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  • C#/.NET Little Wonders: Fun With Enum Methods

    - by James Michael Hare
    Once again lets dive into the Little Wonders of .NET, those small things in the .NET languages and BCL classes that make development easier by increasing readability, maintainability, and/or performance. So probably every one of us has used an enumerated type at one time or another in a C# program.  The enumerated types we create are a great way to represent that a value can be one of a set of discrete values (or a combination of those values in the case of bit flags). But the power of enum types go far beyond simple assignment and comparison, there are many methods in the Enum class (that all enum types “inherit” from) that can give you even more power when dealing with them. IsDefined() – check if a given value exists in the enum Are you reading a value for an enum from a data source, but are unsure if it is actually a valid value or not?  Casting won’t tell you this, and Parse() isn’t guaranteed to balk either if you give it an int or a combination of flags.  So what can we do? Let’s assume we have a small enum like this for result codes we want to return back from our business logic layer: 1: public enum ResultCode 2: { 3: Success, 4: Warning, 5: Error 6: } In this enum, Success will be zero (unless given another value explicitly), Warning will be one, and Error will be two. So what happens if we have code like this where perhaps we’re getting the result code from another data source (could be database, could be web service, etc)? 1: public ResultCode PerformAction() 2: { 3: // set up and call some method that returns an int. 4: int result = ResultCodeFromDataSource(); 5:  6: // this will suceed even if result is < 0 or > 2. 7: return (ResultCode) result; 8: } So what happens if result is –1 or 4?  Well, the cast does not fail, so what we end up with would be an instance of a ResultCode that would have a value that’s outside of the bounds of the enum constants we defined. This means if you had a block of code like: 1: switch (result) 2: { 3: case ResultType.Success: 4: // do success stuff 5: break; 6:  7: case ResultType.Warning: 8: // do warning stuff 9: break; 10:  11: case ResultType.Error: 12: // do error stuff 13: break; 14: } That you would hit none of these blocks (which is a good argument for always having a default in a switch by the way). So what can you do?  Well, there is a handy static method called IsDefined() on the Enum class which will tell you if an enum value is defined.  1: public ResultCode PerformAction() 2: { 3: int result = ResultCodeFromDataSource(); 4:  5: if (!Enum.IsDefined(typeof(ResultCode), result)) 6: { 7: throw new InvalidOperationException("Enum out of range."); 8: } 9:  10: return (ResultCode) result; 11: } In fact, this is often recommended after you Parse() or cast a value to an enum as there are ways for values to get past these methods that may not be defined. If you don’t like the syntax of passing in the type of the enum, you could clean it up a bit by creating an extension method instead that would allow you to call IsDefined() off any isntance of the enum: 1: public static class EnumExtensions 2: { 3: // helper method that tells you if an enum value is defined for it's enumeration 4: public static bool IsDefined(this Enum value) 5: { 6: return Enum.IsDefined(value.GetType(), value); 7: } 8: }   HasFlag() – an easier way to see if a bit (or bits) are set Most of us who came from the land of C programming have had to deal extensively with bit flags many times in our lives.  As such, using bit flags may be almost second nature (for a quick refresher on bit flags in enum types see one of my old posts here). However, in higher-level languages like C#, the need to manipulate individual bit flags is somewhat diminished, and the code to check for bit flag enum values may be obvious to an advanced developer but cryptic to a novice developer. For example, let’s say you have an enum for a messaging platform that contains bit flags: 1: // usually, we pluralize flags enum type names 2: [Flags] 3: public enum MessagingOptions 4: { 5: None = 0, 6: Buffered = 0x01, 7: Persistent = 0x02, 8: Durable = 0x04, 9: Broadcast = 0x08 10: } We can combine these bit flags using the bitwise OR operator (the ‘|’ pipe character): 1: // combine bit flags using 2: var myMessenger = new Messenger(MessagingOptions.Buffered | MessagingOptions.Broadcast); Now, if we wanted to check the flags, we’d have to test then using the bit-wise AND operator (the ‘&’ character): 1: if ((options & MessagingOptions.Buffered) == MessagingOptions.Buffered) 2: { 3: // do code to set up buffering... 4: // ... 5: } While the ‘|’ for combining flags is easy enough to read for advanced developers, the ‘&’ test tends to be easy for novice developers to get wrong.  First of all you have to AND the flag combination with the value, and then typically you should test against the flag combination itself (and not just for a non-zero)!  This is because the flag combination you are testing with may combine multiple bits, in which case if only one bit is set, the result will be non-zero but not necessarily all desired bits! Thanks goodness in .NET 4.0 they gave us the HasFlag() method.  This method can be called from an enum instance to test to see if a flag is set, and best of all you can avoid writing the bit wise logic yourself.  Not to mention it will be more readable to a novice developer as well: 1: if (options.HasFlag(MessagingOptions.Buffered)) 2: { 3: // do code to set up buffering... 4: // ... 5: } It is much more concise and unambiguous, thus increasing your maintainability and readability. It would be nice to have a corresponding SetFlag() method, but unfortunately generic types don’t allow you to specialize on Enum, which makes it a bit more difficult.  It can be done but you have to do some conversions to numeric and then back to the enum which makes it less of a payoff than having the HasFlag() method.  But if you want to create it for symmetry, it would look something like this: 1: public static T SetFlag<T>(this Enum value, T flags) 2: { 3: if (!value.GetType().IsEquivalentTo(typeof(T))) 4: { 5: throw new ArgumentException("Enum value and flags types don't match."); 6: } 7:  8: // yes this is ugly, but unfortunately we need to use an intermediate boxing cast 9: return (T)Enum.ToObject(typeof (T), Convert.ToUInt64(value) | Convert.ToUInt64(flags)); 10: } Note that since the enum types are value types, we need to assign the result to something (much like string.Trim()).  Also, you could chain several SetFlag() operations together or create one that takes a variable arg list if desired. Parse() and ToString() – transitioning from string to enum and back Sometimes, you may want to be able to parse an enum from a string or convert it to a string - Enum has methods built in to let you do this.  Now, many may already know this, but may not appreciate how much power are in these two methods. For example, if you want to parse a string as an enum, it’s easy and works just like you’d expect from the numeric types: 1: string optionsString = "Persistent"; 2:  3: // can use Enum.Parse, which throws if finds something it doesn't like... 4: var result = (MessagingOptions)Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result == MessagingOptions.Persistent) 7: { 8: Console.WriteLine("It worked!"); 9: } Note that Enum.Parse() will throw if it finds a value it doesn’t like.  But the values it likes are fairly flexible!  You can pass in a single value, or a comma separated list of values for flags and it will parse them all and set all bits: 1: // for string values, can have one, or comma separated. 2: string optionsString = "Persistent, Buffered"; 3:  4: var result = (MessagingOptions)Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 7: { 8: Console.WriteLine("It worked!"); 9: } Or you can parse in a string containing a number that represents a single value or combination of values to set: 1: // 3 is the combination of Buffered (0x01) and Persistent (0x02) 2: var optionsString = "3"; 3:  4: var result = (MessagingOptions) Enum.Parse(typeof (MessagingOptions), optionsString); 5:  6: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 7: { 8: Console.WriteLine("It worked again!"); 9: } And, if you really aren’t sure if the parse will work, and don’t want to handle an exception, you can use TryParse() instead: 1: string optionsString = "Persistent, Buffered"; 2: MessagingOptions result; 3:  4: // try parse returns true if successful, and takes an out parm for the result 5: if (Enum.TryParse(optionsString, out result)) 6: { 7: if (result.HasFlag(MessagingOptions.Persistent) && result.HasFlag(MessagingOptions.Buffered)) 8: { 9: Console.WriteLine("It worked!"); 10: } 11: } So we covered parsing a string to an enum, what about reversing that and converting an enum to a string?  The ToString() method is the obvious and most basic choice for most of us, but did you know you can pass a format string for enum types that dictate how they are written as a string?: 1: MessagingOptions value = MessagingOptions.Buffered | MessagingOptions.Persistent; 2:  3: // general format, which is the default, 4: Console.WriteLine("Default : " + value); 5: Console.WriteLine("G (default): " + value.ToString("G")); 6:  7: // Flags format, even if type does not have Flags attribute. 8: Console.WriteLine("F (flags) : " + value.ToString("F")); 9:  10: // integer format, value as number. 11: Console.WriteLine("D (num) : " + value.ToString("D")); 12:  13: // hex format, value as hex 14: Console.WriteLine("X (hex) : " + value.ToString("X")); Which displays: 1: Default : Buffered, Persistent 2: G (default): Buffered, Persistent 3: F (flags) : Buffered, Persistent 4: D (num) : 3 5: X (hex) : 00000003 Now, you may not really see a difference here between G and F because I used a [Flags] enum, the difference is that the “F” option treats the enum as if it were flags even if the [Flags] attribute is not present.  Let’s take a non-flags enum like the ResultCode used earlier: 1: // yes, we can do this even if it is not [Flags] enum. 2: ResultCode value = ResultCode.Warning | ResultCode.Error; And if we run that through the same formats again we get: 1: Default : 3 2: G (default): 3 3: F (flags) : Warning, Error 4: D (num) : 3 5: X (hex) : 00000003 Notice that since we had multiple values combined, but it was not a [Flags] marked enum, the G and default format gave us a number instead of a value name.  This is because the value was not a valid single-value constant of the enum.  However, using the F flags format string, it broke out the value into its component flags even though it wasn’t marked [Flags]. So, if you want to get an enum to display appropriately for whether or not it has the [Flags] attribute, use G which is the default.  If you always want it to attempt to break down the flags, use F.  For numeric output, obviously D or  X are the best choice depending on whether you want decimal or hex. Summary Hopefully, you learned a couple of new tricks with using the Enum class today!  I’ll add more little wonders as I think of them and thanks for all the invaluable input!   Technorati Tags: C#,.NET,Little Wonders,Enum,BlackRabbitCoder

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  • How can I promote clean coding at my workplace?

