Search Results

Search found 31491 results on 1260 pages for 'simple talk'.

Page 124/1260 | < Previous Page | 120 121 122 123 124 125 126 127 128 129 130 131  | Next Page >

• Thoughts on C# Extension Methods

  - by Damon

  I'm not a huge fan of extension methods.  When they first came out, I remember seeing a method on an object that was fairly useful, but when I went to use it another piece of code that method wasn't available.  Turns out it was an extension method and I hadn't included the appropriate assembly and imports statement in my code to use it.  I remember being a bit confused at first about how the heck that could happen (hey, extension methods were new, cut me some slack) and it took a bit of time to track down exactly what it was that I needed to include to get that method back.  I just imagined a new developer trying to figure out why a method was missing and fruitlessly searching on MSDN for a method that didn't exist and it just didn't sit well with me. I am of the opinion that if you have an object, then you shouldn't have to include additional assemblies to get additional instance level methods out of that object.  That opinion applies to namespaces as well - I do not like it when the contents of a namespace are split out into multiple assemblies.  I prefer to have static utility classes instead of extension methods to keep things nicely packaged into a cohesive unit.  It also makes it abundantly clear where utility methods are used in code.  I will concede, however, that it can make code a bit more verbose and lengthy.  There is always a trade-off. Some people harp on extension methods because it breaks the tenants of object oriented development and allows you to add methods to sealed classes.  Whatever.  Extension methods are just utility methods that you can tack onto an object after the fact.  Extension methods do not give you any more access to an object than the developer of that object allows, so I say that those who cry OO foul on extension methods really don't have much of an argument on which to stand.  In fact, I have to concede that my dislike of them is really more about style than anything of great substance. One interesting thing that I found regarding extension methods is that you can call them on null objects. Take a look at this extension method: namespace ExtensionMethods {   public static class StringUtility   {     public static int WordCount(this string str)     {       if(str == null) return 0;       return str.Split(new char[] { ' ', '.', '?' },         StringSplitOptions.RemoveEmptyEntries).Length;     }   }   } Notice that the extension method checks to see if the incoming string parameter is null.  I was worried that the runtime would perform a check on the object instance to make sure it was not null before calling an extension method, but that is apparently not the case.  So, if you call the following code it runs just fine. string s = null; int words = s.WordCount(); I am a big fan of things working, but this seems to go against everything I've come to know about instance level methods.  However, an extension method is really a static method masquerading as an instance-level method, so I suppose it would be far more frustrating if it failed since there is really no reason it shouldn't succeed. Although I'm not a fan of extension methods, I will say that if you ever find yourself at an impasse with a die-hard fan of either the utility class or extension method approach, then there is a common ground.  Extension methods are defined in static classes, and you call them from those static classes as well as directly from the objects they extend.  So if you build your utility classes using extension methods, then you can have it your way and they can have it theirs. 

  Read the article

• The spork/platypus average: shameless self promotion

  - by Roger Hart

  This is the video of presentation I gave at UA Europe and TCUK this year. The actual sub-title was "Content strategy at Red Gate Software", but this heading feels more honest. For anybody who missed it, or is just vaguely interested, here's a link to me talking about de-suckifying the web. You can find the slideshare deck here, too* Watching it back is more than a little embarrassing, and makes me really, really want to do a follow up, so I can do three things: explain the rest of the big web project, now we've done it give some data on the outcome of the content review make a grovelling apology to our marketing guys, who I've been unfairly mean to in a childish effort to look cool There are a whole bunch of other TCUK presentations online, too. You can find them all here: http://tiny.cc/tcuk10_videos I'd particularly recommend Chris Atherton's: "Everything you always wanted to know about psychology and technical communication" - it's full of cool stuff. You should probably also watch David Black's opening keynote, which managed to make my hour of precocious grandstanding look measured, meek, and helpful. He actually makes some interesting points, but you'd basically have to ship Richard Dawkins off to Utah, if you wanted to go further out of your way to aggravate your audience. It does give an engaging account of running a large tech comms project, and raise some questions about how we propose to understand a world where increasing amounts of our stuff gets done by increasingly many increasingly complicated tissues of APIs. Well, sort of. That's what all the notes I made were about, anyway.   *Slideshare ate my fonts. Just so we're clear on this: I'd never use badly-kerned Arial in a presentation. Don't worry.

