Monthly Archives

Articles indexed in May 2012

Page 11/39 | < Previous Page | 7 8 9 10 11 12 13 14 15 16 17 18  | Next Page >

  • Antenna Aligner part 2: Finding the right direction

    - by Chris George
    Last time I managed to get "my first app(tm)" built, published and running on my iPhone. This was really cool, a piece of my code running on my very own device. Ok, so I'm easily pleased! The next challenge was actually trying to determine what it was I wanted this app to do, and how to do it. Reverting back to good old paper and pen, I started sketching out designs for the app. I knew I wanted it to get a list of transmitters, then clicking on a transmitter would display a compass type view, with an arrow pointing the right way. I figured there would not be much point in continuing until I know I could do the graphical part of the project, i.e. the rotating compass, so armed with that reasoning (plus the fact I just wanted to get on and code!), I once again dived into visual studio. Using my friend (google) I found some example code for getting the compass data from the phone using the PhoneGap framework. // onSuccess: Get the current heading // function onSuccess(heading) {    alert('Heading: ' + heading); } navigator.compass.getCurrentHeading(onSuccess, onError); Using the ripple mobile emulator this showed that it was successfully getting the compass heading. But it didn't work when uploaded to my phone. It turns out that the examples I had been looking at were for PhoneGap 1.0, and Nomad uses PhoneGap 1.4.1. In 1.4.1, getCurrentHeading provides a compass object to onSuccess, not just a numeric value, so the code now looks like // onSuccess: Get the current magnetic heading // function onSuccess(heading) {    alert('Heading: ' + heading.magneticHeading); }; navigator.compass.getCurrentHeading(onSuccess, onError); So the lesson learnt from this... read the documentation for the version you are actually using! This does, however, lead to compatibility problems with ripple as it only supports 1.0 which is a real pain. I hope that the ripple system is updated sometime soon.

    Read the article

  • Antenna Aligner part 1: In the beginning.

    - by Chris George
    Picture the scene, it's 9pm, I'm in my caravan (yes I know, I've heard all the jokes!) with my family and I'm trying to tune the tv by moving the aerial, retuning, moving the aerial again, retuning... 45 mins and much cursing later I succeed. Surely there must be an easier way than this? Aha, an app; there must be an app for that? So I search in the AppStore for such an app, but curiously drew a blank. Then the seeds of the idea started to grow. I can code, I work in a software house with lots of very clever people, surely I can make an app that points to the nearest digital tv transmitter! Not having looked into app development before, I investigated how one goes about making an iPhone app and was quickly greeted by a now familiar answer "Buy a mac!". That was not an option for many reasons, mostly wife related! My dreams were starting to fade until one of my colleagues pointed out that within Red Gate, the very company I work for, there was on-going development on a piece of software that would allow me to write an app using Visual Studio on a Windows machine, Nomad! Once I signed up for the beta program I got to work learning the Jquery mobile / Phonegap framework. Within a couple of hours I had written (in Visual Studio), built in the cloud (using Nomad) and published (via TestFlight) my first iPhone app onto my iPhone ! It didn't do much, but it was a step in the right direction. To be continued...

    Read the article

  • I'm blogging again, and about time too

    - by fatherjack
    No, seriously, this one is about time. I recently had an issue in a work database where a query was giving random results, sometimes the query would return a row and other times it wouldn't. There was quite a bit of work distilling the query down to find the reason for this and I'll try to explain by demonstrating what was happening by using some sample data in a table with rather a contrived use case. Let's assume we have a table that is designed to have a start and end date for something, maybe...(read more)

    Read the article

  • What Counts For a DBA: Imagination

    - by drsql
    "Imagination…One little spark, of inspiration… is at the heart, of all creation." – From the song "One Little Spark", by the Sherman Brothers I have a confession to make. Despite my great enthusiasm for databases and programming, it occurs to me that every database system I've ever worked on has been, in terms of its inputs and outputs, downright dull. Most have been glorified e-spreadsheets, many replacing manual systems built on actual spreadsheets. I've created a lot of database-driven software whose main job was to "count stuff"; phone calls, web visitors, payments, donations, pieces of equipment and so on. Sometimes, instead of counting stuff, the database recorded values from other stuff, such as data from sensors or networking devices. Yee hah! So how do we, as DBAs, maintain high standards and high spirits when we realize that so much of our work would fail to raise the pulse of even the most easily excitable soul? The answer lies in our imagination. To understand what I mean by this, consider a role that, in terms of its output, offers an extreme counterpoint to that of the DBA: the Disney Imagineer. Their job is to design Disney's Theme Parks, of which I'm a huge fan. To me this has always seemed like a fascinating and exciting job. What must an Imagineer do, every day, to inspire the feats of creativity that are so clearly evident in those spectacular rides and shows? Here, if ever there was one, is a role where "dull moments" must be rare indeed, surely? I wanted to find out, and so parted with a considerable sum of money for my wife and I to have lunch with one; I reasoned that if I found one small way to apply their secrets to my own career, it would be money well spent. Early in the conversation with our Imagineer (Cindy Cote), the job did indeed sound magical. However, as talk turned to management meetings, budget-wrangling and insane deadlines, I came to the strange realization that, in fact, her job was a lot more like mine than I would ever have guessed. Much like databases, all those spectacular Disney rides bring with them a vast array of complex plumbing, lighting, safety features, and all manner of other "boring bits", kept well out of sight of the end user, but vital for creating the desired experience; and, of course, it is these "boring bits" that take up much of the Imagineer's time. Naturally, there is still a vital part of their job that is spent testing out new ideas, putting themselves in the place of a park visitor, from a 9-year-old boy to a 90-year-old grandmother, and trying to imagine what experiences they'd like to have. It is these small, but vital, sparks of imagination and creativity that have the biggest impact. The real feat of a successful Imagineer is clearly to never to lose sight of this fact, in among all the rote tasks. It is the same for a DBA. Not matter how seemingly dull is the task at hand, try to put yourself in the shoes of the end user, and imagine how your input will affect the experience he or she will have with the database you're building, and how that may affect the world beyond the bits stored in your database. Then, despite the inevitable rush to be "done", find time to go the extra mile and hone the design so that it delivers something as close to that imagined experience as you can get. OK, our output still can't and won't reach the same spectacular heights as the "Journey into The Imagination" ride at EPCOT Theme Park in Orlando, where I first heard "One Little Spark". However, our imaginative sparks and efforts can, and will, make a difference to the user who now feels slightly more at home with a database application, or to the manager holding a report presented with enough clarity to drive an interesting decision or two. They are small victories, but worth having, and appreciated, or at least that's how I imagine it.

    Read the article

  • .NET Demon support for VS 11 dark theme

    - by Alex.Davies
    I'm pleased to announce that .NET Demon will be shipping simultaneously with Visual Studio 11, whenever it ends up being released. That means we're going to make sure that a version of .NET Demon is released very near to the Visual Studio 11 final release which supports the new version of VS fully. The interesting part of this support is going to be the new dark theme of VS, which I'm looking forward to using. I'm told dark colours reduce eye strain for developers. It's important that extensions like .NET Demon switch to a dark theme when the rest of the IDE changes, or the dark theme will look silly. Unfortunately, none of my favourite extensions look right in the dark theme yet, so even though I use Visual Studio 11 beta for my day-to-day development already, I can't use the dark theme. Luckily .NET Demon uses WPF throughout, and the team at Microsoft are helping us to use the WPF Style system to make it easy for me to implement the support without having to add colour attributes to all the controls manually. We should have dark theme support in .NET Demon in the next month or so.

    Read the article

  • List of resources for database continuous integration

    - by David Atkinson
    Because there is so little information on database continuous integration out in the wild, I've taken it upon myself to aggregate as much as possible and post the links to this blog. Because it's my area of expertise, this will focus on SQL Server and Red Gate tooling, although I am keen to include any quality articles that discuss the topic in general terms. Please let me know if you find a resource that I haven't listed! General database Continuous Integration · What is Database Continuous Integration? (David Atkinson) · Continuous Integration for SQL Server Databases (Troy Hunt) · Installing NAnt to drive database continuous integration (David Atkinson) · Continuous Integration Tip #3 - Version your Databases as part of your automated build (Doug Rathbone) · How the "migrations" approach makes database continuous integration possible (David Atkinson) · Continuous Integration for the Database (Keith Bloom) Setting up Continuous Integration with Red Gate tools · Continuous integration for databases using Red Gate tools - A technical overview (White Paper, Roger Hart and David Atkinson) · Continuous integration for databases using Red Gate SQL tools (Product pages) · Database continuous integration step by step (David Atkinson) · Database Continuous Integration with Red Gate Tools (video, David Atkinson) · Database schema synchronisation with RedGate (Vincent Brouillet) · Database continuous integration and deployment with Red Gate tools (David Duffett) · Automated database releases with TeamCity and Red Gate (Troy Hunt) · How to build a database from source control (David Atkinson) · Continuous Integration Automated Database Update Process (Lance Lyons) Other · Evolutionary Database Design (Martin Fowler) · Recipes for Continuous Database Integration: Evolutionary Database Development (book, Pramod J Sadalage) · Recipes for Continuous Database Integration (book, Pramod Sadalage) · The Red Gate Guide to SQL Server Team-based Development (book, Phil Factor, Grant Fritchey, Alex Kuznetsov, Mladen Prajdic) · Using SQL Test Database Unit Testing with TeamCity Continuous Integration (Dave Green) · Continuous Database Integration (covers MySQL, Perason Education) Technorati Tags: SQL Server,Continous Integration

    Read the article

  • Inside Red Gate - Ricky Leeks

    - by Simon Cooper
    So, one of our profilers has a problem. Red Gate produces two .NET profilers - ANTS Performance Profiler (APP) and ANTS Memory Profiler (AMP). Both products help .NET developers solve problems they are virtually guaranteed to encounter at some point in their careers - slow code, and high memory usage, respectively. Everyone understands slow code - the symptoms are very obvious (an operation takes 2 hours when it should take 10 seconds), you know when you've solved it (the same operation now takes 15 seconds), and everyone understands how you can use a profiler like APP to help solve your particular problem. High memory usage is a much more subtle and misunderstood concept. How can .NET have memory leaks? The garbage collector, and how the CLR uses and frees memory, is one of the most misunderstood concepts in .NET. There's hundreds of blog posts out there covering various aspects of the GC and .NET memory, some of them helpful, some of them confusing, and some of them are just plain wrong. There's a lot of misconceptions out there. And, if you have got an application that uses far too much memory, it can be hard to wade through all the contradictory information available to even get an idea as to what's going on, let alone trying to solve it. That's where a memory profiler, like AMP, comes into play. Unfortunately, that's not the end of the issue. .NET memory management is a large, complicated, and misunderstood problem. Even armed with a profiler, you need to understand what .NET is doing with your objects, how it processes them, and how it frees them, to be able to use the profiler effectively to solve your particular problem. And that's what's wrong with AMP - even with all the thought, designs, UX sessions, and research we've put into AMP itself, some users simply don't have the knowledge required to be able to understand what AMP is telling them about how their application uses memory, and so they have problems understanding & solving their memory problem. Ricky Leeks This is where Ricky Leeks comes in. Created by one of the many...colourful...people in Red Gate, he headlines and promotes several tutorials, pages, and articles all with information on how .NET memory management actually works, with the goal to help educate developers on .NET memory management. And educating us all on how far you can push various vegetable-based puns. This, in turn, not only helps them understand and solve any memory issues they may be having, but helps them proactively code against such memory issues in their existing code. Ricky's latest outing is an interview on .NET Rocks, providing information on the Top 5 .NET Memory Management Gotchas, along with information on a free ebook on .NET Memory Management. Don't worry, there's loads more vegetable-based jokes where those came from...

