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  • Why is Scala's type inferencer not able to resolve this?

    - by Levi Greenspan
    In the code snippet below - why do I have to give a type annotation for Nil? Welcome to Scala version 2.8.0.RC2 (OpenJDK Server VM, Java 1.6.0_18). Type in expressions to have them evaluated. Type :help for more information. scala> List(Some(1), Some(2), Some(3), None).foldLeft(Nil)((lst, o) => o match { case Some(i) => i::lst; case None => lst }) <console>:6: error: type mismatch; found : List[Int] required: object Nil List(Some(1), Some(2), Some(3), None).foldLeft(Nil)((lst, o) => o match { case Some(i) => i::lst; case None => lst }) ^ scala> List(Some(1), Some(2), Some(3), None).foldLeft(Nil:List[Int])((lst, o) => o match { case Some(i) => i::lst; case None => lst }) res1: List[Int] = List(3, 2, 1)

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  • Sed: regular expression match lines without <!--

    - by sixtyfootersdude
    I have a sed command to comment out xml commands sed 's/^\([ \t]*\)\(.*[0-9a-zA-Z<].*\)$/\1<!-- Security: \2 -->/' web.xml Takes: <a> <!-- Comment --> <b> bla </b> </a> Produces: <!-- Security: <a> --> <!-- Security: <!-- Comment --> --> // NOTE: there are two end comments. <!-- Security: <b> --> <!-- Security: bla --> <!-- Security: </b> --> <!-- Security: </a> --> Ideally I would like to not use my sed script to comment things that are already commented. Ie: <!-- Security: <a> --> <!-- Comment --> <!-- Security: <b> --> <!-- Security: bla --> <!-- Security: </b> --> <!-- Security: </a> --> I could do something like this: sed 's/^\([ \t]*\)\(.*[0-9a-zA-Z<].*\)$/\1<!-- Security: \2 -->/' web.xml sed 's/^[ \t]*<!-- Security: \(<!--.*-->\) -->/\1/' web.xml but I think a one liner is cleaner (?) This is pretty similar: http://stackoverflow.com/questions/436850/matching-a-line-that-doesnt-contain-specific-text-with-regular-expressions

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  • Effective simulation of compound poisson process in Matlab

    - by Henrik
    I need to simulate a huge bunch of compound poisson processes in Matlab on a very fine grid so I am looking to do it most effectively. I need to do a lot of simulations on the same random numbers but with parameters changing so it is practical to draw the uniforms and normals beforehand even though it means i have to draw a lot more than i will probably need and won't matter much because it will only need to be done once compared to in the order 500*n repl times the actual compound process generation. My method is the following: Let T be for how long i need to simulate and N the grid points, then my grid is: t=linspace(1,T,N); Let nrepl be the number of processes i need then I simulate P=poissrnd(lambda,nrepl,1); % Number of jumps for each replication U=(T-1)*rand(10000,nrepl)+1; % Set of uniforms on (1,T) for jump times N=randn(10000,nrepl); % Set of normals for jump size Then for replication j: Poiss=P(j); % Jumps for replication Uni=U(1:Poiss,j);% Jump times Norm=mu+sigma*N(1:Poiss,j);% Jump sizes Then this I guess is where I need your advice, I use this one-liner but it seems very slow: CPP_norm=sum(bsxfun(@times,bsxfun(@gt,t,Uni),Norm),1); In the inner for each jump it creates a series of same length as t with 0 until jump and then 1 after, multiplying this will create a grid with zeroes until jump has arrived and then the jump size and finally adding all these will produce the entire jump process on the grid. How can this be done more effectively? Thank you very much.

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  • byte and short data types in Java can accept the value outside the range by explicit cast. The higher data types however can not. Why?

    - by Lion
    Let's consider the following expressions in Java. byte a = 32; byte b = (byte) 250; int i = a + b; This is valid in Java even though the expression byte b = (byte) 250; is forced to assign the value 250 to b which is outside the range of the type byte. Therefore, b is assigned -6 and consequently i is assigned the value 26 through the statement int i = a + b;. The same thing is possible with short as follows. short s1=(short) 567889999; Although the specified value is outside the range of short, this statement is legal. The same thing is however wrong with higher data types such int, double, folat etc and hence, the following case is invalid and causes a compile-time error. int z=2147483648; This is illegal, since the range of int in Java is from -2,147,483,648 to 2147483647 which the above statement exceeds and issues a compile-time error. Why is such not wrong with byte and short data types in Java?

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  • actionscript find and convert text to url

    - by gravesit
    I have this script that grabs a twitter feed and displays in a little widget. What I want to do is look at the text for a url and convert that url to a link. public class Main extends MovieClip { private var twitterXML:XML; // This holds the xml data public function Main() { // This is Untold Entertainment's Twitter id. Did you grab yours? var myTwitterID= "username"; // Fire the loadTwitterXML method, passing it the url to your Twitter info: loadTwitterXML("http://twitter.com/statuses/user_timeline/" + myTwitterID + ".xml"); } private function loadTwitterXML(URL:String):void { var urlLoader:URLLoader = new URLLoader(); // When all the junk has been pulled in from the url, we'll fire finishedLoadingXML: urlLoader.addEventListener(Event.COMPLETE, finishLoadingXML); urlLoader.load(new URLRequest(URL)); } private function finishLoadingXML(e:Event = null):void { // All the junk has been pulled in from the xml! Hooray! // Remove the eventListener as a bit of housecleaning: e.target.removeEventListener(Event.COMPLETE, finishLoadingXML); // Populate the xml object with the xml data: twitterXML = new XML(e.target.data); showTwitterStatus(); } private function addTextToField(text:String,field:TextField):void{ /*Regular expressions for replacement, g: replace all, i: no lower/upper case difference Finds all strings starting with "http://", followed by any number of characters niether space nor new line.*/ var reg:RegExp=/(\b(https?|ftp|file):\/\/[-A-Z0-9+&@#\/%?=~_|!:,.;]*[-A-Z0-9+&@#\/%=~_|])/ig; //Replaces Note: "$&" stands for the replaced string. text.replace(reg,"<a href=\"$&\">$&</a>"); field.htmlText=text; } private function showTwitterStatus():void { // Uncomment this line if you want to see all the fun stuff Twitter sends you: //trace(twitterXML); // Prep the text field to hold our latest Twitter update: twitter_txt.wordWrap = true; twitter_txt.autoSize = TextFieldAutoSize.LEFT; // Populate the text field with the first element in the status.text nodes: addTextToField(twitterXML.status.text[0], twitter_txt); }

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  • syntax for MySQL INSERT with an array of columns

    - by Mike_Laird
    I'm new to PHP and MySQL query construction. I have a processor for a large form. A few fields are required, most fields are user optional. In my case, the HTML ids and the MySQL column names are identical. I've found tutorials about using arrays to convert $_POST into the fields and values for INSERT INTO, but I can't get them working - after many hours. I've stepped back to make a very simple INSERT using arrays and variables, but I'm still stumped. The following line works and INSERTs 5 items into a database with over 100 columns. The first 4 items are strings, the 5th item, monthlyRental is an integer. $query = "INSERT INTO `$table` (country, stateProvince, city3, city3Geocode, monthlyRental) VALUES ( '$country', '$stateProvince', '$city3', '$city3Geocode', '$monthlyRental')"; When I make an array for the fields and use it, as follows: $colsx = array('country,', 'stateProvince,', 'city3,', 'city3Geocode,', 'monthlyRental'); $query = "INSERT INTO `$table` ('$colsx') VALUES ( '$country', '$stateProvince', '$city3', '$city3Geocode', '$monthlyRental')"; I get a MySQL error - check the manual that corresponds to your MySQL server version for the right syntax to use near ''Array') VALUES ( 'US', 'New York', 'Fairport, Monroe County, New York', '(43.09)' at line 1. I get this error whether the array items have commas inside the single quotes or not. I've done a lot of reading and tried many combinations and I can't get it. I want to see the proper syntax on a small scale before I go back to foreach expressions to process $_POST and both the fields and values are arrays. And yes, I know I should use mysql_real_escape_string, but that is an easy later step in the foreach. Lastly, some clues about the syntax for an array of values would be helpful, particularly if it is different from the fields array. I know I need to add a null as the first array item to trigger the MySQL autoincrement id. What else? I'm pretty new, so please be specific.