    - by Michael
    I work with a lot of legacy Java and RPG code on an internal company application. As you might expect, a lot of the code is written in many different styles, and often is difficult to read because of poorly named variables, inconsistent formatting, and contradictory comments (if they're there at all). Also, a good amount of code is not robust. Many times code is pushed to production quickly by the more experienced programmers, while code by newer programmers is held back by "code reviews" that IMO are unsatisfactory. (They usually take the form of, "It works, must be ok," than a serious critique of the code.) We have a fair number of production issues, which I feel could be lessened by giving more thought to the original design and testing. I have been working for this company for about 4 months, and have been complimented on my coding style a couple of times. My manager is also a fan of cleaner coding than is the norm. Is it my place to try to push for better style and better defensive coding, or should I simply code in the best way I can, and hope that my example will help others see how cleaner, more robust code (as well as aggressive refactoring) will result in less debugging and change time?

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  • Code style Tip: Case insensitive string comparison

    - by Michael Freidgeim
    Goodif (String.Compare(myString, ALL_TEXT, StringComparison.OrdinalIgnoreCase) == 0)                                {                                         return true;                                }OK(not obvious what true means) if (String.Compare(myString, ALL_TEXT, true) == 0)                                {                                         return true;                                }BAD: (non null safe) if (myString.ToLower()==ALL_TEXT.ToLower()                                {                                         return true;                                }

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  • Pella Increases Online Appointment Scheduling and Rapidly Personalizes and Updates Marketing Initiatives

    - by Michael Snow
    Originally posted on Oracle Customers page.Oracle Customer: Pella CorporationLocation:  Pella, IowaIndustry: Industrial Manufacturing Employees:  7,100 Pella Corporation is an innovative leader in creating a better view for homes and businesses by designing, testing, manufacturing, and installing quality windows and doors for new construction, remodeling, and replacement applications. A family-owned company, Pella has an 88-year history of innovation and, today, is the second-largest manufacturer in the country of windows and doors, including patio, entry, and storm doors. The company has 10 manufacturing facilities in United States and window and door showrooms across the United States and Canada. In-home consultations are an important part of Pella’s sales process. Several years ago, the company launched an online appointment scheduling tool to improve customer convenience. While the functionality worked well, the company wanted to increase online conversion rates and decrease the number of incomplete, online appointment schedules. It also wanted to give its business analysts and other line-of-business personnel the ability to update the scheduling tool and interface quickly, without needing IT team intervention and recoding, to better capitalize on opportunities and personalize the interface for specific markets. Pella also looked to reduce IT complexity by selecting a system that integrated easily with its Oracle E-Business Suite Release 12.1 enterprise applications.Pella, which has a large Oracle footprint, selected Oracle WebCenter Sites as the foundation for its new, real-time appointment scheduling application. It used the solution to re-engineer the scheduling process and the information required to set up an appointment. Just a few months after launch, it is seeing improvement in the number of appointments booked online and experiencing fewer abandoned appointments during the scheduling process. As important, Pella can now quickly and easily make changes to images, video, and content displayed on the scheduling tool interface, delivering greater business agility. Previously, such changes required a developer and weeks of coding and testing. Today, a member of Pella’s business analyst team can complete the changes in hours. This capability enables Pella to personalize the Web experience for customers. For example, it can display different products or images for clients in different regions.The solution is also highly scalable. Pella is using Oracle WebCenter Sites for appointment scheduling now and plans to migrate Pella.com, its configurator tool, and dealer microsites onto the platform. Further, Pella plans to leverage the solution to optimize mobile devices. “Moving ahead, we expect to extensively leverage Oracle WebCenter Sites to gain greater flexibility in updating the Web experience, thanks to the ability to make updates quickly without developer resources. Segmentation and targeting capabilities will allow us to create a more personalized experience across both traditional and mobile platforms,” said Teri Lancaster, IT manager, customer experience applications, Pella Corporation. A word from Pella Corporation "Oracle WebCenter Sites?from the start?delivered important benefits. We’ve redesigned the online scheduling process and are seeing more potential customers completing consultation bookings online. More important, the solution opens a world of other possibilities as we plan to migrate Pella.com and our dealer microsites to the platform, and leverage it to optimize the Web experience for our mobile devices.” – Teri Lancaster, IT Manager, Customer Experience Applications, Pella Corporation Oracle Product and Services Oracle WebCenter Sites Why Oracle Pella has a long-standing relationship with Oracle. “We look to Oracle first for a solution. Our Oracle account team came to us with several solutions, and Oracle WebCenter Sites delivered the scalability, ease-of-use, flexibility, and scalability that we required for the appointment scheduling initiative and other Web projects on the horizon, including migrating Pella.com and optimizing our site for mobile platforms,”said Teri Lancaster, IT manager, customer experience applications, Pella Corporation. Implementation Process The Pella implementation team, working with Oracle partner Element Solutions, LLC, integrated the appointment setting application with Pella.com as well as the company’s Oracle E-Business Suite customer relationship management applications. Using Oracle WebCenter Site’s development tools and subversion capabilities to develop the application, the Element Solutions and Pella teams could work remotely and collaboratively, accelerating deployment. Pella went live with the new scheduling tool in just six months. Partner Oracle PartnerElement Solutions, LLC Element Solutions was instrumental at every major stage of the project, including design creation and approval, development, training, and rollout. “Element Solutions was a vital partner for our Oracle WebCenter Sites initiative. The team provided guidance, and more important, critical knowledge transfer at every stage?which equipped us to get the most out of this powerful and versatile solution. We were definitely collaboration partners,” Lancaster said. Resources Pella Corporation Upgrades Enterprise Applications to Continue to Improve Manufacturing Efficiency Thousands of Customers Successfully and Smoothly Upgrade to Oracle E-Business Suite 12.1 for New Functionality, Lower Operating Costs and Improved Shared Operations Managing the Virtual World

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  • Nokia vs. The World

    - by Michael B. McLaughlin
    I’m looking forward to the launch of the Nokia Lumia 920. Why? Well, it stacks up better than the competition for one thing. Then there’s also that security problem that certain other phones have. Mostly, though, it’s because I love my Lumia 900 and the 920, with Windows Phone 8, will be even better. Before I got my Lumia 900, I just took it as given that smart phone cameras couldn’t be good. The Lumia taught me that smart phone cameras can be good if the manufacturer treats them as an important component worth spending time and money on (rather than some thing that consumers expect such that they’d better throw one in). I’m extremely pleased with the quality of pictures that my Lumia 900 gives me as well as the range of settings it provides (you can delve in to tell it a film speed, an f-stop, and a whole range of other settings). And the image stabilization features in the Lumia 920 deliver far better results than the others. Nokia has had great maps for a long time and they continue to improve. Even better, they made a deal that puts many of their excellent maps into Windows Phone 8 itself. There are still Nokia-exclusive features such as Nokia City Lens, of course. But by giving the core OS a great set of fundamental map data and technologies, they help ensure that customers know that buying a Windows Phone 8 will give them a great map experience no matter who made the phone. I’ll be getting a 920, myself, but the HTC and Samsung devices that have been announced have some compelling features, too, and it’s great to know that people who buy one of these won’t need to worry about where their maps might lead them. I’m looking forward to the NFC capabilities and Qi wireless charging my Lumia 920 will have. With the availability of DirectX and C++ programming on Windows Phone 8, I’m also excited about all the great games that will be added to the Windows Phone environment. I love my Xbox Phone. I love my Office phone. I love my Facebook phone. I love my GPS phone. I love my camera phone. I love my SkyDrive phone. In short, I love my Windows Phone!

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  • Behaviour Driven Maturity Model

    - by Michael Stephenson
    Originally posted on: http://geekswithblogs.net/michaelstephenson/archive/2013/07/02/153326.aspxFor anyone who is interested I have written a small paper about the theory behind the BizTalk Maturity Assessment using a generic framework I have called the "Behaviour Driven Maturity Model" and then how it could be applied to the assessment of other subjects.The paper is on the following link:http://btsmaturity.blob.core.windows.net/behaviour-driven-model/Behaviour%20Based%20Maturity%20Model%20-%20Introduction.pdfIf you would like to create a model for a different subject area based on the details of this paper then I would encourage this as much as possible, all I ask is the following:1. Let us know your doing it so we can help tell people about each others activities2. Make it free to the community3. Reference back to BizTalkMaturity.com as the source of your model

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  • 3 Key Trends For Mobile Commerce – Location, Location, Location

    - by Michael Hylton
    This past weekend I was at a major bookstore chain and looking for a particular book.  Rather than ask the clerk, I went to my smartphone and went online to find the book title, author, and competing price.  I know I’m not alone in this effort and more and more individuals (and businesses) will use the power of mobility to tilt the scale in their favor. Armed with a mobile device – smartphone or tablet – folks will use them to research, compare, and ultimately purchase.  A recent PayPal survey found that 46% of respondents plan to use a mobile device this holiday season to make a purchase.   An astounding 27% of consumers in an e-tailing group survey commissioned by Oracle, use a tablet device daily or several times a week to research products and services. Beyond researching or making purchases, 35% of consumers use their smartphone to receive offers and coupons, and 32% access coupons and redeem them at their local retail store.  And with GPS capabilities in smartphones and tablet (and with user’s approval), retailers will start pushing coupons and offers directly to phone users based on their proximity to their store (or their competitors). Security is one concern that both shoppers, companies and phone manufacturers will have to deal with in the coming years.  In that same Oracle-sponsored e-tailing group consumer survey, 32% of consumers were concerned about giving their credit card information via a smartphone. You can gain further insight into the mind of today’s consumer by reading the e-tailing group white paper, titled “the connected consumer”.

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  • 3 Key Trends For Mobile Commerce – Location, Location, Location

    - by Michael Hylton
    This past weekend I was at a major bookstore chain and looking for a particular book.  Rather than ask the clerk, I went to my smartphone and went online to find the book title, author, and competing price.  I know I’m not alone in this effort and more and more individuals (and businesses) will use the power of mobility to tilt the scale in their favor. Armed with a mobile device – smartphone or tablet – folks will use them to research, compare, and ultimately purchase.  A recent PayPal survey found that 46% of respondents plan to use a mobile device this holiday season to make a purchase.   An astounding 27% of consumers in an e-tailing group survey commissioned by Oracle, use a tablet device daily or several times a week to research products and services. Beyond researching or making purchases, 35% of consumers use their smartphone to receive offers and coupons, and 32% access coupons and redeem them at their local retail store.  And with GPS capabilities in smartphones and tablet (and with user’s approval), retailers will start pushing coupons and offers directly to phone users based on their proximity to their store (or their competitors). Security is one concern that both shoppers, companies and phone manufacturers will have to deal with in the coming years.  In that same Oracle-sponsored e-tailing group consumer survey, 32% of consumers were concerned about giving their credit card information via a smartphone. You can gain further insight into the mind of today’s consumer by reading the e-tailing group white paper, titled “the connected consumer”.