    Read the article

  • Metrics - A little knowledge can be a dangerous thing (or 'Why you're not clever enough to interpret metrics data')

    - by Jason Crease
    At RedGate Software, I work on a .NET obfuscator  called SmartAssembly.  Various features of it use a database to store various things (exception reports, name-mappings, etc.) The user is given the option of using either a SQL-Server database (which requires them to have Microsoft SQL Server), or a Microsoft Access MDB file (which requires nothing). MDB is the default option, but power-users soon switch to using a SQL Server database because it offers better performance and data-sharing. In the fashionable spirit of optimization and metrics, an obvious product-management question is 'Which is the most popular? SQL Server or MDB?' We've collected data about this fact, using our 'Feature-Usage-Reporting' technology (available as part of SmartAssembly) and more recently our 'Application Metrics' technology: Parameter Number of users % of total users Number of sessions Number of usages SQL Server 28 19.0 8115 8115 MDB 114 77.6 1449 1449 (As a disclaimer, please note than SmartAssembly has far more than 132 users . This data is just a selection of one build) So, it would appear that SQL-Server is used by fewer users, but more often. Great. But here's why these numbers are useless to me: Only the original developers understand the data What does a single 'usage' of 'MDB' mean? Does this happen once per run? Once per option change? On clicking the 'Obfuscate Now' button? When running the command-line version or just from the UI version? Each question could skew the data 10-fold either way, and the answers only known by the developer that instrumented the application in the first place. In other words, only the original developer can interpret the data - product-managers cannot interpret the data unaided. Most of the data is from uninterested users About half of people who download and run a free-trial from the internet quit it almost immediately. Only a small fraction use it sufficiently to make informed choices. Since the MDB option is the default one, we don't know how many of those 114 were people CHOOSING to use the MDB, or how many were JUST HAPPENING to use this MDB default for their 20-second trial. This is a problem we see across all our metrics: Are people are using X because it's the default or are they using X because they want to use X? We need to segment the data further - asking what percentage of each percentage meet our criteria for an 'established user' or 'informed user'. You end up spending hours writing sophisticated and dubious SQL queries to segment the data further. Not fun. You can't find out why they used this feature Metrics can answer the when and what, but not the why. Why did people use feature X? If you're anything like me, you often click on random buttons in unfamiliar applications just to explore the feature-set. If we listened uncritically to metrics at RedGate, we would eliminate the most-important and more-complex features which people actually buy the software for, leaving just big buttons on the main page and the About-Box. "Ah, that's interesting!" rather than "Ah, that's actionable!" People do love data. Did you know you eat 1201 chickens in a lifetime? But just 4 cows? Interesting, but useless. Often metrics give you a nice number: '5.8% of users have 3 or more monitors' . But unless the statistic is both SUPRISING and ACTIONABLE, it's useless. Most metrics are collected, reviewed with lots of cooing. and then forgotten. Unless a piece-of-data could change things, it's useless collecting it. People get obsessed with significance levels The first things that lots of people do with this data is do a t-test to get a significance level ("Hey! We know with 99.64% confidence that people prefer SQL Server to MDBs!") Believe me: other causes of error/misinterpretation in your data are FAR more significant than your t-test could ever comprehend. Confirmation bias prevents objectivity If the data appears to match our instinct, we feel satisfied and move on. If it doesn't, we suspect the data and dig deeper, plummeting down a rabbit-hole of segmentation and filtering until we give-up and move-on. Data is only useful if it can change our preconceptions. Do you trust this dodgy data more than your own understanding, knowledge and intelligence?  I don't. There's always multiple plausible ways to interpret/action any data Let's say we segment the above data, and get this data: Post-trial users (i.e. those using a paid version after the 14-day free-trial is over): Parameter Number of users % of total users Number of sessions Number of usages SQL Server 13 9.0 1115 1115 MDB 5 4.2 449 449 Trial users: Parameter Number of users % of total users Number of sessions Number of usages SQL Server 15 10.0 7000 7000 MDB 114 77.6 1000 1000 How do you interpret this data? It's one of: Mostly SQL Server users buy our software. People who can't afford SQL Server tend to be unable to afford or unwilling to buy our software. Therefore, ditch MDB-support. Our MDB support is so poor and buggy that our massive MDB user-base doesn't buy it.  Therefore, spend loads of money improving it, and think about ditching SQL-Server support. People 'graduate' naturally from MDB to SQL Server as they use the software more. Things are fine the way they are. We're marketing the tool wrong. The large number of MDB users represent uninformed downloaders. Tell marketing to aggressively target SQL Server users. To choose an interpretation you need to segment again. And again. And again, and again. Opting-out is correlated with feature-usage Metrics tends to be opt-in. This skews the data even further. Between 5% and 30% of people choose to opt-in to metrics (often called 'customer improvement program' or something like that). Casual trial-users who are uninterested in your product or company are less likely to opt-in. This group is probably also likely to be MDB users. How much does this skew your data by? Who knows? It's not all doom and gloom. There are some things metrics can answer well. Environment facts. How many people have 3 monitors? Have Windows 7? Have .NET 4 installed? Have Japanese Windows? Minor optimizations.  Is the text-box big enough for average user-input? Performance data. How long does our app take to start? How many databases does the average user have on their server? As you can see, questions about who-the-user-is rather than what-the-user-does are easier to answer and action. Conclusion Use SmartAssembly. If not for the metrics (called 'Feature-Usage-Reporting'), then at least for the obfuscation/error-reporting. Data raises more questions than it answers. Questions about environment are the easiest to answer.

    Read the article

  • .NET Demon 1.0 Released

    - by theo.spears
    Today we're officially releasing version 1.0 of .NET Demon, the Visual Studio Extension Alex Davies and I have been working on for the last 6 months. There have been beta versions available for a while, but we have now released the first "official" version and made it available to purchase. If you haven't yet tried the tool, it's all about reducing the time between when you write a line of code and when you are able to try it out so you don't have to wait: Continuous compilation We use spare CPU cycles on your machine to compile your code in the background when you make changes, so assemblies are up to date whenever you want to run them. Some clever logic means we only recompile code which may have been affected by your changes. Continuous save .NET Demon can perform background saving, so you don't lose any work in case of crashes or power failures, and are less likely to forget to commit changed files. Continuous testing (Experimental) The testing tool in .NET Demon watches which code you change in your solution, and automatically reruns tests which are impacted, so you learn about any breaking changes as quickly as possible. It also gives you inline test coverage information inside Visual Studio. Continuous testing is still experimental - it will work fine in many cases, but we know it's not yet perfect. Releasing version 1.0 doesn't mean we're pausing development or pushing out improvements. We will still be regularly providing new versions with improved functionality and fixes for any bugs people come across. Visit the .NET Demon product page to download

    Read the article

  • Subterranean IL: The ThreadLocal type

    - by Simon Cooper
    I came across ThreadLocal<T> while I was researching ConcurrentBag. To look at it, it doesn't really make much sense. What's all those extra Cn classes doing in there? Why is there a GenericHolder<T,U,V,W> class? What's going on? However, digging deeper, it's a rather ingenious solution to a tricky problem. Thread statics Declaring that a variable is thread static, that is, values assigned and read from the field is specific to the thread doing the reading, is quite easy in .NET: [ThreadStatic] private static string s_ThreadStaticField; ThreadStaticAttribute is not a pseudo-custom attribute; it is compiled as a normal attribute, but the CLR has in-built magic, activated by that attribute, to redirect accesses to the field based on the executing thread's identity. TheadStaticAttribute provides a simple solution when you want to use a single field as thread-static. What if you want to create an arbitary number of thread static variables at runtime? Thread-static fields can only be declared, and are fixed, at compile time. Prior to .NET 4, you only had one solution - thread local data slots. This is a lesser-known function of Thread that has existed since .NET 1.1: LocalDataStoreSlot threadSlot = Thread.AllocateNamedDataSlot("slot1"); string value = "foo"; Thread.SetData(threadSlot, value); string gettedValue = (string)Thread.GetData(threadSlot); Each instance of LocalStoreDataSlot mediates access to a single slot, and each slot acts like a separate thread-static field. As you can see, using thread data slots is quite cumbersome. You need to keep track of LocalDataStoreSlot objects, it's not obvious how instances of LocalDataStoreSlot correspond to individual thread-static variables, and it's not type safe. It's also relatively slow and complicated; the internal implementation consists of a whole series of classes hanging off a single thread-static field in Thread itself, using various arrays, lists, and locks for synchronization. ThreadLocal<T> is far simpler and easier to use. ThreadLocal ThreadLocal provides an abstraction around thread-static fields that allows it to be used just like any other class; it can be used as a replacement for a thread-static field, it can be used in a List<ThreadLocal<T>>, you can create as many as you need at runtime. So what does it do? It can't just have an instance-specific thread-static field, because thread-static fields have to be declared as static, and so shared between all instances of the declaring type. There's something else going on here. The values stored in instances of ThreadLocal<T> are stored in instantiations of the GenericHolder<T,U,V,W> class, which contains a single ThreadStatic field (s_value) to store the actual value. This class is then instantiated with various combinations of the Cn types for generic arguments. In .NET, each separate instantiation of a generic type has its own static state. For example, GenericHolder<int,C0,C1,C2> has a completely separate s_value field to GenericHolder<int,C1,C14,C1>. This feature is (ab)used by ThreadLocal to emulate instance thread-static fields. Every time an instance of ThreadLocal is constructed, it is assigned a unique number from the static s_currentTypeId field using Interlocked.Increment, in the FindNextTypeIndex method. The hexadecimal representation of that number then defines the specific Cn types that instantiates the GenericHolder class. That instantiation is therefore 'owned' by that instance of ThreadLocal. This gives each instance of ThreadLocal its own ThreadStatic field through a specific unique instantiation of the GenericHolder class. Although GenericHolder has four type variables, the first one is always instantiated to the type stored in the ThreadLocal<T>. This gives three free type variables, each of which can be instantiated to one of 16 types (C0 to C15). This puts an upper limit of 4096 (163) on the number of ThreadLocal<T> instances that can be created for each value of T. That is, there can be a maximum of 4096 instances of ThreadLocal<string>, and separately a maximum of 4096 instances of ThreadLocal<object>, etc. However, there is an upper limit of 16384 enforced on the total number of ThreadLocal instances in the AppDomain. This is to stop too much memory being used by thousands of instantiations of GenericHolder<T,U,V,W>, as once a type is loaded into an AppDomain it cannot be unloaded, and will continue to sit there taking up memory until the AppDomain is unloaded. The total number of ThreadLocal instances created is tracked by the ThreadLocalGlobalCounter class. So what happens when either limit is reached? Firstly, to try and stop this limit being reached, it recycles GenericHolder type indexes of ThreadLocal instances that get disposed using the s_availableIndices concurrent stack. This allows GenericHolder instantiations of disposed ThreadLocal instances to be re-used. But if there aren't any available instantiations, then ThreadLocal falls back on a standard thread local slot using TLSHolder. This makes it very important to dispose of your ThreadLocal instances if you'll be using lots of them, so the type instantiations can be recycled. The previous way of creating arbitary thread-static variables, thread data slots, was slow, clunky, and hard to use. In comparison, ThreadLocal can be used just like any other type, and each instance appears from the outside to be a non-static thread-static variable. It does this by using the CLR type system to assign each instance of ThreadLocal its own instantiated type containing a thread-static field, and so delegating a lot of the bookkeeping that thread data slots had to do to the CLR type system itself! That's a very clever use of the CLR type system.

