. This said, I developed a query to ascertain process run times, the average nightly run times and applied some KPI’s to the end query. The end goal being to enable me to quickly detect anomalies and processes that are running beyond their normal times. As many of you are aware, most of the necessary data for this type of query, lies within the MSDB database. The core portion of the query is shown below.select sj.name,sh.run_date, sh.run_duration, case when len(sh.run_duration) = 6 then convert(varchar(8),sh.run_duration) when len(sh.run_duration) = 5 then '0' + convert(varchar(8),sh.run_duration) when len(sh.run_duration) = 4 then '00' + convert(varchar(8),sh.run_duration) when len(sh.run_duration) = 3 then '000' + convert(varchar(8),sh.run_duration) when len(sh.run_duration) = 2 then '0000' + convert(varchar(8),sh.run_duration) when len(sh.run_duration) = 1 then '00000' + convert(varchar(8),sh.run_duration) end as tt from dbo.sysjobs sj with (nolock) inner join dbo.sysjobHistory sh with (nolock) on sj.job_id = sh.job_id where sj.name = 'My Agent Job' and [sh.Message] like '%The job%') Run_date and run_duration are obvious fields. The field ‘Name’ is the name of the job that we wish to follow. The only major challenge was that the format of the run duration which was not as ‘user friendly’ as I would have liked. As an example, the run duration 1 hour 10 minutes and 3 seconds would be displayed as 11003; whereas I wanted it to display this in a more user friendly manner as 01:10:03. In order to achieve this effect, we need to add leading zeros to the run_duration based upon the case logic shown above. At this point what we need to do add colons between the hours and minutes and one between the minutes and seconds. To achieve this I nested the query shown above (in purple) within a ‘super’ query. Thus the run time ([Run Time]) is constructed concatenating a series of substrings (See below in Blue). select run_date,substring(convert(varchar(20),tt),1,2) + ':' +substring(convert(varchar(20),tt),3,2) + ':' +substring(convert(varchar(20),tt),5,2) as [run_time] from (select sj.name,sh.run_date, sh.run_duration,case when len(sh.run_duration) = 6 then convert(varchar(8),sh.run_duration)when len(sh.run_duration) = 5 then '0' + convert(varchar(8),sh.run_duration)when len(sh.run_duration) = 4 then '00' + convert(varchar(8),sh.run_duration)when len(sh.run_duration) = 3 then '000' + convert(varchar(8),sh.run_duration)when len(sh.run_duration) = 2 then '0000' + convert(varchar(8),sh.run_duration)when len(sh.run_duration) = 1 then '00000' + convert(varchar(8),sh.run_duration)end as ttfrom dbo.sysjobs sj with (nolock)inner join dbo.sysjobHistory sh with (nolock) on sj.job_id = sh.job_id where sj.name = 'My Agent Job'and [sh.Message] like '%The job%') a Now that I had each nightly run time in hours, minutes and seconds (01:10:03), I decided that it would very productive to calculate a rolling run time average. To do this, I decided to do the calculations in base units of seconds. This said, I encapsulated the query shown above into a further ‘super’ query (see the code in RED below). This encapsulation is shown below. The astute reader will note that I used implied casting from integer to string, which is not the best method to use however it works. This said and if I were constructing the query again I would definitely do an explicit convert. To Recap: I now have a key field of ‘1’, each and every applicable run date and the total number of SECONDS that the process ran for each run date, all of this data within the #rawdata1 temporary table. Select 1 as keyy,run_date,(substring(b.run_time,1,2)*3600) + (substring(b.run_time,4,2)*60) + (substring(b.run_time,7,2)) as run_time_in_Seconds,run_time into #rawdata1 from ( select run_date,substring(convert(varchar(20),tt),1,2) + ':' + substring(convert(varchar(20),tt),3,2) + ':' +substring(convert(varchar(20),tt),5,2) as [run_time] from (select sj.name,sh.run_date, sh.run_duration, case when len(sh.run_duration) = 6 then convert(varchar(8),sh.run_duration)when len(sh.run_duration) = 5 then '0' + convert(varchar(8),sh.run_duration)when len(sh.run_duration) = 4 then '00' + convert(varchar(8),sh.run_duration)when len(sh.run_duration)    = 3 then '000' + convert(varchar(8),sh.run_duration)when len(sh.run_duration)    = 2 then '0000' + convert(varchar(8),sh.run_duration)when len(sh.run_duration) = 1 then '00000' + convert(varchar(8),sh.run_duration)end as ttfrom dbo.sysjobs sj with (nolock)inner join dbo.sysjobHistory sh with (nolock)on sj.job_id = sh.job_id where sj.name = 'My Agent Job'and [sh.Message] like '%The job%') a )b   Calculating the average run time We now select each run time in seconds from #rawdata1 and place the values into another temporary table called #rawdata2. Once again we create a ‘key’, a hardwired ‘1’. select 1 as Keyy, run_time_in_Seconds into #rawdata2 from #rawdata1The purpose of doing so is to make the average time AVG() available to the query immediately without having to do adverse grouping. Applying KPI Logic At this point, we shall apply some logic to determine whether processing times are within the norms. We do this by applying colour names. Obviously, this example is a super one for SSRS and traffic light icons.select rd1.run_date, rd1.run_time, rd1.run_time_in_Seconds ,Avg(rd2.run_time_in_Seconds) as Average_run_time_in_seconds,casewhenConvert(decimal(10,1),rd1.run_time_in_Seconds)/Avg(rd2.run_time_in_Seconds)<= 1.2 then 'Green' when Convert(decimal(10,1),rd1.run_time_in_Seconds)/Avg(rd2.run_time_in_Seconds)< 1.4 then 'Yellow' else 'Red'end as [color], Calculating the Average Run Time in Hours Minutes and Seconds and the end of the query. casewhen len(convert(varchar(2),Avg(rd2.run_time_in_Seconds)/(3600))) = 1 then '0' + convert(varchar(2),Avg(rd2.run_time_in_Seconds)/(3600))else convert(varchar(2),Avg(rd2.run_time_in_Seconds)/(3600))end + ':' + case when len(convert(varchar(2),Avg(rd2.run_time_in_Seconds)%(3600)/60)) = 1 then '0' + convert(varchar(2),Avg(rd2.run_time_in_Seconds)%(3600)/60)else convert(varchar(2),Avg(rd2.run_time_in_Seconds)%(3600)/60)end + ':' + case when len(convert(varchar(2),Avg(rd2.run_time_in_Seconds)%60)) = 1 then '0' + convert(varchar(2),Avg(rd2.run_time_in_Seconds)%60)else convert(varchar(2),Avg(rd2.run_time_in_Seconds)%60)end as [Average Run Time HH:MM:SS] from #rawdata2 rd2 innerjoin #rawdata1 rd1on rd1.keyy = rd2.keyygroup by run_date,rd1.run_time ,rd1.run_time_in_Seconds order by run_date descThe complete code example use msdbgo/*drop table #rawdata1drop table #rawdata2go*/select 1 as keyy,run_date,(substring(b.run_time,1,2)*3600) + (substring(b.run_time,4,2)*60) + (substring(b.run_time,7,2)) as run_time_in_Seconds,run_time into #rawdata1 from (select run_date,substring(convert(varchar(20),tt),1,2) + ':' +substring(convert(varchar(20),tt),3,2) + ':' +substring(convert(varchar(20),tt),5,2) as [run_time] from (select name,run_date, run_duration, casewhenlen(run_duration) = 6 then convert(varchar(8),run_duration)whenlen(run_duration) = 5 then '0' + convert(varchar(8),run_duration)whenlen(run_duration) = 4 then '00' + convert(varchar(8),run_duration)whenlen(run_duration) = 3 then '000' + convert(varchar(8),run_duration)whenlen(run_duration) = 2 then '0000' + convert(varchar(8),run_duration)whenlen(run_duration) = 1 then '00000' + convert(varchar(8),run_duration)end as ttfrom dbo.sysjobs sj with (nolock)innerjoin dbo.sysjobHistory sh with (nolock) on sj.job_id = sh.job_id where name = 'My Agent Job'and [Message] like '%The job%') a ) bselect 1 as Keyy, run_time_in_Seconds into #rawdata2 from #rawdata1select rd1.run_date, rd1.run_time, rd1.run_time_in_Seconds ,Avg(rd2.run_time_in_Seconds) as Average_run_time_in_seconds,casewhenConvert(decimal(10,1),rd1.run_time_in_Seconds)/Avg(rd2.run_time_in_Seconds)<= 1.2 then 'Green' when Convert(decimal(10,1),rd1.run_time_in_Seconds)/Avg(rd2.run_time_in_Seconds)< 1.4 then 'Yellow' else 'Red'end as [color],Case when len(convert(varchar(2),Avg(rd2.run_time_in_Seconds)/(3600))) = 1 then '0' + convert(varchar(2),Avg(rd2.run_time_in_Seconds)/(3600))else convert(varchar(2),Avg(rd2.run_time_in_Seconds)/(3600))end + ':' + case when len(convert(varchar(2),Avg(rd2.run_time_in_Seconds)%(3600)/60)) = 1 then '0' + convert(varchar(2),Avg(rd2.run_time_in_Seconds)%(3600)/60)else convert(varchar(2),Avg(rd2.run_time_in_Seconds)%(3600)/60)end + ':' + case when len(convert(varchar(2),Avg(rd2.run_time_in_Seconds)%60)) = 1 then '0' + convert(varchar(2),Avg(rd2.run_time_in_Seconds)%60)else convert(varchar(2),Avg(rd2.run_time_in_Seconds)%60)end as [Average Run Time HH:MM:SS] from #rawdata2 rd2 innerjoin #rawdata1 rd1on rd1.keyy = rd2.keyygroup by run_date,rd1.run_time ,rd1.run_time_in_Seconds order by run_date desc  