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  • Dynamic programming Approach- Knapsack Puzzle

    - by idalsin
    I'm trying to solve the Knapsack problem with the dynamical programming(DP) approach, with Python 3.x. My TA pointed us towards this code for a head start. I've tried to implement it, as below: def take_input(infile): f_open = open(infile, 'r') lines = [] for line in f_open: lines.append(line.strip()) f_open.close() return lines def create_list(jewel_lines): #turns the jewels into a list of lists jewels_list = [] for x in jewel_lines: weight = x.split()[0] value = x.split()[1] jewels_list.append((int(value), int(weight))) jewels_list = sorted(jewels_list, key = lambda x : (-x[0], x[1])) return jewels_list def dynamic_grab(items, max_weight): table = [[0 for weight in range(max_weight+1)] for j in range(len(items)+1)] for j in range(1,len(items)+1): val= items[j-1][0] wt= items[j-1][1] for weight in range(1, max_weight+1): if wt > weight: table[j][weight] = table[j-1][weight] else: table[j][weight] = max(table[j-1][weight],table[j-1][weight-wt] + val) result = [] weight = max_weight for j in range(len(items),0,-1): was_added = table[j][weight] != table[j-1][weight] if was_added: val = items[j-1][0] wt = items[j-1][1] result.append(items[j-1]) weight -= wt return result def totalvalue(comb): #total of a combo of items totwt = totval = 0 for val, wt in comb: totwt += wt totval += val return (totval, -totwt) if totwt <= max_weight else (0,0) #required setup of variables infile = "JT_test1.txt" given_input = take_input(infile) max_weight = int(given_input[0]) given_input.pop(0) jewels_list = create_list(given_input) #test lines print(jewels_list) print(greedy_grab(jewels_list, max_weight)) bagged = dynamic_grab(jewels_list, max_weight) print(totalvalue(bagged)) The sample case is below. It is in the format line[0] = bag_max, line[1:] is in form(weight, value): 575 125 3000 50 100 500 6000 25 30 I'm confused as to the logic of this code in that it returns me a tuple and I'm not sure what the output tuple represents. I've been looking at this for a while and just don't understand what the code is pointing me at. Any help would be appreciated.

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  • Detect some conflictive characters in a string with javascript

    - by FranQ
    Hello. I have a file input in a form that uploads a mp3 file, but I´d like to detect conflictive characters to my system in the filename, like ! @ or any other. All codes I´ve found replace these characters, but I just want to detect them to alert the user. I think it will be easy with regular expressions, but I dont know about them. I´m using jquery/javascript. Thanks in advance for your help Edit to improve my problem description: I´m working in a CodeIgniter application that allows user to upload mp3 files to the server. I use jQuery to manage client side forms. The CI upload class converts spaces in the file name to underscores and everything works. But testing the application I uploaded a mp3 file with a (!) in the name, and I got troubles with it. I just want to insert a javascript conditional before the file is uploaded to evaluate if the user´s filename contains a (!) (or any other I´d like to add later) to ask for the file to be renamed if it does.

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  • <%: %> brackets for HTML Encoding in ASP.NET 4.0

    - by Slauma
    Accidentally I found this post about a new feature in ASP.NET 4.0: Expressions enclosed in these new brackets <%: Content %> should be rendered as HTML encoded. I've tried this within a databound label in a FormView like so: <asp:Label ID="MyLabel" runat="server" Text='<%: Eval("MyTextProperty") %>' /> But it doesn't work: The text property contains script tags (for testing), but the output is blank. Using the traditional way works: <asp:Label ID="MyLabel" runat="server" Text='<%# HttpUtility.HtmlEncode(Eval("MyTextProperty")) %>' /> What am I doing wrong? (On a sidenote: I am too stupid to find any information: Google refuses to search for that thing. The VS2010 Online help on MSDN offers a lot of hits, but nothing related to my search. Stackoverflow search too. And I don't know how these "things" (the brackets I mean) are officially called to have a better search term.) Any info and additional links and resources are welcome! Thanks in advance!

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  • Postfix flow/hook reference, or high-level overview?

    - by threecheeseopera
    The Postfix MTA consists of several components/services that work together to perform the different stages of delivery and receipt of mail; these include the smtp daemon, the pickup and cleanup processes, the queue manager, the smtp service, pipe/spawn/virtual/rewrite ... and others (including the possibility of custom components). Postfix also provides several types of hooks that allow it to integrate with external software, such as policy servers, filters, bounce handlers, loggers, and authentication mechanisms; these hooks can be connected to different components/stages of the delivery process, and can communicate via (at least) IPC, network, database, several types of flat files, or a predefined protocol (e.g. milter). An old and very limited example of this is shown at this page. My question: Does anyone have access to a resource that describes these hooks, the components/delivery stages that the hook can interact with, and the supported communication methods? Or, more likely, documentation of the various Postfix components and the hooks/methods that they support? For example: Given the requirement "if the recipient primary MX server matches 'shadysmtpd', check the recipient address against a list; if there is a match, terminate the SMTP connection without notice". My software would need to 1) integrate into the proper part of the SMTP process, 2) use some method to perform the address check (TCP map server? regular expressions? mysql?), and 3) implement the required action (connection termination). Additionally, there will probably be several methods to accomplish this, and another requirement would be to find that which best fits (ex: a network server might be faster than a flat-file lookup; or, if a large volume of mail might be affected by this check, it should be performed as early in the mail process as possible). Real-world example: The apolicy policy server (performs checks on addresses according to user-defined rules) is designed as a standalone TCP server that hooks into Postfix inside the smtpd component via the directive 'check_policy_service inet:127.0.0.1:10001' in the 'smtpd_client_restrictions' configuration option. This means that, when Postfix first receives an item of mail to be delivered, it will create a TCP connection to the policy server address:port for the purpose of determining if the client is allowed to send mail from this server (in addition to whatever other restrictions / restriction lookup methods are defined in that option); the proper action will be taken based on the server's response. Notes: 1)The Postfix architecture page describes some of this information in ascii art; what I am hoping for is distilled, condensed, reference material. 2) Please correct me if I am wrong on any level; there is a mountain of material, and I am just one man ;) Thanks!

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  • How do i return integers from a string ?

    - by kannan.ambadi
    Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Suppose you are passing a string(for e.g.: “My name has 1 K, 2 A and 3 N”)  which may contain integers, letters or special characters. I want to retrieve only numbers from the input string. We can implement it in many ways such as splitting the string into an array or by using TryParse method. I would like to share another idea, that’s by using Regular expressions. All you have to do is, create an instance of Regular Expression with a specified pattern for integer. Regular expression class defines a method called Split, which splits the specified input string based on the pattern provided during object initialization.     We can write the code as given below:   public static int[] SplitIdSeqenceValues(object combinedArgs)         {             var _argsSeperator = new Regex(@"\D+", RegexOptions.Compiled);               string[] splitedIntegers = _argsSeperator.Split(combinedArgs.ToString());               var args = new int[splitedIntegers.Length];               for (int i = 0; i < splitedIntegers.Length; i++)                 args[i] = MakeSafe.ToSafeInt32(splitedIntegers[i]);                           return args;         }    It would be better, if we set to RegexOptions.Compiled so that the regular expression will have performance boost by faster compilation.   Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Happy Programming  :))   

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  • C# 5 Async, Part 1: Simplifying Asynchrony – That for which we await

    - by Reed
    Today’s announcement at PDC of the future directions C# is taking excite me greatly.  The new Visual Studio Async CTP is amazing.  Asynchronous code – code which frustrates and demoralizes even the most advanced of developers, is taking a huge leap forward in terms of usability.  This is handled by building on the Task functionality in .NET 4, as well as the addition of two new keywords being added to the C# language: async and await. This core of the new asynchronous functionality is built upon three key features.  First is the Task functionality in .NET 4, and based on Task and Task<TResult>.  While Task was intended to be the primary means of asynchronous programming with .NET 4, the .NET Framework was still based mainly on the Asynchronous Pattern and the Event-based Asynchronous Pattern. The .NET Framework added functionality and guidance for wrapping existing APIs into a Task based API, but the framework itself didn’t really adopt Task or Task<TResult> in any meaningful way.  The CTP shows that, going forward, this is changing. One of the three key new features coming in C# is actually a .NET Framework feature.  Nearly every asynchronous API in the .NET Framework has been wrapped into a new, Task-based method calls.  In the CTP, this is done via as external assembly (AsyncCtpLibrary.dll) which uses Extension Methods to wrap the existing APIs.  However, going forward, this will be handled directly within the Framework.  This will have a unifying effect throughout the .NET Framework.  This is the first building block of the new features for asynchronous programming: Going forward, all asynchronous operations will work via a method that returns Task or Task<TResult> The second key feature is the new async contextual keyword being added to the language.  The async keyword is used to declare an asynchronous function, which is a method that either returns void, a Task, or a Task<T>. Inside the asynchronous function, there must be at least one await expression.  This is a new C# keyword (await) that is used to automatically take a series of statements and break it up to potentially use discontinuous evaluation.  This is done by using await on any expression that evaluates to a Task or Task<T>. For example, suppose we want to download a webpage as a string.  There is a new method added to WebClient: Task<string> WebClient.DownloadStringTaskAsync(Uri).  Since this returns a Task<string> we can use it within an asynchronous function.  Suppose, for example, that we wanted to do something similar to my asynchronous Task example – download a web page asynchronously and check to see if it supports XHTML 1.0, then report this into a TextBox.  This could be done like so: private async void button1_Click(object sender, RoutedEventArgs e) { string url = "http://reedcopsey.com"; string content = await new WebClient().DownloadStringTaskAsync(url); this.textBox1.Text = string.Format("Page {0} supports XHTML 1.0: {1}", url, content.Contains("XHTML 1.0")); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Let’s walk through what’s happening here, step by step.  By adding the async contextual keyword to the method definition, we are able to use the await keyword on our WebClient.DownloadStringTaskAsync method call. When the user clicks this button, the new method (Task<string> WebClient.DownloadStringTaskAsync(string)) is called, which returns a Task<string>.  By adding the await keyword, the runtime will call this method that returns Task<string>, and execution will return to the caller at this point.  This means that our UI is not blocked while the webpage is downloaded.  Instead, the UI thread will “await” at this point, and let the WebClient do it’s thing asynchronously. When the WebClient finishes downloading the string, the user interface’s synchronization context will automatically be used to “pick up” where it left off, and the Task<string> returned from DownloadStringTaskAsync is automatically unwrapped and set into the content variable.  At this point, we can use that and set our text box content. There are a couple of key points here: Asynchronous functions are declared with the async keyword, and contain one or more await expressions In addition to the obvious benefits of shorter, simpler code – there are some subtle but tremendous benefits in this approach.  When the execution of this asynchronous function continues after the first await statement, the initial synchronization context is used to continue the execution of this function.  That means that we don’t have to explicitly marshal the call that sets textbox1.Text back to the UI thread – it’s handled automatically by the language and framework!  Exception handling around asynchronous method calls also just works. I’d recommend every C# developer take a look at the documentation on the new Asynchronous Programming for C# and Visual Basic page, download the Visual Studio Async CTP, and try it out.