    Read the article

  • SQL Server source control from Visual Studio

    - by David Atkinson
    Developers have long since had to context switch between two IDEs, Visual Studio for application code development and SQL Server Management Studio for database development. While this is accepted, especially given the richness of the database development feature set in SSMS, loading a separate tool can seem a little overkill. This is where SQL Connect comes in. This is an add-in to Visual Studio that provides a connected development experience for the SQL Server developer. Connected database development involves modifying a development sandbox database, as opposed to offline development, where SQL text files are modified independently of the database. One of the main complaints of Data Dude (VS DBPro) is that it enforces the offline approach. This gripe is what SQL Connect addresses. If you don't already use SQL Source Control, you can get up and running with SQL Connect by adding a new project to your Visual Studio solution as follows: Then choose your existing development database and you're ready to go. If you already use SQL Source Control, you will need to link SQL Connect to your existing database scripts folder repository, so SQL Connect and SQL Source Control can be used collaboratively (note that SQL Source Control v.3.0.9.18 or later is required). Locate the repository (this can be found in the Setup tab in SQL Source Control). .and create a working folder for it (here I'm using TortoiseSVN). Back in Visual Studio, locate the SQL Connect panel (in the View menu if it hasn't auto loaded) and select Import SQL Source Control project Locate your working folder and click Import. This creates a Red Gate database project under your solution: From here you can modify your development database, and manage your changes in source control. To associate your development database with the project, right click on the project node, select Properties, set the database and Save. Now you're ready to make some changes. Locate the object you'd like to modify in the Solution Explorer, and double click it to invoke a query window or table designer. You also have the option to edit the creation SQL directly using Edit SQL File in Project. Keeping the development database and Visual Studio project in sync is as easy as clicking on a button. One you've made your change, you can use whichever mechanism you choose to commit to source control. Here I'm using the free open-source AnkhSVN to integrate Subversion with Visual Studio. Maintaining your database in a Visual Studio solution means that you can commit database changes and application code changes in the same changeset. This is desirable if you have continuous integration set up as you want to ensure that all files related to a change are committed atomically, so you avoid an interim "broken build". More discussion on SQL Connect and its benefits can be found in the following article on Simple Talk: No More Disconnected SQL Development in Visual Studio The SQL Connect project team is currently assessing the backlog for the next development effort, and they'd appreciate your feature suggestions, as well as your votes on their suggestions site: http://redgate.uservoice.com/forums/140800-sql-connect-for-visual-studio- A 28-day free trial of SQL Connect is available from the Red Gate website. Technorati Tags: SQL Server

    Read the article

  • DIVs of equal height

    - by Richard Mitchell
    It's the same old old problem you want to make a set of columns the same height but life it too short for the CSS only version. It's technically possible to do but nowadays you can't run the web without having javascript turned on. There must be an easier way. After a short amount of googling I came across a few solutions. A couple were GPL'd which ruled them straight out as I want Red Gate to pay for my mortgage. The best simple solution was found at. http://www.cssnewbie.com/equal-height-columns-with-jquery/...(read more)

    Read the article

  • IT Admin for Thrill Seekers

    - by Tony Davis
    A developer suggested to me recently that the life of the DBA was, surely, a dull one. My first reaction was indignation, but quickly followed by the thought that for many people excitement isn't necessarily the most desirable aspect of their job. It's true that some aspects of the DBA role seem guaranteed to quieten the pulse; in the days of tape backups, time must have slowed to eternity for the person whose job it was to oversee this process, placing tapes into secure containers, ensuring correct labeling, and.sorry, I drifted off there for a second. On the other hand, if you follow the adventures of the likes of Brent Ozar or Tom LaRock, you'd be forgiven for thinking that much of a database guy's time is spent, metaphorically, diving through plate glass windows in tight fitting underwear in order to extract grateful occupants from burning database applications. Alas it isn't true of the majority, but it isn't as dull as some people imagine, and is a helter-skelter ride compared with some other IT roles. Every IT department has people who toil away in shadowy corners doing quiet but mysterious tasks. When you ask them to explain what they do, you almost immediately want them to stop, but you hear enough to appreciate that these tasks are often absolutely vital to the smooth functioning of an IT organization. Compared with them, the DBAs are prima donnas. Here are a few nominations: Installation engineer - install all of the company's laptops and workstations, and software, deal with licensing, shipping and data entry.many organizations, especially those subject to tight regulation, would simply grind to a halt without their efforts. Localization engineer - Not quite software engineering, not quite translation, the job is to rebuild a product in a different language and make sure everything still works. QA Tester - firstly, I should say that the testers at Red Gate seem to me some of the most-fulfilled in the company. I refer here to the QA Tester whose job is more-or-less entirely to read a script, click some buttons and make sure the actual and expected values match. Configuration manager - for example, someone whose main job is to configure build environments so that devs can access their source code; assuredly necessary for the smooth functioning and productivity of the team, and hopefully well-paid. So what other sort of job in IT should one choose if the work of a DBA proves to be too exciting? Or are these roles secretly more exciting than many imagine? I invite you all to put forward your own suggestions. Cheers, Tony.

    Read the article

  • How the "migrations" approach makes database continuous integration possible

    - by David Atkinson
    Testing a database upgrade script as part of a continuous integration process will only work if there is an easy way to automate the generation of the upgrade scripts. There are two common approaches to managing upgrade scripts. The first is to maintain a set of scripts as-you-go-along. Many SQL developers I've encountered will store these in a folder prefixed numerically to ensure they are ordered as they are intended to be run. Occasionally there is an accompanying document or a batch file that ensures that the scripts are run in the defined order. Writing these scripts during the course of development requires discipline. It's all too easy to load up the table designer and to make a change directly to the development database, rather than to save off the ALTER statement that is required when the same change is made to production. This discipline can add considerable overhead to the development process. However, come the end of the project, everything is ready for final testing and deployment. The second development paradigm is to not do the above. Changes are made to the development database without considering the incremental update scripts required to effect the changes. At the end of the project, the SQL developer or DBA, is tasked to work out what changes have been made, and to hand-craft the upgrade scripts retrospectively. The end of the project is the wrong time to be doing this, as the pressure is mounting to ship the product. And where data deployment is involved, it is prudent not to feel rushed. Schema comparison tools such as SQL Compare have made this latter technique more bearable. These tools work by analyzing the before and after states of a database schema, and calculating the SQL required to transition the database. Problem solved? Not entirely. Schema comparison tools are huge time savers, but they have their limitations. There are certain changes that can be made to a database that can't be determined purely from observing the static schema states. If a column is split, how do we determine the algorithm required to copy the data into the new columns? If a NOT NULL column is added without a default, how do we populate the new field for existing records in the target? If we rename a table, how do we know we've done a rename, as we could equally have dropped a table and created a new one? All the above are examples of situations where developer intent is required to supplement the script generation engine. SQL Source Control 3 and SQL Compare 10 introduced a new feature, migration scripts, allowing developers to add custom scripts to replace the default script generation behavior. These scripts are committed to source control alongside the schema changes, and are associated with one or more changesets. Before this capability was introduced, any schema change that required additional developer intent would break any attempt at auto-generation of the upgrade script, rendering deployment testing as part of continuous integration useless. SQL Compare will now generate upgrade scripts not only using its diffing engine, but also using the knowledge supplied by developers in the guise of migration scripts. In future posts I will describe the necessary command line syntax to leverage this feature as part of an automated build process such as continuous integration.