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  • Silverlight Cream for April 24, 2010 -- #846

    - by Dave Campbell
    In this Issue: Michael Washington, Timmy Kokke, Pete Brown, Paul Yanez, Emil Stoychev, Jeremy Likness, and Pavan Podila. Shoutouts: If you've got some time to spend, the User Experience Kit is packed with info: User Experience Kit, and just plain fun to navigate ... thanks Scott Barnes for reminding me about it! Jesse Liberty is looking for some help organizing and cataloging posts for a new project he's got going: Help Wanted Emil Stoychev posted Slides and demos from my talk on Silverlight 4 From SilverlightCream.com: Silverlight 4 Drag and Drop File Manager Michael Washington has a post up about a Silverlight Drag and Drop File Manager in MVVM, but a secondary important point about the post is that he and Alan Beasley followed strict Designer/Developer rules on this... you recognized Alan's ListBox didn't you? Changing CSS with jQuery syntax in Silverlight using jLight Timmy Kokke is using jLight as introduced in a prior post to interact with the DOM from Silverlight. Essential Silverlight and WPF Skills: The UI Thread, Dispatchers, Background Workers and Async Network Programming Pete Brown has a great backrounder up for WPF and Silverlight devs on threading and networking, good comments too so far. Fluid layout and Fullscreen in Silverlight Paul Yanez has a quick post and demo up on forcing full-screen with a fluid layout, all code included -- and it doesn't take much Data Binding in Silverlight Emil Stoychev has a great long tutorial up on DataBinding in Silverlight ... he hits all the major points with text, samples, and code... definitely one to read! Yet Another MVVM Locator Pattern Another not-necessarily Silverlight post from Jeremy Likness -- but definitely a good one on MVVM and locator patterns. The SpiderWebControl for Silverlight Pavan Podila has a 'SpiderWebControl' for Silverlight 4 up... this is a great network graph control with any sort of feature I can think of... check out the demo, then grab the code... or the other way around, your choice :) Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • CCNet TFS Migration - Dealing with left over folders

    - by Michael Stephenson
    Im currently in the process of migrating our many BizTalk projects from MKS source control to TFS.  While we will be using TFS for work item tracking and source control etc we will be continuing to use Cruise Control for continuous integration although im updating this to CCNet 1.5 at the same time. Ill post a few things as much as a reminder to myself about some of the problems we come across. Problem After the first build of our code the next time a build is triggered an error is encountered by the TFS source control block refreshing the source code. System.IO.IOException: The directory is not empty.    at System.IO.Directory.DeleteHelper(String fullPath, String userPath, Boolean recursive)    at System.IO.Directory.Delete(String fullPath, String userPath, Boolean recursive)    at ThoughtWorks.CruiseControl.Core.Sourcecontrol.Vsts.deleteDirectory(String path)    at ThoughtWorks.CruiseControl.Core.Sourcecontrol.Vsts.GetSource(IIntegrationResult result)    at ThoughtWorks.CruiseControl.Core.IntegrationRunner.Build(IIntegrationResult result)    at ThoughtWorks.CruiseControl.Core.IntegrationRunner.Integrate(IntegrationRequest request) System.IO.IOException: The directory is not empty. at System.IO.Directory.DeleteHelper(String fullPath, String userPath, Boolean recursive) at System.IO.Directory.Delete(String fullPath, String userPath, Boolean recursive) at ThoughtWorks.CruiseControl.Core.Sourcecontrol.Vsts.deleteDirectory(String path) at ThoughtWorks.CruiseControl.Core.Sourcecontrol.Vsts.GetSource(IIntegrationResult result) at ThoughtWorks.CruiseControl.Core.IntegrationRunner.Build(IIntegrationResult result) at ThoughtWorks.CruiseControl.Core.IntegrationRunner.Integrate(IntegrationRequest request) Project: Bupa.BPI.Documents Date of build: 2011-01-28 14:54:21 Running time: 00:00:05 Integration Request: Build (ForceBuild) triggered from VMOPBZDEV11 Solution The problem seems to be with a folder called TestLocations which is created by the build process and used along with the file adapter as a way to get messages into BizTalk.  For some reason the source control block when it does a full refresh of the code does not get rid of this folder and then complains thats a problem and fails the build. Interestingly there are other folders created by the build which are deleted fine.  My assumption is that this if something to do with the file adapter polling the directory.  However note that we have not had this problem with other source control blocks in the past. To workaround this I have added a prebuild task to the ccnet.config file to delete this folder before the source control block is executed.  See below for example < prebuild> exec>executable>cmd.exe</executable>buildArgs>/c "if exist "C:\<MyCode>\TestLocations" rd /s /q "C:\<MyCode>\TestLocations""</buildArgs>exec> prebuild> < < < </ </

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  • Disable messages “Login failed for user” in Event log

    - by Michael Freidgeim
    I’ve noticed multiple messages in EventLog on my machineLogin failed for user 'NT AUTHORITY\ANONYMOUS LOGON'. Reason: Token-based server access validation failed with an infrastructure error. Check for previous errors. [CLIENT: 10.222.25.129]I’ve found that there are machines of my co-workers, but they were not sure, which processes tried to access my SQL server.I’ve tried a few things and finally in SQL Server Configuration Manager disabled tcp, as it was suggested inhttp://blogs.msdn.com/b/psssql/archive/2010/03/09/what-spn-do-i-use-and-how-does-it-get-there.aspx

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  • Segfault when iterating over a map<string, string> and drawing its contents using SDL_TTF

    - by Michael Stahre
    I'm not entirely sure this question belongs on gamedev.stackexchange, but I'm technically working on a game and working with SDL, so it might not be entirely offtopic. I've written a class called DebugText. The point of the class is to have a nice way of printing values of variables to the game screen. The idea is to call SetDebugText() with the variables in question every time they change or, as is currently the case, every time the game's Update() is called. The issue is that when iterating over the map that contains my variables and their latest updated values, I get segfaults. See the comments in DrawDebugText() below, it specifies where the error happens. I've tried splitting the calls to it-first and it-second into separate lines and found that the problem doesn't always happen when calling it-first. It alters between it-first and it-second. I can't find a pattern. It doesn't fail on every call to DrawDebugText() either. It might fail on the third time DrawDebugText() is called, or it might fail on the fourth. Class header: #ifndef CLIENT_DEBUGTEXT_H #define CLIENT_DEBUGTEXT_H #include <Map> #include <Math.h> #include <sstream> #include <SDL.h> #include <SDL_ttf.h> #include "vector2.h" using std::string; using std::stringstream; using std::map; using std::pair; using game::Vector2; namespace game { class DebugText { private: TTF_Font* debug_text_font; map<string, string>* debug_text_list; public: void SetDebugText(string var, bool value); void SetDebugText(string var, float value); void SetDebugText(string var, int value); void SetDebugText(string var, Vector2 value); void SetDebugText(string var, string value); int DrawDebugText(SDL_Surface*, SDL_Rect*); void InitDebugText(); void Clear(); }; } #endif Class source file: #include "debugtext.h" namespace game { // Copypasta function for handling the toString conversion template <class T> inline string to_string (const T& t) { stringstream ss (stringstream::in | stringstream::out); ss << t; return ss.str(); } // Initializes SDL_TTF and sets its font void DebugText::InitDebugText() { if(TTF_WasInit()) TTF_Quit(); TTF_Init(); debug_text_font = TTF_OpenFont("LiberationSans-Regular.ttf", 16); TTF_SetFontStyle(debug_text_font, TTF_STYLE_NORMAL); } // Iterates over the current debug_text_list and draws every element on the screen. // After drawing with SDL you need to get a rect specifying the area on the screen that was changed and tell SDL that this part of the screen needs to be updated. this is done in the game's Draw() function // This function sets rects_to_update to the new list of rects provided by all of the surfaces and returns the number of rects in the list. These two parameters are used in Draw() when calling on SDL_UpdateRects(), which takes an SDL_Rect* and a list length int DebugText::DrawDebugText(SDL_Surface* screen, SDL_Rect* rects_to_update) { if(debug_text_list == NULL) return 0; if(!TTF_WasInit()) InitDebugText(); rects_to_update = NULL; // Specifying the font color SDL_Color font_color = {0xff, 0x00, 0x00, 0x00}; // r, g, b, unused int row_count = 0; string line; // The iterator variable map<string, string>::iterator it; // Gets the iterator and iterates over it for(it = debug_text_list->begin(); it != debug_text_list->end(); it++) { // Takes the first value (the name of the variable) and the second value (the value of the parameter in string form) //---------THIS LINE GIVES ME SEGFAULTS----- line = it->first + ": " + it->second; //------------------------------------------ // Creates a surface with the text on it that in turn can be rendered to the screen itself later SDL_Surface* debug_surface = TTF_RenderText_Solid(debug_text_font, line.c_str(), font_color); if(debug_surface == NULL) { // A standard check for errors fprintf(stderr, "Error: %s", TTF_GetError()); return NULL; } else { // If SDL_TTF did its job right, then we now set a destination rect row_count++; SDL_Rect dstrect = {5, 5, 0, 0}; // x, y, w, h dstrect.x = 20; dstrect.y = 20*row_count; // Draws the surface with the text on it to the screen int res = SDL_BlitSurface(debug_surface,NULL,screen,&dstrect); if(res != 0) { //Just an error check fprintf(stderr, "Error: %s", SDL_GetError()); return NULL; } // Creates a new rect to specify the area that needs to be updated with SDL_Rect* new_rect_to_update = (SDL_Rect*) malloc(sizeof(SDL_Rect)); new_rect_to_update->h = debug_surface->h; new_rect_to_update->w = debug_surface->w; new_rect_to_update->x = dstrect.x; new_rect_to_update->y = dstrect.y; // Just freeing the surface since it isn't necessary anymore SDL_FreeSurface(debug_surface); // Creates a new list of rects with room for the new rect SDL_Rect* newtemp = (SDL_Rect*) malloc(row_count*sizeof(SDL_Rect)); // Copies the data from the old list of rects to the new one memcpy(newtemp, rects_to_update, (row_count-1)*sizeof(SDL_Rect)); // Adds the new rect to the new list newtemp[row_count-1] = *new_rect_to_update; // Frees the memory used by the old list free(rects_to_update); // And finally redirects the pointer to the old list to the new list rects_to_update = newtemp; newtemp = NULL; } } // When the entire map has been iterated over, return the number of lines that were drawn, ie. the number of rects in the returned rect list return row_count; } // The SetDebugText used by all the SetDebugText overloads // Takes two strings, inserts them into the map as a pair void DebugText::SetDebugText(string var, string value) { if (debug_text_list == NULL) { debug_text_list = new map<string, string>(); } debug_text_list->erase(var); debug_text_list->insert(pair<string, string>(var, value)); } // Writes the bool to a string and calls SetDebugText(string, string) void DebugText::SetDebugText(string var, bool value) { string result; if (value) result = "True"; else result = "False"; SetDebugText(var, result); } // Does the same thing, but uses to_string() to convert the float void DebugText::SetDebugText(string var, float value) { SetDebugText(var, to_string(value)); } // Same as above, but int void DebugText::SetDebugText(string var, int value) { SetDebugText(var, to_string(value)); } // Vector2 is a struct of my own making. It contains the two float vars x and y void DebugText::SetDebugText(string var, Vector2 value) { SetDebugText(var + ".x", to_string(value.x)); SetDebugText(var + ".y", to_string(value.y)); } // Empties the list. I don't actually use this in my code. Shame on me for writing something I don't use. void DebugText::Clear() { if(debug_text_list != NULL) debug_text_list->clear(); } }