  Read the article

• Back to Basics: Structuring a Web Page with CSS and ASP.NET

  Nick explains why such habits as using nested HTML Tables to position content in the right place on the browser page is bad practice and, nowadays, avoidable. This is just one 'Markup smell' that he discusses on the way to demonstrating the benefits of CSS Style-sheets and ASP.NET Master Pages.

  Read the article

• SQL Prompt Easter Egg

  - by Johnm

  Having Red Gate's SQL Prompt installed with SQL Server Management Studio has saved me many headaches over the years of its use. It is extremely nice to type in a table name and see not only the column names, but also their data types and identification of primary keys. Another cool feature is the built-in short cut scripts that are included toward the bottom of the suggestion box. An example of these short cut scripts would be to type in the letters  cv and then hit enter and the following template for CREATE VIEW will appear: CREATE VIEW --WITH ENCRYPTION, SCHEMABINDING, VIEW_METADATA AS     SELECT /* query specification */ -- WITH CHECK OPTION GO These scripts are great, and on occasion rather humorous. Recently, I was writing an UPDATE statement that would update a derived and aliased set of data in . An example of such a statement is as follows: UPDATE y SET a.[FieldA] = b.[FieldB] FROM     (         SELECT             a.[FieldA]             ,b.[FieldB]         FROM             [MyTableA] a             INNER JOIN [MyTableB] b                 ON a.[PKA] = b.[PKB]     ) y; Upon typing the UPDATE y portion I hit enter and the expression "A A A A R G H !" appeared resulting in an unexpected burst of laughter. With a dash of curiosity and a pinch of research I discovered that at the bottom of the SQL Prompt suggestion box resides a short cut script called "yell", which is described as "Vent your frustration". Another humorous short cut script is "neo", which is described as "-- I know Kung-Fu". All is required for these to activate is to type the first letter and hit enter. I wonder if there are any undocumented ones?

  Read the article

• A Slice of Raspberry Pi

  - by Phil Factor

  Guest editorial for the ITPro/SysAdmin newsletter The Raspberry Pi Foundation has done a superb design job on their new $35 network-enabled Linux computer. This tiny machine, incorporating an ARM processor on a Broadcom BCM2835 multimedia chip, aims to put the fun back into learning computing. The public response has been overwhelmingly positive.Note that aim: "…to put the fun back". Education in Information Technology is in dire straits. It always has been, but seems to have deteriorated further still, even in the face of improved provision of equipment.In many countries, the government controls the curriculum. It predicted a shortage in office-based IT skills, and so geared the ICT curriculum toward mind-numbing training in word-processing and spreadsheet skills. Instead, the shortage has turned out to be in people with an engineering-mindset, who can solve problems with whatever technologies are available and learn new techniques quickly, in a rapidly-changing field.In retrospect, the assumption that specific training was required rather than an education was an idiotic response to the arrival of mainstream information technology. As a result, ICT became a disaster area, which discouraged a generation of youngsters from a career in IT, and thereby led directly to the shortage of people with the skills that are required to exploit the potential of Information Technology..Raspberry Pi aims to reverse the trend. This is a rig that is geared to fast graphics in high resolution. It is no toy. It should be a superb games machine. However, the use of Fedora, Debian, or Arch Linux ARM shows the more serious educational intent behind the Foundation's work. It looks like it will even do some office work too!So, get hold of any power supply that provides a 5VDC source at the required 700mA; an old Blackberry charger will do or, alternatively, it will run off four AA cells. You'll need a USB hub to support the mouse and keyboard, and maybe a hard drive. You'll want a DVI monitor (with audio out) or TV (sound and video). You'll also need to be able to cope with wired Ethernet 10/100, if you want networking.With this lot assembled, stick the paraphernalia on the back of the HDTV with Blu Tack, get a nice keyboard, and you have a classy Linux-based home computer. The major cost is in the T.V and the keyboard. If you're not already writing software for this platform, then maybe, at a time when some countries are talking of orders in the millions, you should consider it.