    Read the article

  • What Counts For A DBA: Foresight

    - by drsql
    Of all the valuable attributes of a DBA covered so far in this series, ranging from passion to humility to practicality, perhaps one of the most important attributes may turn out to be the most seemingly-nebulous: foresight. According to Free Dictionary foresight is the "perception of the significance and nature of events before they have occurred". Foresight does not come naturally to most people, as the parent of any teenager will attest. No matter how clearly you see their problems coming they won't listen, and have to fail before eventually (hopefully) learning for themselves. Having graduated from the school of hard knocks, the DBA, the naive teenager no longer, acquires the ability to foretell how events will unfold in response to certain actions or attitudes with the unerring accuracy of a doom-laden prophet. Like Simba in the Lion King, after a few blows to the head, we foretell that a sore head that will be the inevitable consequence of a swing of Rafiki's stick, and we take evasive action. However, foresight is about more than simply learning when to duck. It's about taking the time to understand and prevent the habits that caused the stick to swing in the first place. And based on this definition, I often think there is a lot less foresight on display in my industry than there ought to be. Most DBAs reading this blog will spot a line such as the following in a piece of "working" code, understand immediately why it is less than optimimum, and take evasive action. …WHERE CAST (columnName as int) = 1 However, the programmers who regularly write this sort of code clearly lack that foresight, and this and numerous other examples of similarly-malodorous code prevail throughout our industry (and provide premium-grade fertilizer for the healthy growth of many a consultant's bank account). Sometimes, perhaps harried by impatient managers and painfully tight deadlines, everyone makes mistakes. Yes, I too occasionally write code that "works", but basically stinks. When the problems manifest, it is sometimes accompanied by a sense of grim recognition that somewhere in me existed the foresight to know that that approach would lead to this problem. However, in the headlong rush, warning signs got overlooked, lessons learned previously, which could supply the foresight to the current project, were lost and not applied.   Of course, the problem often is a simple lack of skills, training and knowledge in the relevant technology and/or business space; programmers and DBAs forced to do their best in the face of inadequate training, or to apply their skills in areas where they lack experience. However, often the problem goes deeper than this; I detect in some DBAs and programmers a certain laziness of attitude.   They veer from one project to the next, going with "whatever works", unwilling or unable to take the time to understand where their actions are leading them. Of course, the whole "Agile" mindset is often interpreted to favor flexibility and rapid production over aiming to get things right the first time. The faster you try to travel in the dark, frequently changing direction, the more important it is to have someone who has the foresight to know at least roughly where you are heading. This is doubly true for the data tier which, no matter how you try to deny it, simply cannot be "redone" every month as you learn aspects of the world you are trying to model that, with a little bit of foresight, you would have seen coming.   Sometimes, when as a DBA you can glance briefly at 200 lines of working SQL code and know instinctively why it will cause problems, foresight can feel like magic, but it isn't; it's more like muscle memory. It is acquired as the consequence of good experience, useful communication with those around you, and a willingness to learn continually, through continued education as well as from failure. Foresight can be deployed only by finding time to understand how the lessons learned from other DBAs, and other projects, can help steer the current project in the right direction.   C.S. Lewis once said "The future is something which everyone reaches at the rate of sixty minutes an hour, whatever he does, whoever he is." It cannot be avoided; the quality of what you build now is going to affect you, and others, at some point in the future. Take the time to acquire foresight; it is a love letter to your future self, to say you cared.

    Read the article

  • Database continuous integration step by step

    - by David Atkinson
    This post will describe how to set up basic database continuous integration using TeamCity to initiate the build process, SQL Source Control to put your database under source control, and the SQL Compare command line to keep a test database up to date. In my example I will be using Subversion as my source control repository. If you wish to follow my steps verbatim, please make sure you have TortoiseSVN, SQL Compare and SQL Source Control installed. Downloading and Installing TeamCity TeamCity (http://www.jetbrains.com/teamcity/index.html) is free for up to three agents, so it a great no-risk tool you can use to experiment with. 1. Download the latest version from the JetBrains website. For some reason the TeamCity executable didn't download properly for me, stalling frustratingly at 99%, so I tried again with the zip file download option (see screenshot below), which worked flawlessly. 2. Run the installer using the defaults. This results in a set-up with the server component and agent installed on the same machine, which is ideal for getting started with ease. 3. Check that the build agent is pointing to the server correctly. This has caught me out a few times before. This setting is in C:\TeamCity\buildAgent\conf\buildAgent.properties and for my installation is serverUrl=http\://localhost\:80 . If you need to change this value, if for example you've had to install the Server console to a different port number, the TeamCity Build Agent Service will need to be restarted for the change to take effect. 4. Open the TeamCity admin console on http://localhost , and specify your own designated username and password at first startup. Putting your database in source control using SQL Source Control 5. Assuming you've got SQL Source Control installed, select a development database in the SQL Server Management Studio Object Explorer and select Link Database to Source Control. 6. For the Link step you can either create your own empty folder in source control, or you can select Just Evaluating, which just creates a local subversion repository for you behind the scenes. 7. Once linked, note that your database turns green in the Object Explorer. Visit the Commit tab to do an initial commit of your database objects by typing in an appropriate comment and clicking Commit. 8. There is a hidden feature in SQL Source Control that opens up TortoiseSVN (provided it is installed) pointing to the linked repository. Keep Shift depressed and right click on the text to the right of 'Linked to', in the example below, it's the red Evaluation Repository text. Select Open TortoiseSVN Repo Browser. This screen should give you an idea of how SQL Source Control manages the object files behind the scenes. Back in the TeamCity admin console, we'll now create a new project to monitor the above repository location and to trigger a 'build' each time the repository changes. 9. In TeamCity Adminstration, select Create Project and give it a name, such as "My first database CI", and click Create. 10. Click on Create Build Configuration, and name it something like "Integration build". 11. Click VCS settings and then Create And Attach new VCS root. This is where you will tell TeamCity about the repository it should monitor. 12. In my case since I'm using the Just Evaluating option in SQL Source Control, I should select Subversion. 13. In the URL field paste your repository location. In my case this is file:///C:/Users/David.Atkinson/AppData/Local/Red Gate/SQL Source Control 3/EvaluationRepositories/WidgetDevelopment/WidgetDevelopment 14. Click on Test Connection to ensure that you can communicate with your source control system. Click Save. 15. Click Add Build Step, and Runner Type: Command Line. Should you be familiar with the other runner types, such as NAnt, MSBuild or Powershell, you can opt for these, but for the same of keeping it simple I will pick the simplest option. 16. If you have installed SQL Compare in the default location, set the Command Executable field to: C:\Program Files (x86)\Red Gate\SQL Compare 10\sqlcompare.exe 17. Flip back to SSMS briefly and add a new database to your server. This will be the database used for continuous integration testing. 18. Set the command parameters according to your server and the name of the database you have created. In my case I created database RedGateCI on server .\sql2008r2 /scripts1:. /server2:.\sql2008r2 /db2:RedGateCI /sync /verbose Note that if you pick a server instance that isn't on your local machine, you'll need the TCP/IP protocol enabled in SQL Server Configuration Manager otherwise the SQL Compare command line will not be able to connect. 19. Save and select Build Triggering / Add New Trigger / VCS Trigger. This is where you tell TeamCity when it should initiate a build. Click Save. 20. Now return to SQL Server Management Studio and make a schema change (eg add a new object) to your linked development database. A blue indicator will appear in the Object Explorer. Commit this change, typing in an appropriate check-in comment. All being good, within 60 seconds (a TeamCity default that can be changed) a build will be triggered. 21. Click on Projects in TeamCity to get back to the overview screen: The build log will show you the console output, which is useful for troubleshooting any issues: That's it! You now have continuous integration on your database. In future posts I'll cover how you can generate and test the database creation script, the database upgrade script, and run database unit tests as part of your continuous integration script. If you have any trouble getting this up and running please let me know, either by commenting on this post, or email me directly using the email address below. Technorati Tags: SQL Server

    Read the article

  • Attend my GTC sessions

    - by Daniel Moth
    The last GTC conference in the US was 2 years ago and I was there as an attendee. You may recall from that blog post that we were running UX studies at the time. It really feels great 2 years later, to be back at GTC presenting two sessions on C++ AMP, demonstrating our progress that includes input from those early studies. If you are attending GTC (in person or virtually later), be sure to watch my two-part session. Part 1 is S0242 on Wednesday 5pm and part 2 is S0244 on Thursday 10am. Here is the shared abstract for both parts: Harnessing GPU Compute with C++ AMP C++ AMP is an open specification for taking advantage of accelerators like the GPU. In this session we will explore the C++ AMP implementation in Microsoft Visual Studio 11 Beta. After a quick overview of the technology understanding its goals and its differentiation compared with other approaches, we will dive into the programming model and its modern C++ API. This is a code heavy, interactive, two-part session, where every part of the library will be explained. Demos will include showing off the richest parallel and GPU debugging story on the market, in the upcoming Visual Studio release. See you there! Comments about this post by Daniel Moth welcome at the original blog.

    Read the article

  • Visual Studio Exceptions dialogs

    - by Daniel Moth
    Previously I covered step 1 of live debugging with start and attach. Once the debugger is attached, you want to go to step 2 of live debugging, which is to break. One way to break under the debugger is to do nothing, and just wait for an exception to occur in your code. This is true for all types of code that you debug in Visual Studio, and let's consider the following piece of C# code:3: static void Main() 4: { 5: try 6: { 7: int i = 0; 8: int r = 5 / i; 9: } 10: catch (System.DivideByZeroException) {/*gulp. sue me.*/} 11: System.Console.ReadLine(); 12: } If you run this under the debugger do you expect an exception on line 8? It is a trick question: you have to know whether I have configured the debugger to break when exceptions are thrown (first-chance exceptions) or only when they are unhandled. The place you do that is in the Exceptions dialog which is accessible from the Debug->Exceptions menu and on my installation looks like this: Note that I have checked all CLR exceptions. I could have expanded (like shown for the C++ case in my screenshot) and selected specific exceptions. To read more about this dialog, please read the corresponding Exception Handling debugging msdn topic and all its subtopics. So, for the code above, the debugger will break execution due to the thrown exception (exactly as if the try..catch was not there), so I see the following Exception Thrown dialog: Note the following: I can hit continue (or hit break and then later continue) and the program will continue fine since I have a catch handler. If this was an unhandled exception, then that is what the dialog would say (instead of first chance exception) and continuing would crash the app. That hyperlinked text ("Open Exception Settings") opens the Exceptions dialog I described further up. The coolest thing to note is the checkbox - this is new in this latest release of Visual Studio: it is a shortcut to the checkbox in the Exceptions dialog, so you don't have to open it to change this setting for this specific exception - you can toggle that option right from this dialog. Finally, if you try the code above on your system, you may observe a couple of differences from my screenshots. The first is that you may have an additional column of checkboxes in the Exceptions dialog. The second is that the last dialog I shared may look different to you. It all depends on the Debug->Options settings, and the two relevant settings are in this screenshot: The Exception assistant is what configures the look of the UI when the debugger wants to indicate exception to you, and the Just My Code setting controls the extra column in the Exception dialog. You can read more about those options on MSDN: How to break on User-Unhandled exceptions (plus Gregg’s post) and Exception Assistant. Before I leave you to go play with this stuff a bit more, please note that this level of debugging is now available for JavaScript too, and if you are looking at the Exceptions dialog and wondering what the "GPU Memory Access Exceptions" node is about, stay tuned on the C++ AMP blog ;-) Comments about this post by Daniel Moth welcome at the original blog.