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  • Silverlight Cream for November 24, 2011 -- #1173

    - by Dave Campbell
    In this Thanksgiving Day Issue: Andrea Boschin, Samidip Basu, Ollie Riches, WindowsPhoneGeek, Sumit Dutta, Dhananjay Kumar, Daniel Egan, Doug Mair, Chris Woodruff, and Debal Saha.Happy Thanksgiving Everybody! Above the Fold: Silverlight: "Silverlight CommandBinding with Simple MVVM Toolkit" Debal Saha WP7: "How many pins can Bing Maps handle in a WP7 app - part 3" Ollie Riches Shoutouts: Michael Palermo's latest Desert Mountain Developers is up Michael Washington's latest Visual Studio #LightSwitch Daily is up From SilverlightCream.com:Windows Phone 7.5 - Play with musicAndrea Boschin's latest WP7 post is up on SilverlightShow... he's talking about the improvements in the music hub and also the programmability of musicOData caching in Windows PhoneSamidip Basu has an OData post up on SilverlightShow also, and he's talking about data caching strategies on WP7How many pins can Bing Maps handle in a WP7 app - part 3Ollie Riches has part 3 of his series on Bing Maps and pins... sepecifically how to deal with a large number of them... after going through discussing pins, he is suggesting using a heat map which looks pretty darn good, and renders fast... except when on a device :(Improvements in the LongListSelector Selection with Nov `11 release of WP ToolkitWindowsPhoneGeek's latest is this tutorial on the LongListSelector in the WP Toolkit... check out the previous info in his free eBook to get ready then dig into this tutorial for improvements in the control.Part 25 - Windows Phone 7 - Device StatusSumit Dutta's latest post is number 25 in his WP7 series, and time out he's digging into device status in the Microsoft.Phone.Info namespaceVideo on How to work with Picture in Windows Phone 7Dhananjay Kumar's latest video tutorial on WP7 is up, and he's talking about working with Photos.Live Tiles–Windows Phone WorkshopDaniel Egan has the video up of a Windows Phone Workshop done earlier this week on Live Tiles31 Days of Mango | Day #15: The Progress BarDoug Mair shares the show with Jeff Blankenburg in Jeff's Day 15 in his 31 Day quest of Mango, talking about the progressbar: Indeterminate and Determinate Modes abound31 Days of Mango | Day #14: Using ODataChris Woodruff has a guest spot on Jeff Blankenburg's 31 Days series with this post on OData... long detailed tutorial with all the codeSilverlight CommandBinding with Simple MVVM ToolkitDebal Saha has a nice detailed tutorial up on CommandBinding.. he's using the SimpleMVVM Toolkit and shows downloading and installing itStay in the 'Light!Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCreamJoin me @ SilverlightCream | Phoenix Silverlight User GroupTechnorati Tags:Silverlight    Silverlight 3    Silverlight 4    Windows PhoneMIX10

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  • Review: A Quick Look at Reflector

    - by James Michael Hare
    I, like many, was disappointed when I heard that Reflector 7 was not free, and perhaps that’s why I waited so long to try it and just kept using my version 6 (which continues to be free).  But though I resisted for so long, I longed for the better features that were being developed, and began to wonder if I should upgrade.  Thus, I began to look into the features being offered in Reflector 7.5 to see what was new. Multiple Editions Reflector 7.5 comes in three flavors, each building on the features of the previous version: Standard – Contains just the Standalone application ($70) VS – Same as Standard but adds Reflector Object Browser for Visual Studio ($130) VSPro – Same as VS but adds ability to set breakpoints and step into decompiled code ($190) So let’s examine each of these features. The Standalone Application (Standard, VS, VSPro editions) Popping open Reflector 7.5 and looking at the GUI, we see much of the same familiar features, with a few new ones as well: Most notably, the disassembler window now has a tabbed window with navigation buttons.  This makes it much easier to back out of a deep-dive into many layers of decompiled code back to a previous point. Also, there is now an analyzer which can be used to determine dependencies for a given method, property, type, etc. For example, if we select System.Net.Sockets.TcpClient and hit the Analyze button, we’d see a window with the following nodes we could expand: This gives us the ability to see what a given type uses, what uses it, who exposes it, and who instantiates it. Now obviously, for low-level types (like DateTime) this list would be enormous, but this can give a lot of information on how a given type is connected to the larger code ecosystem. One of the other things I like about using Reflector 7.5 is that it does a much better job of displaying iterator blocks than Reflector 6 did. For example, if you were to take a look at the Enumerable.Cast() extension method in System.Linq, and dive into the CastIterator in Reflector 6, you’d see this: But now, in Reflector 7.5, we see the iterator logic much more clearly: This is a big improvement in the quality of their code disassembler and for me was one of the main reasons I decided to take the plunge and get version 7.5. The Reflector Object Browser (VS, VSPro editions) If you have the .NET Reflector VS or VSPro editions, you’ll find you have in Visual Studio a Reflector Object Browser window available where you can select and decompile any assembly right in Visual Studio. For example, if you want to take a peek at how System.Collections.Generic.List<T> works, you can either select List<T> in the Reflector Object Browser, or even simpler just select a usage of it in your code and CTRL + Click to dive in. – And it takes you right to a source window with the decompiled source: Setting Breakpoints and Stepping Into Decompiled Code (VSPro) If you have the VSPro edition, in addition to all the things said above, you also get the additional ability to set breakpoints in this decompiled code and step through it as if it were your own code: This can be a handy feature when you need to see why your code’s use of a BCL or other third-party library isn’t working as you expect. Summary Yes, Reflector is no longer free, and yes, that’s a bit of a bummer. But it always was and still is a very fine tool. If you still have Reflector 6, you aren’t forced to upgrade any longer, but getting the nicer disassembler (especially for iterator blocks) and the handy VS integration is worth at least considering upgrading for.  So I leave it up to you, these are some of the features of Reflector 7.5, what’s your thoughts? Technorati Tags: .NET,Reflector

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  • Translate jQuery UI Datepicker format to .Net Date format

    - by Michael Freidgeim
    I needed to use the same date format in client jQuery UI Datepicker and server ASP.NET code. The actual format can be different for different localization cultures.I decided to translate Datepicker format to .Net Date format similar as it was asked to do opposite operation in http://stackoverflow.com/questions/8531247/jquery-datepickers-dateformat-how-to-integrate-with-net-current-culture-date Note that replace command need to replace whole words and order of calls is importantFunction that does opposite operation (translate  .Net Date format toDatepicker format) is described in http://www.codeproject.com/Articles/62031/JQueryUI-Datepicker-in-ASP-NET-MVC /// <summary> /// Uses regex '\b' as suggested in //http://stackoverflow.com/questions/6143642/way-to-have-string-replace-only-hit-whole-words /// </summary> /// <param name="original"></param> /// <param name="wordToFind"></param> /// <param name="replacement"></param> /// <param name="regexOptions"></param> /// <returns></returns> static public string ReplaceWholeWord(this string original, string wordToFind, string replacement, RegexOptions regexOptions = RegexOptions.None) { string pattern = String.Format(@"\b{0}\b", wordToFind); string ret=Regex.Replace(original, pattern, replacement, regexOptions); return ret; } /// <summary> /// E.g "DD, d MM, yy" to ,"dddd, d MMMM, yyyy" /// </summary> /// <param name="datePickerFormat"></param> /// <returns></returns> /// <remarks> /// Idea to replace from http://stackoverflow.com/questions/8531247/jquery-datepickers-dateformat-how-to-integrate-with-net-current-culture-date ///From http://docs.jquery.com/UI/Datepicker/$.datepicker.formatDate to http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx ///Format a date into a string value with a specified format. ///d - day of month (no leading zero) ---.Net the same ///dd - day of month (two digit) ---.Net the same ///D - day name short ---.Net "ddd" ///DD - day name long ---.Net "dddd" ///m - month of year (no leading zero) ---.Net "M" ///mm - month of year (two digit) ---.Net "MM" ///M - month name short ---.Net "MMM" ///MM - month name long ---.Net "MMMM" ///y - year (two digit) ---.Net "yy" ///yy - year (four digit) ---.Net "yyyy" /// </remarks> public static string JQueryDatePickerFormatToDotNetDateFormat(string datePickerFormat) { string sRet = datePickerFormat.ReplaceWholeWord("DD", "dddd").ReplaceWholeWord("D", "ddd"); sRet = sRet.ReplaceWholeWord("M", "MMM").ReplaceWholeWord("MM", "MMMM").ReplaceWholeWord("m", "M").ReplaceWholeWord("mm", "MM");//order is important sRet = sRet.ReplaceWholeWord("yy", "yyyy").ReplaceWholeWord("y", "yy");//order is important return sRet; }

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  • UK Connected Systems User Group - Udi Dahan Event Topic change

    - by Michael Stephenson
    Hi Just wanted to get the word out about a change to the may user group event.  Udi Dahan will present a new topic which he has not presented in the UK before.  Details below. To register for this event please refer to: http://ukconnectedsystemsusergroup.org/UpcomingEvents.aspx Title: High Availability - A Contrarian View   Abstract: Many developers are aware of the importance of high availability, critically analyzing any single points of failure in the infrastructure. Those same developers rarely give a second thought to the periods of time when a system is being upgraded. Even if all the servers are running, most systems cannot function in-between versions. Yet with the increased pace of business, users are demanding ever more frequent releases. The poor maintenance programmers and system administrators are left holding the bag long after the architecture that sealed their fate was formulated. Join Udi for some different perspectives on high availability - architecture and methodology for the real world.