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• Need help with BOOST_FOREACH/compiler bug

  - by Jacek Lawrynowicz

  I know that boost or compiler should be last to blame, but I can't see another explanation here. I'm using msvc 2008 SP1 and boost 1.43. In the following code snippet execution never leaves third BOOST_FOREACH loop typedef Graph<unsigned, unsigned>::VertexIterator Iter; Graph<unsigned, unsigned> g; g.createVertex(0x66); // works fine Iter it = g.getVertices().first, end = g.getVertices().second; for(; it != end; ++it) ; // fine std::pair<Iter, Iter> p = g.getVertices(); BOOST_FOREACH(unsigned handle, p) ; // fine unsigned vertex_count = 0; BOOST_FOREACH(unsigned handle, g.getVertices()) vertex_count++; // oops, infinite loop vertex_count = 0; BOOST_FOREACH(unsigned handle, g.getVertices()) vertex_count++; vertex_count = 0; BOOST_FOREACH(unsigned handle, g.getVertices()) vertex_count++; // ... last block repeated 7 times Iterator code: class Iterator : public boost::iterator_facade<Iterator, unsigned const, boost::bidirectional_traversal_tag> { public: Iterator() : list(NULL), handle(INVALID_ELEMENT_HANDLE) {} explicit Iterator(const VectorElementsList &list, unsigned handle = INVALID_ELEMENT_HANDLE) : list(&list), handle(handle) {} friend std::ostream& operator<<(std::ostream &s, const Iterator &it) { s << "[list: " << it.list <<", handle: " << it.handle << "]"; return s; } private: friend class boost::iterator_core_access; void increment() { handle = list->getNext(handle); } void decrement() { handle = list->getPrev(handle); } unsigned const& dereference() const { return handle; } bool equal(Iterator const& other) const { return handle == other.handle && list == other.list; } const VectorElementsList<T> *list; unsigned handle; }; Some ASM fun: vertex_count = 0; BOOST_FOREACH(unsigned handle, g.getVertices()) // initialization 013E1369 mov edi,dword ptr [___defaultmatherr+8 (13E5034h)] // end iterator handle: 0xFFFFFFFF 013E136F mov ebp,dword ptr [esp+0ACh] // begin iterator handle: 0x0 013E1376 lea esi,[esp+0A8h] // begin iterator list pointer 013E137D mov ebx,esi 013E137F nop // forever loop begin 013E1380 cmp ebp,edi 013E1382 jne main+238h (13E1388h) 013E1384 cmp ebx,esi 013E1386 je main+244h (13E1394h) 013E1388 lea eax,[esp+18h] 013E138C push eax // here iterator is incremented in ram 013E138D call boost::iterator_facade<detail::VectorElementsList<Graph<unsigned int,unsigned int>::VertexWrapper>::Iterator,unsigned int const ,boost::bidirectional_traversal_tag,unsigned int const &,int>::operator++ (13E18E0h) 013E1392 jmp main+230h (13E1380h) vertex_count++; // forever loop end It's easy to see that iterator handle is cached in EBP and it never gets incremented despite of a call to iterator operator++() function. I've replaced Itarator implmentation with one deriving from std::iterator and the issue persisted, so this is not iterator_facade fault. This problem exists only on msvc 2008 SP1 x86 and amd64 release builds. Debug builds on msvc 2008 and debug/release builds on msvc 2010 and gcc 4.4 (linux) works fine. Furthermore the BOOST_FOREACH block must be repeaded exacly 10 times. If it's repeaded 9 times, it's all OK. I guess that due to BOOST_FOREACH use of template trickery (const auto_any), compiler assumes that iterator handle is constant and never reads its real value again. I would be very happy to hear that my code is wrong, correct it and move on with BOOST_FOREACH, which I'm very found of (as opposed to BOOST_FOREVER :). May be related to: http://stackoverflow.com/questions/1275852/why-does-boost-foreach-not-work-sometimes-with-c-strings

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• Set-Cookie Headers getting stripped in ASP.NET HttpHandlers

  - by Rick Strahl

  Yikes, I ran into a real bummer of an edge case yesterday in one of my older low level handler implementations (for West Wind Web Connection in this case). Basically this handler is a connector for a backend Web framework that creates self contained HTTP output. An ASP.NET Handler captures the full output, and then shoves the result down the ASP.NET Response object pipeline writing out the content into the Response.OutputStream and seperately sending the HttpHeaders in the Response.Headers collection. The headers turned out to be the problem and specifically Http Cookies, which for some reason ended up getting stripped out in some scenarios. My handler works like this: Basically the HTTP response from the backend app would return a full set of HTTP headers plus the content. The ASP.NET handler would read the headers one at a time and then dump them out via Response.AppendHeader(). But I found that in some situations Set-Cookie headers sent along were simply stripped inside of the Http Handler. After a bunch of back and forth with some folks from Microsoft (thanks Damien and Levi!) I managed to pin this down to a very narrow edge scenario. It's easiest to demonstrate the problem with a simple example HttpHandler implementation. The following simulates the very much simplified output generation process that fails in my handler. Specifically I have a couple of headers including a Set-Cookie header and some output that gets written into the Response object.using System.Web; namespace wwThreads { public class Handler : IHttpHandler { /* NOTE: * * Run as a web.config set handler (see entry below) * * Best way is to look at the HTTP Headers in Fiddler * or Chrome/FireBug/IE tools and look for the * WWHTREADSID cookie in the outgoing Response headers * ( If the cookie is not there you see the problem! ) */ public void ProcessRequest(HttpContext context) { HttpRequest request = context.Request; HttpResponse response = context.Response; // If ClearHeaders is used Set-Cookie header gets removed! // if commented header is sent... response.ClearHeaders(); response.ClearContent(); // Demonstrate that other headers make it response.AppendHeader("RequestId", "asdasdasd"); // This cookie gets removed when ClearHeaders above is called // When ClearHEaders is omitted above the cookie renders response.AppendHeader("Set-Cookie", "WWTHREADSID=ThisIsThEValue; path=/"); // *** This always works, even when explicit // Set-Cookie above fails and ClearHeaders is called //response.Cookies.Add(new HttpCookie("WWTHREADSID", "ThisIsTheValue")); response.Write(@"Output was created.<hr/> Check output with Fiddler or HTTP Proxy to see whether cookie was sent."); } public bool IsReusable { get { return false; } } } } In order to see the problem behavior this code has to be inside of an HttpHandler, and specifically in a handler defined in web.config with: <add name=".ck_handler" path="handler.ck" verb="*" type="wwThreads.Handler" preCondition="integratedMode" /> Note: Oddly enough this problem manifests only when configured through web.config, not in an ASHX handler, nor if you paste that same code into an ASPX page or MVC controller. What's the problem exactly? The code above simulates the more complex code in my live handler that picks up the HTTP response from the backend application and then peels out the headers and sends them one at a time via Response.AppendHeader. One of the headers in my app can be one or more Set-Cookie. I found that the Set-Cookie headers were not making it into the Response headers output. Here's the Chrome Http Inspector trace: Notice, no Set-Cookie header in the Response headers! Now, running the very same request after removing the call to Response.ClearHeaders() command, the cookie header shows up just fine: As you might expect it took a while to track this down. At first I thought my backend was not sending the headers but after closer checks I found that indeed the headers were set in the backend HTTP response, and they were indeed getting set via Response.AppendHeader() in the handler code. Yet, no cookie in the output. In the simulated example the problem is this line:response.AppendHeader("Set-Cookie", "WWTHREADSID=ThisIsThEValue; path=/"); which in my live code is more dynamic ( ie. AppendHeader(token[0],token[1[]) )as it parses through the headers. Bizzaro Land: Response.ClearHeaders() causes Cookie to get stripped Now, here is where it really gets bizarre: The problem occurs only if: Response.ClearHeaders() was called before headers are added It only occurs in Http Handlers declared in web.config Clearly this is an edge of an edge case but of course - knowing my relationship with Mr. Murphy - I ended up running smack into this problem. So in the code above if you remove the call to ClearHeaders(), the cookie gets set!  Add it back in and the cookie is not there. If I run the above code in an ASHX handler it works. If I paste the same code (with a Response.End()) into an ASPX page, or MVC controller it all works. Only in the HttpHandler configured through Web.config does it fail! Cue the Twilight Zone Music. Workarounds As is often the case the fix for this once you know the problem is not too difficult. The difficulty lies in tracking inconsistencies like this down. Luckily there are a few simple workarounds for the Cookie issue. Don't use AppendHeader for Cookies The easiest and obvious solution to this problem is simply not use Response.AppendHeader() to set Cookies. Duh! Under normal circumstances in application level code there's rarely a reason to write out a cookie like this:response.AppendHeader("Set-Cookie", "WWTHREADSID=ThisIsThEValue; path=/"); but rather create the cookie using the Response.Cookies collection:response.Cookies.Add(new HttpCookie("WWTHREADSID", "ThisIsTheValue")); Unfortunately, in my case where I dynamically read headers from the original output and then dynamically  write header key value pairs back  programmatically into the Response.Headers collection, I actually don't look at each header specifically so in my case the cookie is just another header. My first thought was to simply trap for the Set-Cookie header and then parse out the cookie and create a Cookie object instead. But given that cookies can have a lot of different options this is not exactly trivial, plus I don't really want to fuck around with cookie values which can be notoriously brittle. Don't use Response.ClearHeaders() The real mystery in all this is why calling Response.ClearHeaders() prevents a cookie value later written with Response.AppendHeader() to fail. I fired up Reflector and took a quick look at System.Web and HttpResponse.ClearHeaders. There's all sorts of resetting going on but nothing that seems to indicate that headers should be removed later on in the request. The code in ClearHeaders() does access the HttpWorkerRequest, which is the low level interface directly into IIS, and so I suspect it's actually IIS that's stripping the headers and not ASP.NET, but it's hard to know. Somebody from Microsoft and the IIS team would have to comment on that. In my application it's probably safe to simply skip ClearHeaders() in my handler. The ClearHeaders/ClearContent was mainly for safety but after reviewing my code there really should never be a reason that headers would be set prior to this method firing. However, if for whatever reason headers do need to be cleared, it's easy enough to manually clear the headers out:private void RemoveHeaders(HttpResponse response) { List<string> headers = new List<string>(); foreach (string header in response.Headers) { headers.Add(header); } foreach (string header in headers) { response.Headers.Remove(header); } response.Cookies.Clear(); } Now I can replace the call the Response.ClearHeaders() and I don't get the funky side-effects from Response.ClearHeaders(). Summary I realize this is a total edge case as this occurs only in HttpHandlers that are manually configured. It looks like you'll never run into this in any of the higher level ASP.NET frameworks or even in ASHX handlers - only web.config defined handlers - which is really, really odd. After all those frameworks use the same underlying ASP.NET architecture. Hopefully somebody from Microsoft has an idea what crazy dependency was triggered here to make this fail. IAC, there are workarounds to this should you run into it, although I bet when you do run into it, it'll likely take a bit of time to find the problem or even this post in a search because it's not easily to correlate the problem to the solution. It's quite possible that more than cookies are affected by this behavior. Searching for a solution I read a few other accounts where headers like Referer were mysteriously disappearing, and it's possible that something similar is happening in those cases. Again, extreme edge case, but I'm writing this up here as documentation for myself and possibly some others that might have run into this. © Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET   IIS7   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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• List of Commonly Used Value Types in XNA Games

