http://www.gideondsouza.com:80/Tags/winformsGideon Dsouza - winformshttp://www.gideondsouza.com:80/blog/implementing-simple-instant-search-with-rx-reactive-extensions<p>Haven't heard of Rx, this could be a little starter tutorial for you.</p> <p>Rx or Microsoft's <a href="http://msdn.microsoft.com/en-us/data/gg577609">Reactive extensions </a>makes life simple when it comes to asychronous programming</p> <p>My most favorite thing about Rx is how simple it makes <em>instant</em> search! A while ago I <a href="http://stackoverflow.com/questions/4278069/implement-instant-threaded-search-algorithm">asked around on stackoverflow</a> and just architecturing it was so difficult.</p> <p>So I'm going to go through a dead simple example, where we're going to have an <strong>instant search</strong>, but, we'll have some dummy data in memory that we're going to search.</p> <p><strong>Update</strong> : I wrote a continuation of this article <a href="http://gideondsouza.com/blog/abstracting-reactive-extensions-for-sql-server-compact-and-implementing-an-instant-search">here</a> where I describe instant search with Rx on a SqlCE database and a nice clean abstraction.</p> <p>Here's what it'll look like:</p> <p><img src="http://www.gideondsouza.com/Media/Default/BlogPost/blog/appCapture.JPG" alt="Instant Search App"></p> <p>I hope to do a post on searching real data, maybe with sql-compact 4, and then I'll get on to how to write <a href="http://stackoverflow.com/questions/5349140/iasyncrepository-or-iobservablerepository-for-silverlight-4-wcf-data-services">Observable Repositories</a> which makes life easier, especially for Silverlight!</p> <p><strong>How To:</strong></p> <p>So head over to Visual Studio and create a new form (or you can <a href="http://www.gideondsouza.com/Media/Default/Misc/BasicRxSearchClean.zip">download the sample</a>). Add a textbox and listbox like the screenshot.</p> <p>We need to install <a href="http://nuget.org/List/Packages/Rx-Main">Rx-Main</a> and <a href="http://nuget.org/List/Packages/Rx-WinForms">Rx-WinForms</a> from nuget.</p> <p>You can right click your solution and choose <code>Manage Nuget Packages..</code> and search and install these.</p> <p><img src="http://www.gideondsouza.com/Media/Default/BlogPost/blog/nugetScrenie.JPG" alt="Visual Studio Package Manager"></p> <p>This is the code then:</p> <script src="https://gist.github.com/1422982.js"> </script> <p><strong>What/How/Why?</strong> :</p> <p>The starting point to observables is the <a href="http://msdn.microsoft.com/en-us/library/hh244252(v=VS.103).aspx">Observable</a> class, the <a href="http://msdn.microsoft.com/en-us/library/hh229251(v=VS.103).aspx">FromEventPattern</a> method creates an observable sequence from the <code>TextChanged</code> event of the textbox. </p> <p>Think of this like a list of notifications coming to you. </p> <p>We then chain a method call to <a href="http://msdn.microsoft.com/en-us/library/hh229400(v=VS.103).aspx">Throttle</a> (my fav part!), it well, throttles this list of notifications by 500 milliseconds. </p> <p>Here, for win-forms you need the <a href="http://msdn.microsoft.com/en-us/library/hh212067(v=VS.103).aspx">ControlScheduler</a> class otherwise the throttling doesn't work too well. This class comes from the Rx-WinForms package we added earlier. The <a href="http://msdn.microsoft.com/en-us/library/hh228941(v=VS.103).aspx">Do</a> method just does the metho you want to run, and you send off the text from the the textbox over. Lastly, calling Subscribe starts off the notifications.</p> <p><a href="http://www.gideondsouza.com/Media/Default/Misc/BasicRxSearchClean.zip">Download the Sample here.</a>(1.3MB) It's a clean solution but with the Rx nuget packages.</p> <p>Hope this was useful!</p> Thu, 17 Nov 2011 19:21:00 GMThttp://www.gideondsouza.com:80/blog/implementing-simple-instant-search-with-rx-reactive-extensions