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  • Silverlight Cream for April 19, 2010 -- #841

    - by Dave Campbell
    In this Issue: Michael Washington, Jeremy Likness, Giorgetti Alessandro, Antoni Dol, Mike Taulty, and Braulio Diez. Shoutout: Bart Czernicki lists compelling reasons to use Silverlight 4 for LOB apps: Silverlight 4 - What is New for Business Intelligence Scenarios From SilverlightCream.com: Silverlight Advanced MVVM Video Player After the initial posting on his Simple MVVM Video player, Michael Washington got some feedback and decided to do a part 2 demonstrating exactly how easy it is to customize... great tutorial and all the code. Model-View-ViewModel (MVVM) Explained Jeremy Likness has a post up that begins "The purpose of this post is to provide an introduction to the Model-View-ViewModel (MVVM) pattern." -- 'nuff said... If you're not there yet, get there now :) Castle Windsor – Silverlight 4 binaries Giorgetti Alessandro has produced workable Castle Windsor binaries for Silverlight 4. No Unit Tests at this point, but read the post for that information. Silverlight Togglebutton Push Pin Style with IsoStore Antoni Dol has a very nice ToggleButton redone as a pushpin for pinning an app, plus it saves the pinned information to Isolated Storage ... all with source! Silverlight and Xml Binding Mike Taulty fleshes out a sketchy idea he has surrounding databinding Silverlight to XML data by using the ability to databind to string indexers and XPath support. WinToolbar Silverlight widget available on Codeplex Braulio Diez announced a Toolbar library that he and Sebastian Stehlehave posted on CodePlex that looks awesome... you may as well just go get it now, you're going to want to! Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • Of C# Iterators and Performance

    - by James Michael Hare
    Some of you reading this will be wondering, "what is an iterator" and think I'm locked in the world of C++.  Nope, I'm talking C# iterators.  No, not enumerators, iterators.   So, for those of you who do not know what iterators are in C#, I will explain it in summary, and for those of you who know what iterators are but are curious of the performance impacts, I will explore that as well.   Iterators have been around for a bit now, and there are still a bunch of people who don't know what they are or what they do.  I don't know how many times at work I've had a code review on my code and have someone ask me, "what's that yield word do?"   Basically, this post came to me as I was writing some extension methods to extend IEnumerable<T> -- I'll post some of the fun ones in a later post.  Since I was filtering the resulting list down, I was using the standard C# iterator concept; but that got me wondering: what are the performance implications of using an iterator versus returning a new enumeration?   So, to begin, let's look at a couple of methods.  This is a new (albeit contrived) method called Every(...).  The goal of this method is to access and enumeration and return every nth item in the enumeration (including the first).  So Every(2) would return items 0, 2, 4, 6, etc.   Now, if you wanted to write this in the traditional way, you may come up with something like this:       public static IEnumerable<T> Every<T>(this IEnumerable<T> list, int interval)     {         List<T> newList = new List<T>();         int count = 0;           foreach (var i in list)         {             if ((count++ % interval) == 0)             {                 newList.Add(i);             }         }           return newList;     }     So basically this method takes any IEnumerable<T> and returns a new IEnumerable<T> that contains every nth item.  Pretty straight forward.   The problem?  Well, Every<T>(...) will construct a list containing every nth item whether or not you care.  What happens if you were searching this result for a certain item and find that item after five tries?  You would have generated the rest of the list for nothing.   Enter iterators.  This C# construct uses the yield keyword to effectively defer evaluation of the next item until it is asked for.  This can be very handy if the evaluation itself is expensive or if there's a fair chance you'll never want to fully evaluate a list.   We see this all the time in Linq, where many expressions are chained together to do complex processing on a list.  This would be very expensive if each of these expressions evaluated their entire possible result set on call.    Let's look at the same example function, this time using an iterator:       public static IEnumerable<T> Every<T>(this IEnumerable<T> list, int interval)     {         int count = 0;         foreach (var i in list)         {             if ((count++ % interval) == 0)             {                 yield return i;             }         }     }   Notice it does not create a new return value explicitly, the only evidence of a return is the "yield return" statement.  What this means is that when an item is requested from the enumeration, it will enter this method and evaluate until it either hits a yield return (in which case that item is returned) or until it exits the method or hits a yield break (in which case the iteration ends.   Behind the scenes, this is all done with a class that the CLR creates behind the scenes that keeps track of the state of the iteration, so that every time the next item is asked for, it finds that item and then updates the current position so it knows where to start at next time.   It doesn't seem like a big deal, does it?  But keep in mind the key point here: it only returns items as they are requested. Thus if there's a good chance you will only process a portion of the return list and/or if the evaluation of each item is expensive, an iterator may be of benefit.   This is especially true if you intend your methods to be chainable similar to the way Linq methods can be chained.    For example, perhaps you have a List<int> and you want to take every tenth one until you find one greater than 10.  We could write that as:       List<int> someList = new List<int>();         // fill list here         someList.Every(10).TakeWhile(i => i <= 10);     Now is the difference more apparent?  If we use the first form of Every that makes a copy of the list.  It's going to copy the entire list whether we will need those items or not, that can be costly!    With the iterator version, however, it will only take items from the list until it finds one that is > 10, at which point no further items in the list are evaluated.   So, sounds neat eh?  But what's the cost is what you're probably wondering.  So I ran some tests using the two forms of Every above on lists varying from 5 to 500,000 integers and tried various things.    Now, iteration isn't free.  If you are more likely than not to iterate the entire collection every time, iterator has some very slight overhead:   Copy vs Iterator on 100% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 5 Copy 5 5 5 Iterator 5 50 50 Copy 28 50 50 Iterator 27 500 500 Copy 227 500 500 Iterator 247 5000 5000 Copy 2266 5000 5000 Iterator 2444 50,000 50,000 Copy 24,443 50,000 50,000 Iterator 24,719 500,000 500,000 Copy 250,024 500,000 500,000 Iterator 251,521   Notice that when iterating over the entire produced list, the times for the iterator are a little better for smaller lists, then getting just a slight bit worse for larger lists.  In reality, given the number of items and iterations, the result is near negligible, but just to show that iterators come at a price.  However, it should also be noted that the form of Every that returns a copy will have a left-over collection to garbage collect.   However, if we only partially evaluate less and less through the list, the savings start to show and make it well worth the overhead.  Let's look at what happens if you stop looking after 80% of the list:   Copy vs Iterator on 80% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 4 Copy 5 5 4 Iterator 5 50 40 Copy 27 50 40 Iterator 23 500 400 Copy 215 500 400 Iterator 200 5000 4000 Copy 2099 5000 4000 Iterator 1962 50,000 40,000 Copy 22,385 50,000 40,000 Iterator 19,599 500,000 400,000 Copy 236,427 500,000 400,000 Iterator 196,010       Notice that the iterator form is now operating quite a bit faster.  But the savings really add up if you stop on average at 50% (which most searches would typically do):     Copy vs Iterator on 50% of Collection (10,000 iterations) Collection Size Num Iterated Type Total ms 5 2 Copy 5 5 2 Iterator 4 50 25 Copy 25 50 25 Iterator 16 500 250 Copy 188 500 250 Iterator 126 5000 2500 Copy 1854 5000 2500 Iterator 1226 50,000 25,000 Copy 19,839 50,000 25,000 Iterator 12,233 500,000 250,000 Copy 208,667 500,000 250,000 Iterator 122,336   Now we see that if we only expect to go on average 50% into the results, we tend to shave off around 40% of the time.  And this is only for one level deep.  If we are using this in a chain of query expressions it only adds to the savings.   So my recommendation?  If you have a resonable expectation that someone may only want to partially consume your enumerable result, I would always tend to favor an iterator.  The cost if they iterate the whole thing does not add much at all -- and if they consume only partially, you reap some really good performance gains.   Next time I'll discuss some of my favorite extensions I've created to make development life a little easier and maintainability a little better.