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  • Silverlight 5 Hosting :: Features in Silverlight 5 and Release Date

    - by mbridge
    Silverlight 5 is finally announced in the Silverlight FireStarter Event on the 2nd December, 2010. This new version of Silverlight which was earlier labeled as 'Future of Microsoft Silverlight' has now come much closer to go live as the first Silverlight 5 Beta version is expected to be shipped during the early months of 2011. However for the full fledged and the final release of Silverlight 5, we have to wait many more months as the same is likely to be made available within the Q3 2011. As would have been usually expected, this latest edition would feature many new capabilities thereby extending the developer productivity to a whole new dimension of premium media experience and feature-rich business applications. It comes along with many new feature updates as well as the inclusion of new technologies to improve the standard of the Silverlight applications which are now fine-tuned to produce next generation business and media solutions that is capable to meet the requirements of the advanced web-based app development. The Silverlight 5 is all set to replace the previous fourth version which now includes more than forty new features while also dropping various deprecated elements that was prevalent earlier. It has brought around some major performance enhancements and also included better support for various other tools and technologies. Following are some of the changes that are registered to be available under the Silverlight 5 Beta edition which is scheduled to be launched during the Q1 2011. Silverlight 5 : Premium Media Experiences The media features of Silverlight 5 has seen some major enhancements with a lot of optimizations being made to deliver richer solutions. It's capability has now been extended to make things easier, faster and capable of performing the desired tasks in the most efficient manner. The Silverlight media solutions has already been a part of many companies in the recent days where various on-demand Silverlight services were featured but with the arrival of the next generation premium media solution of Silverlight 5, it is expected to register new heights of success and global user acclamation for using it with many esteemed web-based projects and media solutions. - The most happening element in the new Silverlight 5 will be its support for utilizing the GPU based hardware acceleration which is intended to lower down the CPU load to a significant extent and thereby allowing faster rendering of media contents without consuming much resources. This feature is believed to be particularly helpful for low configured machines to run full HD media content without any lagging caused due to processor load. It will hence be one great feature to revolutionize the new generation high quality media contents to be available within the web in a more efficient manner with its hardware decoded video playback capabilities. - With the inclusion of hardware video decoding to minimize the processor load, the Silverlight 5 also comes with another optimization enhancement to also reduce the power consumption level by making new methods to deal with the power-saver settings. With this optimization in effect, the computer would be automatically allowed to switch to sleep mode while no video playback is in progress and also to prevent any screensavers to popup and cause annoyances during any video playback. There would also be other power saver options which will be made available to best suit the users requirements and purpose. - The Silverlight trickplay feature is another great way to tweak any silverlight powered media content as is used for many video tutorial sites or for dealing with any sort of presentations. This feature enables the user to modify the playback speed to either slowdown or speedup during the playback durations based on the requirements without compromising on the quality of output. Normally such manipulations always makes the content's audio to go off-pitch, but the same will not be the case with TrickPlay and the audio would seamlessly progress with the video without skipping any of its part. - In addition to all of the above, the new Silverlight 5 will be featuring wireless control of all the media contents by making use of remote controllers. With the use of such remote devices, it will be easier to handle the various media playback controls thereby providing more freedom while experiencing the premium media services. Silverlight 5 : Business Application Development The application development standard has been extended with more possibilities by bringing forth new and useful technologies and also reviving the existing methods to work better than what it was used to. From the UI improvements to advanced technical aspects, the Silverlight 5 scores high on all grounds to produce great next generation business delivered applications by putting in more creativity and resourceful touch to all the apps being produced with it. - The WPF feature of Silverlight is made more effective by introducing new standards of Databinding which is intended to improve the productivity standards of the Silverlight application developer. It brings in a lot of convenience in debugging the databinding components or expressions and hence making things work in a flawless manner. Some additional features related to databinding includes that of Ancestor RelativeSource, Implicit DataTemplates and Model View ViewModel (MVVM) support with DataContextChanged event and many other new features relating it. - It now comes with a refined text and printing service which facilitates better clarity of the text rendering and also many positive changes which are being applied to the layout pattern. New supports has been added to include OpenType font, multi-column text, linked-text containers and character leading support to name a few among the available features.This also includes some important printing aspects like that of Postscript Vector Printing API which allows to program our printing tasks in a user defined way and Pivot functionality for visualization concerns of informations. - The Graphics support is the key improvements being incorporated which now enables to utilize three dimensional graphics pattern using GPU acceleration. It can manage to provide some really cool visualizations being curved to provide media contents within the business apps with also the support for full HD contents at 1080p quality. - Silverlight 5 includes the support for 64-bit operating systems and relevant browsers and is also optimized to provide better performance. It can support the background thread for the networking which can reduce the latency of the network to a considerable extent. The Out-of-Browser functionality adds the support for utilizing various libraries and also the Win32 API. It also comes with testing support with VS 2010 which is mostly an automated procedure and has also enabled increased security aspects of all the Silverlight 5 developed applications by using the improved version of group policy support.

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  • Dynamic Grouping and Columns

    - by Tim Dexter
    Some good collaboration between myself and Kan Nishida (Oracle BIP Consulting) over at bipconsulting on a question that came in yesterday to an internal mailing list. Is there a way to allow columns to be place into a template dynamically? This would be similar to the Answers Column selector. A customer has said Crystal can do this and I am trying to see how BI Pub can do the same. Example: Report has Regions as a dimension in a table, they want the user to select a parameter that will insert either Units or Dollars without having to create multiple templates. Now whether Crystal can actually do it or not is another question, can Publisher? Yes we can! Kan took the first stab. His approach, was to allow to swap out columns in a table in the report. Some quick steps: 1. Create a parameter from BIP server UI 2. Declare the parameter in RTF template You can check this post to see how you can declare the parameter from the server. http://bipconsulting.blogspot.com/2010/02/how-to-pass-user-input-values-to-report.html 3. Use the parameter value to condition if a particular column needs to be displayed or not. You can use <?if@column:.....?> syntax for Column level IF condition. The if@column is covered in user documentation. This would allow a developer to create a report with the parameter or multiple parameters to allow the user to pick a column to be included in the report. I took a slightly different tack, with the mention of the column selector in the Answers report I took that to mean that the user wanted to select more of a dimensional column and then have the report recalculate all its totals and subtotals based on that selected column. This is a little bit more involved and involves some smart XSL and XPATH expressions, but still very doable. The user can select a column as a parameter, that is passed to the template rather than the query. The parameter value that is actually passed is the element name that you want to regroup the data by. Inside the template we then reference that parameter value in our for-each-group loop. That's where we need the trixy XSL/XPATH code to get the regrouping to happen. At this juncture, I need to hat tip to Klaus, for his article on dynamic sorting that he wrote back in 2006. I basically took his sorting code and applied it to the for-each loop. You can follow both of Kan's first two steps above i.e. Create a parameter from BIP server UI - this just needs to be based on a 'list' type list of value with name/value pairs e.g. Department/DEPARTMENT_NAME, Job/JOB_TITLE, etc. The user picks the 'friendly' value and the server passes the element name to the template. Declare the parameter in RTF template - been here before lots of times right? <?param@begin:group1;'"DEPARTMENT_NAME"'?> I have used a default value so that I can test the funtionality inside the template builder (notice the single and double quotes.) Next step is to use the template builder to build a re-grouped report layout. It does not matter if its hard coded right now; we will add in the dynamic piece next. Once you have a functioning template that is re-grouping correctly. Open up the for-each-group field and modify it to use the parameter: <?for-each-group:ROW;./*[name(.) = $group1]?> 'group1' is my grouping parameter, declared above. We need the XPATH expression to find the column in the XML structure we want to group that matches the one passed by the parameter. Its essentially looking through the data tree for a match. We can show the actual grouping value in the report output with a similar XPATH expression <?./*[name(.) = $group1]?> In my example, I took things a little further so that I could have a dynamic label for the parameter value. For instance if I am using MANAGER as the parameter I want to show: Manager: Tim Dexter My XML elements are readable e.g. DEPARTMENT_NAME. Its a simple case of replacing the underscore with a space and then 'initcapping' the result: <?xdoxslt:init_cap(translate($group1,'_',' '))?> With this in place, the user can now select a grouping column in the BIP report viewer and the layout will re-group the data and any calculations based on that column. I built a group above report but you could equally build the group left version to truly mimic the Answers column selector. If you are interested you can get an example report, sample data and layout template here. Of course, you can combine Klaus' dynamic sorting, Kan's conditional column approach and this dynamic grouping to build a real kick ass report for users that will keep them happy for hours..