  - by Michael B. McLaughlin

  Most XNA programmers are concerned about generating garbage. More specifically about allocating GC-managed memory (GC stands for “garbage collector” and is both the name of the class that provides access to the garbage collector and an acronym for the garbage collector (as a concept) itself). Two of the major target platforms for XNA (Windows Phone 7 and Xbox 360) use variants of the .NET Compact Framework. On both variants, the GC runs under various circumstances (Windows Phone 7 and Xbox 360). Of concern to XNA programmers is the fact that it runs automatically after a fixed amount of GC-managed memory has been allocated (currently 1MB on both systems). Many beginning XNA programmers are unaware of what constitutes GC-managed memory, though. So here’s a quick overview. In .NET, there are two different “types” of types: value types and reference types. Only reference types are managed by the garbage collector. Value types are not managed by the garbage collector and are instead managed in other ways that are implementation dependent. For purposes of XNA programming, the important point is that they are not managed by the GC and thus do not, by themselves, increment that internal 1 MB allocation counter. (n.b. Structs are value types. If you have a struct that has a reference type as a member, then that reference type, when instantiated, will still be allocated in the GC-managed memory and will thus count against the 1 MB allocation counter. Putting it in a struct doesn’t change the fact that it gets allocated on the GC heap, but the struct itself is created outside of the GC’s purview). Both value types and reference types use the keyword ‘new’ to allocate a new instance of them. Sometimes this keyword is hidden by a method which creates new instances for you, e.g. XmlReader.Create. But the important thing to determine is whether or not you are dealing with a value types or a reference type. If it’s a value type, you can use the ‘new’ keyword to allocate new instances of that type without incrementing the GC allocation counter (except as above where it’s a struct with a reference type in it that is allocated by the constructor, but there are no .NET Framework or XNA Framework value types that do this so it would have to be a struct you created or that was in some third-party library you were using for that to even become an issue). The following is a list of most all of value types you are likely to use in a generic XNA game: AudioCategory (used with XACT; not available on WP7) AvatarExpression (Xbox 360 only, but exposed on Windows to ease Xbox development) bool BoundingBox BoundingSphere byte char Color DateTime decimal double any enum (System.Enum itself is a class, but all enums are value types such that there are no GC allocations for enums) float GamePadButtons GamePadCapabilities GamePadDPad GamePadState GamePadThumbSticks GamePadTriggers GestureSample int IntPtr (rarely but occasionally used in XNA) KeyboardState long Matrix MouseState nullable structs (anytime you see, e.g. int? something, that ‘?’ denotes a nullable struct, also called a nullable type) Plane Point Quaternion Ray Rectangle RenderTargetBinding sbyte (though I’ve never seen it used since most people would just use a short) short TimeSpan TouchCollection TouchLocation TouchPanelCapabilities uint ulong ushort Vector2 Vector3 Vector4 VertexBufferBinding VertexElement VertexPositionColor VertexPositionColorTexture VertexPositionNormalTexture VertexPositionTexture Viewport So there you have it. That’s not quite a complete list, mind you. For example: There are various structs in the .NET framework you might make use of. I left out everything from the Microsoft.Xna.Framework.Graphics.PackedVector namespace, since everything in there ventures into the realm of advanced XNA programming anyway (n.b. every single instantiable thing in that namespace is a struct and thus a value type; there are also two interfaces but interfaces cannot be instantiated at all and thus don’t figure in to this discussion). There are so many enums you’re likely to use (PlayerIndex, SpriteSortMode, SpriteEffects, SurfaceFormat, etc.) that including them would’ve flooded the list and reduced its utility. So I went with “any enum” and trust that you can figure out what the enums are (and it’s rare to use ‘new’ with an enum anyway). That list also doesn’t include any of the pre-defined static instances of some of the classes (e.g. BlendState.AlphaBlend, BlendState.Opaque, etc.) which are already allocated such that using them doesn’t cause any new allocations and therefore doesn’t increase that 1 MB counter. That list also has a few misleading things. VertexElement, VertexPositionColor, and all the other vertex types are structs. But you’re only likely to ever use them as an array (for use with VertexBuffer or DynamicVertexBuffer), and all arrays are reference types (even arrays of value types such as VertexPositionColor[ ] or int[ ]). * So that’s it for now. The note below may be a bit confusing (it deals with how the GC works and how arrays are managed in .NET). If so, you can probably safely ignore it for now but feel free to ask any questions regardless. * Arrays of value types (where the value type doesn’t contain any reference type members) are much faster for the GC to examine than arrays of reference types, so there is a definite benefit to using arrays of value types where it makes sense. But creating arrays of value types does cause the GC’s allocation counter to increase. Indeed, allocating a large array of a value type is one of the quickest ways to increment the allocation counter since a .NET array is a sequential block of memory. An array of reference types is just a sequential block of references (typically 4 bytes each) while an array of value types is a sequential block of instances of that type. So for an array of Vector3s it would be 12 bytes each since each float is 4 bytes and there are 3 in a Vector3; for an array of VertexPositionNormalTexture structs it would typically be 32 bytes each since it has two Vector3s and a Vector2. (Note that there are a few additional bytes taken up in the creation of an array, typically 12 but sometimes 16 or possibly even more, which depend on the implementation details of the array type on the particular platform the code is running on).

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• SQLAlchemy session management in long-running process

  - by codeape

  Scenario: A .NET-based application server (Wonderware IAS/System Platform) hosts automation objects that communicate with various equipment on the factory floor. CPython is hosted inside this application server (using Python for .NET). The automation objects have scripting functionality built-in (using a custom, .NET-based language). These scripts call Python functions. The Python functions are part of a system to track Work-In-Progress on the factory floor. The purpose of the system is to track the produced widgets along the process, ensure that the widgets go through the process in the correct order, and check that certain conditions are met along the process. The widget production history and widget state is stored in a relational database, this is where SQLAlchemy plays its part. For example, when a widget passes a scanner, the automation software triggers the following script (written in the application server's custom scripting language): ' wiget_id and scanner_id provided by automation object ' ExecFunction() takes care of calling a CPython function retval = ExecFunction("WidgetScanned", widget_id, scanner_id); ' if the python function raises an Exception, ErrorOccured will be true ' in this case, any errors should cause the production line to stop. if (retval.ErrorOccured) then ProductionLine.Running = False; InformationBoard.DisplayText = "ERROR: " + retval.Exception.Message; InformationBoard.SoundAlarm = True end if; The script calls the WidgetScanned python function: # pywip/functions.py from pywip.database import session from pywip.model import Widget, WidgetHistoryItem from pywip import validation, StatusMessage from datetime import datetime def WidgetScanned(widget_id, scanner_id): widget = session.query(Widget).get(widget_id) validation.validate_widget_passed_scanner(widget, scanner) # raises exception on error widget.history.append(WidgetHistoryItem(timestamp=datetime.now(), action=u"SCANNED", scanner_id=scanner_id)) widget.last_scanner = scanner_id widget.last_update = datetime.now() return StatusMessage("OK") # ... there are a dozen similar functions My question is: How do I best manage SQLAlchemy sessions in this scenario? The application server is a long-running process, typically running months between restarts. The application server is single-threaded. Currently, I do it the following way: I apply a decorator to the functions I make avaliable to the application server: # pywip/iasfunctions.py from pywip import functions def ias_session_handling(func): def _ias_session_handling(*args, **kwargs): try: retval = func(*args, **kwargs) session.commit() return retval except: session.rollback() raise return _ias_session_handling # ... actually I populate this module with decorated versions of all the functions in pywip.functions dynamically WidgetScanned = ias_session_handling(functions.WidgetScanned) Question: Is the decorator above suitable for handling sessions in a long-running process? Should I call session.remove()? The SQLAlchemy session object is a scoped session: # pywip/database.py from sqlalchemy.orm import scoped_session, sessionmaker session = scoped_session(sessionmaker()) I want to keep the session management out of the basic functions. For two reasons: There is another family of functions, sequence functions. The sequence functions call several of the basic functions. One sequence function should equal one database transaction. I need to be able to use the library from other environments. a) From a TurboGears web application. In that case, session management is done by TurboGears. b) From an IPython shell. In that case, commit/rollback will be explicit. (I am truly sorry for the long question. But I felt I needed to explain the scenario. Perhaps not necessary?)