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  • Visual Studio 10 crashed when tried to open one of solutions

    - by Michael Freidgeim
    Visual Studio 10 crashed when I tried to open  one of my solutions. Closing Visual Studio and rebooting the machine didn’t help.The error message that was logged(see below), didn’t give any useful ideas.Finally It was fixed after I’ve deleted MySolution.suo file, which was quite big, and also Resharper folders.Log Name:      ApplicationSource:        Application ErrorEvent ID:      1000Task Category: (100)Level:         ErrorKeywords:      ClassicUser:          N/ADescription:Faulting application name: devenv.exe, version: 10.0.40219.1, time stamp: 0x4d5f2a73Faulting module name: msenv.dll, version: 10.0.40219.1, time stamp: 0x4d5f2d48Exception code: 0xc0000005Fault offset: 0x00355770Faulting process id: 0x1dc0Faulting application start time: 0x01cd1836888599f4Faulting application path: C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\devenv.exeFaulting module path: c:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\msenv.dllReport Id: 9924b2f9-844e-11e1-bc19-782bcba513eaEvent Xml:<Event >  <System>    <Provider Name="Application Error" />    <EventID Qualifiers="0">1000</EventID>    <Level>2</Level>    <Task>100</Task>    <Keywords>0x80000000000000</Keywords>    <TimeCreated SystemTime="2012-04-12T03:21:31.000000000Z" />    <EventRecordID>401998</EventRecordID>    <Channel>Application</Channel>    <Security />  </System>  <EventData>    <Data>devenv.exe</Data>    <Data>10.0.40219.1</Data>    <Data>4d5f2a73</Data>    <Data>msenv.dll</Data>    <Data>10.0.40219.1</Data>    <Data>4d5f2d48</Data>    <Data>c0000005</Data>    <Data>00355770</Data>    <Data>1dc0</Data>    <Data>01cd1836888599f4</Data>    <Data>C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\devenv.exe</Data>    <Data>c:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\msenv.dll</Data>    <Data>9924b2f9-844e-11e1-bc19-782bcba513ea</Data>  </EventData></Event>v

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  • rails bundler error installing nokigiri (1.5.5), and Bundler cannot continue

    - by Michael Durrant
    An error occurred while installing nokogiri (1.5.5), and Bundler cannot continue How to fix and get past the error? Installing nokogiri (1.5.5) with native extensions Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension. /usr/bin/ruby1.8 extconf.rb checking for libxml/parser.h... yes checking for libxslt/xslt.h... no ----- libxslt is missing. please visit http://nokogiri.org/tutorials/installing_nokogiri.html for help with installing dependencies.

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  • ANTS Memory Profiler 7.0 Review

    - by Michael B. McLaughlin
    (This is my first review as a part of the GeeksWithBlogs.net Influencers program. It’s a program in which I (and the others who have been selected for it) get the opportunity to check out new products and services and write reviews about them. We don’t get paid for this, but we do generally get to keep a copy of the software or retain an account for some period of time on the service that we review. In this case I received a copy of Red Gate Software’s ANTS Memory Profiler 7.0, which was released in January. I don’t have any upgrade rights nor is my review guided, restrained, influenced, or otherwise controlled by Red Gate or anyone else. But I do get to keep the software license. I will always be clear about what I received whenever I do a review – I leave it up to you to decide whether you believe I can be objective. I believe I can be. If I used something and really didn’t like it, keeping a copy of it wouldn’t be worth anything to me. In that case though, I would simply uninstall/deactivate/whatever the software or service and tell the company what I didn’t like about it so they could (hopefully) make it better in the future. I don’t think it’d be polite to write up a terrible review, nor do I think it would be a particularly good use of my time. There are people who get paid for a living to review things, so I leave it to them to tell you what they think is bad and why. I’ll only spend my time telling you about things I think are good.) Overview of Common .NET Memory Problems When coming to land of managed memory from the wilds of unmanaged code, it’s easy to say to one’s self, “Wow! Now I never have to worry about memory problems again!” But this simply isn’t true. Managed code environments, such as .NET, make many, many things easier. You will never have to worry about memory corruption due to a bad pointer, for example (unless you’re working with unsafe code, of course). But managed code has its own set of memory concerns. For example, failing to unsubscribe from events when you are done with them leaves the publisher of an event with a reference to the subscriber. If you eliminate all your own references to the subscriber, then that memory is effectively lost since the GC won’t delete it because of the publishing object’s reference. When the publishing object itself becomes subject to garbage collection then you’ll get that memory back finally, but that could take a very long time depending of the life of the publisher. Another common source of resource leaks is failing to properly release unmanaged resources. When writing a class that contains members that hold unmanaged resources (e.g. any of the Stream-derived classes, IsolatedStorageFile, most classes ending in “Reader” or “Writer”), you should always implement IDisposable, making sure to use a properly written Dispose method. And when you are using an instance of a class that implements IDisposable, you should always make sure to use a 'using' statement in order to ensure that the object’s unmanaged resources are disposed of properly. (A ‘using’ statement is a nicer, cleaner looking, and easier to use version of a try-finally block. The compiler actually translates it as though it were a try-finally block. Note that Code Analysis warning 2202 (CA2202) will often be triggered by nested using blocks. A properly written dispose method ensures that it only runs once such that calling dispose multiple times should not be a problem. Nonetheless, CA2202 exists and if you want to avoid triggering it then you should write your code such that only the innermost IDisposable object uses a ‘using’ statement, with any outer code making use of appropriate try-finally blocks instead). Then, of course, there are situations where you are operating in a memory-constrained environment or else you want to limit or even eliminate allocations within a certain part of your program (e.g. within the main game loop of an XNA game) in order to avoid having the GC run. On the Xbox 360 and Windows Phone 7, for example, for every 1 MB of heap allocations you make, the GC runs; the added time of a GC collection can cause a game to drop frames or run slowly thereby making it look bad. Eliminating allocations (or else minimizing them and calling an explicit Collect at an appropriate time) is a common way of avoiding this (the other way is to simplify your heap so that the GC’s latency is low enough not to cause performance issues). ANTS Memory Profiler 7.0 When the opportunity to review Red Gate’s recently released ANTS Memory Profiler 7.0 arose, I jumped at it. In order to review it, I was given a free copy (which does not include upgrade rights for future versions) which I am allowed to keep. For those of you who are familiar with ANTS Memory Profiler, you can find a list of new features and enhancements here. If you are an experienced .NET developer who is familiar with .NET memory management issues, ANTS Memory Profiler is great. More importantly still, if you are new to .NET development or you have no experience or limited experience with memory profiling, ANTS Memory Profiler is awesome. From the very beginning, it guides you through the process of memory profiling. If you’re experienced and just want dive in however, it doesn’t get in your way. The help items GAHSFLASHDAJLDJA are well designed and located right next to the UI controls so that they are easy to find without being intrusive. When you first launch it, it presents you with a “Getting Started” screen that contains links to “Memory profiling video tutorials”, “Strategies for memory profiling”, and the “ANTS Memory Profiler forum”. I’m normally the kind of person who looks at a screen like that only to find the “Don’t show this again” checkbox. Since I was doing a review, though, I decided I should examine them. I was pleasantly surprised. The overview video clocks in at three minutes and fifty seconds. It begins by showing you how to get started profiling an application. It explains that profiling is done by taking memory snapshots periodically while your program is running and then comparing them. ANTS Memory Profiler (I’m just going to call it “ANTS MP” from here) analyzes these snapshots in the background while your application is running. It briefly mentions a new feature in Version 7, a new API that give you the ability to trigger snapshots from within your application’s source code (more about this below). You can also, and this is the more common way you would do it, take a memory snapshot at any time from within the ANTS MP window by clicking the “Take Memory Snapshot” button in the upper right corner. The overview video goes on to demonstrate a basic profiling session on an application that pulls information from a database and displays it. It shows how to switch which snapshots you are comparing, explains the different sections of the Summary view and what they are showing, and proceeds to show you how to investigate memory problems using the “Instance Categorizer” to track the path from an object (or set of objects) to the GC’s root in order to find what things along the path are holding a reference to it/them. For a set of objects, you can then click on it and get the “Instance List” view. This displays all of the individual objects (including their individual sizes, values, etc.) of that type which share the same path to the GC root. You can then click on one of the objects to generate an “Instance Retention Graph” view. This lets you track directly up to see the reference chain for that individual object. In the overview video, it turned out that there was an event handler which was holding on to a reference, thereby keeping a large number of strings that should have been freed in memory. Lastly the video shows the “Class List” view, which lets you dig in deeply to find problems that might not have been clear when following the previous workflow. Once you have at least one memory snapshot you can begin analyzing. The main interface is in the “Analysis” tab. You can also switch to the “Session Overview” tab, which gives you several bar charts highlighting basic memory data about the snapshots you’ve taken. If you hover over the individual bars (and the individual colors in bars that have more than one), you will see a detailed text description of what the bar is representing visually. The Session Overview is good for a quick summary of memory usage and information about the different heaps. You are going to spend most of your time in the Analysis tab, but it’s good to remember that the Session Overview is there to give you some quick feedback on basic memory usage stats. As described above in the summary of the overview video, there is a certain natural workflow to the Analysis tab. You’ll spin up your application and take some snapshots at various times such as before and after clicking a button to open a window or before and after closing a window. Taking these snapshots lets you examine what is happening with memory. You would normally expect that a lot of memory would be freed up when closing a window or exiting a document. By taking snapshots before and after performing an action like that you can see whether or not the memory is really being freed. If you already know an area that’s giving you trouble, you can run your application just like normal until just before getting to that part and then you can take a few strategic snapshots that should help you pin down the problem. Something the overview didn’t go into is how to use the “Filters” section at the bottom of ANTS MP together with the Class List view in order to narrow things down. The video tutorials page has a nice 3 minute intro video called “How to use the filters”. It’s a nice introduction and covers some of the basics. I’m going to cover a bit more because I think they’re a really neat, really helpful feature. Large programs can bring up thousands of classes. Even simple programs can instantiate far more classes than you might realize. In a basic .NET 4 WPF application for example (and when I say basic, I mean just MainWindow.xaml with a button added to it), the unfiltered Class List view will have in excess of 1000 classes (my simple test app had anywhere from 1066 to 1148 classes depending on which snapshot I was using as the “Current” snapshot). This is amazing in some ways as it shows you how in stark detail just how immensely powerful the WPF framework is. But hunting through 1100 classes isn’t productive, no matter how cool it is that there are that many classes instantiated and doing all sorts of awesome things. Let’s say you wanted to examine just the classes your application contains source code for (in my simple example, that would be the MainWindow and App). Under “Basic Filters”, click on “Classes with source” under “Show only…”. Voilà. Down from 1070 classes in the snapshot I was using as “Current” to 2 classes. If you then click on a class’s name, it will show you (to the right of the class name) two little icon buttons. Hover over them and you will see that you can click one to view the Instance Categorizer for the class and another to view the Instance List for the class. You can also show classes based on which heap they live on. If you chose both a Baseline snapshot and a Current snapshot then you can use the “Comparing snapshots” filters to show only: “New objects”; “Surviving objects”; “Survivors in growing classes”; or “Zombie objects” (if you aren’t sure what one of these means, you can click the helpful “?” in a green circle icon to bring up a popup that explains them and provides context). Remember that your selection(s) under the “Show only…” heading will still apply, so you should update those selections to make sure you are seeing the view you want. There are also links under the “What is my memory problem?” heading that can help you diagnose the problems you are seeing including one for “I don’t know which kind I have” for situations where you know generally that your application has some problems but aren’t sure what the behavior you have been seeing (OutOfMemoryExceptions, continually growing memory usage, larger memory use than expected at certain points in the program). The Basic Filters are not the only filters there are. “Filter by Object Type” gives you the ability to filter by: “Objects that are disposable”; “Objects that are/are not disposed”; “Objects that are/are not GC roots” (GC roots are things like static variables); and “Objects that implement _______”. “Objects that implement” is particularly neat. Once you check the box, you can then add one or more classes and interfaces that an object must implement in order to survive the filtering. Lastly there is “Filter by Reference”, which gives you the option to pare down the list based on whether an object is “Kept in memory exclusively by” a particular item, a class/interface, or a namespace; whether an object is “Referenced by” one or more of those choices; and whether an object is “Never referenced by” one or more of those choices. Remember that filtering is cumulative, so anything you had set in one of the filter sections still remains in effect unless and until you go back and change it. There’s quite a bit more to ANTS MP – it’s a very full featured product – but I think I touched on all of the most significant pieces. You can use it to debug: a .NET executable; an ASP.NET web application (running on IIS); an ASP.NET web application (running on Visual Studio’s built-in web development server); a Silverlight 4 browser application; a Windows service; a COM+ server; and even something called an XBAP (local XAML browser application). You can also attach to a .NET 4 process to profile an application that’s already running. The startup screen also has a large number of “Charting Options” that let you adjust which statistics ANTS MP should collect. The default selection is a good, minimal set. It’s worth your time to browse through the charting options to examine other statistics that may also help you diagnose a particular problem. The more statistics ANTS MP collects, the longer it will take to collect statistics. So just turning everything on is probably a bad idea. But the option to selectively add in additional performance counters from the extensive list could be a very helpful thing for your memory profiling as it lets you see additional data that might provide clues about a particular problem that has been bothering you. ANTS MP integrates very nicely with all versions of Visual Studio that support plugins (i.e. all of the non-Express versions). Just note that if you choose “Profile Memory” from the “ANTS” menu that it will launch profiling for whichever project you have set as the Startup project. One quick tip from my experience so far using ANTS MP: if you want to properly understand your memory usage in an application you’ve written, first create an “empty” version of the type of project you are going to profile (a WPF application, an XNA game, etc.) and do a quick profiling session on that so that you know the baseline memory usage of the framework itself. By “empty” I mean just create a new project of that type in Visual Studio then compile it and run it with profiling – don’t do anything special or add in anything (except perhaps for any external libraries you’re planning to use). The first thing I tried ANTS MP out on was a demo XNA project of an editor that I’ve been working on for quite some time that involves a custom extension to XNA’s content pipeline. The first time I ran it and saw the unmanaged memory usage I was convinced I had some horrible bug that was creating extra copies of texture data (the demo project didn’t have a lot of texture data so when I saw a lot of unmanaged memory I instantly figured I was doing something wrong). Then I thought to run an empty project through and when I saw that the amount of unmanaged memory was virtually identical, it dawned on me that the CLR itself sits in unmanaged memory and that (thankfully) there was nothing wrong with my code! Quite a relief. Earlier, when discussing the overview video, I mentioned the API that lets you take snapshots from within your application. I gave it a quick trial and it’s very easy to integrate and make use of and is a really nice addition (especially for projects where you want to know what, if any, allocations there are in a specific, complicated section of code). The only concern I had was that if I hadn’t watched the overview video I might never have known it existed. Even then it took me five minutes of hunting around Red Gate’s website before I found the “Taking snapshots from your code" article that explains what DLL you need to add as a reference and what method of what class you should call in order to take an automatic snapshot (including the helpful warning to wrap it in a try-catch block since, under certain circumstances, it can raise an exception, such as trying to call it more than 5 times in 30 seconds. The difficulty in discovering and then finding information about the automatic snapshots API was one thing I thought could use improvement. Another thing I think would make it even better would be local copies of the webpages it links to. Although I’m generally always connected to the internet, I imagine there are more than a few developers who aren’t or who are behind very restrictive firewalls. For them (and for me, too, if my internet connection happens to be down), it would be nice to have those documents installed locally or to have the option to download an additional “documentation” package that would add local copies. Another thing that I wish could be easier to manage is the Filters area. Finding and setting individual filters is very easy as is understanding what those filter do. And breaking it up into three sections (basic, by object, and by reference) makes sense. But I could easily see myself running a long profiling session and forgetting that I had set some filter a long while earlier in a different filter section and then spending quite a bit of time trying to figure out why some problem that was clearly visible in the data wasn’t showing up in, e.g. the instance list before remembering to check all the filters for that one setting that was only culling a few things from view. Some sort of indicator icon next to the filter section names that appears you have at least one filter set in that area would be a nice visual clue to remind me that “oh yeah, I told it to only show objects on the Gen 2 heap! That’s why I’m not seeing those instances of the SuperMagic class!” Something that would be nice (but that Red Gate cannot really do anything about) would be if this could be used in Windows Phone 7 development. If Microsoft and Red Gate could work together to make this happen (even if just on the WP7 emulator), that would be amazing. Especially given the memory constraints that apps and games running on mobile devices need to work within, a good memory profiler would be a phenomenally helpful tool. If anyone at Microsoft reads this, it’d be really great if you could make something like that happen. Perhaps even a (subsidized) custom version just for WP7 development. (For XNA games, of course, you can create a Windows version of the game and use ANTS MP on the Windows version in order to get a better picture of your memory situation. For Silverlight on WP7, though, there’s quite a bit of educated guess work and WeakReference creation followed by forced collections in order to find the source of a memory problem.) The only other thing I found myself wanting was a “Back” button. Between my Windows Phone 7, Zune, and other things, I’ve grown very used to having a “back stack” that lets me just navigate back to where I came from. The ANTS MP interface is surprisingly easy to use given how much it lets you do, and once you start using it for any amount of time, you learn all of the different areas such that you know where to go. And it does remember the state of the areas you were previously in, of course. So if you go to, e.g., the Instance Retention Graph from the Class List and then return back to the Class List, it will remember which class you had selected and all that other state information. Still, a “Back” button would be a welcome addition to a future release. Bottom Line ANTS Memory Profiler is not an inexpensive tool. But my time is valuable. I can easily see ANTS MP saving me enough time tracking down memory problems to justify it on a cost basis. More importantly to me, knowing what is happening memory-wise in my programs and having the confidence that my code doesn’t have any hidden time bombs in it that will cause it to OOM if I leave it running for longer than I do when I spin it up real quickly for debugging or just to see how a new feature looks and feels is a good feeling. It’s a feeling that I like having and want to continue to have. I got the current version for free in order to review it. Having done so, I’ve now added it to my must-have tools and will gladly lay out the money for the next version when it comes out. It has a 14 day free trial, so if you aren’t sure if it’s right for you or if you think it seems interesting but aren’t really sure if it’s worth shelling out the money for it, give it a try.

