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  • WPF binding: Doing a temperature converter app

    - by Bob
    Hi there, I'm doing a little app that basically has 2 text boxes. You'll enter Fahrenheit into TextBoxA and Celsius into TextBoxB. As the text changes in TextBoxA I want the equivalent Celsius value to be displayed in TextBoxB and vice versa. I can come up with a solution pretty easy for this but i'm trying to be a little clever. Is there a way to do it all in Xaml except for a Convert class that does the maths? So basically I want the TextChanged event of one textBox to pass in it's value into a Converter class that is evaluated and sent to the other TextBox and visa versa. Anyone know how I can achieve this ... and if it's possible at all?

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  • How does * work in Python

    - by Deqing
    Just switched from C++ to Python, and found that sometimes it is a little hard to understand ideas behind Python. I guess, a variable is a reference to the real object. For example, a=(1,2,5) meaning a - (1,2,5), so if b=a, then b and a are 2 references pointing to the same (1,2,5). It is a little like pointers in C/C++. If I have: def foo(a,b,c): print a,b,c a=(1,3,5) foo(*a) What does * mean here? Looks like it expands tuple a to a[0], a[1] and a[2]. But why print(*a) is not working while print(a[0],a[1],a[2]) works fine?

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  • What you would learn. [closed]

    - by NDeveloper
    Hi, I have a little free time and would like to learn new development language/technology. I know it can be very subective, but please share with us what you would learn and why. I have about 4 years of .NET development experience mostly distributed applications. And a little more than 2 years of c/c++. There are a lot of options to choose like Google Go/F#/Python/Scala/Java/ASP.NET/Mobile App development like for Android, BB, iPhone.../DB (MS SQL, Oracle or even MongoDB or CouchDB)/any new concepts, etc... I would like to use the time for investment, so gained knowledge will be useful.

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  • Would Lisp be extremely difficult for a new(ish) programmer to learn?

    - by Rubber Duchy
    I've got a little experience with Python (enough to where I can do if/else/elif and some random number generation), but I've always had a weird fascination with the Lisp languages. I downloaded some scheme source code to look at the syntax but it was pretty much gibberish to me. For a programmer with only a little programming experience like myself, given some good books, websites, and some time, would it be particularly difficult to learn either Common Lisp or Scheme? Which of the two would be easier? How do they compare with Python and C, as far as ease of learning? Thanks