  Read the article

• Some non-generic collections

  - by Simon Cooper

  Although the collections classes introduced in .NET 2, 3.5 and 4 cover most scenarios, there are still some .NET 1 collections that don't have generic counterparts. In this post, I'll be examining what they do, why you might use them, and some things you'll need to bear in mind when doing so. BitArray System.Collections.BitArray is conceptually the same as a List<bool>, but whereas List<bool> stores each boolean in a single byte (as that's what the backing bool[] does), BitArray uses a single bit to store each value, and uses various bitmasks to access each bit individually. This means that BitArray is eight times smaller than a List<bool>. Furthermore, BitArray has some useful functions for bitmasks, like And, Xor and Not, and it's not limited to 32 or 64 bits; a BitArray can hold as many bits as you need. However, it's not all roses and kittens. There are some fundamental limitations you have to bear in mind when using BitArray: It's a non-generic collection. The enumerator returns object (a boxed boolean), rather than an unboxed bool. This means that if you do this: foreach (bool b in bitArray) { ... } Every single boolean value will be boxed, then unboxed. And if you do this: foreach (var b in bitArray) { ... } you'll have to manually unbox b on every iteration, as it'll come out of the enumerator an object. Instead, you should manually iterate over the collection using a for loop: for (int i=0; i<bitArray.Length; i++) { bool b = bitArray[i]; ... } Following on from that, if you want to use BitArray in the context of an IEnumerable<bool>, ICollection<bool> or IList<bool>, you'll need to write a wrapper class, or use the Enumerable.Cast<bool> extension method (although Cast would box and unbox every value you get out of it). There is no Add or Remove method. You specify the number of bits you need in the constructor, and that's what you get. You can change the length yourself using the Length property setter though. It doesn't implement IList. Although not really important if you're writing a generic wrapper around it, it is something to bear in mind if you're using it with pre-generic code. However, if you use BitArray carefully, it can provide significant gains over a List<bool> for functionality and efficiency of space. OrderedDictionary System.Collections.Specialized.OrderedDictionary does exactly what you would expect - it's an IDictionary that maintains items in the order they are added. It does this by storing key/value pairs in a Hashtable (to get O(1) key lookup) and an ArrayList (to maintain the order). You can access values by key or index, and insert or remove items at a particular index. The enumerator returns items in index order. However, the Keys and Values properties return ICollection, not IList, as you might expect; CopyTo doesn't maintain the same ordering, as it copies from the backing Hashtable, not ArrayList; and any operations that insert or remove items from the middle of the collection are O(n), just like a normal list. In short; don't use this class. If you need some sort of ordered dictionary, it would be better to write your own generic dictionary combining a Dictionary<TKey, TValue> and List<KeyValuePair<TKey, TValue>> or List<TKey> for your specific situation. ListDictionary and HybridDictionary To look at why you might want to use ListDictionary or HybridDictionary, we need to examine the performance of these dictionaries compared to Hashtable and Dictionary<object, object>. For this test, I added n items to each collection, then randomly accessed n/2 items: So, what's going on here? Well, ListDictionary is implemented as a linked list of key/value pairs; all operations on the dictionary require an O(n) search through the list. However, for small n, the constant factor that big-o notation doesn't measure is much lower than the hashing overhead of Hashtable or Dictionary. HybridDictionary combines a Hashtable and ListDictionary; for small n, it uses a backing ListDictionary, but switches to a Hashtable when it gets to 9 items (you can see the point it switches from a ListDictionary to Hashtable in the graph). Apart from that, it's got very similar performance to Hashtable. So why would you want to use either of these? In short, you wouldn't. Any gain in performance by using ListDictionary over Dictionary<TKey, TValue> would be offset by the generic dictionary not having to cast or box the items you store, something the graphs above don't measure. Only if the performance of the dictionary is vital, the dictionary will hold less than 30 items, and you don't need type safety, would you use ListDictionary over the generic Dictionary. And even then, there's probably more useful performance gains you can make elsewhere.