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  • Microsoft, jQuery, and Templating

    - by Stephen Walther
    About two months ago, John Resig and I met at Café Algiers in Harvard square to discuss how Microsoft can contribute to the jQuery project. Today, Scott Guthrie announced in his second-day MIX keynote that Microsoft is throwing its weight behind jQuery and making it the primary way to develop client-side Ajax applications using Microsoft technologies. What does this announcement mean? It means that Microsoft is shifting its resources to invest in jQuery. Developers on the ASP.NET team are now working full-time to contribute features to the core jQuery library. Furthermore, we are working with other teams at Microsoft to ensure that our technologies work great with jQuery. We are contributing to the open-source jQuery project in the exact same way that any other company or individual from the community can contribute to jQuery. We are writing proposals, submitting the proposals to the jQuery forums, and revising the proposals in response to community feedback. The jQuery team can decide to reject or accept any feature that we propose. Any feature that Microsoft contributes to jQuery will be platform neutral. In other words, Microsoft contributions will benefit PHP and RAILS developers just as much as they benefit ASP.NET developers. Microsoft contributions to jQuery will improve the web for everyone. Contributing Support for Templates to jQuery Core Our first proposal concerns templating. We want to contribute support for templates to jQuery so that JavaScript developers can use jQuery to easily display a set of database records. You can read our templating proposal here: http://wiki.github.com/nje/jquery/jquery-templates-proposal You can download and play with our prototype for templating here: http://github.com/nje/jquery-tmpl The following code illustrates how you can use a template to display a set of products in a bulleted list: <script type="text/javascript"> jQuery(function(){ var products = [ { name: "Product 1", price: 12.99}, { name: "Product 2", price: 9.99}, { name: "Product 3", price: 35.59} ]; $("ul").append("#template", products); }); </script> <script id="template" type="text/html"> <li>{%= name %} - {%= price %}</li> </script> <ul></ul> The template is contained in a SCRIPT element that has a TYPE=”text/html” attribute. Browsers ignore the contents of a SCRIPT element when they don’t understand the content type. Notice that the placeholder {%=...%} is used within the template to indicate where the name and price of a product should appear. The delimiters {%=…%} are used for expressions and the delimiters {%...%} are used for code. Finally, the products are rendered using the template with the call to $(“ul”).append(“#template”, products). The standard jQuery DOM manipulation methods have been modified to support templates. When the page above is rendered, you get the bulleted list displayed in the following figure. Our goal is to keep our proposal for templates as simple as possible. After support for templating has been added to jQuery, plug-in authors can take advantage of templating when building complex data-driven plug-ins such as a DataGrid plug-in. The Ajax Control Toolkit Over 100,000 developers download the Ajax Control Toolkit every month. That’s a mind-boggling number of downloads. We realize that the Ajax Control Toolkit is extremely popular among ASP.NET Web Forms developers and we want to continue to invest in the Ajax Control Toolkit. If you are adding JavaScript interactivity to an ASP.NET Web Forms application, and you don’t want to write JavaScript, then we recommend that you use the server controls in the Ajax Control Toolkit. Using the Ajax Control Toolkit does not require knowledge of JavaScript and the toolkit enables you to build applications with the concepts familiar to ASP.NET Web Forms applications developers. If, however, you are interested in creating client-side interactivity without server controls then we recommend that you use jQuery. We plan to continue to release new versions of the Ajax Control Toolkit every few months. Our goal is to continue to improve the quality of the Ajax Control Toolkit and to make it easier for the community to contribute code, bug fixes, and documentation. The ASP.NET Ajax Library We are moving the ASP.NET Ajax Library into the Ajax Control Toolkit. If you currently use ASP.NET Ajax Library client templates, client data-binding, or the client script loader then you can continue to use these features by downloading the Ajax Control Toolkit. Be aware that our focus with the Ajax Control Toolkit is server-side Ajax.  For client-side Ajax, we are shifting our focus to jQuery. For example, if you have been using ASP.NET Ajax Library client templates then we recommend that you shift to using jQuery instead. Conclusion Our plan is to focus on jQuery as the primary technology for building client-side Ajax applications moving forward. We want to adapt Microsoft technologies to work great with jQuery and we want to contribute features to jQuery that will make the web better for everyone. We are very excited to be working with the jQuery core team.

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  • LLBLGen Pro v3.5 has been released!

    - by FransBouma
    Last weekend we released LLBLGen Pro v3.5! Below the list of what's new in this release. Of course, not everything is on this list, like the large amount of work we put in refactoring the runtime framework. The refactoring was necessary because our framework has two paradigms which are added to the framework at a different time, and from a design perspective in the wrong order (the paradigm we added first, SelfServicing, should have been built on top of Adapter, the other paradigm, which was added more than a year after the first released version). The refactoring made sure the framework re-uses more code across the two paradigms (they already shared a lot of code) and is better prepared for the future. We're not done yet, but refactoring a massive framework like ours without breaking interfaces and existing applications is ... a bit of a challenge ;) To celebrate the release of v3.5, we give every customer a 30% discount! Use the coupon code NR1ORM with your order :) The full list of what's new: Designer Rule based .NET Attribute definitions. It's now possible to specify a rule using fine-grained expressions with an attribute definition to define which elements of a given type will receive the attribute definition. Rules can be assigned to attribute definitions on the project level, to make it even easier to define attribute definitions in bulk for many elements in the project. More information... Revamped Project Settings dialog. Multiple project related properties and settings dialogs have been merged into a single dialog called Project Settings, which makes it easier to configure the various settings related to project elements. It also makes it easier to find features previously not used  by many (e.g. type conversions) More information... Home tab with Quick Start Guides. To make new users feel right at home, we added a home tab with quick start guides which guide you through four main use cases of the designer. System Type Converters. Many common conversions have been implemented by default in system type converters so users don't have to develop their own type converters anymore for these type conversions. Bulk Element Setting Manipulator. To change setting values for multiple project elements, it was a little cumbersome to do that without a lot of clicking and opening various editors. This dialog makes changing settings for multiple elements very easy. EDMX Importer. It's now possible to import entity model data information from an existing Entity Framework EDMX file. Other changes and fixes See for the full list of changes and fixes the online documentation. LLBLGen Pro Runtime Framework WCF Data Services (OData) support has been added. It's now possible to use your LLBLGen Pro runtime framework powered domain layer in a WCF Data Services application using the VS.NET tools for WCF Data Services. WCF Data Services is a Microsoft technology for .NET 4 to expose your domain model using OData. More information... New query specification and execution API: QuerySpec. QuerySpec is our new query specification and execution API as an alternative to Linq and our more low-level API. It's build, like our Linq provider, on top of our lower-level API. More information... SQL Server 2012 support. The SQL Server DQE allows paging using the new SQL Server 2012 style. More information... System Type converters. For a common set of types the LLBLGen Pro runtime framework contains built-in type conversions so you don't need to write your own type converters anymore. Public/NonPublic property support. It's now possible to mark a field / navigator as non-public which is reflected in the runtime framework as an internal/friend property instead of a public property. This way you can hide properties from the public interface of a generated class and still access it through code added to the generated code base. FULL JOIN support. It's now possible to perform FULL JOIN joins using the native query api and QuerySpec. It's left to the developer to check whether the used target database supports FULL (OUTER) JOINs. Using a FULL JOIN with entity fetches is not recommended, and should only be used when both participants in the join aren't the target of the fetch. Dependency Injection Tracing. It's now possible to enable tracing on dependency injection. Enable tracing at level '4' on the traceswitch 'ORMGeneral'. This will emit trace information about which instance of which type got an instance of type T injected into property P. Entity Instances in projections in Linq. It's now possible to return an entity instance in a custom Linq projection. It's now also possible to pass this instance to a method inside the query projection. Inheritance fully supported in this construct. Entity Framework support The Entity Framework has been updated in the recent year with code-first support and a new simpler context api: DbContext (with DbSet). The amount of code to generate is smaller and the context simpler. LLBLGen Pro v3.5 comes with support for DbContext and DbSet and generates code which utilizes these new classes. NHibernate support NHibernate v3.2+ built-in proxy factory factory support. By default the built-in ProxyFactoryFactory is selected. FluentNHibernate Session Manager uses 1.2 syntax. Fluent NHibernate mappings generate a SessionManager which uses the v1.2 syntax for the ProxyFactoryFactory location Optionally emit schema / catalog name in mappings Two settings have been added which allow the user to control whether the catalog name and/or schema name as known in the project in the designer is emitted into the mappings.