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• Cross-language Extension Method Calling

  - by Tom Hines

  Extension methods are a concise way of binding functions to particular types. In my last post, I showed how Extension methods can be created in the .NET 2.0 environment. In this post, I discuss calling the extensions from other languages. Most of the differences I find between the Dot Net languages are mainly syntax.  The declaration of Extensions is no exception.  There is, however, a distinct difference with the framework accepting excensions made with C++ that differs from C# and VB.  When calling the C++ extension from C#, the compiler will SOMETIMES say there is no definition for DoCPP with the error: 'string' does not contain a definition for 'DoCPP' and no extension method 'DoCPP' accepting a first argument of type 'string' could be found (are you missing a using directive or an assembly reference?) If I recompile, the error goes away. The strangest problem with calling the C++ extension from C# is that I first must make SOME type of reference to the class BEFORE using the extension or it will not be recognized at all.  So, if I first call the DoCPP() as a static method, the extension works fine later.  If I make a dummy instantiation of the class, it works.  If I have no forward reference of the class, I get the same error as before and recompiling does not fix it.  It seems as if this none of this is supposed to work across the languages. I have made a few work-arounds to get the examples to compile and run. Note the following examples: Extension in C# using System; namespace Extension_CS {    public static class CExtension_CS    {  //in C#, the "this" keyword is the key.       public static void DoCS(this string str)       {          Console.WriteLine("CS\t{0:G}\tCS", str);       }    } } Extension in C++ /****************************************************************************\  * Here is the C++ implementation.  It is the least elegant and most quirky,  * but it works. \****************************************************************************/ #pragma once using namespace System; using namespace System::Runtime::CompilerServices;     //<-Essential // Reference: System.Core.dll //<- Essential namespace Extension_CPP {        public ref class CExtension_CPP        {        public:               [Extension] // or [ExtensionAttribute] /* either works */               static void DoCPP(String^ str)               {                      Console::WriteLine("C++\t{0:G}\tC++", str);               }        }; } Extension in VB ' Here is the VB implementation.  This is not as elegant as the C#, but it's ' functional. Imports System.Runtime.CompilerServices ' Public Module modExtension_VB 'Extension methods can be defined only in modules.    <Extension()> _       Public Sub DoVB(ByVal str As String)       Console.WriteLine("VB" & Chr(9) & "{0:G}" & Chr(9) & "VB", str)    End Sub End Module   Calling program in C# /******************************************************************************\  * Main calling program  * Intellisense and VS2008 complain about the CPP implementation, but with a  * little duct-tape, it works just fine. \******************************************************************************/ using System; using Extension_CPP; using Extension_CS; using Extension_VB; // vitual namespace namespace TestExtensions {    public static class CTestExtensions    {       /**********************************************************************\        * For some reason, this needs a direct reference into the C++ version        * even though it does nothing than add a null reference.        * The constructor provides the fake usage to please the compiler.       \**********************************************************************/       private static CExtension_CPP x = null;   // <-DUCT_TAPE!       static CTestExtensions()       {          // Fake usage to stop compiler from complaining          if (null != x) {} // <-DUCT_TAPE       }       static void Main(string[] args)       {          string strData = "from C#";          strData.DoCPP();          strData.DoCS();          strData.DoVB();       }    } }   Calling program in VB  Imports Extension_CPP Imports Extension_CS Imports Extension_VB Imports System.Runtime.CompilerServices Module TestExtensions_VB    <Extension()> _       Public Sub DoCPP(ByVal str As String)       'Framework does not treat this as an extension, so use the static       CExtension_CPP.DoCPP(str)    End Sub    Sub Main()       Dim strData As String = "from VB"       strData.DoCS()       strData.DoVB()       strData.DoCPP() 'fake    End Sub End Module  Calling program in C++ // TestExtensions_CPP.cpp : main project file. #include "stdafx.h" using namespace System; using namespace Extension_CPP; using namespace Extension_CS; using namespace Extension_VB; void main(void) {        /*******************************************************\         * Extension methods are called like static methods         * when called from C++.  There may be a difference in         * syntax when calling the VB extension as VB Extensions         * are embedded in Modules instead of classes        \*******************************************************/     String^ strData = "from C++";     CExtension_CPP::DoCPP(strData);     CExtension_CS::DoCS(strData);     modExtension_VB::DoVB(strData); //since Extensions go in Modules }

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• Get and Set property accessors are ‘actually’ methods

  - by nmarun

  Well, they are ‘special’ methods, but they indeed are methods. See the class below: 1: public class Person 2: { 3: private string _name; 4:  5: public string Name 6: { 7: get 8: { 9: return _name; 10: } 11: set 12: { 13: if (value == "aaa") 14: { 15: throw new ArgumentException("Invalid Name"); 16: } 17: _name = value; 18: } 19: } 20:  21: public void Save() 22: { 23: Console.WriteLine("Saving..."); 24: } 25: } Ok, so a class with a field, a property with the get and set accessors and a method. Now my calling code says: 1: static void Main() 2: { 3: try 4: { 5: Person person1 = new Person 6: { 7: Name = "aaa", 8: }; 9:  10: } 11: catch (Exception ex) 12: { 13: Console.WriteLine(ex.Message); 14: Console.WriteLine(ex.StackTrace); 15: Console.WriteLine("--------------------"); 16: } 17: } When the code is run, you’ll get the following exception message displayed: Now, you see the first line of the stack trace where it says that the exception was thrown in the method set_Name(String value). Wait a minute, we have not declared any method with that name in our Person class. Oh no, we actually have. When you create a property, this is what happens behind the screen. The CLR creates two methods for each get and set property accessor. Let’s look at the signature once again: set_Name(String value) This also tells you where the ‘value’ keyword comes from in our set property accessor. You’re actually wiring up a method parameter to a field. 1: set 2: { 3: if (value == "aaa") 4: { 5: throw new ArgumentException("Invalid Name"); 6: } 7: _name = value; 8: } Digging deeper on this, I ran the ILDasm tool and this is what I see: We see the ‘free’ constructor (named .ctor) that the compiler gives us, the _name field, the Name property and the Save method. We also see the get_Name and set_Name methods. In order to compare the Save and the set_Name methods, I double-clicked on the two methods and this is what I see: The ‘.method’ keyword tells that both Save and set_Name are both methods (no guessing there!). Seeing the set_Name method as a public method did kinda surprise me. So I said, why can’t I do a person1.set_Name(“abc”) since it is declared as public. This cannot be done because the get_Name and set_Name methods have an extra attribute called ‘specialname’. This attribute is used to identify an IL (Intermediate Language) token that can be treated with special care by the .net language. So the thumb-rule is that any method with the ‘specialname’ attribute cannot be generally called / invoked by the user (a simple test using intellisense proves this). Their functionality is exposed through other ways. In our case, this is done through the property itself. The same concept gets extended to constructors as well making them special methods too. These so-called ‘special’ methods can be identified through reflection. 1: static void ReflectOnPerson() 2: { 3: Type personType = typeof(Person); 4:  5: MethodInfo[] methods = personType.GetMethods(); 6:  7: for (int i = 0; i < methods.Length; i++) 8: { 9: Console.Write("Method: {0}", methods[i].Name); 10: // Determine whether or not each method is a special name. 11: if (methods[i].IsSpecialName) 12: { 13: Console.Write(" has 'SpecialName' attribute"); 14: } 15: Console.WriteLine(); 16: } 17: } Line 11 shows the ‘IsSpecialName’ boolean property. So a method with a ‘specialname’ attribute gets mapped to the IsSpecialName property. The output is displayed as: Wuhuuu! There they are.. our special guests / methods. Verdict: Getting to know the internals… helps!

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• Simple Preferred time control using silverlight 3.