  Read the article

• SQL Search- The Search and the Sequel

  It started out as an experiment to try to explore different ways of creating a software tool that people would want. It ended up as a tool that Red Gate is giving away to the SQL Server community in return for the contribution to the project of so many of Red Gate's friends within the community. But was it easy to do? Bob Cramblitt and Richard Collins went to find out by talking to Tanya Joseph, who managed the project that turned the concept into a product.

  Read the article

• Customizing the Outlook Address Book

  It is possible to change the fields in the Outlook address book to make them a better fit for your organisation. Exchange provides templates for Users, Contacts, Groups, Public Folders, and Mailbox Agents that are downloaded to Outlook. Any changes will be visible in the address book. As usual with Exchange, careful planning before you make changes pays dividends, Ben Lye explains.

  Read the article

• Why enumerator structs are a really bad idea

  - by Simon Cooper

  If you've ever poked around the .NET class libraries in Reflector, I'm sure you would have noticed that the generic collection classes all have implementations of their IEnumerator as a struct rather than a class. As you will see, this design decision has some rather unfortunate side effects... As is generally known in the .NET world, mutable structs are a Very Bad Idea; and there are several other blogs around explaining this (Eric Lippert's blog post explains the problem quite well). In the BCL, the generic collection enumerators are all mutable structs, as they need to keep track of where they are in the collection. This bit me quite hard when I was coding a wrapper around a LinkedList<int>.Enumerator. It boils down to this code: sealed class EnumeratorWrapper : IEnumerator<int> { private readonly LinkedList<int>.Enumerator m_Enumerator; public EnumeratorWrapper(LinkedList<int> linkedList) { m_Enumerator = linkedList.GetEnumerator(); } public int Current { get { return m_Enumerator.Current; } } object System.Collections.IEnumerator.Current { get { return Current; } } public bool MoveNext() { return m_Enumerator.MoveNext(); } public void Reset() { ((System.Collections.IEnumerator)m_Enumerator).Reset(); } public void Dispose() { m_Enumerator.Dispose(); } } The key line here is the MoveNext method. When I initially coded this, I thought that the call to m_Enumerator.MoveNext() would alter the enumerator state in the m_Enumerator class variable and so the enumeration would proceed in an orderly fashion through the collection. However, when I ran this code it went into an infinite loop - the m_Enumerator.MoveNext() call wasn't actually changing the state in the m_Enumerator variable at all, and my code was looping forever on the first collection element. It was only after disassembling that method that I found out what was going on The MoveNext method above results in the following IL: .method public hidebysig newslot virtual final instance bool MoveNext() cil managed { .maxstack 1 .locals init ( [0] bool CS$1$0000, [1] valuetype [System]System.Collections.Generic.LinkedList`1/Enumerator CS$0$0001) L_0000: nop L_0001: ldarg.0 L_0002: ldfld valuetype [System]System.Collections.Generic.LinkedList`1/Enumerator EnumeratorWrapper::m_Enumerator L_0007: stloc.1 L_0008: ldloca.s CS$0$0001 L_000a: call instance bool [System]System.Collections.Generic.LinkedList`1/Enumerator::MoveNext() L_000f: stloc.0 L_0010: br.s L_0012 L_0012: ldloc.0 L_0013: ret } Here, the important line is 0002 - m_Enumerator is accessed using the ldfld operator, which does the following: Finds the value of a field in the object whose reference is currently on the evaluation stack. So, what the MoveNext method is doing is the following: public bool MoveNext() { LinkedList<int>.Enumerator CS$0$0001 = this.m_Enumerator; bool CS$1$0000 = CS$0$0001.MoveNext(); return CS$1$0000; } The enumerator instance being modified by the call to MoveNext is the one stored in the CS$0$0001 variable on the stack, and not the one in the EnumeratorWrapper class instance. Hence why the state of m_Enumerator wasn't getting updated. Hmm, ok. Well, why is it doing this? If you have a read of Eric Lippert's blog post about this issue, you'll notice he quotes a few sections of the C# spec. In particular, 7.5.4: ...if the field is readonly and the reference occurs outside an instance constructor of the class in which the field is declared, then the result is a value, namely the value of the field I in the object referenced by E. And my m_Enumerator field is readonly! Indeed, if I remove the readonly from the class variable then the problem goes away, and the code works as expected. The IL confirms this: .method public hidebysig newslot virtual final instance bool MoveNext() cil managed { .maxstack 1 .locals init ( [0] bool CS$1$0000) L_0000: nop L_0001: ldarg.0 L_0002: ldflda valuetype [System]System.Collections.Generic.LinkedList`1/Enumerator EnumeratorWrapper::m_Enumerator L_0007: call instance bool [System]System.Collections.Generic.LinkedList`1/Enumerator::MoveNext() L_000c: stloc.0 L_000d: br.s L_000f L_000f: ldloc.0 L_0010: ret } Notice on line 0002, instead of the ldfld we had before, we've got a ldflda, which does this: Finds the address of a field in the object whose reference is currently on the evaluation stack. Instead of loading the value, we're loading the address of the m_Enumerator field. So now the call to MoveNext modifies the enumerator stored in the class rather than on the stack, and everything works as expected. Previously, I had thought enumerator structs were an odd but interesting feature of the BCL that I had used in the past to do linked list slices. However, effects like this only underline how dangerous mutable structs are, and I'm at a loss to explain why the enumerators were implemented as structs in the first place. (interestingly, the SortedList<TKey, TValue> enumerator is a struct but is private, which makes it even more odd - the only way it can be accessed is as a boxed IEnumerator!). I would love to hear people's theories as to why the enumerators are implemented in such a fashion. And bonus points if you can explain why LinkedList<int>.Enumerator.Reset is an explicit implementation but Dispose is implicit... Note to self: never ever ever code a mutable struct.