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  • Creating an ASP.NET report using Visual Studio 2010 - Part 2

    - by rajbk
    We continue building our report in this three part series. Creating an ASP.NET report using Visual Studio 2010 - Part 1 Creating an ASP.NET report using Visual Studio 2010 - Part 3 Creating the Client Report Definition file (RDLC) Add a folder called “RDLC”. This will hold our RDLC report.   Right click on the RDLC folder, select “Add new item..” and add an “RDLC” name of “Products”. We will use the “Report Wizard” to walk us through the steps of creating the RDLC.   In the next dialog, give the dataset a name called “ProductDataSet”. Change the data source to “NorthwindReports.DAL” and select “ProductRepository(GetProductsProjected)”. The fields that are returned from the method are shown on the right. Click next.   Drag and drop the ProductName, CategoryName, UnitPrice and Discontinued into the Values container. Note that you can create much more complex grouping using this UI. Click Next.   Most of the selections on this screen are grayed out because we did not choose a grouping in the previous screen. Click next. Choose a style for your report. Click next. The report graphic design surface is now visible. Right click on the report and add a page header and page footer. With the report design surface active, drag and drop a TextBox from the tool box to the page header. Drag one more textbox to the page header. We will use the text boxes to add some header text as shown in the next figure. You can change the font size and other properties of the textboxes using the formatting tool bar (marked in red). You can also resize the columns by moving your cursor in between columns and dragging. Adding Expressions Add two more text boxes to the page footer. We will use these to add the time the report was generated and page numbers. Right click on the first textbox in the page footer and select “Expression”. Add the following expression for the print date (note the = sign at the left of the expression in the dialog below) "© Northwind Traders " & Format(Now(),"MM/dd/yyyy hh:mm tt") Right click on the second text box and add the following for the page count.   Globals.PageNumber & " of " & Globals.TotalPages Formatting the page footer is complete.   We are now going to format the “Unit Price” column so it displays the number in currency format.  Right click on the [UnitPrice] column (not header) and select “Text Box Properties..” Under “Number”, select “Currency”. Hit OK. Adding a chart With the design surface active, go to the toolbox and drag and drop a chart control. You will need to move the product list table down first to make space for the chart contorl. The document can also be resized by dragging on the corner or at the page header/footer separator. In the next dialog, pick the first chart type. This can be changed later if needed. Click OK. The chart gets added to the design surface.   Click on the blue bars in the chart (not legend). This will bring up drop locations for dropping the fields. Drag and drop the UnitPrice and CategoryName into the top (y axis) and bottom (x axis) as shown below. This will give us the total unit prices for a given category. That is the best I could come up with as far as what report to render, sorry :-) Delete the legend area to get more screen estate. Resize the chart to your liking. Change the header, x axis and y axis text by double clicking on those areas. We made it this far. Let’s impress the client by adding a gradient to the bar graph :-) Right click on the blue bar and select “Series properties”. Under “Fill”, add a color and secondary color and select the Gradient style. We are done designing our report. In the next section you will see how to add the report to the report viewer control, bind to the data and make it refresh when the filter criteria are changed.   Creating an ASP.NET report using Visual Studio 2010 - Part 3

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  • Parallelism in .NET – Part 17, Think Continuations, not Callbacks

    - by Reed
    In traditional asynchronous programming, we’d often use a callback to handle notification of a background task’s completion.  The Task class in the Task Parallel Library introduces a cleaner alternative to the traditional callback: continuation tasks. Asynchronous programming methods typically required callback functions.  For example, MSDN’s Asynchronous Delegates Programming Sample shows a class that factorizes a number.  The original method in the example has the following signature: public static bool Factorize(int number, ref int primefactor1, ref int primefactor2) { //... .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } However, calling this is quite “tricky”, even if we modernize the sample to use lambda expressions via C# 3.0.  Normally, we could call this method like so: int primeFactor1 = 0; int primeFactor2 = 0; bool answer = Factorize(10298312, ref primeFactor1, ref primeFactor2); Console.WriteLine("{0}/{1} [Succeeded {2}]", primeFactor1, primeFactor2, answer); If we want to make this operation run in the background, and report to the console via a callback, things get tricker.  First, we need a delegate definition: public delegate bool AsyncFactorCaller( int number, ref int primefactor1, ref int primefactor2); Then we need to use BeginInvoke to run this method asynchronously: int primeFactor1 = 0; int primeFactor2 = 0; AsyncFactorCaller caller = new AsyncFactorCaller(Factorize); caller.BeginInvoke(10298312, ref primeFactor1, ref primeFactor2, result => { int factor1 = 0; int factor2 = 0; bool answer = caller.EndInvoke(ref factor1, ref factor2, result); Console.WriteLine("{0}/{1} [Succeeded {2}]", factor1, factor2, answer); }, null); This works, but is quite difficult to understand from a conceptual standpoint.  To combat this, the framework added the Event-based Asynchronous Pattern, but it isn’t much easier to understand or author. Using .NET 4’s new Task<T> class and a continuation, we can dramatically simplify the implementation of the above code, as well as make it much more understandable.  We do this via the Task.ContinueWith method.  This method will schedule a new Task upon completion of the original task, and provide the original Task (including its Result if it’s a Task<T>) as an argument.  Using Task, we can eliminate the delegate, and rewrite this code like so: var background = Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }); background.ContinueWith(task => Console.WriteLine("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result)); This is much simpler to understand, in my opinion.  Here, we’re explicitly asking to start a new task, then continue the task with a resulting task.  In our case, our method used ref parameters (this was from the MSDN Sample), so there is a little bit of extra boiler plate involved, but the code is at least easy to understand. That being said, this isn’t dramatically shorter when compared with our C# 3 port of the MSDN code above.  However, if we were to extend our requirements a bit, we can start to see more advantages to the Task based approach.  For example, supposed we need to report the results in a user interface control instead of reporting it to the Console.  This would be a common operation, but now, we have to think about marshaling our calls back to the user interface.  This is probably going to require calling Control.Invoke or Dispatcher.Invoke within our callback, forcing us to specify a delegate within the delegate.  The maintainability and ease of understanding drops.  However, just as a standard Task can be created with a TaskScheduler that uses the UI synchronization context, so too can we continue a task with a specific context.  There are Task.ContinueWith method overloads which allow you to provide a TaskScheduler.  This means you can schedule the continuation to run on the UI thread, by simply doing: Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }).ContinueWith(task => textBox1.Text = string.Format("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result), TaskScheduler.FromCurrentSynchronizationContext()); This is far more understandable than the alternative.  By using Task.ContinueWith in conjunction with TaskScheduler.FromCurrentSynchronizationContext(), we get a simple way to push any work onto a background thread, and update the user interface on the proper UI thread.  This technique works with Windows Presentation Foundation as well as Windows Forms, with no change in methodology.

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  • An Alphabet of Eponymous Aphorisms, Programming Paradigms, Software Sayings, Annoying Alliteration

    - by Brian Schroer
    Malcolm Anderson blogged about “Einstein’s Razor” yesterday, which reminded me of my favorite software development “law”, the name of which I can never remember. It took much Wikipedia-ing to find it (Hofstadter’s Law – see below), but along the way I compiled the following list: Amara’s Law: We tend to overestimate the effect of a technology in the short run and underestimate the effect in the long run. Brook’s Law: Adding manpower to a late software project makes it later. Clarke’s Third Law: Any sufficiently advanced technology is indistinguishable from magic. Law of Demeter: Each unit should only talk to its friends; don't talk to strangers. Einstein’s Razor: “Make things as simple as possible, but not simpler” is the popular paraphrase, but what he actually said was “It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience”, an overly complicated quote which is an obvious violation of Einstein’s Razor. (You can tell by looking at a picture of Einstein that the dude was hardly an expert on razors or other grooming apparati.) Finagle's Law of Dynamic Negatives: Anything that can go wrong, will—at the worst possible moment. - O'Toole's Corollary: The perversity of the Universe tends towards a maximum. Greenspun's Tenth Rule: Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp. (Morris’s Corollary: “…including Common Lisp”) Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law. Issawi’s Omelet Analogy: One cannot make an omelet without breaking eggs - but it is amazing how many eggs one can break without making a decent omelet. Jackson’s Rules of Optimization: Rule 1: Don't do it. Rule 2 (for experts only): Don't do it yet. Kaner’s Caveat: A program which perfectly meets a lousy specification is a lousy program. Liskov Substitution Principle (paraphrased): Functions that use pointers or references to base classes must be able to use objects of derived classes without knowing it Mason’s Maxim: Since human beings themselves are not fully debugged yet, there will be bugs in your code no matter what you do. Nils-Peter Nelson’s Nil I/O Rule: The fastest I/O is no I/O.    Occam's Razor: The simplest explanation is usually the correct one. Parkinson’s Law: Work expands so as to fill the time available for its completion. Quentin Tarantino’s Pie Principle: “…you want to go home have a drink and go and eat pie and talk about it.” (OK, he was talking about movies, not software, but I couldn’t find a “Q” quote about software. And wouldn’t it be cool to write a program so great that the users want to eat pie and talk about it?) Raymond’s Rule: Computer science education cannot make anybody an expert programmer any more than studying brushes and pigment can make somebody an expert painter.  Sowa's Law of Standards: Whenever a major organization develops a new system as an official standard for X, the primary result is the widespread adoption of some simpler system as a de facto standard for X. Turing’s Tenet: We shall do a much better programming job, provided we approach the task with a full appreciation of its tremendous difficulty, provided that we respect the intrinsic limitations of the human mind and approach the task as very humble programmers.  Udi Dahan’s Race Condition Rule: If you think you have a race condition, you don’t understand the domain well enough. These rules didn’t exist in the age of paper, there is no reason for them to exist in the age of computers. When you have race conditions, go back to the business and find out actual rules. Van Vleck’s Kvetching: We know about as much about software quality problems as they knew about the Black Plague in the 1600s. We've seen the victims' agonies and helped burn the corpses. We don't know what causes it; we don't really know if there is only one disease. We just suffer -- and keep pouring our sewage into our water supply. Wheeler’s Law: All problems in computer science can be solved by another level of indirection... Except for the problem of too many layers of indirection. Wheeler also said “Compatibility means deliberately repeating other people's mistakes.”. The Wrong Road Rule of Mr. X (anonymous): No matter how far down the wrong road you've gone, turn back. Yourdon’s Rule of Two Feet: If you think your management doesn't know what it's doing or that your organisation turns out low-quality software crap that embarrasses you, then leave. Zawinski's Law of Software Envelopment: Every program attempts to expand until it can read mail. Zawinski is also responsible for “Some people, when confronted with a problem, think 'I know, I'll use regular expressions.' Now they have two problems.” He once commented about X Windows widget toolkits: “Using these toolkits is like trying to make a bookshelf out of mashed potatoes.”