  - by mohanbrij

  Here I am going to show you a simple preferred time control, where you can select the day of the week and the time of the day. This can be used in lots of place where you may need to display the users preferred times. Sample screenshot is attached below. This control is developed using Silverlight 3 and VS2008, I am also attaching the source code with this post. This is a very basic example. You can download and customize if further for your requirement if you want. I am trying to explain in few words how this control works and what are the different ways in which you can customize it further. File: PreferredTimeControl.xaml, in this file I have just hardcoded the controls and their positions which you can see in the screenshot above. In this example, to change the start day of the week and time, you will have to go and change the design in XAML file, its not controlled by your properties or implementation classes. You can also customize it to change the start day of the week, Language, Display format, styles, etc, etc. File: PreferredTimeControl.xaml.cs, In this control using the code below, first I am taking all the checkbox from my form and store it in the Global Variable, which I can use across my page. List<CheckBox> checkBoxList; #region Constructor public PreferredTimeControl() { InitializeComponent(); GetCheckboxes();//Keep all the checkbox in List in the Load itself } #endregion #region Helper Methods private List<CheckBox> GetCheckboxes() { //Get all the CheckBoxes in the Form checkBoxList = new List<CheckBox>(); foreach (UIElement element in LayoutRoot.Children) { if (element.GetType().ToString() == "System.Windows.Controls.CheckBox") { checkBoxList.Add(element as CheckBox); } } return checkBoxList; } Then I am exposing the two methods which you can use in the container form to get and set the values in this controls. /// <summary> /// Set the Availability on the Form, with the Provided Timings /// </summary> /// <param name="selectedTimings">Provided timings comes from the DB in the form 11,12,13....37 /// Where 11 refers to Monday Morning, 12 Tuesday Morning, etc /// Here 1, 2, 3 is for Morning, Afternoon and Evening respectively, and for weekdays /// 1,2,3,4,5,6,7 where 1 is for Monday, Tuesday, Wednesday, Thrusday, Friday, Saturday and Sunday respectively /// So if we want Monday Morning, we can can denote it as 11, similarly for Saturday Evening we can write 36, etc /// </param> public void SetAvailibility(string selectedTimings) { foreach (CheckBox chk in checkBoxList) { chk.IsChecked = false; } if (!String.IsNullOrEmpty(selectedTimings)) { string[] selectedString = selectedTimings.Split(','); foreach (string selected in selectedString) { foreach (CheckBox chk in checkBoxList) { if (chk.Tag.ToString() == selected) { chk.IsChecked = true; } } } } } /// <summary> /// Gets the Availibility from the selected checkboxes /// </summary> /// <returns>String in the format of 11,12,13...41,42...31,32...37</returns> public string GetAvailibility() { string selectedText = string.Empty; foreach (CheckBox chk in GetCheckboxes()) { if (chk.IsChecked == true) { selectedText = chk.Tag.ToString() + "," + selectedText; } } return selectedText; }   In my example I am using the matrix format for Day and Time, for example Monday=1, Tuesday=2, Wednesday=3, Thursday = 4, Friday = 5, Saturday = 6, Sunday=7. And Morning = 1, Afternoon =2, Evening = 3. So if I want to represent Morning-Monday I will have to represent it as 11, Afternoon-Tuesday as 22, Morning-Wednesday as 13, etc. And in the other way to set the values in the control I am passing the values in the control in the same format as preferredTimeControl.SetAvailibility("11,12,13,16,23,22"); So this will set the checkbox value for Morning-Monday, Morning-Tuesday, Morning-Wednesday, Morning-Saturday, Afternoon of Tuesday and Afternoon of Wednesday. To implement this control, first I have to import this control in xmlns namespace as xmlns:controls="clr-namespace:PreferredTimeControlApp" and finally put in your page wherever you want, <Grid x:Name="LayoutRoot" Style="{StaticResource LayoutRootGridStyle}"> <Border x:Name="ContentBorder" Style="{StaticResource ContentBorderStyle}"> <controls:PreferredTimeControl x:Name="preferredTimeControl"></controls:PreferredTimeControl> </Border> </Grid> And in the code behind you can just include this code: private void InitializeControl() { preferredTimeControl.SetAvailibility("11,12,13,16,23,22"); } And you are ready to go. For more details you can refer to my code attached. I know there can be even simpler and better way to do this. Let me know if any other ideas. Sorry, Guys Still I have used Silverlight 3 and VS2008, as from the system I am uploading this is still not upgraded, but still you can use the same code with Silverlight 4 and VS2010 without any changes. May be just it will ask you to upgrade your project which will take care of rest. Download Source Code.   Thanks ~Brij

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• Preventing multiple repeat selection of synchronized Controls ?

  - by BillW

  The working code sample here synchronizes (single) selection in a TreeView, ListView, and ComboBox via the use of lambda expressions in a dictionary where the Key in the dictionary is a Control, and the Value of each Key is an Action<int. Where I am stuck is that I am getting multiple repetitions of execution of the code that sets the selection in the various controls in a way that's unexpected : it's not recursing : there's no StackOverFlow error happening; but, I would like to figure out why the current strategy for preventing multiple selection of the same controls is not working. Perhaps the real problem here is distinguishing between a selection update triggered by the end-user and a selection update triggered by the code that synchronizes the other controls ? Note: I've been experimenting with using Delegates, and forms of Delegates like Action<T>, to insert executable code in Dictionaries : I "learn best" by posing programming "challenges" to myself, and implementing them, as well as studying, at the same time, the "golden words" of luminaries like Skeet, McDonald, Liberty, Troelsen, Sells, Richter. Note: Appended to this question/code, for "deep background," is a statement of how I used to do things in pre C#3.0 days where it seemed like I did need to use explicit measures to prevent recursion when synchronizing selection. Code : Assume a WinForms standard TreeView, ListView, ComboBox, all with the same identical set of entries (i.e., the TreeView has only root nodes; the ListView, in Details View, has one Column). private Dictionary<Control, Action<int>> ControlToAction = new Dictionary<Control, Action<int>>(); private void Form1_Load(object sender, EventArgs e) { // add the Controls to be synchronized to the Dictionary // with appropriate Action<int> lambda expressions ControlToAction.Add(treeView1, (i => { treeView1.SelectedNode = treeView1.Nodes[i]; })); ControlToAction.Add(listView1, (i => { listView1.Items[i].Selected = true; })); ControlToAction.Add(comboBox1, (i => { comboBox1.SelectedIndex = i; })); } private void synchronizeSelection(int i, Control currentControl) { foreach(Control theControl in ControlToAction.Keys) { // skip the 'current control' if (theControl == currentControl) continue; // for debugging only Console.WriteLine(theControl.Name + " synchronized"); // execute the Action<int> associated with the Control ControlToAction[theControl](i); } } private void treeView1_AfterSelect(object sender, TreeViewEventArgs e) { synchronizeSelection(e.Node.Index, treeView1); } private void listView1_SelectedIndexChanged(object sender, EventArgs e) { // weed out ListView SelectedIndexChanged firing // with SelectedIndices having a Count of #0 if (listView1.SelectedIndices.Count > 0) { synchronizeSelection(listView1.SelectedIndices[0], listView1); } } private void comboBox1_SelectedValueChanged(object sender, EventArgs e) { if (comboBox1.SelectedIndex > -1) { synchronizeSelection(comboBox1.SelectedIndex, comboBox1); } } background : pre C# 3.0 Seems like, back in pre C# 3.0 days, I was always using a boolean flag to prevent recursion when multiple controls were updated. For example, I'd typically have code like this for synchronizing a TreeView and ListView : assuming each Item in the ListView was synchronized with a root-level node of the TreeView via a common index : // assume ListView is in 'Details View,' has a single column, // MultiSelect = false // FullRowSelect = true // HideSelection = false; // assume TreeView // HideSelection = false // FullRowSelect = true // form scoped variable private bool dontRecurse = false; private void treeView1_AfterSelect(object sender, TreeViewEventArgs e) { if(dontRecurse) return; dontRecurse = true; listView1.Items[e.Node.Index].Selected = true; dontRecurse = false; } private void listView1_SelectedIndexChanged(object sender, EventArgs e) { if(dontRecurse) return // weed out ListView SelectedIndexChanged firing // with SelectedIndices having a Count of #0 if (listView1.SelectedIndices.Count > 0) { dontRecurse = true; treeView1.SelectedNode = treeView1.Nodes[listView1.SelectedIndices[0]]; dontRecurse = false; } } Then it seems, somewhere around FrameWork 3~3.5, I could get rid of the code to suppress recursion, and there was was no recursion (at least not when synchronizing a TreeView and a ListView). By that time it had become a "habit" to use a boolean flag to prevent recursion, and that may have had to do with using a certain third party control.

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• ASP.NET MVC 2 / Localization / Dynamic Default Value?