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  • OutOfMemoryException in Microsoft WSE 3.0 Diagnostics.TraceInputFilter

    - by Michael Freidgeim
    We are still using Microsoft WSE 3.0 and on test server started to get   Event Type:        Error Event Source:    Microsoft WSE 3.0 WSE054: An error occurred during the operation of the TraceInputFilter: System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.    at System.String.GetStringForStringBuilder(String value, Int32 startIndex, Int32 length, Int32 capacity)    at System.Text.StringBuilder.GetThreadSafeString(IntPtr& tid)    at System.Text.StringBuilder.set_Length(Int32 value)    at System.Xml.BufferBuilder.Clear()    at System.Xml.BufferBuilder.set_Length(Int32 value)    at System.Xml.XmlTextReaderImpl.ParseText()    at System.Xml.XmlTextReaderImpl.ParseElementContent()    at System.Xml.XmlTextReaderImpl.Read()    at System.Xml.XmlLoader.LoadNode(Boolean skipOverWhitespace)    at System.Xml.XmlLoader.LoadDocSequence(XmlDocument parentDoc)    at System.Xml.XmlLoader.Load(XmlDocument doc, XmlReader reader, Boolean preserveWhitespace)    at System.Xml.XmlDocument.Load(XmlReader reader)    at System.Xml.XmlDocument.Load(Stream inStream)    at Microsoft.Web.Services3.Diagnostics.TraceInputFilter.OpenLoadExistingFile(String path)    at Microsoft.Web.Services3.Diagnostics.TraceInputFilter.Load(String path)    at Microsoft.Web.Services3.Diagnostics.TraceInputFilter.TraceMessage(String messageId, Collection`1 traceEntries).   After investigation it was found, that the problem related to trace files, that become too big. When they were deleted and new files were created, error gone.

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  • Digital Darwinism: How Brands Can Survive the Rapid Evolution of Society and Technology

    - by Michael Hylton
    Do you want to learn how to thrive in an era of connected consumerism and digital disruptions? Come attend this free webinar on December 13th at 10:00 am PST / 1:00 pm EST as Brian Solis, Altimeter Group analyst, shares his thoughts on how our changing society and technology shifts are impacting brands today. Click here to register for this webcast, part of Oracle’s Social Business Thought Leaders Series.