    Read the article

  • Metro Walkthrough: Creating a Task List with a ListView and IndexedDB

    - by Stephen.Walther
    The goal of this blog entry is to describe how you can work with data in a Metro style application written with JavaScript. In particular, we create a super simple Task List application which enables you to create and delete tasks. Here’s a video which demonstrates how the Task List application works: In order to build this application, I had to take advantage of several features of the WinJS library and technologies including: IndexedDB – The Task List application stores data in an IndexedDB database. HTML5 Form Validation – The Task List application uses HTML5 validation to ensure that a required field has a value. ListView Control – The Task List application displays the tasks retrieved from the IndexedDB database in a WinJS ListView control. Creating the IndexedDB Database The Task List application stores all of its data in an IndexedDB database named TasksDB. This database is opened/created with the following code: var db; var req = window.msIndexedDB.open("TasksDB", 1); req.onerror = function () { console.log("Could not open database"); }; req.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement:true }); }; The msIndexedDB.open() method accepts two parameters: the name of the database to open and the version of the database to open. If a database with a matching version already exists, then calling the msIndexedDB.open() method opens a connection to the existing database. If the database does not exist then the upgradeneeded event is raised. You handle the upgradeneeded event to create a new database. In the code above, the upgradeneeded event handler creates an object store named “tasks” (An object store roughly corresponds to a database table). When you add items to the tasks object store then each item gets an id property with an auto-incremented value automatically. The code above also includes an error event handler. If the IndexedDB database cannot be opened or created, for whatever reason, then an error message is written to the Visual Studio JavaScript Console window. Displaying a List of Tasks The TaskList application retrieves its list of tasks from the tasks object store, which we created above, and displays the list of tasks in a ListView control. Here is how the ListView control is declared: <div id="tasksListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: TaskList.tasks.dataSource, itemTemplate: select('#taskTemplate'), tapBehavior: 'toggleSelect', selectionMode: 'multi', layout: { type: WinJS.UI.ListLayout } }"> </div> The ListView control is bound to the TaskList.tasks.dataSource data source. The TaskList.tasks.dataSource is created with the following code: // Create the data source var tasks = new WinJS.Binding.List(); // Open the database var db; var req = window.msIndexedDB.open("TasksDB", 1); req.onerror = function () { console.log("Could not open database"); }; req.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement:true }); }; // Load the data source with data from the database req.onsuccess = function () { db = req.result; var tran = db.transaction("tasks"); tran.objectStore("tasks").openCursor().onsuccess = function(event) { var cursor = event.target.result; tasks.dataSource.beginEdits(); if (cursor) { tasks.dataSource.insertAtEnd(null, cursor.value); cursor.continue(); } else { tasks.dataSource.endEdits(); }; }; }; // Expose the data source and functions WinJS.Namespace.define("TaskList", { tasks: tasks }); Notice the success event handler. This handler is called when a database is successfully opened/created. In the code above, all of the items from the tasks object store are retrieved into a cursor and added to a WinJS.Binding.List object named tasks. Because the ListView control is bound to the WinJS.Binding.List object, copying the tasks from the object store into the WinJS.Binding.List object causes the tasks to appear in the ListView: Adding a New Task You add a new task in the Task List application by entering the title of a new task into an HTML form and clicking the Add button. Here’s the markup for creating the form: <form id="addTaskForm"> <input id="newTaskTitle" title="New Task" required /> <button>Add</button> </form> Notice that the INPUT element includes a required attribute. In a Metro application, you can take advantage of HTML5 Validation to validate form fields. If you don’t enter a value for the newTaskTitle field then the following validation error message is displayed: For a brief introduction to HTML5 validation, see my previous blog entry: http://stephenwalther.com/blog/archive/2012/03/13/html5-form-validation.aspx When you click the Add button, the form is submitted and the form submit event is raised. The following code is executed in the default.js file: // Handle Add Task document.getElementById("addTaskForm").addEventListener("submit", function (evt) { evt.preventDefault(); var newTaskTitle = document.getElementById("newTaskTitle"); TaskList.addTask({ title: newTaskTitle.value }); newTaskTitle.value = ""; }); The code above retrieves the title of the new task and calls the addTask() method in the tasks.js file. Here’s the code for the addTask() method which is responsible for actually adding the new task to the IndexedDB database: // Add a new task function addTask(taskToAdd) { var transaction = db.transaction("tasks", IDBTransaction.READ_WRITE); var addRequest = transaction.objectStore("tasks").add(taskToAdd); addRequest.onsuccess = function (evt) { taskToAdd.id = evt.target.result; tasks.dataSource.insertAtEnd(null, taskToAdd); } } The code above does two things. First, it adds the new task to the tasks object store in the IndexedDB database. Second, it adds the new task to the data source bound to the ListView. The dataSource.insertAtEnd() method is called to add the new task to the data source so the new task will appear in the ListView (with a nice little animation). Deleting Existing Tasks The Task List application enables you to select one or more tasks by clicking or tapping on one or more tasks in the ListView. When you click the Delete button, the selected tasks are removed from both the IndexedDB database and the ListView. For example, in the following screenshot, two tasks are selected. The selected tasks appear with a teal background and a checkmark: When you click the Delete button, the following code in the default.js file is executed: // Handle Delete Tasks document.getElementById("btnDeleteTasks").addEventListener("click", function (evt) { tasksListView.winControl.selection.getItems().then(function(items) { items.forEach(function (item) { TaskList.deleteTask(item); }); }); }); The selected tasks are retrieved with the TaskList selection.getItem() method. In the code above, the deleteTask() method is called for each of the selected tasks. Here’s the code for the deleteTask() method: // Delete an existing task function deleteTask(listViewItem) { // Database key != ListView key var dbKey = listViewItem.data.id; var listViewKey = listViewItem.key; // Remove item from db and, if success, remove item from ListView var transaction = db.transaction("tasks", IDBTransaction.READ_WRITE); var deleteRequest = transaction.objectStore("tasks").delete(dbKey); deleteRequest.onsuccess = function () { tasks.dataSource.remove(listViewKey); } } This code does two things: it deletes the existing task from the database and removes the existing task from the ListView. In both cases, the right task is removed by using the key associated with the task. However, the task key is different in the case of the database and in the case of the ListView. In the case of the database, the task key is the value of the task id property. In the case of the ListView, on the other hand, the task key is auto-generated by the ListView. When the task is removed from the ListView, an animation is used to collapse the tasks which appear above and below the task which was removed. The Complete Code Above, I did a lot of jumping around between different files in the application and I left out sections of code. For the sake of completeness, I want to include the entire code here: the default.html, default.js, and tasks.js files. Here are the contents of the default.html file. This file contains the UI for the Task List application: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Task List</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- TaskList references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> <script type="text/javascript" src="js/tasks.js"></script> <style type="text/css"> body { font-size: x-large; } form { display: inline; } #appContainer { margin: 20px; width: 600px; } .win-container { padding: 10px; } </style> </head> <body> <div> <!-- Templates --> <div id="taskTemplate" data-win-control="WinJS.Binding.Template"> <div> <span data-win-bind="innerText:title"></span> </div> </div> <h1>Super Task List</h1> <div id="appContainer"> <form id="addTaskForm"> <input id="newTaskTitle" title="New Task" required /> <button>Add</button> </form> <button id="btnDeleteTasks">Delete</button> <div id="tasksListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: TaskList.tasks.dataSource, itemTemplate: select('#taskTemplate'), tapBehavior: 'toggleSelect', selectionMode: 'multi', layout: { type: WinJS.UI.ListLayout } }"> </div> </div> </div> </body> </html> Here is the code for the default.js file. This code wires up the Add Task form and Delete button: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll().then(function () { // Get reference to Tasks ListView var tasksListView = document.getElementById("tasksListView"); // Handle Add Task document.getElementById("addTaskForm").addEventListener("submit", function (evt) { evt.preventDefault(); var newTaskTitle = document.getElementById("newTaskTitle"); TaskList.addTask({ title: newTaskTitle.value }); newTaskTitle.value = ""; }); // Handle Delete Tasks document.getElementById("btnDeleteTasks").addEventListener("click", function (evt) { tasksListView.winControl.selection.getItems().then(function(items) { items.forEach(function (item) { TaskList.deleteTask(item); }); }); }); }); } }; app.start(); })(); Finally, here is the tasks.js file. This file contains all of the code for opening, creating, and interacting with IndexedDB: (function () { "use strict"; // Create the data source var tasks = new WinJS.Binding.List(); // Open the database var db; var req = window.msIndexedDB.open("TasksDB", 1); req.onerror = function () { console.log("Could not open database"); }; req.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement:true }); }; // Load the data source with data from the database req.onsuccess = function () { db = req.result; var tran = db.transaction("tasks"); tran.objectStore("tasks").openCursor().onsuccess = function(event) { var cursor = event.target.result; tasks.dataSource.beginEdits(); if (cursor) { tasks.dataSource.insertAtEnd(null, cursor.value); cursor.continue(); } else { tasks.dataSource.endEdits(); }; }; }; // Add a new task function addTask(taskToAdd) { var transaction = db.transaction("tasks", IDBTransaction.READ_WRITE); var addRequest = transaction.objectStore("tasks").add(taskToAdd); addRequest.onsuccess = function (evt) { taskToAdd.id = evt.target.result; tasks.dataSource.insertAtEnd(null, taskToAdd); } } // Delete an existing task function deleteTask(listViewItem) { // Database key != ListView key var dbKey = listViewItem.data.id; var listViewKey = listViewItem.key; // Remove item from db and, if success, remove item from ListView var transaction = db.transaction("tasks", IDBTransaction.READ_WRITE); var deleteRequest = transaction.objectStore("tasks").delete(dbKey); deleteRequest.onsuccess = function () { tasks.dataSource.remove(listViewKey); } } // Expose the data source and functions WinJS.Namespace.define("TaskList", { tasks: tasks, addTask: addTask, deleteTask: deleteTask }); })(); Summary I wrote this blog entry because I wanted to create a walkthrough of building a simple database-driven application. In particular, I wanted to demonstrate how you can use a ListView control with an IndexedDB database to store and retrieve database data.