  - by cyberblast

  Hello In an ASP.NET MVC 2 application, i'm having a route like this: routes.MapRoute( "Default", // Route name "{lang}/{controller}/{action}/{id}", // URL with parameters new // Parameter defaults { controller = "Home", action = "Index", lang = "de", id = UrlParameter.Optional }, new { lang = new AllowedValuesRouteConstraint(new string[] { "de", "en", "fr", "it" }, StringComparison.InvariantCultureIgnoreCase) } Now, basically I would like to set the thread's culture according the language passed in. But there is one exception: If the user requests the page for the first time, like calling "http://www.mysite.com" I want to set the initial language if possible to the one "preferred by the browser". How can I distinguish in an early procesing stage (like global.asax), if the default parameter has been set because of the default value or mentioned explicit through the URL? (I would prefer a solution where the request URL is not getting parsed). Is there a way to dynamically provide a default-value for a paramter? Something like a hook? Or where can I override the default value (good application event?). This is the code i'm actually experimenting with: protected void Application_AcquireRequestState(object sender, EventArgs e) { string activeLanguage; string[] validLanguages; string defaultLanguage; string browsersPreferredLanguage; try { HttpContextBase contextBase = new HttpContextWrapper(Context); RouteData activeRoute = RouteTable.Routes.GetRouteData(new HttpContextWrapper(Context)); if (activeRoute == null) { return; } activeLanguage = activeRoute.GetRequiredString("lang"); Route route = (Route)activeRoute.Route; validLanguages = ((AllowedValuesRouteConstraint)route.Constraints["lang"]).AllowedValues; defaultLanguage = route.Defaults["lang"].ToString(); browsersPreferredLanguage = GetBrowsersPreferredLanguage(); //TODO: Better way than parsing the url bool defaultInitialized = contextBase.Request.Url.ToString().IndexOf(string.Format("/{0}/", defaultLanguage), StringComparison.InvariantCultureIgnoreCase) > -1; string languageToActivate = defaultLanguage; if (!defaultInitialized) { if (validLanguages.Contains(browsersPreferredLanguage, StringComparer.InvariantCultureIgnoreCase)) { languageToActivate = browsersPreferredLanguage; } } //TODO: Where and how to overwrtie the default value that it gets passed to the controller? contextBase.RewritePath(contextBase.Request.Path.Replace("/de/", "/en/")); SetLanguage(languageToActivate); } catch (Exception ex) { //TODO: Log Console.WriteLine(ex.Message); } } protected string GetBrowsersPreferredLanguage() { string acceptedLang = string.Empty; if (HttpContext.Current.Request.UserLanguages != null && HttpContext.Current.Request.UserLanguages.Length > 0) { acceptedLang = HttpContext.Current.Request.UserLanguages[0].Substring(0, 2); } return acceptedLang; } protected void SetLanguage(string languageToActivate) { CultureInfo cultureInfo = new CultureInfo(languageToActivate); if (!Thread.CurrentThread.CurrentUICulture.TwoLetterISOLanguageName.Equals(languageToActivate, StringComparison.InvariantCultureIgnoreCase)) { Thread.CurrentThread.CurrentUICulture = cultureInfo; } if (!Thread.CurrentThread.CurrentCulture.TwoLetterISOLanguageName.Equals(languageToActivate, StringComparison.InvariantCultureIgnoreCase)) { Thread.CurrentThread.CurrentCulture = CultureInfo.CreateSpecificCulture(cultureInfo.Name); } } The RouteConstraint to reproduce the sample: public class AllowedValuesRouteConstraint : IRouteConstraint { private string[] _allowedValues; private StringComparison _stringComparism; public string[] AllowedValues { get { return _allowedValues; } } public AllowedValuesRouteConstraint(string[] allowedValues, StringComparison stringComparism) { _allowedValues = allowedValues; _stringComparism = stringComparism; } public AllowedValuesRouteConstraint(string[] allowedValues) { _allowedValues = allowedValues; _stringComparism = StringComparison.InvariantCultureIgnoreCase; } public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection) { if (_allowedValues != null) { return _allowedValues.Any(a => a.Equals(values[parameterName].ToString(), _stringComparism)); } else { return false; } } } Can someone help me out with that problem? Thanks, Martin

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• Monitoring your WCF Web Apis with AppFabric

  - by cibrax

  The other day, Ron Jacobs made public a template in the Visual Studio Gallery for enabling monitoring capabilities to any existing WCF Http service hosted in Windows AppFabric. I thought it would be a cool idea to reuse some of that for doing the same thing on the new WCF Web Http stack. Windows AppFabric provides a dashboard that you can use to dig into some metrics about the services usage, such as number of calls, errors or information about different events during a service call. Those events not only include information about the WCF pipeline, but also custom events that any developer can inject and make sense for troubleshooting issues.      This monitoring capabilities can be enabled on any specific IIS virtual directory by using the AppFabric configuration tool or adding the following configuration sections to your existing web app, <system.serviceModel> <serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true" /> <diagnostics etwProviderId="3e99c707-3503-4f33-a62d-2289dfa40d41"> <endToEndTracing propagateActivity="true" messageFlowTracing="true" /> </diagnostics> <behaviors> <serviceBehaviors> <behavior name=""> <etwTracking profileName="EndToEndMonitoring Tracking Profile" /> </behavior> </serviceBehaviors> </behaviors> </system.serviceModel>   <microsoft.applicationServer> <monitoring> <default enabled="true" connectionStringName="ApplicationServerMonitoringConnectionString" monitoringLevel="EndToEndMonitoring" /> </monitoring> </microsoft.applicationServer> Bad news is that none of the configuration above can be easily set on code by using the new configuration model for WCF Web stack.  A good thing is that you easily disable it in the configuration when you no longer need it, and also uses ETW, a general-purpose and high-speed tracing facility provided by the operating system (it’s part of the windows kernel). By adding that configuration section, AppFabric will start monitoring your service automatically and providing some basic event information about the service calls. You need some custom code for injecting custom events in the monitoring data. What I did here is to copy and refactor the “WCFUserEventProvider” class provided as sample in the Ron’s template to make it more TDD friendly when using IoC. I created a simple interface “ILogger” that any service (or resource) can use to inject custom events or monitoring information in the AppFabric database. public interface ILogger { bool WriteError(string name, string format, params object[] args); bool WriteWarning(string name, string format, params object[] args); bool WriteInformation(string name, string format, params object[] args); } The “WCFUserEventProvider” class implements this interface by making possible to send the events to the AppFabric monitoring database. The service or resource implementation can receive an “ILogger” as part of the constructor. [ServiceContract] [Export] public class OrderResource { IOrderRepository repository; ILogger logger;   [ImportingConstructor] public OrderResource(IOrderRepository repository, ILogger logger) { this.repository = repository; this.logger = logger; }   [WebGet(UriTemplate = "{id}")] public Order Get(string id, HttpResponseMessage response) { var order = this.repository.All.FirstOrDefault(o => o.OrderId == int.Parse(id, CultureInfo.InvariantCulture)); if (order == null) { response.StatusCode = HttpStatusCode.NotFound; response.Content = new StringContent("Order not found"); }   this.logger.WriteInformation("Order Requested", "Order Id {0}", id);   return order; } } The example above uses “MEF” as IoC for injecting a repository and the logger implementation into the service. You can also see how the logger is used to write an information event in the monitoring database. The following image illustrates how the custom event is injected and the information becomes available for any user in the dashboard. An issue that you might run into and I hope the WCF and AppFabric teams fixed soon is that any WCF service that uses friendly URLs with ASP.NET routing does not get listed as a available service in the WCF services tab in the AppFabric console. The complete example is available to download from here.

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• Finding the Right Solution to Source and Manage Your Contractors