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  • Microsoft and jQuery

    - by Rick Strahl
    The jQuery JavaScript library has been steadily getting more popular and with recent developments from Microsoft, jQuery is also getting ever more exposure on the ASP.NET platform including now directly from Microsoft. jQuery is a light weight, open source DOM manipulation library for JavaScript that has changed how many developers think about JavaScript. You can download it and find more information on jQuery on www.jquery.com. For me jQuery has had a huge impact on how I develop Web applications and was probably the main reason I went from dreading to do JavaScript development to actually looking forward to implementing client side JavaScript functionality. It has also had a profound impact on my JavaScript skill level for me by seeing how the library accomplishes things (and often reviewing the terse but excellent source code). jQuery made an uncomfortable development platform (JavaScript + DOM) a joy to work on. Although jQuery is by no means the only JavaScript library out there, its ease of use, small size, huge community of plug-ins and pure usefulness has made it easily the most popular JavaScript library available today. As a long time jQuery user, I’ve been excited to see the developments from Microsoft that are bringing jQuery to more ASP.NET developers and providing more integration with jQuery for ASP.NET’s core features rather than relying on the ASP.NET AJAX library. Microsoft and jQuery – making Friends jQuery is an open source project but in the last couple of years Microsoft has really thrown its weight behind supporting this open source library as a supported component on the Microsoft platform. When I say supported I literally mean supported: Microsoft now offers actual tech support for jQuery as part of their Product Support Services (PSS) as jQuery integration has become part of several of the ASP.NET toolkits and ships in several of the default Web project templates in Visual Studio 2010. The ASP.NET MVC 3 framework (still in Beta) also uses jQuery for a variety of client side support features including client side validation and we can look forward toward more integration of client side functionality via jQuery in both MVC and WebForms in the future. In other words jQuery is becoming an optional but included component of the ASP.NET platform. PSS support means that support staff will answer jQuery related support questions as part of any support incidents related to ASP.NET which provides some piece of mind to some corporate development shops that require end to end support from Microsoft. In addition to including jQuery and supporting it, Microsoft has also been getting involved in providing development resources for extending jQuery’s functionality via plug-ins. Microsoft’s last version of the Microsoft Ajax Library – which is the successor to the native ASP.NET AJAX Library – included some really cool functionality for client templates, databinding and localization. As it turns out Microsoft has rebuilt most of that functionality using jQuery as the base API and provided jQuery plug-ins of these components. Very recently these three plug-ins were submitted and have been approved for inclusion in the official jQuery plug-in repository and been taken over by the jQuery team for further improvements and maintenance. Even more surprising: The jQuery-templates component has actually been approved for inclusion in the next major update of the jQuery core in jQuery V1.5, which means it will become a native feature that doesn’t require additional script files to be loaded. Imagine this – an open source contribution from Microsoft that has been accepted into a major open source project for a core feature improvement. Microsoft has come a long way indeed! What the Microsoft Involvement with jQuery means to you For Microsoft jQuery support is a strategic decision that affects their direction in client side development, but nothing stopped you from using jQuery in your applications prior to Microsoft’s official backing and in fact a large chunk of developers did so readily prior to Microsoft’s announcement. Official support from Microsoft brings a few benefits to developers however. jQuery support in Visual Studio 2010 means built-in support for jQuery IntelliSense, automatically added jQuery scripts in many projects types and a common base for client side functionality that actually uses what most developers are already using. If you have already been using jQuery and were worried about straying from the Microsoft line and their internal Microsoft Ajax Library – worry no more. With official support and the change in direction towards jQuery Microsoft is now following along what most in the ASP.NET community had already been doing by using jQuery, which is likely the reason for Microsoft’s shift in direction in the first place. ASP.NET AJAX and the Microsoft AJAX Library weren’t bad technology – there was tons of useful functionality buried in these libraries. However, these libraries never got off the ground, mainly because early incarnations were squarely aimed at control/component developers rather than application developers. For all the functionality that these controls provided for control developers they lacked in useful and easily usable application developer functionality that was easily accessible in day to day client side development. The result was that even though Microsoft shipped support for these tools in the box (in .NET 3.5 and 4.0), other than for the internal support in ASP.NET for things like the UpdatePanel and the ASP.NET AJAX Control Toolkit as well as some third party vendors, the Microsoft client libraries were largely ignored by the developer community opening the door for other client side solutions. Microsoft seems to be acknowledging developer choice in this case: Many more developers were going down the jQuery path rather than using the Microsoft built libraries and there seems to be little sense in continuing development of a technology that largely goes unused by the majority of developers. Kudos for Microsoft for recognizing this and gracefully changing directions. Note that even though there will be no further development in the Microsoft client libraries they will continue to be supported so if you’re using them in your applications there’s no reason to start running for the exit in a panic and start re-writing everything with jQuery. Although that might be a reasonable choice in some cases, jQuery and the Microsoft libraries work well side by side so that you can leave existing solutions untouched even as you enhance them with jQuery. The Microsoft jQuery Plug-ins – Solid Core Features One of the most interesting developments in Microsoft’s embracing of jQuery is that Microsoft has started contributing to jQuery via standard mechanism set for jQuery developers: By submitting plug-ins. Microsoft took some of the nicest new features of the unpublished Microsoft Ajax Client Library and re-wrote these components for jQuery and then submitted them as plug-ins to the jQuery plug-in repository. Accepted plug-ins get taken over by the jQuery team and that’s exactly what happened with the three plug-ins submitted by Microsoft with the templating plug-in even getting slated to be published as part of the jQuery core in the next major release (1.5). The following plug-ins are provided by Microsoft: jQuery Templates – a client side template rendering engine jQuery Data Link – a client side databinder that can synchronize changes without code jQuery Globalization – provides formatting and conversion features for dates and numbers The first two are ports of functionality that was slated for the Microsoft Ajax Library while functionality for the globalization library provides functionality that was already found in the original ASP.NET AJAX library. To me all three plug-ins address a pressing need in client side applications and provide functionality I’ve previously used in other incarnations, but with more complete implementations. Let’s take a close look at these plug-ins. jQuery Templates http://api.jquery.com/category/plugins/templates/ Client side templating is a key component for building rich JavaScript applications in the browser. Templating on the client lets you avoid from manually creating markup by creating DOM nodes and injecting them individually into the document via code. Rather you can create markup templates – similar to the way you create classic ASP server markup – and merge data into these templates to render HTML which you can then inject into the document or replace existing content with. Output from templates are rendered as a jQuery matched set and can then be easily inserted into the document as needed. Templating is key to minimize client side code and reduce repeated code for rendering logic. Instead a single template can be used in many places for updating and adding content to existing pages. Further if you build pure AJAX interfaces that rely entirely on client rendering of the initial page content, templates allow you to a use a single markup template to handle all rendering of each specific HTML section/element. I’ve used a number of different client rendering template engines with jQuery in the past including jTemplates (a PHP style templating engine) and a modified version of John Resig’s MicroTemplating engine which I built into my own set of libraries because it’s such a commonly used feature in my client side applications. jQuery templates adds a much richer templating model that allows for sub-templates and access to the data items. Like John Resig’s original Micro Template engine, the core basics of the templating engine create JavaScript code which means that templates can include JavaScript code. To give you a basic idea of how templates work imagine I have an application that downloads a set of stock quotes based on a symbol list then displays them in the document. To do this you can create an ‘item’ template that describes how each of the quotes is renderd as a template inside of the document: <script id="stockTemplate" type="text/x-jquery-tmpl"> <div id="divStockQuote" class="errordisplay" style="width: 500px;"> <div class="label">Company:</div><div><b>${Company}(${Symbol})</b></div> <div class="label">Last Price:</div><div>${LastPrice}</div> <div class="label">Net Change:</div><div> {{if NetChange > 0}} <b style="color:green" >${NetChange}</b> {{else}} <b style="color:red" >${NetChange}</b> {{/if}} </div> <div class="label">Last Update:</div><div>${LastQuoteTimeString}</div> </div> </script> The ‘template’ is little more than HTML with some markup expressions inside of it that define the template language. Notice the embedded ${} expressions which reference data from the quote objects returned from an AJAX call on the server. You can embed any JavaScript or value expression in these template expressions. There are also a number of structural commands like {{if}} and {{each}} that provide for rudimentary logic inside of your templates as well as commands ({{tmpl}} and {{wrap}}) for nesting templates. You can find more about the full set of markup expressions available in the documentation. To load up this data you can use code like the following: <script type="text/javascript"> //var Proxy = new ServiceProxy("../PageMethods/PageMethodsService.asmx/"); $(document).ready(function () { $("#btnGetQuotes").click(GetQuotes); }); function GetQuotes() { var symbols = $("#txtSymbols").val().split(","); $.ajax({ url: "../PageMethods/PageMethodsService.asmx/GetStockQuotes", data: JSON.stringify({ symbols: symbols }), // parameter map type: "POST", // data has to be POSTed contentType: "application/json", timeout: 10000, dataType: "json", success: function (result) { var quotes = result.d; var jEl = $("#stockTemplate").tmpl(quotes); $("#quoteDisplay").empty().append(jEl); }, error: function (xhr, status) { alert(status + "\r\n" + xhr.responseText); } }); }; </script> In this case an ASMX AJAX service is called to retrieve the stock quotes. The service returns an array of quote objects. The result is returned as an object with the .d property (in Microsoft service style) that returns the actual array of quotes. The template is applied with: var jEl = $("#stockTemplate").tmpl(quotes); which selects the template script tag and uses the .tmpl() function to apply the data to it. The result is a jQuery matched set of elements that can then be appended to the quote display element in the page. The template is merged against an array in this example. When the result is an array the template is automatically applied to each each array item. If you pass a single data item – like say a stock quote – the template works exactly the same way but is applied only once. Templates also have access to a $data item which provides the current data item and information about the tempalte that is currently executing. This makes it possible to keep context within the context of the template itself and also to pass context from a parent template to a child template which is very powerful. Templates can be evaluated by using the template selector and calling the .tmpl() function on the jQuery matched set as shown above or you can use the static $.tmpl() function to provide a template as a string. This allows you to dynamically create templates in code or – more likely – to load templates from the server via AJAX calls. In short there are options The above shows off some of the basics, but there’s much for functionality available in the template engine. Check the documentation link for more information and links to additional examples. The plug-in download also comes with a number of examples that demonstrate functionality. jQuery templates will become a native component in jQuery Core 1.5, so it’s definitely worthwhile checking out the engine today and get familiar with this interface. As much as I’m stoked about templating becoming part of the jQuery core because it’s such an integral part of many applications, there are also a couple shortcomings in the current incarnation: Lack of Error Handling Currently if you embed an expression that is invalid it’s simply not rendered. There’s no error rendered into the template nor do the various  template functions throw errors which leaves finding of bugs as a runtime exercise. I would like some mechanism – optional if possible – to be able to get error info of what is failing in a template when it’s rendered. No String Output Templates are always rendered into a jQuery matched set and there’s no way that I can see to directly render to a string. String output can be useful for debugging as well as opening up templating for creating non-HTML string output. Limited JavaScript Access Unlike John Resig’s original MicroTemplating Engine which was entirely based on JavaScript code generation these templates are limited to a few structured commands that can ‘execute’. There’s no code execution inside of script code which means you’re limited to calling expressions available in global objects or the data item passed in. This may or may not be a big deal depending on the complexity of your template logic. Error handling has been discussed quite a bit and it’s likely there will be some solution to that particualar issue by the time jQuery templates ship. The others are relatively minor issues but something to think about anyway. jQuery Data Link http://api.jquery.com/category/plugins/data-link/ jQuery Data Link provides the ability to do two-way data binding between input controls and an underlying object’s properties. The typical scenario is linking a textbox to a property of an object and have the object updated when the text in the textbox is changed and have the textbox change when the value in the object or the entire object changes. The plug-in also supports converter functions that can be applied to provide the conversion logic from string to some other value typically necessary for mapping things like textbox string input to say a number property and potentially applying additional formatting and calculations. In theory this sounds great, however in reality this plug-in has some serious usability issues. Using the plug-in you can do things like the following to bind data: person = { firstName: "rick", lastName: "strahl"}; $(document).ready( function() { // provide for two-way linking of inputs $("form").link(person); // bind to non-input elements explicitly $("#objFirst").link(person, { firstName: { name: "objFirst", convertBack: function (value, source, target) { $(target).text(value); } } }); $("#objLast").link(person, { lastName: { name: "objLast", convertBack: function (value, source, target) { $(target).text(value); } } }); }); This code hooks up two-way linking between a couple of textboxes on the page and the person object. The first line in the .ready() handler provides mapping of object to form field with the same field names as properties on the object. Note that .link() does NOT bind items into the textboxes when you call .link() – changes are mapped only when values change and you move out of the field. Strike one. The two following commands allow manual binding of values to specific DOM elements which is effectively a one-way bind. You specify the object and a then an explicit mapping where name is an ID in the document. The converter is required to explicitly assign the value to the element. Strike two. You can also detect changes to the underlying object and cause updates to the input elements bound. Unfortunately the syntax to do this is not very natural as you have to rely on the jQuery data object. To update an object’s properties and get change notification looks like this: function updateFirstName() { $(person).data("firstName", person.firstName + " (code updated)"); } This works fine in causing any linked fields to be updated. In the bindings above both the firstName input field and objFirst DOM element gets updated. But the syntax requires you to use a jQuery .data() call for each property change to ensure that the changes are tracked properly. Really? Sure you’re binding through multiple layers of abstraction now but how is that better than just manually assigning values? The code savings (if any) are going to be minimal. As much as I would like to have a WPF/Silverlight/Observable-like binding mechanism in client script, this plug-in doesn’t help much towards that goal in its current incarnation. While you can bind values, the ‘binder’ is too limited to be really useful. If initial values can’t be assigned from the mappings you’re going to end up duplicating work loading the data using some other mechanism. There’s no easy way to re-bind data with a different object altogether since updates trigger only through the .data members. Finally, any non-input elements have to be bound via code that’s fairly verbose and frankly may be more voluminous than what you might write by hand for manual binding and unbinding. Two way binding can be very useful but it has to be easy and most importantly natural. If it’s more work to hook up a binding than writing a couple of lines to do binding/unbinding this sort of thing helps very little in most scenarios. In talking to some of the developers the feature set for Data Link is not complete and they are still soliciting input for features and functionality. If you have ideas on how you want this feature to be more useful get involved and post your recommendations. As it stands, it looks to me like this component needs a lot of love to become useful. For this component to really provide value, bindings need to be able to be refreshed easily and work at the object level, not just the property level. It seems to me we would be much better served by a model binder object that can perform these binding/unbinding tasks in bulk rather than a tool where each link has to be mapped first. I also find the choice of creating a jQuery plug-in questionable – it seems a standalone object – albeit one that relies on the jQuery library – would provide a more intuitive interface than the current forcing of options onto a plug-in style interface. Out of the three Microsoft created components this is by far the least useful and least polished implementation at this point. jQuery Globalization http://github.com/jquery/jquery-global Globalization in JavaScript applications often gets short shrift and part of the reason for this is that natively in JavaScript there’s little support for formatting and parsing of numbers and dates. There are a number of JavaScript libraries out there that provide some support for globalization, but most are limited to a particular portion of globalization. As .NET developers we’re fairly spoiled by the richness of APIs provided in the framework and when dealing with client development one really notices the lack of these features. While you may not necessarily need to localize your application the globalization plug-in also helps with some basic tasks for non-localized applications: Dealing with formatting and parsing of dates and time values. Dates in particular are problematic in JavaScript as there are no formatters whatsoever except the .toString() method which outputs a verbose and next to useless long string. With the globalization plug-in you get a good chunk of the formatting and parsing functionality that the .NET framework provides on the server. You can write code like the following for example to format numbers and dates: var date = new Date(); var output = $.format(date, "MMM. dd, yy") + "\r\n" + $.format(date, "d") + "\r\n" + // 10/25/2010 $.format(1222.32213, "N2") + "\r\n" + $.format(1222.33, "c") + "\r\n"; alert(output); This becomes even more useful if you combine it with templates which can also include any JavaScript expressions. Assuming the globalization plug-in is loaded you can create template expressions that use the $.format function. Here’s the template I used earlier for the stock quote again with a couple of formats applied: <script id="stockTemplate" type="text/x-jquery-tmpl"> <div id="divStockQuote" class="errordisplay" style="width: 500px;"> <div class="label">Company:</div><div><b>${Company}(${Symbol})</b></div> <div class="label">Last Price:</div> <div>${$.format(LastPrice,"N2")}</div> <div class="label">Net Change:</div><div> {{if NetChange > 0}} <b style="color:green" >${NetChange}</b> {{else}} <b style="color:red" >${NetChange}</b> {{/if}} </div> <div class="label">Last Update:</div> <div>${$.format(LastQuoteTime,"MMM dd, yyyy")}</div> </div> </script> There are also parsing methods that can parse dates and numbers from strings into numbers easily: alert($.parseDate("25.10.2010")); alert($.parseInt("12.222")); // de-DE uses . for thousands separators As you can see culture specific options are taken into account when parsing. The globalization plugin provides rich support for a variety of locales: Get a list of all available cultures Query cultures for culture items (like currency symbol, separators etc.) Localized string names for all calendar related items (days of week, months) Generated off of .NET’s supported locales In short you get much of the same functionality that you already might be using in .NET on the server side. The plugin includes a huge number of locales and an Globalization.all.min.js file that contains the text defaults for each of these locales as well as small locale specific script files that define each of the locale specific settings. It’s highly recommended that you NOT use the huge globalization file that includes all locales, but rather add script references to only those languages you explicitly care about. Overall this plug-in is a welcome helper. Even if you use it with a single locale (like en-US) and do no other localization, you’ll gain solid support for number and date formatting which is a vital feature of many applications. Changes for Microsoft It’s good to see Microsoft coming out of its shell and away from the ‘not-built-here’ mentality that has been so pervasive in the past. It’s especially good to see it applied to jQuery – a technology that has stood in drastic contrast to Microsoft’s own internal efforts in terms of design, usage model and… popularity. It’s great to see that Microsoft is paying attention to what customers prefer to use and supporting the customer sentiment – even if it meant drastically changing course of policy and moving into a more open and sharing environment in the process. The additional jQuery support that has been introduced in the last two years certainly has made lives easier for many developers on the ASP.NET platform. It’s also nice to see Microsoft submitting proposals through the standard jQuery process of plug-ins and getting accepted for various very useful projects. Certainly the jQuery Templates plug-in is going to be very useful to many especially since it will be baked into the jQuery core in jQuery 1.5. I hope we see more of this type of involvement from Microsoft in the future. Kudos!© Rick Strahl, West Wind Technologies, 2005-2010Posted in jQuery  ASP.NET  