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  • C#/.NET Little Wonders: The Predicate, Comparison, and Converter Generic Delegates

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. In the last three weeks, we examined the Action family of delegates (and delegates in general), the Func family of delegates, and the EventHandler family of delegates and how they can be used to support generic, reusable algorithms and classes. This week I will be completing my series on the generic delegates in the .NET Framework with a discussion of three more, somewhat less used, generic delegates: Predicate<T>, Comparison<T>, and Converter<TInput, TOutput>. These are older generic delegates that were introduced in .NET 2.0, mostly for use in the Array and List<T> classes.  Though older, it’s good to have an understanding of them and their intended purpose.  In addition, you can feel free to use them yourself, though obviously you can also use the equivalents from the Func family of delegates instead. Predicate<T> – delegate for determining matches The Predicate<T> delegate was a very early delegate developed in the .NET 2.0 Framework to determine if an item was a match for some condition in a List<T> or T[].  The methods that tend to use the Predicate<T> include: Find(), FindAll(), FindLast() Uses the Predicate<T> delegate to finds items, in a list/array of type T, that matches the given predicate. FindIndex(), FindLastIndex() Uses the Predicate<T> delegate to find the index of an item, of in a list/array of type T, that matches the given predicate. The signature of the Predicate<T> delegate (ignoring variance for the moment) is: 1: public delegate bool Predicate<T>(T obj); So, this is a delegate type that supports any method taking an item of type T and returning bool.  In addition, there is a semantic understanding that this predicate is supposed to be examining the item supplied to see if it matches a given criteria. 1: // finds first even number (2) 2: var firstEven = Array.Find(numbers, n => (n % 2) == 0); 3:  4: // finds all odd numbers (1, 3, 5, 7, 9) 5: var allEvens = Array.FindAll(numbers, n => (n % 2) == 1); 6:  7: // find index of first multiple of 5 (4) 8: var firstFiveMultiplePos = Array.FindIndex(numbers, n => (n % 5) == 0); This delegate has typically been succeeded in LINQ by the more general Func family, so that Predicate<T> and Func<T, bool> are logically identical.  Strictly speaking, though, they are different types, so a delegate reference of type Predicate<T> cannot be directly assigned to a delegate reference of type Func<T, bool>, though the same method can be assigned to both. 1: // SUCCESS: the same lambda can be assigned to either 2: Predicate<DateTime> isSameDayPred = dt => dt.Date == DateTime.Today; 3: Func<DateTime, bool> isSameDayFunc = dt => dt.Date == DateTime.Today; 4:  5: // ERROR: once they are assigned to a delegate type, they are strongly 6: // typed and cannot be directly assigned to other delegate types. 7: isSameDayPred = isSameDayFunc; When you assign a method to a delegate, all that is required is that the signature matches.  This is why the same method can be assigned to either delegate type since their signatures are the same.  However, once the method has been assigned to a delegate type, it is now a strongly-typed reference to that delegate type, and it cannot be assigned to a different delegate type (beyond the bounds of variance depending on Framework version, of course). Comparison<T> – delegate for determining order Just as the Predicate<T> generic delegate was birthed to give Array and List<T> the ability to perform type-safe matching, the Comparison<T> was birthed to give them the ability to perform type-safe ordering. The Comparison<T> is used in Array and List<T> for: Sort() A form of the Sort() method that takes a comparison delegate; this is an alternate way to custom sort a list/array from having to define custom IComparer<T> classes. The signature for the Comparison<T> delegate looks like (without variance): 1: public delegate int Comparison<T>(T lhs, T rhs); The goal of this delegate is to compare the left-hand-side to the right-hand-side and return a negative number if the lhs < rhs, zero if they are equal, and a positive number if the lhs > rhs.  Generally speaking, null is considered to be the smallest value of any reference type, so null should always be less than non-null, and two null values should be considered equal. In most sort/ordering methods, you must specify an IComparer<T> if you want to do custom sorting/ordering.  The Array and List<T> types, however, also allow for an alternative Comparison<T> delegate to be used instead, essentially, this lets you perform the custom sort without having to have the custom IComparer<T> class defined. It should be noted, however, that the LINQ OrderBy(), and ThenBy() family of methods do not support the Comparison<T> delegate (though one could easily add their own extension methods to create one, or create an IComparer() factory class that generates one from a Comparison<T>). So, given this delegate, we could use it to perform easy sorts on an Array or List<T> based on custom fields.  Say for example we have a data class called Employee with some basic employee information: 1: public sealed class Employee 2: { 3: public string Name { get; set; } 4: public int Id { get; set; } 5: public double Salary { get; set; } 6: } And say we had a List<Employee> that contained data, such as: 1: var employees = new List<Employee> 2: { 3: new Employee { Name = "John Smith", Id = 2, Salary = 37000.0 }, 4: new Employee { Name = "Jane Doe", Id = 1, Salary = 57000.0 }, 5: new Employee { Name = "John Doe", Id = 5, Salary = 60000.0 }, 6: new Employee { Name = "Jane Smith", Id = 3, Salary = 59000.0 } 7: }; Now, using the Comparison<T> delegate form of Sort() on the List<Employee>, we can sort our list many ways: 1: // sort based on employee ID 2: employees.Sort((lhs, rhs) => Comparer<int>.Default.Compare(lhs.Id, rhs.Id)); 3:  4: // sort based on employee name 5: employees.Sort((lhs, rhs) => string.Compare(lhs.Name, rhs.Name)); 6:  7: // sort based on salary, descending (note switched lhs/rhs order for descending) 8: employees.Sort((lhs, rhs) => Comparer<double>.Default.Compare(rhs.Salary, lhs.Salary)); So again, you could use this older delegate, which has a lot of logical meaning to it’s name, or use a generic delegate such as Func<T, T, int> to implement the same sort of behavior.  All this said, one of the reasons, in my opinion, that Comparison<T> isn’t used too often is that it tends to need complex lambdas, and the LINQ ability to order based on projections is much easier to use, though the Array and List<T> sorts tend to be more efficient if you want to perform in-place ordering. Converter<TInput, TOutput> – delegate to convert elements The Converter<TInput, TOutput> delegate is used by the Array and List<T> delegate to specify how to convert elements from an array/list of one type (TInput) to another type (TOutput).  It is used in an array/list for: ConvertAll() Converts all elements from a List<TInput> / TInput[] to a new List<TOutput> / TOutput[]. The delegate signature for Converter<TInput, TOutput> is very straightforward (ignoring variance): 1: public delegate TOutput Converter<TInput, TOutput>(TInput input); So, this delegate’s job is to taken an input item (of type TInput) and convert it to a return result (of type TOutput).  Again, this is logically equivalent to a newer Func delegate with a signature of Func<TInput, TOutput>.  In fact, the latter is how the LINQ conversion methods are defined. So, we could use the ConvertAll() syntax to convert a List<T> or T[] to different types, such as: 1: // get a list of just employee IDs 2: var empIds = employees.ConvertAll(emp => emp.Id); 3:  4: // get a list of all emp salaries, as int instead of double: 5: var empSalaries = employees.ConvertAll(emp => (int)emp.Salary); Note that the expressions above are logically equivalent to using LINQ’s Select() method, which gives you a lot more power: 1: // get a list of just employee IDs 2: var empIds = employees.Select(emp => emp.Id).ToList(); 3:  4: // get a list of all emp salaries, as int instead of double: 5: var empSalaries = employees.Select(emp => (int)emp.Salary).ToList(); The only difference with using LINQ is that many of the methods (including Select()) are deferred execution, which means that often times they will not perform the conversion for an item until it is requested.  This has both pros and cons in that you gain the benefit of not performing work until it is actually needed, but on the flip side if you want the results now, there is overhead in the behind-the-scenes work that support deferred execution (it’s supported by the yield return / yield break keywords in C# which define iterators that maintain current state information). In general, the new LINQ syntax is preferred, but the older Array and List<T> ConvertAll() methods are still around, as is the Converter<TInput, TOutput> delegate. Sidebar: Variance support update in .NET 4.0 Just like our descriptions of Func and Action, these three early generic delegates also support more variance in assignment as of .NET 4.0.  Their new signatures are: 1: // comparison is contravariant on type being compared 2: public delegate int Comparison<in T>(T lhs, T rhs); 3:  4: // converter is contravariant on input and covariant on output 5: public delegate TOutput Contravariant<in TInput, out TOutput>(TInput input); 6:  7: // predicate is contravariant on input 8: public delegate bool Predicate<in T>(T obj); Thus these delegates can now be assigned to delegates allowing for contravariance (going to a more derived type) or covariance (going to a less derived type) based on whether the parameters are input or output, respectively. Summary Today, we wrapped up our generic delegates discussion by looking at three lesser-used delegates: Predicate<T>, Comparison<T>, and Converter<TInput, TOutput>.  All three of these tend to be replaced by their more generic Func equivalents in LINQ, but that doesn’t mean you shouldn’t understand what they do or can’t use them for your own code, as they do contain semantic meanings in their names that sometimes get lost in the more generic Func name.   Tweet Technorati Tags: C#,CSharp,.NET,Little Wonders,delegates,generics,Predicate,Converter,Comparison

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  • Silverlight Cream for April 12, 2010 -- #837

    - by Dave Campbell
    In this Issue: Michael Washington, Joe McBride, Kirupa, Maurice de Beijer, Brad Abrams, Phil Middlemiss, and CorrinaB. Shoutout: Charlie Kindel has a post up about the incompatibility between VS2010RTM and what we currently have for WP7: Visual Studio 2010 RTM and the Windows Phone Developer Tools CTP and if you want to be notified when that changes, submit your email here. Erik Mork and Co. have their latest This Week in Silverlight 4.9.2010 posted. From SilverlightCream.com: Simplified MVVM: Silverlight Video Player Michael Washington created a 'designable' video player using MVVM that allows any set of controls to implement the player. Great tutorial and all the code. Windows Phone 7 Panorama Behaviors Joe McBride posted a link to a couple WP7 gesture behaviors and a link out to some more by smartyP. Event Bubbling and Tunneling Kirupa has a great article up on Event Bubbling and Tunneling... showing the route that events take through your WPF or Silverlight app. Using dynamic objects in Silverlight 4 Maurice de Beijer has a blog up about binding to indexed properties in Silverlight 4... in other words, you don't have to know what you're binging to at design time. Silverlight 4 + RIA Services - Ready for Business: Ajax Endpoint Brad Abrams is still continuing his RIA series. His latest is on exposing your RIA Services in JSON. Changing Data-Templates at run-time from the VM Looks like I missed Phil Middlemiss' latest post on Changing DataTemplates at run-time. He has a visual of why you might need this right up-front, and is a very common issue. Check out the solution he provides us. Windows System Color Theme for Silverlight - Part Three CorrinaB blogged screenshots and discussion of 3 new themes that are going to be coming up, and what they've done to the controls in general. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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