  - by mark.rosenberg(at)oracle.com

  Many of our PeopleSoft Enterprise applications customers operate in service-based industries, and all of our customers have at least some internal service units, such as IT, marketing, and facilities. Employing the services of contractors, often referred to as "contingent labor," to deliver either or both internal and external services is common practice. As we've transitioned from an industrial age to a knowledge age, talent has become a primary competitive advantage for most organizations. Contingent labor offers talent on flexible terms; it offers the ability to scale up operations, close skill gaps, and manage risk in the process of delivering services. Talent comes from many sources and the rise in the contingent worker (contractor, consultant, temporary, part time) has increased significantly in the past decade and is expected to reach 40 percent in the next decade. Managing the total pool of talent in a seamless integrated fashion not only saves organizations money and increases efficiency, but creates a better place for workers of all kinds to work. Although the term "contingent labor" is frequently used to describe both contractors and employees who have flexible schedules and relationships with an organization, the remainder of this discussion focuses on contractors. The term "contingent labor" is used interchangeably with "contractor." Recognizing the importance of contingent labor, our PeopleSoft customers often ask our team, "What Oracle vendor management system (VMS) applications should I evaluate for managing contractors?" In response, I thought it would be useful to describe and compare the three most common Oracle-based options available to our customers. They are:   The enterprise licensed software model in which you implement and utilize the PeopleSoft Services Procurement (sPro) application and potentially other PeopleSoft applications;  The software-as-a-service model in which you gain access to a derivative of PeopleSoft sPro from an Oracle Business Process Outsourcing Partner; and  The managed service provider (MSP) model in which staffing industry professionals utilize either your enterprise licensed software or the software-as-a-service application to administer your contingent labor program. At this point, you may be asking yourself, "Why three options?" The answer is that since there is no "one size fits all" in terms of talent, there is also no "one size fits all" for effectively sourcing and managing contingent workers. Various factors influence how an organization thinks about and relates to its contractors, and each of the three Oracle-based options addresses an organization's needs and preferences differently. For the purposes of this discussion, I will describe the options with respect to (A) pricing and software provisioning models; (B) control and flexibility; (C) level of engagement with contractors; and (D) approach to sourcing, employment law, and financial settlement. Option 1:  Enterprise Licensed Software In this model, you purchase from Oracle the license and support for the applications you need. Typically, you license PeopleSoft sPro as your VMS tool for sourcing, monitoring, and paying your contract labor. In conjunction with sPro, you can also utilize PeopleSoft Human Capital Management (HCM) applications (if you do not already) to configure more advanced business processes for recruiting, training, and tracking your contractors. Many customers choose this enterprise license software model because of the functionality and natural integration of the PeopleSoft applications and because the cost for the PeopleSoft software is explicit. There is no fee per transaction to source each contractor under this model. Our customers that employ contractors to augment their permanent staff on billable client engagements often find this model appealing because there are no fees to affect their profit margins. With this model, you decide whether to have your own IT organization run the software or have the software hosted and managed by either Oracle or another application services provider. Your organization, perhaps with the assistance of consultants, configures, deploys, and operates the software for managing your contingent workforce. This model offers you the highest level of control and flexibility since your organization can configure the contractor process flow exactly to your business and security requirements and can extend the functionality with PeopleTools. This option has proven very valuable and applicable to our customers engaged in government contracting because their contingent labor management practices are subject to complex standards and regulations. Customers find a great deal of value in the application functionality and configurability the enterprise licensed software offers for managing contingent labor. Some examples of that functionality are... The ability to create a tiered network of preferred suppliers including competencies, pricing agreements, and elaborate candidate management capabilities. Configurable alerts and online collaboration for bid, resource requisition, timesheet, and deliverable entry, routing, and approval for both resource and deliverable-based services. The ability to manage contractors with the same PeopleSoft HCM and Projects applications that are used to manage the permanent workforce. Because it allows you to utilize much of the same PeopleSoft HCM and Projects application functionality for contractors that you use for permanent employees, the enterprise licensed software model supports the deepest level of engagement with the contingent workforce. For example, you can: fill job openings with contingent labor; guide contingent workers through essential safety and compliance training with PeopleSoft Enterprise Learning Management; and source contingent workers directly to project-based assignments in PeopleSoft Resource Management and PeopleSoft Program Management. This option enables contingent workers to collaborate closely with your permanent staff on complex, knowledge-based efforts - R&D projects, billable client contracts, architecture and engineering projects spanning multiple years, and so on. With the enterprise licensed software model, your organization maintains responsibility for the sourcing, onboarding (including adherence to employment laws), and financial settlement processes. This means your organization maintains on staff or hires the expertise in these domains to utilize the software and interact with suppliers and contractors. Option 2:  Software as a Service (SaaS) The effort involved in setting up and operating VMS software to handle a contingent workforce leads many organizations to seek a system that can be activated and configured within a few days and for which they can pay based on usage. Oracle's Business Process Outsourcing partner, Provade, Inc., provides exactly this option to our customers. Provade offers its vendor management software as a service over the Internet and usually charges your organization a fee that is a percentage of your total contingent labor spending processed through the Provade software. (Percentage of spend is the predominant fee model, although not the only one.) In addition to lower implementation costs, the effort of configuring and maintaining the software is largely upon Provade, not your organization. This can be very appealing to IT organizations that are thinly stretched supporting other important information technology initiatives. Built upon PeopleSoft sPro, the Provade solution is tailored for simple and quick deployment and administration. Provade has added capabilities to clone users rapidly and has simplified business documents, like work orders and change orders, to facilitate enterprise-wide, self-service adoption with little to no training. Provade also leverages Oracle Business Intelligence Enterprise Edition (OBIEE) to provide integrated spend analytics and dashboards. Although pure customization is more limited than with the enterprise licensed software model, Provade offers a very effective option for organizations that are regularly on-boarding and off-boarding high volumes of contingent staff hired to perform discrete support tasks (for example, order fulfillment during the holiday season, hourly clerical work, desktop technology repairs, and so on) or project tasks. The software is very configurable and at the same time very intuitive to even the most computer-phobic users. The level of contingent worker engagement your organization can achieve with the Provade option is generally the same as with the enterprise licensed software model since Provade can automatically establish contingent labor resources in your PeopleSoft applications. Provade has pre-built integrations to Oracle's PeopleSoft and the Oracle E-Business Suite procurement, projects, payables, and HCM applications, so that you can evaluate, train, assign, and track contingent workers like your permanent employees. Similar to the enterprise licensed software model, your organization is responsible for the contingent worker sourcing, administration, and financial settlement processes. This means your organization needs to maintain the staff expertise in these domains. Option 3:  Managed Services Provider (MSP) Whether you are using the enterprise licensed model or the SaaS model, you may want to engage the services of sourcing, employment, payroll, and financial settlement professionals to administer your contingent workforce program. Firms that offer this expertise are often referred to as "MSPs," and they are typically staffing companies that also offer permanent and temporary hiring services. (In fact, many of the major MSPs are Oracle applications customers themselves, and they utilize the PeopleSoft Solution for the Staffing Industry to run their own business operations.) Usually, MSPs place their staff on-site at your facilities, and they can utilize either your enterprise licensed PeopleSoft sPro application or the Provade VMS SaaS software to administer the network of suppliers providing contingent workers. When you utilize an MSP, there is a separate fee for the MSP's service that is typically funded by the participating suppliers of the contingent labor. Also in this model, the suppliers of the contingent labor (not the MSP) usually pay the contingent labor force. With an MSP, you are intentionally turning over business process control for the advantages associated with having someone else manage the processes. The software option you choose will to a certain extent affect your process flexibility; however, the MSPs are often able to adapt their processes to the unique demands of your business. When you engage an MSP, you will want to give some thought to the level of engagement and "partnering" you need with your contingent workforce. Because the MSP acts as an intermediary, it can be very valuable in handling high volume, routine contracting for which there is a relatively low need for "partnering" with the contingent workforce. However, if your organization (or part of your organization) engages contingent workers for high-profile client projects that require diplomacy, intensive amounts of interaction, and personal trust, introducing an MSP into the process may prove less effective than handling the process with your own staff. In fact, in many organizations, it is common to enlist an MSP to handle contractors working on internal projects and to have permanent employees handle the contractor relationships that affect the portion of the services portfolio focused on customer-facing, billable projects. One of the key advantages of enlisting an MSP is that you do not have to maintain the expertise required for orchestrating the sourcing, hiring, and paying of contingent workers.  These are the domain of the MSPs. If your own staff members are not prepared to manage the essential "overhead" processes associated with contingent labor, working with an MSP can make solid business sense. Proper administration of a contingent workforce can make the difference between project success and failure, operating profit and loss, and legal compliance and fines. Concluding Thoughts There is little doubt that thoughtfully and purposefully constructing a service delivery strategy that leverages the strengths of contingent workers can lead to better projects, deliverables, and business results. What requires a bit more thinking is determining the platform (or platforms) that will enable each part of your organization to best deliver on its mission.