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  • Xubuntu 13.10 64bit - Slow and buggy "log out" process?

    - by MrKatSwordfish
    I'm a Windows convert who has done only a little bit of dabbling in Ubuntu in the past (back in Dapper Drake a few years back). A lot has changes since then, and I've been yearning to jump back into linux again! So, having just bought a new SSD, I felt that this would be as good of a time as any to set up a dual-boot system again. I've messed around with Ubuntu 13.10 a bit, and while Unity has its issues, I think that it still needs some time to develop. I looked into XFCE and liked it a lot, so I went with Xubuntu. I've installed Xubuntu, and for the most part it's running smoothly and it a pleasure to work with. The customization is great and the minimalistic look and feel is really nice! But here's my problem, whenever I select the "Log Out" option from either the application menu, or the user profiles menu, my PC comes to a crawl, and the dialog box with all the options (shut down, restart, log out, etc.) takes maybe a minute or more to appear. I click the log out button, my PC is brought to a snail's pace, and I have to wait for what seems like an eternity for the logout options to appear! If i try to open something else (even a terminal window) while it's loading the logout options, that other program won't finish loading until the logout screen finally appears. Keep in mind, this is a pretty much vanilla install of Xubuntu 13.10 64bit, on a PC with an intel i7, an SSD, 6gb DDR3 RAM, and a new AMD 7770 gpu (drivers haven't been installed yet, though). Everything else runs fast, most applications open near-instantly! It must be an issue with how the logout options screen initializes or something, but I'm not sure exactly how I can fix it.. Edit - Extra Info: This problem is very consistent when using the "Log Out" buttons in Xubuntu. However, I've found that I'm able to reboot and shutdown much more quickly by going through the "Switch User" screen, and using the reboot or shutdown buttons on that screen. I'm nearly certain that it has something to do with the little Log Out options screen that appears when I select Log Out from the menu, and not the actual process of shutting down.. So what should I do? I really like XFCE so far, and I've never tried a non-ubuntu based distro before, but should I just switch to something else? Is there any known fix for this issue? Are there any work-arounds for logging out/shutting down/rebooting via the terminal so that I can avoid this irritating bug? Is there any that I can monitor the progress of the log out via terminal, allowing me to see which parts are causing the slow-down? What is the best way to report this bug to someone?

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  • Rendering ASP.NET Script References into the Html Header