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  • CLR via C# 3rd Edition is out

    - by Abhijeet Patel
    Time for some book news update. CLR via C#, 3rd Edition seems to have been out for a little while now. The book was released in early Feb this year, and needless to say my copy is on it’s way. I can barely wait to dig in and chew on the goodies that one of the best technical authors and software professionals I respect has in store. The 2nd edition of the book was an absolute treat and this edition promises to be no less. Here is a brief description of what’s new and updated from the 2nd edition. Part I – CLR Basics Chapter 1-The CLR’s Execution Model Added about discussion about C#’s /optimize and /debug switches and how they relate to each other. Chapter 2-Building, Packaging, Deploying, and Administering Applications and Types Improved discussion about Win32 manifest information and version resource information. Chapter 3-Shared Assemblies and Strongly Named Assemblies Added discussion of TypeForwardedToAttribute and TypeForwardedFromAttribute. Part II – Designing Types Chapter 4-Type Fundamentals No new topics. Chapter 5-Primitive, Reference, and Value Types Enhanced discussion of checked and unchecked code and added discussion of new BigInteger type. Also added discussion of C# 4.0’s dynamic primitive type. Chapter 6-Type and Member Basics No new topics. Chapter 7-Constants and Fields No new topics. Chapter 8-Methods Added discussion of extension methods and partial methods. Chapter 9-Parameters Added discussion of optional/named parameters and implicitly-typed local variables. Chapter 10-Properties Added discussion of automatically-implemented properties, properties and the Visual Studio debugger, object and collection initializers, anonymous types, the System.Tuple type and the ExpandoObject type. Chapter 11-Events Added discussion of events and thread-safety as well as showing a cool extension method to simplify the raising of an event. Chapter 12-Generics Added discussion of delegate and interface generic type argument variance. Chapter 13-Interfaces No new topics. Part III – Essential Types Chapter 14-Chars, Strings, and Working with Text No new topics. Chapter 15-Enums Added coverage of new Enum and Type methods to access enumerated type instances. Chapter 16-Arrays Added new section on initializing array elements. Chapter 17-Delegates Added discussion of using generic delegates to avoid defining new delegate types. Also added discussion of lambda expressions. Chapter 18-Attributes No new topics. Chapter 19-Nullable Value Types Added discussion on performance. Part IV – CLR Facilities Chapter 20-Exception Handling and State Management This chapter has been completely rewritten. It is now about exception handling and state management. It includes discussions of code contracts and constrained execution regions (CERs). It also includes a new section on trade-offs between writing productive code and reliable code. Chapter 21-Automatic Memory Management Added discussion of C#’s fixed state and how it works to pin objects in the heap. Rewrote the code for weak delegates so you can use them with any class that exposes an event (the class doesn’t have to support weak delegates itself). Added discussion on the new ConditionalWeakTable class, GC Collection modes, Full GC notifications, garbage collection modes and latency modes. I also include a new sample showing how your application can receive notifications whenever Generation 0 or 2 collections occur. Chapter 22-CLR Hosting and AppDomains Added discussion of side-by-side support allowing multiple CLRs to be loaded in a single process. Added section on the performance of using MarshalByRefObject-derived types. Substantially rewrote the section on cross-AppDomain communication. Added section on AppDomain Monitoring and first chance exception notifications. Updated the section on the AppDomainManager class. Chapter 23-Assembly Loading and Reflection Added section on how to deploy a single file with dependent assemblies embedded inside it. Added section comparing reflection invoke vs bind/invoke vs bind/create delegate/invoke vs C#’s dynamic type. Chapter 24-Runtime Serialization This is a whole new chapter that was not in the 2nd Edition. Part V – Threading Chapter 25-Threading Basics Whole new chapter motivating why Windows supports threads, thread overhead, CPU trends, NUMA Architectures, the relationship between CLR threads and Windows threads, the Thread class, reasons to use threads, thread scheduling and priorities, foreground thread vs background threads. Chapter 26-Performing Compute-Bound Asynchronous Operations Whole new chapter explaining the CLR’s thread pool. This chapter covers all the new .NET 4.0 constructs including cooperative cancelation, Tasks, the aralle class, parallel language integrated query, timers, how the thread pool manages its threads, cache lines and false sharing. Chapter 27-Performing I/O-Bound Asynchronous Operations Whole new chapter explaining how Windows performs synchronous and asynchronous I/O operations. Then, I go into the CLR’s Asynchronous Programming Model, my AsyncEnumerator class, the APM and exceptions, Applications and their threading models, implementing a service asynchronously, the APM and Compute-bound operations, APM considerations, I/O request priorities, converting the APM to a Task, the event-based Asynchronous Pattern, programming model soup. Chapter 28-Primitive Thread Synchronization Constructs Whole new chapter discusses class libraries and thread safety, primitive user-mode, kernel-mode constructs, and data alignment. Chapter 29-Hybrid Thread Synchronization Constructs Whole new chapter discussion various hybrid constructs such as ManualResetEventSlim, SemaphoreSlim, CountdownEvent, Barrier, ReaderWriterLock(Slim), OneManyResourceLock, Monitor, 3 ways to solve the double-check locking technique, .NET 4.0’s Lazy and LazyInitializer classes, the condition variable pattern, .NET 4.0’s concurrent collection classes, the ReaderWriterGate and SyncGate classes.

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  • F# for the C# Programmer

    - by mbcrump
    Are you a C# Programmer and can’t make it past a day without seeing or hearing someone mention F#?  Today, I’m going to walk you through your first F# application and give you a brief introduction to the language. Sit back this will only take about 20 minutes. Introduction Microsoft's F# programming language is a functional language for the .NET framework that was originally developed at Microsoft Research Cambridge by Don Syme. In October 2007, the senior vice president of the developer division at Microsoft announced that F# was being officially productized to become a fully supported .NET language and professional developers were hired to create a team of around ten people to build the product version. In September 2008, Microsoft released the first Community Technology Preview (CTP), an official beta release, of the F# distribution . In December 2008, Microsoft announced that the success of this CTP had encouraged them to escalate F# and it is now will now be shipped as one of the core languages in Visual Studio 2010 , alongside C++, C# 4.0 and VB. The F# programming language incorporates many state-of-the-art features from programming language research and ossifies them in an industrial strength implementation that promises to revolutionize interactive, parallel and concurrent programming. Advantages of F# F# is the world's first language to combine all of the following features: Type inference: types are inferred by the compiler and generic definitions are created automatically. Algebraic data types: a succinct way to represent trees. Pattern matching: a comprehensible and efficient way to dissect data structures. Active patterns: pattern matching over foreign data structures. Interactive sessions: as easy to use as Python and Mathematica. High performance JIT compilation to native code: as fast as C#. Rich data structures: lists and arrays built into the language with syntactic support. Functional programming: first-class functions and tail calls. Expressive static type system: finds bugs during compilation and provides machine-verified documentation. Sequence expressions: interrogate huge data sets efficiently. Asynchronous workflows: syntactic support for monadic style concurrent programming with cancellations. Industrial-strength IDE support: multithreaded debugging, and graphical throwback of inferred types and documentation. Commerce friendly design and a viable commercial market. Lets try a short program in C# then F# to understand the differences. Using C#: Create a variable and output the value to the console window: Sample Program. using System;   namespace ConsoleApplication9 {     class Program     {         static void Main(string[] args)         {             var a = 2;             Console.WriteLine(a);             Console.ReadLine();         }     } } A breeze right? 14 Lines of code. We could have condensed it a bit by removing the “using” statment and tossing the namespace. But this is the typical C# program. Using F#: Create a variable and output the value to the console window: To start, open Visual Studio 2010 or Visual Studio 2008. Note: If using VS2008, then please download the SDK first before getting started. If you are using VS2010 then you are already setup and ready to go. So, click File-> New Project –> Other Languages –> Visual F# –> Windows –> F# Application. You will get the screen below. Go ahead and enter a name and click OK. Now, you will notice that the Solution Explorer contains the following: Double click the Program.fs and enter the following information. Hit F5 and it should run successfully. Sample Program. open System let a = 2        Console.WriteLine a As Shown below: Hmm, what? F# did the same thing in 3 lines of code. Show me the interactive evaluation that I keep hearing about. The F# development environment for Visual Studio 2010 provides two different modes of execution for F# code: Batch compilation to a .NET executable or DLL. (This was accomplished above). Interactive evaluation. (Demo is below) The interactive session provides a > prompt, requires a double semicolon ;; identifier at the end of a code snippet to force evaluation, and returns the names (if any) and types of resulting definitions and values. To access the F# prompt, in VS2010 Goto View –> Other Window then F# Interactive. Once you have the interactive window type in the following expression: 2+3;; as shown in the screenshot below: I hope this guide helps you get started with the language, please check out the following books for further information. F# Books for further reading   Foundations of F# Author: Robert Pickering An introduction to functional programming with F#. Including many samples, this book walks through the features of the F# language and libraries, and covers many of the .NET Framework features which can be leveraged with F#.       Functional Programming for the Real World: With Examples in F# and C# Authors: Tomas Petricek and Jon Skeet An introduction to functional programming for existing C# developers written by Tomas Petricek and Jon Skeet. This book explains the core principles using both C# and F#, shows how to use functional ideas when designing .NET applications and presents practical examples such as design of domain specific language, development of multi-core applications and programming of reactive applications.