    Read the article

  • Metro: Dynamically Switching Templates with a WinJS ListView

    - by Stephen.Walther
    Imagine that you want to display a list of products using the WinJS ListView control. Imagine, furthermore, that you want to use different templates to display different products. In particular, when a product is on sale, you want to display the product using a special “On Sale” template. In this blog entry, I explain how you can switch templates dynamically when displaying items with a ListView control. In other words, you learn how to use more than one template when displaying items with a ListView control. Creating the Data Source Let’s start by creating the data source for the ListView. Nothing special here – our data source is a list of products. Two of the products, Oranges and Apples, are on sale. (function () { "use strict"; var products = new WinJS.Binding.List([ { name: "Milk", price: 2.44 }, { name: "Oranges", price: 1.99, onSale: true }, { name: "Wine", price: 8.55 }, { name: "Apples", price: 2.44, onSale: true }, { name: "Steak", price: 1.99 }, { name: "Eggs", price: 2.44 }, { name: "Mushrooms", price: 1.99 }, { name: "Yogurt", price: 2.44 }, { name: "Soup", price: 1.99 }, { name: "Cereal", price: 2.44 }, { name: "Pepsi", price: 1.99 } ]); WinJS.Namespace.define("ListViewDemos", { products: products }); })(); The file above is saved with the name products.js and referenced by the default.html page described below. Declaring the Templates and ListView Control Next, we need to declare the ListView control and the two Template controls which we will use to display template items. The markup below appears in the default.html file: <!-- Templates --> <div id="productItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="product"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> </div> <div id="productOnSaleTemplate" data-win-control="WinJS.Binding.Template"> <div class="product onSale"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> (On Sale!) </div> </div> <!-- ListView --> <div id="productsListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.products.dataSource, layout: { type: WinJS.UI.ListLayout } }"> </div> In the markup above, two Template controls are declared. The first template is used when rendering a normal product and the second template is used when rendering a product which is on sale. The second template, unlike the first template, includes the text “(On Sale!)”. The ListView control is bound to the data source which we created in the previous section. The ListView itemDataSource property is set to the value ListViewDemos.products.dataSource. Notice that we do not set the ListView itemTemplate property. We set this property in the default.js file. Switching Between Templates All of the magic happens in the default.js file. The default.js file contains the JavaScript code used to switch templates dynamically. Here’s the entire contents of the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll().then(function () { var productsListView = document.getElementById("productsListView"); productsListView.winControl.itemTemplate = itemTemplateFunction; });; } }; function itemTemplateFunction(itemPromise) { return itemPromise.then(function (item) { // Select either normal product template or on sale template var itemTemplate = document.getElementById("productItemTemplate"); if (item.data.onSale) { itemTemplate = document.getElementById("productOnSaleTemplate"); }; // Render selected template to DIV container var container = document.createElement("div"); itemTemplate.winControl.render(item.data, container); return container; }); } app.start(); })(); In the code above, a function is assigned to the ListView itemTemplate property with the following line of code: productsListView.winControl.itemTemplate = itemTemplateFunction;   The itemTemplateFunction returns a DOM element which is used for the template item. Depending on the value of the product onSale property, the DOM element is generated from either the productItemTemplate or the productOnSaleTemplate template. Using Binding Converters instead of Multiple Templates In the previous sections, I explained how you can use different templates to render normal products and on sale products. There is an alternative approach to displaying different markup for normal products and on sale products. Instead of creating two templates, you can create a single template which contains separate DIV elements for a normal product and an on sale product. The following default.html file contains a single item template and a ListView control bound to the template. <!-- Template --> <div id="productItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="product" data-win-bind="style.display: onSale ListViewDemos.displayNormalProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> <div class="product onSale" data-win-bind="style.display: onSale ListViewDemos.displayOnSaleProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> (On Sale!) </div> </div> <!-- ListView --> <div id="productsListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.products.dataSource, itemTemplate: select('#productItemTemplate'), layout: { type: WinJS.UI.ListLayout } }"> </div> The first DIV element is used to render a normal product: <div class="product" data-win-bind="style.display: onSale ListViewDemos.displayNormalProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> The second DIV element is used to render an “on sale” product: <div class="product onSale" data-win-bind="style.display: onSale ListViewDemos.displayOnSaleProduct"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> (On Sale!) </div> Notice that both templates include a data-win-bind attribute. These data-win-bind attributes are used to show the “normal” template when a product is not on sale and show the “on sale” template when a product is on sale. These attributes set the Cascading Style Sheet display attribute to either “none” or “block”. The data-win-bind attributes take advantage of binding converters. The binding converters are defined in the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll(); } }; WinJS.Namespace.define("ListViewDemos", { displayNormalProduct: WinJS.Binding.converter(function (onSale) { return onSale ? "none" : "block"; }), displayOnSaleProduct: WinJS.Binding.converter(function (onSale) { return onSale ? "block" : "none"; }) }); app.start(); })(); The ListViewDemos.displayNormalProduct binding converter converts the value true or false to the value “none” or “block”. The ListViewDemos.displayOnSaleProduct binding converter does the opposite; it converts the value true or false to the value “block” or “none” (Sadly, you cannot simply place a NOT operator before the onSale property in the binding expression – you need to create both converters). The end result is that you can display different markup depending on the value of the product onSale property. Either the contents of the first or second DIV element are displayed: Summary In this blog entry, I’ve explored two approaches to displaying different markup in a ListView depending on the value of a data item property. The bulk of this blog entry was devoted to explaining how you can assign a function to the ListView itemTemplate property which returns different templates. We created both a productItemTemplate and productOnSaleTemplate and displayed both templates with the same ListView control. We also discussed how you can create a single template and display different markup by using binding converters. The binding converters are used to set a DIV element’s display property to either “none” or “block”. We created a binding converter which displays normal products and a binding converter which displays “on sale” products.

    Read the article

  • Metro: Creating a Master/Detail View with a WinJS ListView Control

    - by Stephen.Walther
    The goal of this blog entry is to explain how you can create a simple master/detail view by using the WinJS ListView and Template controls. In particular, I explain how you can use a ListView control to display a list of movies and how you can use a Template control to display the details of the selected movie. Creating a master/detail view requires completing the following four steps: Create the data source – The data source contains the list of movies. Declare the ListView control – The ListView control displays the entire list of movies. It is the master part of the master/detail view. Declare the Details Template control – The Details Template control displays the details for the selected movie. It is the details part of the master/detail view. Handle the selectionchanged event – You handle the selectionchanged event to display the details for a movie when a new movie is selected. Creating the Data Source There is nothing special about our data source. We initialize a WinJS.Binding.List object to represent a list of movies: (function () { "use strict"; var movies = new WinJS.Binding.List([ { title: "Star Wars", director: "Lucas"}, { title: "Shrek", director: "Adamson" }, { title: "Star Trek", director: "Abrams" }, { title: "Spiderman", director: "Raimi" }, { title: "Memento", director: "Nolan" }, { title: "Minority Report", director: "Spielberg" } ]); // Expose the data source WinJS.Namespace.define("ListViewDemos", { movies: movies }); })(); The data source is exposed to the rest of our application with the name ListViewDemos.movies. Declaring the ListView Control The ListView control is declared with the following markup: <div id="movieList" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.movies.dataSource, itemTemplate: select('#masterItemTemplate'), tapBehavior: 'directSelect', selectionMode: 'single', layout: { type: WinJS.UI.ListLayout } }"> </div> The data-win-options attribute is used to set the following properties of the ListView control: itemDataSource – The ListView is bound to the list of movies which we created in the previous section. Notice that the ListView is bound to ListViewDemos.movies.dataSource and not just ListViewDemos.movies. itemTemplate – The item template contains the template used for rendering each item in the ListView. The markup for this template is included below. tabBehavior – This enumeration determines what happens when you tap or click on an item in the ListView. The possible values are directSelect, toggleSelect, invokeOnly, none. Because we want to handle the selectionchanged event, we set tapBehavior to the value directSelect. selectionMode – This enumeration determines whether you can select multiple items or only a single item. The possible values are none, single, multi. In the code above, this property is set to the value single. layout – You can use ListLayout or GridLayout with a ListView. If you want to display a vertical ListView, then you should select ListLayout. You must associate a ListView with an item template if you want to render anything interesting. The ListView above is associated with an item template named #masterItemTemplate. Here’s the markup for the masterItemTemplate: <div id="masterItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="movie"> <span data-win-bind="innerText:title"></span> </div> </div> This template simply renders the title of each movie. Declaring the Details Template Control The details part of the master/detail view is created with the help of a Template control. Here’s the markup used to declare the Details Template control: <div id="detailsTemplate" data-win-control="WinJS.Binding.Template"> <div> <div> Title: <span data-win-bind="innerText:title"></span> </div> <div> Director: <span data-win-bind="innerText:director"></span> </div> </div> </div> The Details Template control displays the movie title and director.   Handling the selectionchanged Event The ListView control can raise two types of events: the iteminvoked and selectionchanged events. The iteminvoked event is raised when you click on a ListView item. The selectionchanged event is raised when one or more ListView items are selected. When you set the tapBehavior property of the ListView control to the value “directSelect” then tapping or clicking a list item raised both the iteminvoked and selectionchanged event. Tapping a list item causes the item to be selected and the item appears with a checkmark. In our code, we handle the selectionchanged event to update the movie details Template when you select a new movie. Here’s the code from the default.js file used to handle the selectionchanged event: var movieList = document.getElementById("movieList"); var detailsTemplate = document.getElementById("detailsTemplate"); var movieDetails = document.getElementById("movieDetails"); // Setup selectionchanged handler movieList.winControl.addEventListener("selectionchanged", function (evt) { if (movieList.winControl.selection.count() > 0) { movieList.winControl.selection.getItems().then(function (items) { // Clear the template container movieDetails.innerHTML = ""; // Render the template detailsTemplate.winControl.render(items[0].data, movieDetails); }); } }); The code above sets up an event handler (listener) for the selectionchanged event. The event handler first verifies that an item has been selected in the ListView (selection.count() > 0). Next, the details for the movie are rendered using the movie details Template (we created this Template in the previous section). The Complete Code For the sake of completeness, I’ve included the complete code for the master/detail view below. I’ve included both the default.html, default.js, and movies.js files. Here is the final code for the default.html file: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>ListViewMasterDetail</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- ListViewMasterDetail references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> <script type="text/javascript" src="js/movies.js"></script> <style type="text/css"> body { font-size: xx-large; } .movie { padding: 5px; } #masterDetail { display: -ms-box; } #movieList { width: 300px; margin: 20px; } #movieDetails { margin: 20px; } </style> </head> <body> <!-- Templates --> <div id="masterItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="movie"> <span data-win-bind="innerText:title"></span> </div> </div> <div id="detailsTemplate" data-win-control="WinJS.Binding.Template"> <div> <div> Title: <span data-win-bind="innerText:title"></span> </div> <div> Director: <span data-win-bind="innerText:director"></span> </div> </div> </div> <!-- Master/Detail --> <div id="masterDetail"> <!-- Master --> <div id="movieList" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.movies.dataSource, itemTemplate: select('#masterItemTemplate'), tapBehavior: 'directSelect', selectionMode: 'single', layout: { type: WinJS.UI.ListLayout } }"> </div> <!-- Detail --> <div id="movieDetails"></div> </div> </body> </html> Here is the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll(); var movieList = document.getElementById("movieList"); var detailsTemplate = document.getElementById("detailsTemplate"); var movieDetails = document.getElementById("movieDetails"); // Setup selectionchanged handler movieList.winControl.addEventListener("selectionchanged", function (evt) { if (movieList.winControl.selection.count() > 0) { movieList.winControl.selection.getItems().then(function (items) { // Clear the template container movieDetails.innerHTML = ""; // Render the template detailsTemplate.winControl.render(items[0].data, movieDetails); }); } }); } }; app.start(); })();   Here is the movies.js file: (function () { "use strict"; var movies = new WinJS.Binding.List([ { title: "Star Wars", director: "Lucas"}, { title: "Shrek", director: "Adamson" }, { title: "Star Trek", director: "Abrams" }, { title: "Spiderman", director: "Raimi" }, { title: "Memento", director: "Nolan" }, { title: "Minority Report", director: "Spielberg" } ]); // Expose the data source WinJS.Namespace.define("ListViewDemos", { movies: movies }); })();   Summary The purpose of this blog entry was to describe how to create a simple master/detail view by taking advantage of the WinJS ListView control. We handled the selectionchanged event of the ListView control to display movie details when you select a movie in the ListView.