    - by Rick Strahl
    One thing that I’ve come to appreciate in control development in ASP.NET that use JavaScript is the ability to have more control over script and script include placement than ASP.NET provides natively. Specifically in ASP.NET you can use either the ClientScriptManager or ScriptManager to embed scripts and script references into pages via code. This works reasonably well, but the script references that get generated are generated into the HTML body and there’s very little operational control for placement of scripts. If you have multiple controls or several of the same control that need to place the same scripts onto the page it’s not difficult to end up with scripts that render in the wrong order and stop working correctly. This is especially critical if you load script libraries with dependencies either via resources or even if you are rendering referenced to CDN resources. Natively ASP.NET provides a host of methods that help embedding scripts into the page via either Page.ClientScript or the ASP.NET ScriptManager control (both with slightly different syntax): RegisterClientScriptBlock Renders a script block at the top of the HTML body and should be used for embedding callable functions/classes. RegisterStartupScript Renders a script block just prior to the </form> tag and should be used to for embedding code that should execute when the page is first loaded. Not recommended – use jQuery.ready() or equivalent load time routines. RegisterClientScriptInclude Embeds a reference to a script from a url into the page. RegisterClientScriptResource Embeds a reference to a Script from a resource file generating a long resource file string All 4 of these methods render their <script> tags into the HTML body. The script blocks give you a little bit of control by having a ‘top’ and ‘bottom’ of the document location which gives you some flexibility over script placement and precedence. Script includes and resource url unfortunately do not even get that much control – references are simply rendered into the page in the order of declaration. The ASP.NET ScriptManager control facilitates this task a little bit with the abililty to specify scripts in code and the ability to programmatically check what scripts have already been registered, but it doesn’t provide any more control over the script rendering process itself. Further the ScriptManager is a bear to deal with generically because generic code has to always check and see if it is actually present. Some time ago I posted a ClientScriptProxy class that helps with managing the latter process of sending script references either to ClientScript or ScriptManager if it’s available. Since I last posted about this there have been a number of improvements in this API, one of which is the ability to control placement of scripts and script includes in the page which I think is rather important and a missing feature in the ASP.NET native functionality. Handling ScriptRenderModes One of the big enhancements that I’ve come to rely on is the ability of the various script rendering functions described above to support rendering in multiple locations: /// <summary> /// Determines how scripts are included into the page /// </summary> public enum ScriptRenderModes { /// <summary> /// Inherits the setting from the control or from the ClientScript.DefaultScriptRenderMode /// </summary> Inherit, /// Renders the script include at the location of the control /// </summary> Inline, /// <summary> /// Renders the script include into the bottom of the header of the page /// </summary> Header, /// <summary> /// Renders the script include into the top of the header of the page /// </summary> HeaderTop, /// <summary> /// Uses ClientScript or ScriptManager to embed the script include to /// provide standard ASP.NET style rendering in the HTML body. /// </summary> Script, /// <summary> /// Renders script at the bottom of the page before the last Page.Controls /// literal control. Note this may result in unexpected behavior /// if /body and /html are not the last thing in the markup page. /// </summary> BottomOfPage } This enum is then applied to the various Register functions to allow more control over where scripts actually show up. Why is this useful? For me I often render scripts out of control resources and these scripts often include things like a JavaScript Library (jquery) and a few plug-ins. The order in which these can be loaded is critical so that jQuery.js always loads before any plug-in for example. Typically I end up with a general script layout like this: Core Libraries- HeaderTop Plug-ins: Header ScriptBlocks: Header or Script depending on other dependencies There’s also an option to render scripts and CSS at the very bottom of the page before the last Page control on the page which can be useful for speeding up page load when lots of scripts are loaded. The API syntax of the ClientScriptProxy methods is closely compatible with ScriptManager’s using static methods and control references to gain access to the page and embedding scripts. For example, to render some script into the current page in the header: // Create script block in header ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "hello_function", "function helloWorld() { alert('hello'); }", true, ScriptRenderModes.Header); // Same again - shouldn't be rendered because it's the same id ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "hello_function", "function helloWorld() { alert('hello'); }", true, ScriptRenderModes.Header); // Create a second script block in header ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "hello_function2", "function helloWorld2() { alert('hello2'); }", true, ScriptRenderModes.Header); // This just calls ClientScript and renders into bottom of document ClientScriptProxy.Current.RegisterStartupScript(this,typeof(ControlResources), "call_hello", "helloWorld();helloWorld2();", true); which generates: <html xmlns="http://www.w3.org/1999/xhtml" > <head><title> </title> <script type="text/javascript"> function helloWorld() { alert('hello'); } </script> <script type="text/javascript"> function helloWorld2() { alert('hello2'); } </script> </head> <body> … <script type="text/javascript"> //<![CDATA[ helloWorld();helloWorld2();//]]> </script> </form> </body> </html> Note that the scripts are generated into the header rather than the body except for the last script block which is the call to RegisterStartupScript. In general I wouldn’t recommend using RegisterStartupScript – ever. It’s a much better practice to use a script base load event to handle ‘startup’ code that should fire when the page first loads. So instead of the code above I’d actually recommend doing: ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "call_hello", "$().ready( function() { alert('hello2'); });", true, ScriptRenderModes.Header); assuming you’re using jQuery on the page. For script includes from a Url the following demonstrates how to embed scripts into the header. This example injects a jQuery and jQuery.UI script reference from the Google CDN then checks each with a script block to ensure that it has loaded and if not loads it from a server local location: // load jquery from CDN ClientScriptProxy.Current.RegisterClientScriptInclude(this, typeof(ControlResources), "http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js", ScriptRenderModes.HeaderTop); // check if jquery loaded - if it didn't we're not online string scriptCheck = @"if (typeof jQuery != 'object') document.write(unescape(""%3Cscript src='{0}' type='text/javascript'%3E%3C/script%3E""));"; string jQueryUrl = ClientScriptProxy.Current.GetWebResourceUrl(this, typeof(ControlResources), ControlResources.JQUERY_SCRIPT_RESOURCE); ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "jquery_register", string.Format(scriptCheck,jQueryUrl),true, ScriptRenderModes.HeaderTop); // Load jquery-ui from cdn ClientScriptProxy.Current.RegisterClientScriptInclude(this, typeof(ControlResources), "http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.2/jquery-ui.min.js", ScriptRenderModes.Header); // check if we need to load from local string jQueryUiUrl = ResolveUrl("~/scripts/jquery-ui-custom.min.js"); ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "jqueryui_register", string.Format(scriptCheck, jQueryUiUrl), true, ScriptRenderModes.Header); // Create script block in header ClientScriptProxy.Current.RegisterClientScriptBlock(this, typeof(ControlResources), "hello_function", "$().ready( function() { alert('hello'); });", true, ScriptRenderModes.Header); which in turn generates this HTML: <html xmlns="http://www.w3.org/1999/xhtml" > <head> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js" type="text/javascript"></script> <script type="text/javascript"> if (typeof jQuery != 'object') document.write(unescape("%3Cscript src='/WestWindWebToolkitWeb/WebResource.axd?d=DIykvYhJ_oXCr-TA_dr35i4AayJoV1mgnQAQGPaZsoPM2LCdvoD3cIsRRitHKlKJfV5K_jQvylK7tsqO3lQIFw2&t=633979863959332352' type='text/javascript'%3E%3C/script%3E")); </script> <title> </title> <script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.7.2/jquery-ui.min.js" type="text/javascript"></script> <script type="text/javascript"> if (typeof jQuery != 'object') document.write(unescape("%3Cscript src='/WestWindWebToolkitWeb/scripts/jquery-ui-custom.min.js' type='text/javascript'%3E%3C/script%3E")); </script> <script type="text/javascript"> $().ready(function() { alert('hello'); }); </script> </head> <body> …</body> </html> As you can see there’s a bit more control in this process as you can inject both script includes and script blocks into the document at the top or bottom of the header, plus if necessary at the usual body locations. This is quite useful especially if you create custom server controls that interoperate with script and have certain dependencies. The above is a good example of a useful switchable routine where you can switch where scripts load from by default – the above pulls from Google CDN but a configuration switch may automatically switch to pull from the local development copies if your doing development for example. How does it work? As mentioned the ClientScriptProxy object mimicks many of the ScriptManager script related methods and so provides close API compatibility with it although it contains many additional overloads that enhance functionality. It does however work against ScriptManager if it’s available on the page, or Page.ClientScript if it’s not so it provides a single unified frontend to script access. There are however many overloads of the original SM methods like the above to provide additional functionality. The implementation of script header rendering is pretty straight forward – as long as a server header (ie. it has to have runat=”server” set) is available. Otherwise these routines fall back to using the default document level insertions of ScriptManager/ClientScript. Given that there is a server header it’s relatively easy to generate the script tags and code and append them to the header either at the top or bottom. I suspect Microsoft didn’t provide header rendering functionality precisely because a runat=”server” header is not required by ASP.NET so behavior would be slightly unpredictable. That’s not really a problem for a custom implementation however. Here’s the RegisterClientScriptBlock implementation that takes a ScriptRenderModes parameter to allow header rendering: /// <summary> /// Renders client script block with the option of rendering the script block in /// the Html header /// /// For this to work Header must be defined as runat="server" /// </summary> /// <param name="control">any control that instance typically page</param> /// <param name="type">Type that identifies this rendering</param> /// <param name="key">unique script block id</param> /// <param name="script">The script code to render</param> /// <param name="addScriptTags">Ignored for header rendering used for all other insertions</param> /// <param name="renderMode">Where the block is rendered</param> public void RegisterClientScriptBlock(Control control, Type type, string key, string script, bool addScriptTags, ScriptRenderModes renderMode) { if (renderMode == ScriptRenderModes.Inherit) renderMode = DefaultScriptRenderMode; if (control.Page.Header == null || renderMode != ScriptRenderModes.HeaderTop && renderMode != ScriptRenderModes.Header && renderMode != ScriptRenderModes.BottomOfPage) { RegisterClientScriptBlock(control, type, key, script, addScriptTags); return; } // No dupes - ref script include only once const string identifier = "scriptblock_"; if (HttpContext.Current.Items.Contains(identifier + key)) return; HttpContext.Current.Items.Add(identifier + key, string.Empty); StringBuilder sb = new StringBuilder(); // Embed in header sb.AppendLine("\r\n<script type=\"text/javascript\">"); sb.AppendLine(script); sb.AppendLine("</script>"); int? index = HttpContext.Current.Items["__ScriptResourceIndex"] as int?; if (index == null) index = 0; if (renderMode == ScriptRenderModes.HeaderTop) { control.Page.Header.Controls.AddAt(index.Value, new LiteralControl(sb.ToString())); index++; } else if(renderMode == ScriptRenderModes.Header) control.Page.Header.Controls.Add(new LiteralControl(sb.ToString())); else if (renderMode == ScriptRenderModes.BottomOfPage) control.Page.Controls.AddAt(control.Page.Controls.Count-1,new LiteralControl(sb.ToString())); HttpContext.Current.Items["__ScriptResourceIndex"] = index; } Note that the routine has to keep track of items inserted by id so that if the same item is added again with the same key it won’t generate two script entries. Additionally the code has to keep track of how many insertions have been made at the top of the document so that entries are added in the proper order. The RegisterScriptInclude method is similar but there’s some additional logic in here to deal with script file references and ClientScriptProxy’s (optional) custom resource handler that provides script compression /// <summary> /// Registers a client script reference into the page with the option to specify /// the script location in the page /// </summary> /// <param name="control">Any control instance - typically page</param> /// <param name="type">Type that acts as qualifier (uniqueness)</param> /// <param name="url">the Url to the script resource</param> /// <param name="ScriptRenderModes">Determines where the script is rendered</param> public void RegisterClientScriptInclude(Control control, Type type, string url, ScriptRenderModes renderMode) { const string STR_ScriptResourceIndex = "__ScriptResourceIndex"; if (string.IsNullOrEmpty(url)) return; if (renderMode == ScriptRenderModes.Inherit) renderMode = DefaultScriptRenderMode; // Extract just the script filename string fileId = null; // Check resource IDs and try to match to mapped file resources // Used to allow scripts not to be loaded more than once whether // embedded manually (script tag) or via resources with ClientScriptProxy if (url.Contains(".axd?r=")) { string res = HttpUtility.UrlDecode( StringUtils.ExtractString(url, "?r=", "&", false, true) ); foreach (ScriptResourceAlias item in ScriptResourceAliases) { if (item.Resource == res) { fileId = item.Alias + ".js"; break; } } if (fileId == null) fileId = url.ToLower(); } else fileId = Path.GetFileName(url).ToLower(); // No dupes - ref script include only once const string identifier = "script_"; if (HttpContext.Current.Items.Contains( identifier + fileId ) ) return; HttpContext.Current.Items.Add(identifier + fileId, string.Empty); // just use script manager or ClientScriptManager if (control.Page.Header == null || renderMode == ScriptRenderModes.Script || renderMode == ScriptRenderModes.Inline) { RegisterClientScriptInclude(control, type,url, url); return; } // Retrieve script index in header int? index = HttpContext.Current.Items[STR_ScriptResourceIndex] as int?; if (index == null) index = 0; StringBuilder sb = new StringBuilder(256); url = WebUtils.ResolveUrl(url); // Embed in header sb.AppendLine("\r\n<script src=\"" + url + "\" type=\"text/javascript\"></script>"); if (renderMode == ScriptRenderModes.HeaderTop) { control.Page.Header.Controls.AddAt(index.Value, new LiteralControl(sb.ToString())); index++; } else if (renderMode == ScriptRenderModes.Header) control.Page.Header.Controls.Add(new LiteralControl(sb.ToString())); else if (renderMode == ScriptRenderModes.BottomOfPage) control.Page.Controls.AddAt(control.Page.Controls.Count-1, new LiteralControl(sb.ToString())); HttpContext.Current.Items[STR_ScriptResourceIndex] = index; } There’s a little more code here that deals with cleaning up the passed in Url and also some custom handling of script resources that run through the ScriptCompressionModule – any script resources loaded in this fashion are automatically cached based on the resource id. Raw urls extract just the filename from the URL and cache based on that. All of this to avoid doubling up of scripts if called multiple times by multiple instances of the same control for example or several controls that all load the same resources/includes. Finally RegisterClientScriptResource utilizes the previous method to wrap the WebResourceUrl as well as some custom functionality for the resource compression module: /// <summary> /// Returns a WebResource or ScriptResource URL for script resources that are to be /// embedded as script includes. /// </summary> /// <param name="control">Any control</param> /// <param name="type">A type in assembly where resources are located</param> /// <param name="resourceName">Name of the resource to load</param> /// <param name="renderMode">Determines where in the document the link is rendered</param> public void RegisterClientScriptResource(Control control, Type type, string resourceName, ScriptRenderModes renderMode) { string resourceUrl = GetClientScriptResourceUrl(control, type, resourceName); RegisterClientScriptInclude(control, type, resourceUrl, renderMode); } /// <summary> /// Works like GetWebResourceUrl but can be used with javascript resources /// to allow using of resource compression (if the module is loaded). /// </summary> /// <param name="control"></param> /// <param name="type"></param> /// <param name="resourceName"></param> /// <returns></returns> public string GetClientScriptResourceUrl(Control control, Type type, string resourceName) { #if IncludeScriptCompressionModuleSupport // If wwScriptCompression Module through Web.config is loaded use it to compress // script resources by using wcSC.axd Url the module intercepts if (ScriptCompressionModule.ScriptCompressionModuleActive) { string url = "~/wwSC.axd?r=" + HttpUtility.UrlEncode(resourceName); if (type.Assembly != GetType().Assembly) url += "&t=" + HttpUtility.UrlEncode(type.FullName); return WebUtils.ResolveUrl(url); } #endif return control.Page.ClientScript.GetWebResourceUrl(type, resourceName); } This code merely retrieves the resource URL and then simply calls back to RegisterClientScriptInclude with the URL to be embedded which means there’s nothing specific to deal with other than the custom compression module logic which is nice and easy. What else is there in ClientScriptProxy? ClientscriptProxy also provides a few other useful services beyond what I’ve already covered here: Transparent ScriptManager and ClientScript calls ClientScriptProxy includes a host of routines that help figure out whether a script manager is available or not and all functions in this class call the appropriate object – ScriptManager or ClientScript – that is available in the current page to ensure that scripts get embedded into pages properly. This is especially useful for control development where controls have no control over the scripting environment in place on the page. RegisterCssLink and RegisterCssResource Much like the script embedding functions these two methods allow embedding of CSS links. CSS links are appended to the header or to a form declared with runat=”server”. LoadControlScript Is a high level resource loading routine that can be used to easily switch between different script linking modes. It supports loading from a WebResource, a url or not loading anything at all. This is very useful if you build controls that deal with specification of resource urls/ids in a standard way. Check out the full Code You can check out the full code to the ClientScriptProxyClass here: ClientScriptProxy.cs ClientScriptProxy Documentation (class reference) Note that the ClientScriptProxy has a few dependencies in the West Wind Web Toolkit of which it is part of. ControlResources holds a few standard constants and script resource links and the ScriptCompressionModule which is referenced in a few of the script inclusion methods. There’s also another useful ScriptContainer companion control  to the ClientScriptProxy that allows scripts to be placed onto the page’s markup including the ability to specify the script location and script minification options. You can find all the dependencies in the West Wind Web Toolkit repository: West Wind Web Toolkit Repository West Wind Web Toolkit Home Page© Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  JavaScript  