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• A Closable jQuery Plug-in

  - by Rick Strahl

  In my client side development I deal a lot with content that pops over the main page. Be it data entry ‘windows’ or dialogs or simple pop up notes. In most cases this behavior goes with draggable windows, but sometimes it’s also useful to have closable behavior on static page content that the user can choose to hide or otherwise make invisible or fade out. Here’s a small jQuery plug-in that provides .closable() behavior to most elements by using either an image that is provided or – more appropriately by using a CSS class to define the picture box layout. /* * * Closable * * Makes selected DOM elements closable by making them * invisible when close icon is clicked * * Version 1.01 * @requires jQuery v1.3 or later * * Copyright (c) 2007-2010 Rick Strahl * http://www.west-wind.com/ * * Licensed under the MIT license: * http://www.opensource.org/licenses/mit-license.php Support CSS: .closebox { position: absolute; right: 4px; top: 4px; background-image: url(images/close.gif); background-repeat: no-repeat; width: 14px; height: 14px; cursor: pointer; opacity: 0.60; filter: alpha(opacity="80"); } .closebox:hover { opacity: 0.95; filter: alpha(opacity="100"); } Options: * handle Element to place closebox into (like say a header). Use if main element and closebox container are two different elements. * closeHandler Function called when the close box is clicked. Return true to close the box return false to keep it visible. * cssClass The CSS class to apply to the close box DIV or IMG tag. * imageUrl Allows you to specify an explicit IMG url that displays the close icon. If used bypasses CSS image styling. * fadeOut Optional provide fadeOut speed. Default no fade out occurs */ (function ($) { $.fn.closable = function (options) { var opt = { handle: null, closeHandler: null, cssClass: "closebox", imageUrl: null, fadeOut: null }; $.extend(opt, options); return this.each(function (i) { var el = $(this); var pos = el.css("position"); if (!pos || pos == "static") el.css("position", "relative"); var h = opt.handle ? $(opt.handle).css({ position: "relative" }) : el; var div = opt.imageUrl ? $("<img>").attr("src", opt.imageUrl).css("cursor", "pointer") : $("<div>"); div.addClass(opt.cssClass) .click(function (e) { if (opt.closeHandler) if (!opt.closeHandler.call(this, e)) return; if (opt.fadeOut) $(el).fadeOut(opt.fadeOut); else $(el).hide(); }); if (opt.imageUrl) div.css("background-image", "none"); h.append(div); }); } })(jQuery); The plugin can be applied against any selector that is a container (typically a div tag). The close image or close box is provided typically by way of a CssClass - .closebox by default – which supplies the image as part of the CSS styling. The default styling for the box looks something like this: .closebox { position: absolute; right: 4px; top: 4px; background-image: url(images/close.gif); background-repeat: no-repeat; width: 14px; height: 14px; cursor: pointer; opacity: 0.60; filter: alpha(opacity="80"); } .closebox:hover { opacity: 0.95; filter: alpha(opacity="100"); } Alternately you can also supply an image URL which overrides the background image in the style sheet. I use this plug-in mostly on pop up windows that can be closed, but it’s also quite handy for remove/delete behavior in list displays like this: you can find this sample here to look to play along: http://www.west-wind.com/WestwindWebToolkit/Samples/Ajax/AmazonBooks/BooksAdmin.aspx For closable windows it’s nice to have something reusable because in my client framework there are lots of different kinds of windows that can be created: Draggables, Modal Dialogs, HoverPanels etc. and they all use the client .closable plug-in to provide the closable operation in the same way with a few options. Plug-ins are great for this sort of thing because they can also be aggregated and so different components can pick and choose the behavior they want. The window here is a draggable, that’s closable and has shadow behavior and the server control can simply generate the appropriate plug-ins to apply to the main <div> tag: $().ready(function() { $('#ctl00_MainContent_panEditBook') .closable({ handle: $('#divEditBook_Header') }) .draggable({ dragDelay: 100, handle: '#divEditBook_Header' }) .shadow({ opacity: 0.25, offset: 6 }); }) The window is using the default .closebox style and has its handle set to the header bar (Book Information). The window is just closable to go away so no event handler is applied. Actually I cheated – the actual page’s .closable is a bit more ugly in the sample as it uses an image from a resources file: .closable({ imageUrl: '/WestWindWebToolkit/Samples/WebResource.axd?d=TooLongAndNastyToPrint', handle: $('#divEditBook_Header')}) so you can see how to apply a custom image, which in this case is generated by the server control wrapping the client DragPanel. More interesting maybe is to apply the .closable behavior to list scenarios. For example, each of the individual items in the list display also are .closable using this plug-in. Rather than having to define each item with Html for an image, event handler and link, when the client template is rendered the closable behavior is attached to the list. Here I’m using client-templating and the code that this is done with looks like this: function loadBooks() { showProgress(); // Clear the content $("#divBookListWrapper").empty(); var filter = $("#" + scriptVars.lstFiltersId).val(); Proxy.GetBooks(filter, function(books) { $(books).each(function(i) { updateBook(this); showProgress(true); }); }, onPageError); } function updateBook(book,highlight) { // try to retrieve the single item in the list by tag attribute id var item = $(".bookitem[tag=" +book.Pk +"]"); // grab and evaluate the template var html = parseTemplate(template, book); var newItem = $(html) .attr("tag", book.Pk.toString()) .click(function() { var pk = $(this).attr("tag"); editBook(this, parseInt(pk)); }) .closable({ closeHandler: function(e) { removeBook(this, e); }, imageUrl: "../../images/remove.gif" }); if (item.length > 0) item.after(newItem).remove(); else newItem.appendTo($("#divBookListWrapper")); if (highlight) { newItem .addClass("pulse") .effect("bounce", { distance: 15, times: 3 }, 400); setTimeout(function() { newItem.removeClass("pulse"); }, 1200); } } Here the closable behavior is applied to each of the items along with an event handler, which is nice and easy compared to having to embed the right HTML and click handling into each item in the list individually via markup. Ideally though (and these posts make me realize this often a little late) I probably should set up a custom cssClass to handle the rendering – maybe a CSS class called .removebox that only changes the image from the default box image. This example also hooks up an event handler that is fired in response to the close. In the list I need to know when the remove button is clicked so I can fire of a service call to the server to actually remove the item from the database. The handler code can also return false; to indicate that the window should not be closed optionally. Returning true will close the window. You can find more information about the .closable class behavior and options here: .closable Documentation Plug-ins make Server Control JavaScript much easier I find this plug-in immensely useful especial as part of server control code, because it simplifies the code that has to be generated server side tremendously. This is true of plug-ins in general which make it so much easier to create simple server code that only generates plug-in options, rather than full blocks of JavaScript code.  For example, here’s the relevant code from the DragPanel server control which generates the .closable() behavior: if (this.Closable && !string.IsNullOrEmpty(DragHandleID) ) { string imageUrl = this.CloseBoxImage; if (imageUrl == "WebResource" ) imageUrl = ScriptProxy.GetWebResourceUrl(this, this.GetType(), ControlResources.CLOSE_ICON_RESOURCE); StringBuilder closableOptions = new StringBuilder("imageUrl: '" + imageUrl + "'"); if (!string.IsNullOrEmpty(this.DragHandleID)) closableOptions.Append(",handle: $('#" + this.DragHandleID + "')"); if (!string.IsNullOrEmpty(this.ClientDialogHandler)) closableOptions.Append(",handler: " + this.ClientDialogHandler); if (this.FadeOnClose) closableOptions.Append(",fadeOut: 'slow'"); startupScript.Append(@" .closable({ " + closableOptions + "})"); } The same sort of block is then used for .draggable and .shadow which simply sets options. Compared to the code I used to have in pre-jQuery versions of my JavaScript toolkit this is a walk in the park. In those days there was a bunch of JS generation which was ugly to say the least. I know a lot of folks frown on using server controls, especially the UI is client centric as the example is. However, I do feel that server controls can greatly simplify the process of getting the right behavior attached more easily and with the help of IntelliSense. Often the script markup is easier is especially if you are dealing with complex, multiple plug-in associations that often express more easily with property values on a control. Regardless of whether server controls are your thing or not this plug-in can be useful in many scenarios. Even in simple client-only scenarios using a plug-in with a few simple parameters is nicer and more consistent than creating the HTML markup over and over again. I hope some of you find this even a small bit as useful as I have. Related Links Download jquery.closable West Wind Web Toolkit jQuery Plug-ins © Rick Strahl, West Wind Technologies, 2005-2010Posted in jQuery   ASP.NET  JavaScript  

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• WPF: Timers

  - by Ilya Verbitskiy

  I believe, once your WPF application will need to execute something periodically, and today I would like to discuss how to do that. There are two possible solutions. You can use classical System.Threading.Timer class or System.Windows.Threading.DispatcherTimer class, which is the part of WPF. I have created an application to show you how to use the API.     Let’s take a look how you can implement timer using System.Threading.Timer class. First of all, it has to be initialized.   1: private Timer timer; 2:   3: public MainWindow() 4: { 5: // Form initialization code 6: 7: timer = new Timer(OnTimer, null, Timeout.InfiniteTimeSpan, Timeout.InfiniteTimeSpan); 8: }   Timer’s constructor accepts four parameters. The first one is the callback method which is executed when timer ticks. I will show it to you soon. The second parameter is a state which is passed to the callback. It is null because there is nothing to pass this time. The third parameter is the amount of time to delay before the callback parameter invokes its methods. I use System.Threading.Timeout helper class to represent infinite timeout which simply means the timer is not going to start at the moment. And the final fourth parameter represents the time interval between invocations of the methods referenced by callback. Infinite timeout timespan means the callback method will be executed just once. Well, the timer has been created. Let’s take a look how you can start the timer.   1: private void StartTimer(object sender, RoutedEventArgs e) 2: { 3: timer.Change(TimeSpan.Zero, new TimeSpan(0, 0, 1)); 4:   5: // Disable the start buttons and enable the reset button. 6: }   The timer is started by calling its Change method. It accepts two arguments: the amount of time to delay before the invoking the callback method and the time interval between invocations of the callback. TimeSpan.Zero means we start the timer immediately and TimeSpan(0, 0, 1) tells the timer to tick every second. There is one method hasn’t been shown yet. This is the callback method OnTimer which does a simple task: it shows current time in the center of the screen. Unfortunately you cannot simple write something like this:   1: clock.Content = DateTime.Now.ToString("hh:mm:ss");   The reason is Timer runs callback method on a separate thread, and it is not possible to access GUI controls from a non-GUI thread. You can avoid the problem using System.Windows.Threading.Dispatcher class.   1: private void OnTimer(object state) 2: { 3: Dispatcher.Invoke(() => ShowTime()); 4: } 5:   6: private void ShowTime() 7: { 8: clock.Content = DateTime.Now.ToString("hh:mm:ss"); 9: }   You can build similar application using System.Windows.Threading.DispatcherTimer class. The class represents a timer which is integrated into the Dispatcher queue. It means that your callback method is executed on GUI thread and you can write a code which updates your GUI components directly.   1: private DispatcherTimer dispatcherTimer; 2:   3: public MainWindow() 4: { 5: // Form initialization code 6:   7: dispatcherTimer = new DispatcherTimer { Interval = new TimeSpan(0, 0, 1) }; 8: dispatcherTimer.Tick += OnDispatcherTimer; 9: } Dispatcher timer has nicer and cleaner API. All you need is to specify tick interval and Tick event handler. The you just call Start method to start the timer.   private void StartDispatcher(object sender, RoutedEventArgs e) { dispatcherTimer.Start(); // Disable the start buttons and enable the reset button. } And, since the Tick event handler is executed on GUI thread, the code which sets the actual time is straightforward.   1: private void OnDispatcherTimer(object sender, EventArgs e) 2: { 3: ShowTime(); 4: } We’re almost done. Let’s take a look how to stop the timers. It is easy with the Dispatcher Timer.   1: dispatcherTimer.Stop(); And slightly more complicated with the Timer. You should use Change method again.   1: timer.Change(Timeout.InfiniteTimeSpan, Timeout.InfiniteTimeSpan); What is the best way to add timer into an application? The Dispatcher Timer has simple interface, but its advantages are disadvantages at the same time. You should not use it if your Tick event handler executes time-consuming operations. It freezes your window which it is executing the event handler method. You should think about using System.Threading.Timer in this case. The code is available on GitHub.

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