    Read the article

  • Metro: Grouping Items in a ListView Control

    - by Stephen.Walther
    The purpose of this blog entry is to explain how you can group list items when displaying the items in a WinJS ListView control. In particular, you learn how to group a list of products by product category. Displaying a grouped list of items in a ListView control requires completing the following steps: Create a Grouped data source from a List data source Create a Grouped Header Template Declare the ListView control so it groups the list items Creating the Grouped Data Source Normally, you bind a ListView control to a WinJS.Binding.List object. If you want to render list items in groups, then you need to bind the ListView to a grouped data source instead. The following code – contained in a file named products.js — illustrates how you can create a standard WinJS.Binding.List object from a JavaScript array and then return a grouped data source from the WinJS.Binding.List object by calling its createGrouped() method: (function () { "use strict"; // Create List data source var products = new WinJS.Binding.List([ { name: "Milk", price: 2.44, category: "Beverages" }, { name: "Oranges", price: 1.99, category: "Fruit" }, { name: "Wine", price: 8.55, category: "Beverages" }, { name: "Apples", price: 2.44, category: "Fruit" }, { name: "Steak", price: 1.99, category: "Other" }, { name: "Eggs", price: 2.44, category: "Other" }, { name: "Mushrooms", price: 1.99, category: "Other" }, { name: "Yogurt", price: 2.44, category: "Other" }, { name: "Soup", price: 1.99, category: "Other" }, { name: "Cereal", price: 2.44, category: "Other" }, { name: "Pepsi", price: 1.99, category: "Beverages" } ]); // Create grouped data source var groupedProducts = products.createGrouped( function (dataItem) { return dataItem.category; }, function (dataItem) { return { title: dataItem.category }; }, function (group1, group2) { return group1.charCodeAt(0) - group2.charCodeAt(0); } ); // Expose the grouped data source WinJS.Namespace.define("ListViewDemos", { products: groupedProducts }); })(); Notice that the createGrouped() method requires three functions as arguments: groupKey – This function associates each list item with a group. The function accepts a data item and returns a key which represents a group. In the code above, we return the value of the category property for each product. groupData – This function returns the data item displayed by the group header template. For example, in the code above, the function returns a title for the group which is displayed in the group header template. groupSorter – This function determines the order in which the groups are displayed. The code above displays the groups in alphabetical order: Beverages, Fruit, Other. Creating the Group Header Template Whenever you create a ListView control, you need to create an item template which you use to control how each list item is rendered. When grouping items in a ListView control, you also need to create a group header template. The group header template is used to render the header for each group of list items. Here’s the markup for both the item template and the group header template: <div id="productTemplate" data-win-control="WinJS.Binding.Template"> <div class="product"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> </div> <div id="productGroupHeaderTemplate" data-win-control="WinJS.Binding.Template"> <div class="productGroupHeader"> <h1 data-win-bind="innerText: title"></h1> </div> </div> You should declare the two templates in the same file as you declare the ListView control – for example, the default.html file. Declaring the ListView Control The final step is to declare the ListView control. Here’s the required markup: <div data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource:ListViewDemos.products.dataSource, itemTemplate:select('#productTemplate'), groupDataSource:ListViewDemos.products.groups.dataSource, groupHeaderTemplate:select('#productGroupHeaderTemplate'), layout: {type: WinJS.UI.GridLayout} }"> </div> In the markup above, six properties of the ListView control are set when the control is declared. First the itemDataSource and itemTemplate are specified. Nothing new here. Next, the group data source and group header template are specified. Notice that the group data source is represented by the ListViewDemos.products.groups.dataSource property of the grouped data source. Finally, notice that the layout of the ListView is changed to Grid Layout. You are required to use Grid Layout (instead of the default List Layout) when displaying grouped items in a ListView. Here’s the entire contents of the default.html page: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>ListViewDemos</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- ListViewDemos references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> <script src="/js/products.js" type="text/javascript"></script> <style type="text/css"> .product { width: 200px; height: 100px; border: white solid 1px; font-size: x-large; } </style> </head> <body> <div id="productTemplate" data-win-control="WinJS.Binding.Template"> <div class="product"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> </div> <div id="productGroupHeaderTemplate" data-win-control="WinJS.Binding.Template"> <div class="productGroupHeader"> <h1 data-win-bind="innerText: title"></h1> </div> </div> <div data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource:ListViewDemos.products.dataSource, itemTemplate:select('#productTemplate'), groupDataSource:ListViewDemos.products.groups.dataSource, groupHeaderTemplate:select('#productGroupHeaderTemplate'), layout: {type: WinJS.UI.GridLayout} }"> </div> </body> </html> Notice that the default.html page includes a reference to the products.js file: <script src=”/js/products.js” type=”text/javascript”></script> The default.html page also contains the declarations of the item template, group header template, and ListView control. Summary The goal of this blog entry was to explain how you can group items in a ListView control. You learned how to create a grouped data source, a group header template, and declare a ListView so that it groups its list items.

    Read the article

  • Metro: Introduction to the WinJS ListView Control

    - by Stephen.Walther
    The goal of this blog entry is to provide a quick introduction to the ListView control – just the bare minimum that you need to know to start using the control. When building Metro style applications using JavaScript, the ListView control is the primary control that you use for displaying lists of items. For example, if you are building a product catalog app, then you can use the ListView control to display the list of products. The ListView control supports several advanced features that I plan to discuss in future blog entries. For example, you can group the items in a ListView, you can create master/details views with a ListView, and you can efficiently work with large sets of items with a ListView. In this blog entry, we’ll keep things simple and focus on displaying a list of products. There are three things that you need to do in order to display a list of items with a ListView: Create a data source Create an Item Template Declare the ListView Creating the ListView Data Source The first step is to create (or retrieve) the data that you want to display with the ListView. In most scenarios, you will want to bind a ListView to a WinJS.Binding.List object. The nice thing about the WinJS.Binding.List object is that it enables you to take a standard JavaScript array and convert the array into something that can be bound to the ListView. It doesn’t matter where the JavaScript array comes from. It could be a static array that you declare or you could retrieve the array as the result of an Ajax call to a remote server. The following JavaScript file – named products.js – contains a list of products which can be bound to a ListView. (function () { "use strict"; var products = new WinJS.Binding.List([ { name: "Milk", price: 2.44 }, { name: "Oranges", price: 1.99 }, { name: "Wine", price: 8.55 }, { name: "Apples", price: 2.44 }, { name: "Steak", price: 1.99 }, { name: "Eggs", price: 2.44 }, { name: "Mushrooms", price: 1.99 }, { name: "Yogurt", price: 2.44 }, { name: "Soup", price: 1.99 }, { name: "Cereal", price: 2.44 }, { name: "Pepsi", price: 1.99 } ]); WinJS.Namespace.define("ListViewDemos", { products: products }); })(); The products variable represents a WinJS.Binding.List object. This object is initialized with a plain-old JavaScript array which represents an array of products. To avoid polluting the global namespace, the code above uses the module pattern and exposes the products using a namespace. The list of products is exposed to the world as ListViewDemos.products. To learn more about the module pattern and namespaces in WinJS, see my earlier blog entry: http://stephenwalther.com/blog/archive/2012/02/22/metro-namespaces-and-modules.aspx Creating the ListView Item Template The ListView control does not know how to render anything. It doesn’t know how you want each list item to appear. To get the ListView control to render something useful, you must create an Item Template. Here’s what our template for rendering an individual product looks like: <div id="productTemplate" data-win-control="WinJS.Binding.Template"> <div class="product"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> </div> This template displays the product name and price from the data source. Normally, you will declare your template in the same file as you declare the ListView control. In our case, both the template and ListView are declared in the default.html file. To learn more about templates, see my earlier blog entry: http://stephenwalther.com/blog/archive/2012/02/27/metro-using-templates.aspx Declaring the ListView The final step is to declare the ListView control in a page. Here’s the markup for declaring a ListView: <div data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource:ListViewDemos.products.dataSource, itemTemplate:select('#productTemplate') }"> </div> You declare a ListView by adding the data-win-control to an HTML DIV tag. The data-win-options attribute is used to set two properties of the ListView. The ListView is associated with its data source with the itemDataSource property. Notice that the data source is ListViewDemos.products.dataSource and not just ListViewDemos.products. You need to associate the ListView with the dataSoure property. The ListView is associated with its item template with the help of the itemTemplate property. The ID of the item template — #productTemplate – is used to select the template from the page. Here’s what the complete version of the default.html page looks like: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>ListViewDemos</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- ListViewDemos references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> <script src="/js/products.js" type="text/javascript"></script> <style type="text/css"> .product { width: 200px; height: 100px; border: white solid 1px; } </style> </head> <body> <div id="productTemplate" data-win-control="WinJS.Binding.Template"> <div class="product"> <span data-win-bind="innerText:name"></span> <span data-win-bind="innerText:price"></span> </div> </div> <div data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource:ListViewDemos.products.dataSource, itemTemplate:select('#productTemplate') }"> </div> </body> </html> Notice that the page above includes a reference to the products.js file: <script src=”/js/products.js” type=”text/javascript”></script> The page above also contains a Template control which contains the ListView item template. Finally, the page includes the declaration of the ListView control. Summary The goal of this blog entry was to describe the minimal set of steps which you must complete to use the WinJS ListView control to display a simple list of items. You learned how to create a data source, declare an item template, and declare a ListView control.