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  • C# 4: The Curious ConcurrentDictionary

    - by James Michael Hare
    In my previous post (here) I did a comparison of the new ConcurrentQueue versus the old standard of a System.Collections.Generic Queue with simple locking.  The results were exactly what I would have hoped, that the ConcurrentQueue was faster with multi-threading for most all situations.  In addition, concurrent collections have the added benefit that you can enumerate them even if they're being modified. So I set out to see what the improvements would be for the ConcurrentDictionary, would it have the same performance benefits as the ConcurrentQueue did?  Well, after running some tests and multiple tweaks and tunes, I have good and bad news. But first, let's look at the tests.  Obviously there's many things we can do with a dictionary.  One of the most notable uses, of course, in a multi-threaded environment is for a small, local in-memory cache.  So I set about to do a very simple simulation of a cache where I would create a test class that I'll just call an Accessor.  This accessor will attempt to look up a key in the dictionary, and if the key exists, it stops (i.e. a cache "hit").  However, if the lookup fails, it will then try to add the key and value to the dictionary (i.e. a cache "miss").  So here's the Accessor that will run the tests: 1: internal class Accessor 2: { 3: public int Hits { get; set; } 4: public int Misses { get; set; } 5: public Func<int, string> GetDelegate { get; set; } 6: public Action<int, string> AddDelegate { get; set; } 7: public int Iterations { get; set; } 8: public int MaxRange { get; set; } 9: public int Seed { get; set; } 10:  11: public void Access() 12: { 13: var randomGenerator = new Random(Seed); 14:  15: for (int i=0; i<Iterations; i++) 16: { 17: // give a wide spread so will have some duplicates and some unique 18: var target = randomGenerator.Next(1, MaxRange); 19:  20: // attempt to grab the item from the cache 21: var result = GetDelegate(target); 22:  23: // if the item doesn't exist, add it 24: if(result == null) 25: { 26: AddDelegate(target, target.ToString()); 27: Misses++; 28: } 29: else 30: { 31: Hits++; 32: } 33: } 34: } 35: } Note that so I could test different implementations, I defined a GetDelegate and AddDelegate that will call the appropriate dictionary methods to add or retrieve items in the cache using various techniques. So let's examine the three techniques I decided to test: Dictionary with mutex - Just your standard generic Dictionary with a simple lock construct on an internal object. Dictionary with ReaderWriterLockSlim - Same Dictionary, but now using a lock designed to let multiple readers access simultaneously and then locked when a writer needs access. ConcurrentDictionary - The new ConcurrentDictionary from System.Collections.Concurrent that is supposed to be optimized to allow multiple threads to access safely. So the approach to each of these is also fairly straight-forward.  Let's look at the GetDelegate and AddDelegate implementations for the Dictionary with mutex lock: 1: var addDelegate = (key,val) => 2: { 3: lock (_mutex) 4: { 5: _dictionary[key] = val; 6: } 7: }; 8: var getDelegate = (key) => 9: { 10: lock (_mutex) 11: { 12: string val; 13: return _dictionary.TryGetValue(key, out val) ? val : null; 14: } 15: }; Nothing new or fancy here, just your basic lock on a private object and then query/insert into the Dictionary. Now, for the Dictionary with ReadWriteLockSlim it's a little more complex: 1: var addDelegate = (key,val) => 2: { 3: _readerWriterLock.EnterWriteLock(); 4: _dictionary[key] = val; 5: _readerWriterLock.ExitWriteLock(); 6: }; 7: var getDelegate = (key) => 8: { 9: string val; 10: _readerWriterLock.EnterReadLock(); 11: if(!_dictionary.TryGetValue(key, out val)) 12: { 13: val = null; 14: } 15: _readerWriterLock.ExitReadLock(); 16: return val; 17: }; And finally, the ConcurrentDictionary, which since it does all it's own concurrency control, is remarkably elegant and simple: 1: var addDelegate = (key,val) => 2: { 3: _concurrentDictionary[key] = val; 4: }; 5: var getDelegate = (key) => 6: { 7: string s; 8: return _concurrentDictionary.TryGetValue(key, out s) ? s : null; 9: };                    Then, I set up a test harness that would simply ask the user for the number of concurrent Accessors to attempt to Access the cache (as specified in Accessor.Access() above) and then let them fly and see how long it took them all to complete.  Each of these tests was run with 10,000,000 cache accesses divided among the available Accessor instances.  All times are in milliseconds. 1: Dictionary with Mutex Locking 2: --------------------------------------------------- 3: Accessors Mostly Misses Mostly Hits 4: 1 7916 3285 5: 10 8293 3481 6: 100 8799 3532 7: 1000 8815 3584 8:  9:  10: Dictionary with ReaderWriterLockSlim Locking 11: --------------------------------------------------- 12: Accessors Mostly Misses Mostly Hits 13: 1 8445 3624 14: 10 11002 4119 15: 100 11076 3992 16: 1000 14794 4861 17:  18:  19: Concurrent Dictionary 20: --------------------------------------------------- 21: Accessors Mostly Misses Mostly Hits 22: 1 17443 3726 23: 10 14181 1897 24: 100 15141 1994 25: 1000 17209 2128 The first test I did across the board is the Mostly Misses category.  The mostly misses (more adds because data requested was not in the dictionary) shows an interesting trend.  In both cases the Dictionary with the simple mutex lock is much faster, and the ConcurrentDictionary is the slowest solution.  But this got me thinking, and a little research seemed to confirm it, maybe the ConcurrentDictionary is more optimized to concurrent "gets" than "adds".  So since the ratio of misses to hits were 2 to 1, I decided to reverse that and see the results. So I tweaked the data so that the number of keys were much smaller than the number of iterations to give me about a 2 to 1 ration of hits to misses (twice as likely to already find the item in the cache than to need to add it).  And yes, indeed here we see that the ConcurrentDictionary is indeed faster than the standard Dictionary here.  I have a strong feeling that as the ration of hits-to-misses gets higher and higher these number gets even better as well.  This makes sense since the ConcurrentDictionary is read-optimized. Also note that I tried the tests with capacity and concurrency hints on the ConcurrentDictionary but saw very little improvement, I think this is largely because on the 10,000,000 hit test it quickly ramped up to the correct capacity and concurrency and thus the impact was limited to the first few milliseconds of the run. So what does this tell us?  Well, as in all things, ConcurrentDictionary is not a panacea.  It won't solve all your woes and it shouldn't be the only Dictionary you ever use.  So when should we use each? Use System.Collections.Generic.Dictionary when: You need a single-threaded Dictionary (no locking needed). You need a multi-threaded Dictionary that is loaded only once at creation and never modified (no locking needed). You need a multi-threaded Dictionary to store items where writes are far more prevalent than reads (locking needed). And use System.Collections.Concurrent.ConcurrentDictionary when: You need a multi-threaded Dictionary where the writes are far more prevalent than reads. You need to be able to iterate over the collection without locking it even if its being modified. Both Dictionaries have their strong suits, I have a feeling this is just one where you need to know from design what you hope to use it for and make your decision based on that criteria.