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  • Editing sqlcmdvariable nodes in SSDT Publish Profile files using msbuild

    - by jamiet
    Publish profile files are a new feature of SSDT database projects that enable you to package up all environment-specific properties into a single file for use at publish time; I have written about them before at Publish Profile Files in SQL Server Data Tools (SSDT) and if it wasn’t obvious from that blog post, I’m a big fan! As I have used Publish Profile files more and more I have realised that there may be times when you need to edit those Publish profile files during your build process, you may think of such an operation as a kind of pre-processor step. In my case I have a sqlcmd variable called DeployTag, it holds a value representing the current build number that later gets inserted into a table using a Post-Deployment script (that’s a technique that I wrote about in Implementing SQL Server solutions using Visual Studio 2010 Database Projects – a compendium of project experiences – search for “Putting a build number into the DB”). Here are the contents of my Publish Profile file (simplified for demo purposes) : Notice that DeployTag defaults to “UNKNOWN”. On my current project we are using msbuild scripts to control what gets built and what I want to do is take the build number from our build engine and edit the Publish profile files accordingly. Here is the pertinent portion of the the msbuild script I came up with to do that:   <ItemGroup>     <Namespaces Include="myns">       <Prefix>myns</Prefix>       <Uri>http://schemas.microsoft.com/developer/msbuild/2003</Uri>     </Namespaces>   </ItemGroup>   <Target Name="UpdateBuildNumber">     <ItemGroup>       <SSDTPublishFiles Include="$(DESTINATION)\**\$(CONFIGURATION)\**\*.publish.xml" />     </ItemGroup>     <MSBuild.ExtensionPack.Xml.XmlFile Condition="%(SSDTPublishFiles.Identity) != ''"                                        TaskAction="UpdateElement"                                        File="%(SSDTPublishFiles.Identity)"                                        Namespaces="@(Namespaces)"                                         XPath="//myns:SqlCmdVariable[@Include='DeployTag']/myns:Value"                                         InnerText="$(BuildNumber)"/>   </Target> The important bits here are the definition of the namespace http://schemas.microsoft.com/developer/msbuild/2003: and the XPath expression //myns:SqlCmdVariable[@Include='DeployTag']/myns:Value: Some extra info: I use a fantastic tool called XMLPad to discover/test XPath expressions, read more at XMLPad – a new tool in my developer utility belt MSBuild.ExtensionPack.Xml.XmlFile is a msbuild task used to edit XML files and is available from Mike Fourie’s MSBuild Extension Pack I’m using a property called $(BuildNumber) to hold the value to substitute into the file and also $(DESTINATION)\**\$(CONFIGURATION)\**\*.publish.xml to define an ItemGroup all of my Publish Profile files. Populating those properties is basic msbuild stuff and is therefore outside the scope of this blog post however if you want to learn more check out MSBuild properties & How To: Use Wildcards to Build All Files in a Directory. Hope this is useful! @Jamiet

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  • Check Your Spelling, Grammar, and Style in Firefox and Chrome

    - by Matthew Guay
    Are you tired of making simple writing mistakes that get past your browser’s spell-check?  Here’s how you can get advanced grammar check and more in Firefox and Chrome with After the Deadline. Microsoft Word has spoiled us with grammar, syntax, and spell checking, but the default spell check in Firefox and Chrome still only does basic checks.  Even webapps like Google Docs don’t check more than basic spelling errors.  However, WordPress.com is an exception; it offers advanced spelling, grammar, and syntax checking with its After the Deadline proofing system.  This helps you keep from making embarrassing mistakes on your blog posts, and now, thanks to a couple free browser plugins, it can help you keep from making these mistakes in any website or webapp. After the Deadline in Google Chrome Add the After the Deadline extension (link below) to Chrome as usual. As soon as it’s installed, you’re ready to start improving your online writing.  To check spelling, grammar, and more, click the ABC button that you’ll now see at the bottom of most text boxes online. After a quick scan, grammar mistakes are highlighted in green, complex expressions and other syntax problems are highlighted in blue, and spelling mistakes are highlighted in red as would be expected.  Click on an underlined word to choose one of its recommended changes or ignore the suggestion. Or, if you want more explanation about what was wrong with that word or phrase, click Explain for more info. And, if you forget to run an After the Deadline scan before submitting a text entry, it will automatically check to make sure you still want to submit it.  Click Cancel to go back and check your writing first.   To change the After the Deadline settings, click its icon in the toolbar and select View Options.  Additionally, if you want to disable it on the site you’re on, you can click Disable on this site directly from the popup. From the settings page, you can choose extra things to check for such as double negatives and redundant phrases, as well as add sites and words to ignore. After the Deadline in Firefox Add the After the Deadline add-on to Firefox (link below) as normal. After the Deadline basically the same in Firefox as it does in Chrome.  Select the ABC icon in the lower right corner of textboxes to check them for problems, and After the Deadline will underline the problems as it did in Chrome.  To view a suggested change in Firefox, right-click on the underlined word and select the recommended change or ignore the suggestion. And, if you forget to check, you’ll see a friendly reminder asking if you’re sure you want to submit your text like it is. You can access the After the Deadline settings in Firefox from the menu bar.  Click Tools, then select AtD Preferences.  In Firefox, the settings are in a options dialog with three tabs, but it includes the same options as the Chrome settings page.  Here you can make After the Deadline as correction-happy as you like.   Conclusion The web has increasingly become an interactive place, and seldom does a day go by that we aren’t entering text in forms and comments that may stay online forever.  Even our insignificant tweets are being archived in the Library of Congress.  After the Deadline can help you make sure that your permanent internet record is as grammatically correct as possible.  Even though it doesn’t catch every problem, and even misses some spelling mistakes, it’s still a great help. Links Download the After the Deadline extension for Google Chrome Download the After the Deadline add-on for Firefox Similar Articles Productive Geek Tips Quick Tip: Disable Favicons in FirefoxStupid Geek Tricks: Duplicate a Tab with a Shortcut Key in Chrome or FirefoxHow to Disable the New Geolocation Feature in Google ChromeStupid Geek Tricks: Compare Your Browser’s Memory Usage with Google ChromeStop YouTube Videos from Automatically Playing in Chrome TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Acronis Online Backup DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows Easily Search Food Recipes With Recipe Chimp Tech Fanboys Field Guide Check these Awesome Chrome Add-ons iFixit Offers Gadget Repair Manuals Online Vista style sidebar for Windows 7 Create Nice Charts With These Web Based Tools