    Read the article

  • Ajax Control Toolkit May 2012 Release

    - by Stephen.Walther
    I’m happy to announce the May 2012 release of the Ajax Control Toolkit. This newest release of the Ajax Control Toolkit includes a new file upload control which displays file upload progress. We’ve also added several significant enhancements to the existing HtmlEditorExtender control such as support for uploading images and Source View. You can download and start using the newest version of the Ajax Control Toolkit by entering the following command in the Library Package Manager console in Visual Studio: Install-Package AjaxControlToolkit Alternatively, you can download the latest version of the Ajax Control Toolkit from CodePlex: http://AjaxControlToolkit.CodePlex.com The New Ajax File Upload Control The most requested new feature for the Ajax Control Toolkit (according to the CodePlex Issue Tracker) has been support for file upload with progress. We worked hard over the last few months to create an entirely new file upload control which displays upload progress. Here is a sample which illustrates how you can use the new AjaxFileUpload control: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="01_FileUpload.aspx.cs" Inherits="WebApplication1._01_FileUpload" %> <html> <head runat="server"> <title>Simple File Upload</title> </head> <body> <form id="form1" runat="server"> <div> <ajaxToolkit:ToolkitScriptManager runat="server" /> <ajaxToolkit:AjaxFileUpload id="ajaxUpload1" OnUploadComplete="ajaxUpload1_OnUploadComplete" runat="server" /> </div> </form> </body> </html> The page above includes a ToolkitScriptManager control. This control is required to use any of the controls in the Ajax Control Toolkit because this control is responsible for loading all of the scripts required by a control. The page also contains an AjaxFileUpload control. The UploadComplete event is handled in the code-behind for the page: namespace WebApplication1 { public partial class _01_FileUpload : System.Web.UI.Page { protected void ajaxUpload1_OnUploadComplete(object sender, AjaxControlToolkit.AjaxFileUploadEventArgs e) { // Generate file path string filePath = "~/Images/" + e.FileName; // Save upload file to the file system ajaxUpload1.SaveAs(MapPath(filePath)); } } } The UploadComplete handler saves each uploaded file by calling the AjaxFileUpload control’s SaveAs() method with a full file path. Here’s a video which illustrates the process of uploading a file: Warning: in order to write to the Images folder on a production IIS server, you need Write permissions on the Images folder. You need to provide permissions for the IIS Application Pool account to write to the Images folder. To learn more, see: http://learn.iis.net/page.aspx/624/application-pool-identities/ Showing File Upload Progress The new AjaxFileUpload control takes advantage of HTML5 upload progress events (described in the XMLHttpRequest Level 2 standard). This standard is supported by Firefox 8+, Chrome 16+, Safari 5+, and Internet Explorer 10+. In other words, the standard is supported by the most recent versions of all browsers except for Internet Explorer which will support the standard with the release of Internet Explorer 10. The AjaxFileUpload control works with all browsers, even browsers which do not support the new XMLHttpRequest Level 2 standard. If you use the AjaxFileUpload control with a downlevel browser – such as Internet Explorer 9 — then you get a simple throbber image during a file upload instead of a progress indicator. Here’s how you specify a throbber image when declaring the AjaxFileUpload control: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="02_FileUpload.aspx.cs" Inherits="WebApplication1._02_FileUpload" %> <html> <head id="Head1" runat="server"> <title>File Upload with Throbber</title> </head> <body> <form id="form1" runat="server"> <div> <ajaxToolkit:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server" /> <ajaxToolkit:AjaxFileUpload id="ajaxUpload1" OnUploadComplete="ajaxUpload1_OnUploadComplete" ThrobberID="MyThrobber" runat="server" /> <asp:Image id="MyThrobber" ImageUrl="ajax-loader.gif" Style="display:None" runat="server" /> </div> </form> </body> </html> Notice that the page above includes an image with the Id MyThrobber. This image is displayed while files are being uploaded. I use the website http://AjaxLoad.info to generate animated busy wait images. Drag-And-Drop File Upload If you are using an uplevel browser then you can drag-and-drop the files which you want to upload onto the AjaxFileUpload control. The following video illustrates how drag-and-drop works: Remember that drag-and-drop will not work on Internet Explorer 9 or older. Accepting Multiple Files By default, the AjaxFileUpload control enables you to upload multiple files at a time. When you open the file dialog, use the CTRL or SHIFT key to select multiple files. If you want to restrict the number of files that can be uploaded then use the MaximumNumberOfFiles property like this: <ajaxToolkit:AjaxFileUpload id="ajaxUpload1" OnUploadComplete="ajaxUpload1_OnUploadComplete" ThrobberID="throbber" MaximumNumberOfFiles="1" runat="server" /> In the code above, the maximum number of files which can be uploaded is restricted to a single file. Restricting Uploaded File Types You might want to allow only certain types of files to be uploaded. For example, you might want to accept only image uploads. In that case, you can use the AllowedFileTypes property to provide a list of allowed file types like this: <ajaxToolkit:AjaxFileUpload id="ajaxUpload1" OnUploadComplete="ajaxUpload1_OnUploadComplete" ThrobberID="throbber" AllowedFileTypes="jpg,jpeg,gif,png" runat="server" /> The code above prevents any files except jpeg, gif, and png files from being uploaded. Enhancements to the HTMLEditorExtender Over the past months, we spent a considerable amount of time making bug fixes and feature enhancements to the existing HtmlEditorExtender control. I want to focus on two of the most significant enhancements that we made to the control: support for Source View and support for uploading images. Adding Source View Support to the HtmlEditorExtender When you click the Source View tag, the HtmlEditorExtender changes modes and displays the HTML source of the contents contained in the TextBox being extended. You can use Source View to make fine-grain changes to HTML before submitting the HTML to the server. For reasons of backwards compatibility, the Source View tab is disabled by default. To enable Source View, you need to declare your HtmlEditorExtender with the DisplaySourceTab property like this: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="05_SourceView.aspx.cs" Inherits="WebApplication1._05_SourceView" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html> <head id="Head1" runat="server"> <title>HtmlEditorExtender with Source View</title> </head> <body> <form id="form1" runat="server"> <div> <ajaxToolkit:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server" /> <asp:TextBox id="txtComments" TextMode="MultiLine" Columns="60" Rows="10" Runat="server" /> <ajaxToolkit:HtmlEditorExtender id="HEE1" TargetControlID="txtComments" DisplaySourceTab="true" runat="server" /> </div> </form> </body> </html> The page above includes a ToolkitScriptManager, TextBox, and HtmlEditorExtender control. The HtmlEditorExtender extends the TextBox so that it supports rich text editing. Notice that the HtmlEditorExtender includes a DisplaySourceTab property. This property causes a button to appear at the bottom of the HtmlEditorExtender which enables you to switch to Source View: Note: when using the HtmlEditorExtender, we recommend that you set the DOCTYPE for the document. Otherwise, you can encounter weird formatting issues. Accepting Image Uploads We also enhanced the HtmlEditorExtender to support image uploads (another very highly requested feature at CodePlex). The following video illustrates the experience of adding an image to the editor: Once again, for backwards compatibility reasons, support for image uploads is disabled by default. Here’s how you can declare the HtmlEditorExtender so that it supports image uploads: <ajaxToolkit:HtmlEditorExtender id="MyHtmlEditorExtender" TargetControlID="txtComments" OnImageUploadComplete="MyHtmlEditorExtender_ImageUploadComplete" DisplaySourceTab="true" runat="server" > <Toolbar> <ajaxToolkit:Bold /> <ajaxToolkit:Italic /> <ajaxToolkit:Underline /> <ajaxToolkit:InsertImage /> </Toolbar> </ajaxToolkit:HtmlEditorExtender> There are two things that you should notice about the code above. First, notice that an InsertImage toolbar button is added to the HtmlEditorExtender toolbar. This HtmlEditorExtender will render toolbar buttons for bold, italic, underline, and insert image. Second, notice that the HtmlEditorExtender includes an event handler for the ImageUploadComplete event. The code for this event handler is below: using System.Web.UI; using AjaxControlToolkit; namespace WebApplication1 { public partial class _06_ImageUpload : System.Web.UI.Page { protected void MyHtmlEditorExtender_ImageUploadComplete(object sender, AjaxFileUploadEventArgs e) { // Generate file path string filePath = "~/Images/" + e.FileName; // Save uploaded file to the file system var ajaxFileUpload = (AjaxFileUpload)sender; ajaxFileUpload.SaveAs(MapPath(filePath)); // Update client with saved image path e.PostedUrl = Page.ResolveUrl(filePath); } } } Within the ImageUploadComplete event handler, you need to do two things: 1) Save the uploaded image (for example, to the file system, a database, or Azure storage) 2) Provide the URL to the saved image so the image can be displayed within the HtmlEditorExtender In the code above, the uploaded image is saved to the ~/Images folder. The path of the saved image is returned to the client by setting the AjaxFileUploadEventArgs PostedUrl property. Not surprisingly, under the covers, the HtmlEditorExtender uses the AjaxFileUpload. You can get a direct reference to the AjaxFileUpload control used by an HtmlEditorExtender by using the following code: void Page_Load() { var ajaxFileUpload = MyHtmlEditorExtender.AjaxFileUpload; ajaxFileUpload.AllowedFileTypes = "jpg,jpeg"; } The code above illustrates how you can restrict the types of images that can be uploaded to the HtmlEditorExtender. This code prevents anything but jpeg images from being uploaded. Summary This was the most difficult release of the Ajax Control Toolkit to date. We iterated through several designs for the AjaxFileUpload control – with each iteration, the goal was to make the AjaxFileUpload control easier for developers to use. My hope is that we were able to create a control which Web Forms developers will find very intuitive. I want to thank the developers on the Superexpert.com team for their hard work on this release.

    Read the article

  • How To Peel Garlic In Quick & Easy Way

    - by Gopinath
    Garlic is very common ingredient used in cooking in many parts of the world. In India it’s an undeniable ingredient in almost all the food items that are made using masala. So every cook of Indian kitchen knows the pain of peeling garlic. It’s a messy and time consuming process to peel of all the dead skin layers to get the tasty cloves. Cooking web site Saveur shows us as easy way to peel an entire garlic in less than 10 seconds using just two bowls.  No knifes, no scissor or any other instruments. Check the embedded video   I’ve not yet tried this trick at home, but looks like very easy one. What do you say? via Lifehacker (thanks vijay). cc image credit: flickr/lightlady

    Read the article

< Previous Page | 7 8 9 10 11 12 13 14 15 16 17 18  | Next Page >