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  • Interesting links week #24 and #25

    - by erwin21
    Below a list of interesting links that I found this week: Interaction: Design Usability and All About It Frontend: CSS Lint – CSS Cleaning Tool 10 HTML Entity Crimes You Really Shouldn’t Commit Development: OWASP Top 10 for .NET developers part 7: Insecure Cryptographic Storage C#/.NET Fundamentals: Choosing the Right Collection Class Mobile: Tips to Design a Website for Mobile Marketing: 30 (New) Google Ranking Factors You May Over- or Underestimate Other: 5 Little-Known Web Files That Can Enhance Your Website Interested in more interesting links follow me at twitter http://twitter.com/erwingriekspoor

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  • Creating STA COM compatible ASP.NET Applications

    - by Rick Strahl
    When building ASP.NET applications that interface with old school COM objects like those created with VB6 or Visual FoxPro (MTDLL), it's extremely important that the threads that are serving requests use Single Threaded Apartment Threading. STA is a COM built-in technology that allows essentially single threaded components to operate reliably in a multi-threaded environment. STA's guarantee that COM objects instantiated on a specific thread stay on that specific thread and any access to a COM object from another thread automatically marshals that thread to the STA thread. The end effect is that you can have multiple threads, but a COM object instance lives on a fixed never changing thread. ASP.NET by default uses MTA (multi-threaded apartment) threads which are truly free spinning threads that pay no heed to COM object marshaling. This is vastly more efficient than STA threading which has a bit of overhead in determining whether it's OK to run code on a given thread or whether some sort of thread/COM marshaling needs to occur. MTA COM components can be very efficient, but STA COM components in a multi-threaded environment always tend to have a fair amount of overhead. It's amazing how much COM Interop I still see today so while it seems really old school to be talking about this topic, it's actually quite apropos for me as I have many customers using legacy COM systems that need to interface with other .NET applications. In this post I'm consolidating some of the hacks I've used to integrate with various ASP.NET technologies when using STA COM Components. STA in ASP.NET Support for STA threading in the ASP.NET framework is fairly limited. Specifically only the original ASP.NET WebForms technology supports STA threading directly via its STA Page Handler implementation or what you might know as ASPCOMPAT mode. For WebForms running STA components is as easy as specifying the ASPCOMPAT attribute in the @Page tag:<%@ Page Language="C#" AspCompat="true" %> which runs the page in STA mode. Removing it runs in MTA mode. Simple. Unfortunately all other ASP.NET technologies built on top of the core ASP.NET engine do not support STA natively. So if you want to use STA COM components in MVC or with class ASMX Web Services, there's no automatic way like the ASPCOMPAT keyword available. So what happens when you run an STA COM component in an MTA application? In low volume environments - nothing much will happen. The COM objects will appear to work just fine as there are no simultaneous thread interactions and the COM component will happily run on a single thread or multiple single threads one at a time. So for testing running components in MTA environments may appear to work just fine. However as load increases and threads get re-used by ASP.NET COM objects will end up getting created on multiple different threads. This can result in crashes or hangs, or data corruption in the STA components which store their state in thread local storage on the STA thread. If threads overlap this global store can easily get corrupted which in turn causes problems. STA ensures that any COM object instance loaded always stays on the same thread it was instantiated on. What about COM+? COM+ is supposed to address the problem of STA in MTA applications by providing an abstraction with it's own thread pool manager for COM objects. It steps in to the COM instantiation pipeline and hands out COM instances from its own internally maintained STA Thread pool. This guarantees that the COM instantiation threads are STA threads if using STA components. COM+ works, but in my experience the technology is very, very slow for STA components. It adds a ton of overhead and reduces COM performance noticably in load tests in IIS. COM+ can make sense in some situations but for Web apps with STA components it falls short. In addition there's also the need to ensure that COM+ is set up and configured on the target machine and the fact that components have to be registered in COM+. COM+ also keeps components up at all times, so if a component needs to be replaced the COM+ package needs to be unloaded (same is true for IIS hosted components but it's more common to manage that). COM+ is an option for well established components, but native STA support tends to provide better performance and more consistent usability, IMHO. STA for non supporting ASP.NET Technologies As mentioned above only WebForms supports STA natively. However, by utilizing the WebForms ASP.NET Page handler internally it's actually possible to trick various other ASP.NET technologies and let them work with STA components. This is ugly but I've used each of these in various applications and I've had minimal problems making them work with FoxPro STA COM components which is about as dififcult as it gets for COM Interop in .NET. In this post I summarize several STA workarounds that enable you to use STA threading with these ASP.NET Technologies: ASMX Web Services ASP.NET MVC WCF Web Services ASP.NET Web API ASMX Web Services I start with classic ASP.NET ASMX Web Services because it's the easiest mechanism that allows for STA modification. It also clearly demonstrates how the WebForms STA Page Handler is the key technology to enable the various other solutions to create STA components. Essentially the way this works is to override the WebForms Page class and hijack it's init functionality for processing requests. Here's what this looks like for Web Services:namespace FoxProAspNet { public class WebServiceStaHandler : System.Web.UI.Page, IHttpAsyncHandler { protected override void OnInit(EventArgs e) { IHttpHandler handler = new WebServiceHandlerFactory().GetHandler( this.Context, this.Context.Request.HttpMethod, this.Context.Request.FilePath, this.Context.Request.PhysicalPath); handler.ProcessRequest(this.Context); this.Context.ApplicationInstance.CompleteRequest(); } public IAsyncResult BeginProcessRequest( HttpContext context, AsyncCallback cb, object extraData) { return this.AspCompatBeginProcessRequest(context, cb, extraData); } public void EndProcessRequest(IAsyncResult result) { this.AspCompatEndProcessRequest(result); } } public class AspCompatWebServiceStaHandlerWithSessionState : WebServiceStaHandler, IRequiresSessionState { } } This class overrides the ASP.NET WebForms Page class which has a little known AspCompatBeginProcessRequest() and AspCompatEndProcessRequest() method that is responsible for providing the WebForms ASPCOMPAT functionality. These methods handle routing requests to STA threads. Note there are two classes - one that includes session state and one that does not. If you plan on using ASP.NET Session state use the latter class, otherwise stick to the former. This maps to the EnableSessionState page setting in WebForms. This class simply hooks into this functionality by overriding the BeginProcessRequest and EndProcessRequest methods and always forcing it into the AspCompat methods. The way this works is that BeginProcessRequest() fires first to set up the threads and starts intializing the handler. As part of that process the OnInit() method is fired which is now already running on an STA thread. The code then creates an instance of the actual WebService handler factory and calls its ProcessRequest method to start executing which generates the Web Service result. Immediately after ProcessRequest the request is stopped with Application.CompletRequest() which ensures that the rest of the Page handler logic doesn't fire. This means that even though the fairly heavy Page class is overridden here, it doesn't end up executing any of its internal processing which makes this code fairly efficient. In a nutshell, we're highjacking the Page HttpHandler and forcing it to process the WebService process handler in the context of the AspCompat handler behavior. Hooking up the Handler Because the above is an HttpHandler implementation you need to hook up the custom handler and replace the standard ASMX handler. To do this you need to modify the web.config file (here for IIS 7 and IIS Express): <configuration> <system.webServer> <handlers> <remove name="WebServiceHandlerFactory-Integrated-4.0" /> <add name="Asmx STA Web Service Handler" path="*.asmx" verb="*" type="FoxProAspNet.WebServiceStaHandler" precondition="integrated"/> </handlers> </system.webServer> </configuration> (Note: The name for the WebServiceHandlerFactory-Integrated-4.0 might be slightly different depending on your server version. Check the IIS Handler configuration in the IIS Management Console for the exact name or simply remove the handler from the list there which will propagate to your web.config). For IIS 5 & 6 (Windows XP/2003) or the Visual Studio Web Server use:<configuration> <system.web> <httpHandlers> <remove path="*.asmx" verb="*" /> <add path="*.asmx" verb="*" type="FoxProAspNet.WebServiceStaHandler" /> </httpHandlers> </system.web></configuration> To test, create a new ASMX Web Service and create a method like this: [WebService(Namespace = "http://foxaspnet.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] public class FoxWebService : System.Web.Services.WebService { [WebMethod] public string HelloWorld() { return "Hello World. Threading mode is: " + System.Threading.Thread.CurrentThread.GetApartmentState(); } } Run this before you put in the web.config configuration changes and you should get: Hello World. Threading mode is: MTA Then put the handler mapping into Web.config and you should see: Hello World. Threading mode is: STA And you're on your way to using STA COM components. It's a hack but it works well! I've used this with several high volume Web Service installations with various customers and it's been fast and reliable. ASP.NET MVC ASP.NET MVC has quickly become the most popular ASP.NET technology, replacing WebForms for creating HTML output. MVC is more complex to get started with, but once you understand the basic structure of how requests flow through the MVC pipeline it's easy to use and amazingly flexible in manipulating HTML requests. In addition, MVC has great support for non-HTML output sources like JSON and XML, making it an excellent choice for AJAX requests without any additional tools. Unlike WebForms ASP.NET MVC doesn't support STA threads natively and so some trickery is needed to make it work with STA threads as well. MVC gets its handler implementation through custom route handlers using ASP.NET's built in routing semantics. To work in an STA handler requires working in the Page Handler as part of the Route Handler implementation. As with the Web Service handler the first step is to create a custom HttpHandler that can instantiate an MVC request pipeline properly:public class MvcStaThreadHttpAsyncHandler : Page, IHttpAsyncHandler, IRequiresSessionState { private RequestContext _requestContext; public MvcStaThreadHttpAsyncHandler(RequestContext requestContext) { if (requestContext == null) throw new ArgumentNullException("requestContext"); _requestContext = requestContext; } public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, object extraData) { return this.AspCompatBeginProcessRequest(context, cb, extraData); } protected override void OnInit(EventArgs e) { var controllerName = _requestContext.RouteData.GetRequiredString("controller"); var controllerFactory = ControllerBuilder.Current.GetControllerFactory(); var controller = controllerFactory.CreateController(_requestContext, controllerName); if (controller == null) throw new InvalidOperationException("Could not find controller: " + controllerName); try { controller.Execute(_requestContext); } finally { controllerFactory.ReleaseController(controller); } this.Context.ApplicationInstance.CompleteRequest(); } public void EndProcessRequest(IAsyncResult result) { this.AspCompatEndProcessRequest(result); } public override void ProcessRequest(HttpContext httpContext) { throw new NotSupportedException("STAThreadRouteHandler does not support ProcessRequest called (only BeginProcessRequest)"); } } This handler code figures out which controller to load and then executes the controller. MVC internally provides the information needed to route to the appropriate method and pass the right parameters. Like the Web Service handler the logic occurs in the OnInit() and performs all the processing in that part of the request. Next, we need a RouteHandler that can actually pick up this handler. Unlike the Web Service handler where we simply registered the handler, MVC requires a RouteHandler to pick up the handler. RouteHandlers look at the URL's path and based on that decide on what handler to invoke. The route handler is pretty simple - all it does is load our custom handler: public class MvcStaThreadRouteHandler : IRouteHandler { public IHttpHandler GetHttpHandler(RequestContext requestContext) { if (requestContext == null) throw new ArgumentNullException("requestContext"); return new MvcStaThreadHttpAsyncHandler(requestContext); } } At this point you can instantiate this route handler and force STA requests to MVC by specifying a route. The following sets up the ASP.NET Default Route:Route mvcRoute = new Route("{controller}/{action}/{id}", new RouteValueDictionary( new { controller = "Home", action = "Index", id = UrlParameter.Optional }), new MvcStaThreadRouteHandler()); RouteTable.Routes.Add(mvcRoute);   To make this code a little easier to work with and mimic the behavior of the routes.MapRoute() functionality extension method that MVC provides, here is an extension method for MapMvcStaRoute(): public static class RouteCollectionExtensions { public static void MapMvcStaRoute(this RouteCollection routeTable, string name, string url, object defaults = null) { Route mvcRoute = new Route(url, new RouteValueDictionary(defaults), new MvcStaThreadRouteHandler()); RouteTable.Routes.Add(mvcRoute); } } With this the syntax to add  route becomes a little easier and matches the MapRoute() method:RouteTable.Routes.MapMvcStaRoute( name: "Default", url: "{controller}/{action}/{id}", defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional } ); The nice thing about this route handler, STA Handler and extension method is that it's fully self contained. You can put all three into a single class file and stick it into your Web app, and then simply call MapMvcStaRoute() and it just works. Easy! To see whether this works create an MVC controller like this: public class ThreadTestController : Controller { public string ThreadingMode() { return Thread.CurrentThread.GetApartmentState().ToString(); } } Try this test both with only the MapRoute() hookup in the RouteConfiguration in which case you should get MTA as the value. Then change the MapRoute() call to MapMvcStaRoute() leaving all the parameters the same and re-run the request. You now should see STA as the result. You're on your way using STA COM components reliably in ASP.NET MVC. WCF Web Services running through IIS WCF Web Services provide a more robust and wider range of services for Web Services. You can use WCF over HTTP, TCP, and Pipes, and WCF services support WS* secure services. There are many features in WCF that go way beyond what ASMX can do. But it's also a bit more complex than ASMX. As a basic rule if you need to serve straight SOAP Services over HTTP I 'd recommend sticking with the simpler ASMX services especially if COM is involved. If you need WS* support or want to serve data over non-HTTP protocols then WCF makes more sense. WCF is not my forte but I found a solution from Scott Seely on his blog that describes the progress and that seems to work well. I'm copying his code below so this STA information is all in one place and quickly explain. Scott's code basically works by creating a custom OperationBehavior which can be specified via an [STAOperation] attribute on every method. Using his attribute you end up with a class (or Interface if you separate the contract and class) that looks like this: [ServiceContract] public class WcfService { [OperationContract] public string HelloWorldMta() { return Thread.CurrentThread.GetApartmentState().ToString(); } // Make sure you use this custom STAOperationBehavior // attribute to force STA operation of service methods [STAOperationBehavior] [OperationContract] public string HelloWorldSta() { return Thread.CurrentThread.GetApartmentState().ToString(); } } Pretty straight forward. The latter method returns STA while the former returns MTA. To make STA work every method needs to be marked up. The implementation consists of the attribute and OperationInvoker implementation. Here are the two classes required to make this work from Scott's post:public class STAOperationBehaviorAttribute : Attribute, IOperationBehavior { public void AddBindingParameters(OperationDescription operationDescription, System.ServiceModel.Channels.BindingParameterCollection bindingParameters) { } public void ApplyClientBehavior(OperationDescription operationDescription, System.ServiceModel.Dispatcher.ClientOperation clientOperation) { // If this is applied on the client, well, it just doesn’t make sense. // Don’t throw in case this attribute was applied on the contract // instead of the implementation. } public void ApplyDispatchBehavior(OperationDescription operationDescription, System.ServiceModel.Dispatcher.DispatchOperation dispatchOperation) { // Change the IOperationInvoker for this operation. dispatchOperation.Invoker = new STAOperationInvoker(dispatchOperation.Invoker); } public void Validate(OperationDescription operationDescription) { if (operationDescription.SyncMethod == null) { throw new InvalidOperationException("The STAOperationBehaviorAttribute " + "only works for synchronous method invocations."); } } } public class STAOperationInvoker : IOperationInvoker { IOperationInvoker _innerInvoker; public STAOperationInvoker(IOperationInvoker invoker) { _innerInvoker = invoker; } public object[] AllocateInputs() { return _innerInvoker.AllocateInputs(); } public object Invoke(object instance, object[] inputs, out object[] outputs) { // Create a new, STA thread object[] staOutputs = null; object retval = null; Thread thread = new Thread( delegate() { retval = _innerInvoker.Invoke(instance, inputs, out staOutputs); }); thread.SetApartmentState(ApartmentState.STA); thread.Start(); thread.Join(); outputs = staOutputs; return retval; } public IAsyncResult InvokeBegin(object instance, object[] inputs, AsyncCallback callback, object state) { // We don’t handle async… throw new NotImplementedException(); } public object InvokeEnd(object instance, out object[] outputs, IAsyncResult result) { // We don’t handle async… throw new NotImplementedException(); } public bool IsSynchronous { get { return true; } } } The key in this setup is the Invoker and the Invoke method which creates a new thread and then fires the request on this new thread. Because this approach creates a new thread for every request it's not super efficient. There's a bunch of overhead involved in creating the thread and throwing it away after each thread, but it'll work for low volume requests and insure each thread runs in STA mode. If better performance is required it would be useful to create a custom thread manager that can pool a number of STA threads and hand off threads as needed rather than creating new threads on every request. If your Web Service needs are simple and you need only to serve standard SOAP 1.x requests, I would recommend sticking with ASMX services. It's easier to set up and work with and for STA component use it'll be significantly better performing since ASP.NET manages the STA thread pool for you rather than firing new threads for each request. One nice thing about Scotts code is though that it works in any WCF environment including self hosting. It has no dependency on ASP.NET or WebForms for that matter. STA - If you must STA components are a  pain in the ass and thankfully there isn't too much stuff out there anymore that requires it. But when you need it and you need to access STA functionality from .NET at least there are a few options available to make it happen. Each of these solutions is a bit hacky, but they work - I've used all of them in production with good results with FoxPro components. I hope compiling all of these in one place here makes it STA consumption a little bit easier. I feel your pain :-) Resources Download STA Handler Code Examples Scott Seely's original STA WCF OperationBehavior Article© Rick Strahl, West Wind Technologies, 2005-2012Posted in FoxPro   ASP.NET  .NET  COM   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Skip “Next Links” with the PageZipper Bookmarklet