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  • LINQ und ArcObjects

    - by Marko Apfel
    LINQ und ArcObjects Motivation LINQ1 (language integrated query) ist eine Komponente des Microsoft .NET Frameworks seit der Version 3.5. Es erlaubt eine SQL-ähnliche Abfrage zu verschiedenen Datenquellen wie SQL, XML u.v.m. Wie SQL auch, bietet LINQ dazu eine deklarative Notation der Problemlösung - d.h. man muss nicht im Detail beschreiben wie eine Aufgabe, sondern was überhaupt zu lösen ist. Das befreit den Entwickler abfrageseitig von fehleranfälligen Iterator-Konstrukten. Ideal wäre es natürlich auf diese Möglichkeiten auch in der ArcObjects-Programmierung mit Features zugreifen zu können. Denkbar wäre dann folgendes Konstrukt: var largeFeatures = from feature in features where (feature.GetValue("SHAPE_Area").ToDouble() > 3000) select feature; bzw. dessen Äquivalent als Lambda-Expression: var largeFeatures = features.Where(feature => (feature.GetValue("SHAPE_Area").ToDouble() > 3000)); Dazu muss ein entsprechender Provider zu Verfügung stehen, der die entsprechende Iterator-Logik managt. Dies ist leichter als man auf den ersten Blick denkt - man muss nur die gewünschten Entitäten als IEnumerable<IFeature> liefern. (Anm.: nicht wundern - die Methoden GetValue() und ToDouble() habe ich nebenbei als Erweiterungsmethoden deklariert.) Im Hintergrund baut LINQ selbständig eine Zustandsmaschine (state machine)2 auf deren Ausführung verzögert ist (deferred execution)3 - d.h. dass erst beim tatsächlichen Anfordern von Entitäten (foreach, Count(), ToList(), ..) eine Instanziierung und Verarbeitung stattfindet, obwohl die Zuweisung schon an ganz anderer Stelle erfolgte. Insbesondere bei mehrfacher Iteration durch die Entitäten reibt man sich bei den ersten Debuggings verwundert die Augen wenn der Ausführungszeiger wie von Geisterhand wieder in die Iterator-Logik springt. Realisierung Eine ganz knappe Logik zum Konstruieren von IEnumerable<IFeature> lässt sich mittels Durchlaufen eines IFeatureCursor realisieren. Dazu werden die einzelnen Feature mit yield ausgegeben. Der einfachen Verwendung wegen, habe ich die Logik in eine Erweiterungsmethode GetFeatures() für IFeatureClass aufgenommen: public static IEnumerable GetFeatures(this IFeatureClass featureClass, IQueryFilter queryFilter, RecyclingPolicy policy) { IFeatureCursor featureCursor = featureClass.Search(queryFilter, RecyclingPolicy.Recycle == policy); IFeature feature; while (null != (feature = featureCursor.NextFeature())) { yield return feature; } //this is skipped in unit tests with cursor-mock if (Marshal.IsComObject(featureCursor)) { Marshal.ReleaseComObject(featureCursor); } } Damit kann man sich nun ganz einfach die IEnumerable<IFeature> erzeugen lassen: IEnumerable features = _featureClass.GetFeatures(RecyclingPolicy.DoNotRecycle); Etwas aufpassen muss man bei der Verwendung des "Recycling-Cursors". Nach einer verzögerten Ausführung darf im selben Kontext nicht erneut über die Features iteriert werden. In diesem Fall wird nämlich nur noch der Inhalt des letzten (recycelten) Features geliefert und alle Features sind innerhalb der Menge gleich. Kritisch würde daher das Konstrukt largeFeatures.ToList(). ForEach(feature => Debug.WriteLine(feature.OID)); weil ToList() schon einmal durch die Liste iteriert und der Cursor somit einmal durch die Features bewegt wurde. Die Erweiterungsmethode ForEach liefert dann immer dasselbe Feature. In derartigen Situationen darf also kein Cursor mit Recycling verwendet werden. Ein mehrfaches Ausführen von foreach ist hingegen kein Problem weil dafür jedes Mal die Zustandsmaschine neu instanziiert wird und somit der Cursor neu durchlaufen wird – das ist die oben schon erwähnte Magie. Ausblick Nun kann man auch einen Schritt weiter gehen und ganz eigene Implementierungen für die Schnittstelle IEnumerable<IFeature> in Angriff nehmen. Dazu müssen nur die Methode und das Property zum Zugriff auf den Enumerator ausprogrammiert werden. Im Enumerator selbst veranlasst man in der Reset()-Methode das erneute Ausführen der Suche – dazu übergibt man beispielsweise ein entsprechendes Delegate in den Konstruktur: new FeatureEnumerator( _featureClass, featureClass => featureClass.Search(_filter, isRecyclingCursor)); und ruft dieses beim Reset auf: public void Reset() {     _featureCursor = _resetCursor(_t); } Auf diese Art und Weise können Enumeratoren für völlig verschiedene Szenarien implementiert werden, die clientseitig restlos identisch nach obigen Schema verwendet werden. Damit verschmelzen Cursors, SelectionSets u.s.w. zu einer einzigen Materie und die Wiederverwendbarkeit von Code steigt immens. Obendrein lässt sich ein IEnumerable in automatisierten Unit-Tests sehr einfach mocken - ein großer Schritt in Richtung höherer Software-Qualität.4 Fazit Nichtsdestotrotz ist Vorsicht mit diesen Konstrukten in performance-relevante Abfragen geboten. Dadurch dass im Hintergrund eine Zustandsmaschine verwalten wird, entsteht einiges an Overhead dessen Verarbeitung zusätzliche Zeit kostet - ca. 20 bis 100 Prozent. Darüber hinaus ist auch das Arbeiten ohne Recycling schnell ein Performance-Gap. Allerdings ist deklarativer LINQ-Code viel eleganter, fehlerfreier und wartungsfreundlicher als das manuelle Iterieren, Vergleichen und Aufbauen einer Ergebnisliste. Der Code-Umfang verringert sich erfahrungsgemäß im Schnitt um 75 bis 90 Prozent! Dafür warte ich gerne ein paar Millisekunden länger. Wie so oft muss abgewogen werden zwischen Wartbarkeit und Performance - wobei für mich Wartbarkeit zunehmend an Priorität gewinnt. Zumeist ist sowieso nicht der Code sondern der Anwender die Bremse im Prozess. Demo-Quellcode support.esri.de   [1] Wikipedia: LINQ http://de.wikipedia.org/wiki/LINQ [2] Wikipedia: Zustandsmaschine http://de.wikipedia.org/wiki/Endlicher_Automat [3] Charlie Calverts Blog: LINQ and Deferred Execution http://blogs.msdn.com/b/charlie/archive/2007/12/09/deferred-execution.aspx [4] Clean Code Developer - gelber Grad/Automatisierte Unit Tests http://www.clean-code-developer.de/Gelber-Grad.ashx#Automatisierte_Unit_Tests_8

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  • Working with Reporting Services Filters–Part 1

    - by smisner
    There are two ways that you can filter data in Reporting Services. The first way, which usually provides a faster performance, is to use query parameters to apply a filter using the WHERE clause in a SQL statement. In that case, the structure of the filter depends upon the syntax recognized by the source database. Another way to filter data in Reporting Services is to apply a filter to a dataset, data region, or a group. Using this latter method, you can even apply multiple filters. However, the use of filter operators or the setup of multiple filters is not always obvious, so in this series of posts, I'll provide some more information about the configuration of filters. First, why not use query parameters exclusively for filtering? Here are a few reasons: You might want to apply a filter to part of the report, but not all of the report. Your dataset might retrieve data from a stored procedure, and doesn't allow you to pass a query parameter for filtering purposes. Your report might be set up as a snapshot on the report server and, in that case, cannot be dynamically filtered based on a query parameter. Next, let's look at how to set up a report filter in general. The process is the same whether you are applying the filter to a dataset, data region, or a group. When you go to the Filters page in the Properties dialog box for whichever of these items you selected (dataset, data region, group), you click the Add button to create a new filter. The interface looks like this: The Expression field is usually a field in the dataset, so to make it easier for you to make a selection,the drop-down list displays all of the current dataset fields. But notice the expression button to the right, which means that you can set up any type of expression-not just a dataset field. To the right of the expression button, you'll find a data type drop-down list. It's important to specify the correct data type for the field or expression you're using. Now for the operators. Here's a list of the options that you have: This Operator Performs This Action =, <>, >, >=, <, <=, Like Compares expression to value Top N, Bottom N Compares expression to Top (Bottom) set of N values (N = integer) Top %, Bottom % Compares expression to Top (Bottom) N percent of values (N = integer or float) Between Determines whether expression is between two values, inclusive In Determines whether expression is found in list of values Last, the Value is what you're comparing to the expression using the operator. The construction of a filter using some operators (=, <>, >, etc.) is fairly simple. If my dataset (for AdventureWorks data) has a Category field, and I have a parameter that prompts the user for a single category, I can set up a filter like this: Expression Data Type Operator Value [Category] Text = [@Category] But if I set the parameter to accept multiple values, I need to change the operator from = to In, just as I would have to do if I were using a query parameter. The parameter expression, [@Category], which translates to =Parameters!Category.Value, doesn’t need to change because it represents an array as soon as I change the parameter to allow multiple values. The “In” operator requires an array. With that in mind, let’s consider a variation on Value. Let’s say that I have a parameter that prompts the user for a particular year – and for simplicity’s sake, this parameter only allows a single value, and I have an expression that evaluates the previous year based on the user’s selection. Then I want to use these two values in two separate filters with an OR condition. That is, I want to filter either by the year selected OR by the year that was computed. If I create two filters, one for each year (as shown below), then the report will only display results if BOTH filter conditions are met – which would never be true. Expression Data Type Operator Value [CalendarYear] Integer = [@Year] [CalendarYear] Integer = =Parameters!Year.Value-1 To handle this scenario, we need to create a single filter that uses the “In” operator, and then set up the Value expression as an array. To create an array, we use the Split function after creating a string that concatenates the two values (highlighted in yellow) as shown below. Expression Data Type Operator Value =Cstr(Fields!CalendarYear.Value) Text In =Split( CStr(Parameters!Year.Value) + ”,” + CStr(Parameters!Year.Value-1) , “,”) Note that in this case, I had to apply a string conversion on the year integer so that I could concatenate the parameter selection with the calculated year. Pay attention to the second argument of the Split function—you must use a comma delimiter for the result to work correctly with the In operator. I also had to change the Expression value from [CalendarYear] (or =Fields!CalendarYear.Value) so that the expression would return a string that I could compare with the values in the string array. More fun with filter expressions in future posts!

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