    - by Asian Angel
    No matter what browser you use sooner or later you will run across a website with an endless number of “next links” used for the sole purpose of generating page views. Now you can simply scroll through those articles without the “next links” using the PageZipper Bookmarklet. The Problem Here is a perfect example of a page view generating article. As you can see our browser is in a non-maximized state and the first part of the article takes up very little room in the browser window. Absolutely horrible… The PageZipper Bookmarklet in Action The bookmarklet is very easy to set up in your browser…simply drag it to your “Bookmarks Toolbar” and you are ready to go. Switching tabs back to the article we never even needed to refresh the page. One nice little click on our new bookmarklet and… It immediately went to work. When you use PageZipper you will see a page count in the upper right corner of the browser window area as shown here. You can see the transition between pages here…nice and smooth. When using the bookmarklet just keep scrolling down as needed to read the entire article. Six pages of reading condensed into one without having to click a single link. Now that is nice! Conclusion If you despise those irritating “next links” then the PageZipper Bookmarklet will be a perfect addition to your favorite browser. Links Add the PageZipper Bookmarklet to Your Favorite Browser Similar Articles Productive Geek Tips Merge a Series of Web Pages into One with PageZipperSee Where Shortened URLs “Link To” in Your Favorite BrowserBookmarklet Fun: Check Google Analytics for Today [update]Add a Google Translation Bar to Your Favorite BrowserShare Your Favorite Webpages with the AddThis Bookmarklet TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 PCmover Professional Beware Hover Kitties Test Drive Mobile Phones Online With TryPhone Ben & Jerry’s Free Cone Day, 3/23/10 New Stinger from McAfee Helps Remove ‘FakeAlert’ Threats Google Apps Marketplace: Tools & Services For Google Apps Users Get News Quick and Precise With Newser

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  • How I use PowerShell to collect Performance Counter data

    - by AaronBertrand
    In a current project, I need to collect performance counters from a set of virtual machines that are performing different tasks and running a variety of workloads. In a similar project last year, I used LogMan to collect performance data. This time I decided to try PowerShell because, well, all the kids are doing it, I felt a little passé, and a lot of the other tasks in this project (such as building out VMs and running workloads) were already being accomplished via PowerShell. And after all, I...(read more)

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  • How I use PowerShell to collect Performance Counter data

    - by AaronBertrand
    In a current project, I need to collect performance counters from a set of virtual machines that are performing different tasks and running a variety of workloads. In a similar project last year, I used LogMan to collect performance data. This time I decided to try PowerShell because, well, all the kids are doing it, I felt a little passé, and a lot of the other tasks in this project (such as building out VMs and running workloads) were already being accomplished via PowerShell. And after all, I...(read more)

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  • Tales from the Trenches – Building a Real-World Silverlight Line of Business Application

    - by dwahlin
    There's rarely a boring day working in the world of software development. Part of the fun associated with being a developer is that change is guaranteed and the more you learn about a particular technology the more you realize there's always a different or better way to perform a task. I've had the opportunity to work on several different real-world Silverlight Line of Business (LOB) applications over the past few years and wanted to put together a list of some of the key things I've learned as well as key problems I've encountered and resolved. There are several different topics I could cover related to "lessons learned" (some of them were more painful than others) but I'll keep it to 5 items for this post and cover additional lessons learned in the future. The topics discussed were put together for a TechEd talk: Pick a Pattern and Stick To It Data Binding and Nested Controls Notify Users of Successes (and failures) Get an Agent – A Service Agent Extend Existing Controls The first topic covered relates to architecture best practices and how the MVVM pattern can save you time in the long run. When I was first introduced to MVVM I thought it was a lot of work for very little payoff. I've since learned (the hard way in some cases) that my initial impressions were dead wrong and that my criticisms of the pattern were generally caused by doing things the wrong way. In addition to MVVM pros the slides and sample app below also jump into data binding tricks in nested control scenarios and discuss how animations and media can be used to enhance LOB applications in subtle ways. Finally, a discussion of creating a re-usable service agent to interact with backend services is discussed as well as how existing controls make good candidates for customization. I tried to keep the samples simple while still covering the topics as much as possible so if you’re new to Silverlight you should definitely be able to follow along with a little study and practice. I’d recommend starting with the SilverlightDemos.View project, moving to the SilverlightDemos.ViewModels project and then going to the SilverlightDemos.ServiceAgents project. All of the backend “Model” code can be found in the SilverlightDemos.Web project. Custom controls used in the app can be found in the SivlerlightDemos.Controls project.   Sample Code and Slides

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  • Build an iPhone 5 Charging Dock for $1 [DIY Project Video]

    - by Asian Angel
    Are you experiencing frustration since no one has built and released an official charging dock for the iPhone 5 yet? Then this quick little DIY charging dock project may be the perfect solution to your problem and serve as a good ‘hold-over’ until a factory version is released. Build an iPhone 5 dock for $1 [via There I Fixed It - Cheezburger Network] 8 Deadly Commands You Should Never Run on Linux 14 Special Google Searches That Show Instant Answers How To Create a Customized Windows 7 Installation Disc With Integrated Updates

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  • Introduction to Lean Software Development and Kanban Systems – Eliminate Waste

    - by Ben Griswold
    In this post, we’ll continue the Lean Software Development and Kanban Systems series by concentrating on Principle #1: Eliminate Waste.   “Muda” is Waste in Japanese. In the next part of the series, we’ll dive into Principle #2: Create Knowledge / Amplify Learning. And I am going to be a little obnoxious about listing my Lean and Kanban references with every series post.  The references are great and they deserve this sort of attention. 

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  • Where did I hide my TSQL mojo?

    - by fatherjack
    LiveJournal Tags: How To,SQL Server,Tips and Tricks,TSQL,Reporting Services A little while ago I wrote a piece about finding database objects that rely on other objects that no longer exist - OK, I have my database ready, now what's missing? . This is linked to that sort of process. Many SQL Server installations are associated in some way with a Reporting Services installation, it's a very logical way to distribute your database contents to system users so they can work effectively. Databases,...(read more)

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  • Introduction to Lean Software Development and Kanban Systems – Create Knowledge and Amplify Learning

    - by Ben Griswold
    In this post, we’ll continue the series by concentrating on Principle #2: Create Knowledge and Amplify Learning In the next part of the series, we’ll dive into Principle #3: Build Integrity and Quality In. And I am going to be a little obnoxious about listing my Lean and Kanban references with every series post.  The references are great and they deserve this sort of attention.  

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  • Perform Unit Conversions with the Windows 7 Calculator

    - by Matthew Guay
    Want to easily convert area, volume, temperature, and many other units?  With the Calculator in Windows 7, it’s easy to convert most any unit into another. The New Calculator in Windows 7 Calculator received a visual overhaul in Windows 7, but at first glance it doesn’t seem to have any new functionality.  Here’s Windows 7’s Calculator on the left, with Vista’s calculator on the right.   But, looks can be deceiving.  Window’s 7’s calculator has lots of new exciting features.  Let’s try them out.  Simply type Calculator in the start menu search. To uncover the new features, click the View menu.  Here you can select many different modes, including Unit Conversion mode which we will look at. When you select the Unit Conversion mode, the Calculator will expand with a form on the left side. This conversions pane has 3 drop-down menus.  From the top one, select the type of unit you want to convert. In the next two menus, select which values you wish to convert to and from.  For instance, here we selected Temperature in the first menu, Degrees Fahrenheit in the second menu, and Degrees Celsius in the third menu. Enter the value you wish to convert in the From box, and the conversion will automatically appear in the bottom box. The Calculator contains dozens of conversion values, including more uncommon ones.  So if you’ve ever wanted to know how many US gallons are in a UK gallon, or how many knots a supersonic jet travels in an hour, this is a great tool for you!   Conclusion Windows 7 is filled with little changes that give you an all-around better experience in Windows to help you work more efficiently and productively.  With the new features in the Calculator, you just might feel a little smarter, too! Similar Articles Productive Geek Tips Add Windows Calculator to the Excel 2007 Quick Launch ToolbarEnjoy Quick & Easy Unit Conversion with Convert for WindowsCalculate with Qalculate on LinuxDisable the Annoying “This device can perform faster” Balloon Message in Windows 7Get stats on your Ruby on Rails code TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Install, Remove and HIDE Fonts in Windows 7 Need Help with Your Home Network? Awesome Lyrics Finder for Winamp & Windows Media Player Download Videos from Hulu Pixels invade Manhattan Convert PDF files to ePub to read on your iPad

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  • The Unspoken Truth About Managing Geeks

    - by Malcolm Anderson
    Late last year, Jeff Ello wrote a great article for cio magazine entitled "The Unspoken Truth About Managing Geeks" (http://www.cio.com/article/501697/The_Unspoken_Truth_About_Managing_Geeks)   If you are a non-geek managing geeks you will find this article enlightening.  It doesn't provide much in the way of soltutions, but it does show you how you can stop digging the hole that you're in, deeper than it already is.   In the event that you are a geek with a manager that just doesn't get it, then just print out this sleek little 4 page article and drop it in your managers in-basket.

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  • SQLAuthority News – Book Review – Beginning T-SQL 2008 by Kathi Kellenberger

    - by pinaldave
    Beginning T-SQL 2008 by Kathi Kellenberger Amazon Link Detail Review: Beginning T-SQL 2008 is one of the best books on the market if you are just beginning to work with Microsoft SQL, or have a little bit of experience and need to learn more quickly. Each chapter of the book introduces a new subject, and builds upon topics covered in previous chapters.  The author of the book, Kathi Kellenberger understands that you need to form a solid foundation of knowledge before moving on to new topics, and sets up each subject nicely.  Because the chapters move in an orderly progression, you continue to use skills you learned earlier. One of the best features of Beginning T-SQL 2008 is that each chapter has multiple examples and exercises.  Many books introduce a topic and then never go back to it.  This book gives enough examples that you will be familiar with the subject when you come across it in real life.  The exercises at the end of the chapter mean that you will be using the skills you learned – and there is no better way to cement a subject in your brain. The book also includes discussions of the common errors that programmers will come across, how to avoid them, and how to fix them if they happen.  Ms. Kellenberger understands that not only do mistakes happen, but they are bound to happen if you aren’t trained properly.  Mistakes are part of the learning process! The book begins by discussions relational theory, so that programmers will understand the way T-SQL works from the ground up.  It also walks readers through writing accurate queries, combining set-based and procedural processing, embedding logic in stored functions, and so much more. Overall, the main goal of Beginning T-SQL 2008 is to introduce novices to SQL programming, and quickly familiarize them with the basics of running the program.  The book is written with the idea that readers will not know any of the technical terms or vocabulary.  However, if you are a little more familiar with SQL and looking to become better, you will still find this book very helpful. Ratting: 4.5+ Stars Summary: I must recommend Beginning T-SQL 2008 highly enough.  If you are going to buy any beginners guide to Transect-SQL, this is the one you should spend your money on.  You can save yourself a lot of time and effort later by using this very affordable manual to learn the basics, which will allow you to become an expert much faster. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Book Review, SQLAuthority News, T SQL, Technology

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