  Read the article

• Tuning Red Gate: #1 of Many

  - by Grant Fritchey

  Everyone runs into performance issues at some point. Same thing goes for Red Gate software. Some of our internal systems were running into some serious bottlenecks. It just so happens that we have this nice little SQL Server monitoring tool. What if I were to, oh, I don't know, use the monitoring tool to identify the bottlenecks, figure out the causes and then apply a fix (where possible) and then start the whole thing all over again? Just a crazy thought. OK, I was asked to. This is my first time looking through these servers, so here's how I'd go about using SQL Monitor to get a quick health check, sort of like checking the vitals on a patient. First time opening up our internal SQL Monitor instance and I was greeted with this: Oh my. Maybe I need to get our internal guys to read my blog. Anyway, I know that there are two servers where most of the load is. I'll drill down on the first. I'm selecting the server, not the instance, by clicking on the server name. That opens up the Global Overview page for the server. The information here much more applicable to the "oh my gosh, I have a problem now" type of monitoring. But, looking at this, I am seeing something immediately. There are four(4) drives on the system. The C:\ has an average read time of 16.9ms, more than double the others. Is that a problem? Not sure, but it's something I'll look at. It's write time is higher too. I'll keep drilling down, first, to the unclosed alerts on the server. Now things get interesting. SQL Monitor has a number of different types of alerts, some related to error states, others to service status, and then some related to performance. Guess what I'm seeing a bunch of right here: Long running queries and long job durations. If you check the dates, they're all recent, within the last 24 hours. If they had just been old, uncleared alerts, I wouldn't be that concerned. But with all these, all performance related, and all in the last 24 hours, yeah, I'm concerned. At this point, I could just start responding to the Alerts. If I click on one of the the Long-running query alerts, I'll get all kinds of cool data that can help me determine why the query ran long. But, I'm not in a reactive mode here yet. I'm still gathering data, trying to understand how the server works. I have the information that we're generating a lot of performance alerts, let's sock that away for the moment. Instead, I'm going to back up and look at the Global Overview for the SQL Instance. It shows all the databases on the server and their status. Then it shows a number of basic metrics about the SQL Server instance, again for that "what's happening now" view or things. Then, down at the bottom, there is the Top 10 expensive queries list: This is great stuff. And no, not because I can see the top queries for the last 5 minutes, but because I can adjust that out 3 days. Now I can see where some serious pain is occurring over the last few days. Databases have been blocked out to protect the guilty. That's it for the moment. I have enough knowledge of what's going on in the system that I can start to try to figure out why the system is running slowly. But, I want to look a little more at some historical data, to understand better how this server is behaving. More next time.

  Read the article

• ANTS Performance Profiler 7.0 has been released!

  - by Michaela Murray

  Please join me in welcoming ANTS Performance Profiler 7 to the world of .NET. ANTS Performance Profiler is a .NET code profiling tool. It lets you identify performance bottlenecks within minutes and therefore enables you to optimize your application performance. Version 7.0 includes integrated decompilation: when profiling methods and assemblies with no source code file, you can generate source code right from the profiler interface. You can then browse and navigate this automatically generated source as if it was your own. If you have an assembly's PDB file but no source, integrated decompilation even lets you view line-level timings for each method, pinpointing the exact cause of performance bottlenecks. Integrated decompilation is powered by .NET Reflector, but you don't need Reflector installed to use the functionality. Watch this video to see it in action. Also new in ANTS Performance Profiler 7.0: · Full support for SharePoint 2010 - No need to manually configure profiling for the latest version of SharePoint · Full support for IIS Express · Azure and Amazon EC2 support, enabling you to profile in the cloud Please click here, for more details about the ANTS Performance Profiler 7.0.

  Read the article

• Don't even believe SSMS when you think it's telling the truth

  - by fatherjack

  LiveJournal Tags: how To,ssms,tips and tricks,tsqlThis is in follow up to my last post How to make sure you see the truth in Management Studio which explained that the time that you see at the bottom of a Management Studio window cannot be believed to represent the time it takes for a query to execute as it also includes the time taken for SSMS to receive and format the data grid. Now, very soon after that went live I received a comment from Dave Ballantyne (Blog | Twitter) mentioning that having...(read more)

  Read the article

• Source-control 'wet-work'?

  - by Phil Factor

  When a design or creative work is flawed beyond remedy, it is often best to destroy it and start again. The other day, I lost the code to a long and intricate SQL batch I was working on. I’d thought it was impossible, but it happened. With all the technology around that is designed to prevent this occurring, this sort of accident has become a rare event.  If it weren’t for a deranged laptop, and my distraction, the code wouldn’t have been lost this time.  As always, I sighed, had a soothing cup of tea, and typed it all in again.  The new code I hastily tapped in  was much better: I’d held in my head the essence of how the code should work rather than the details: I now knew for certain  the start point, the end, and how it should be achieved. Instantly the detritus of half-baked thoughts fell away and I was able to write logical code that performed better.  Because I could work so quickly, I was able to hold the details of all the columns and variables in my head, and the dynamics of the flow of data. It was, in fact, easier and quicker to start from scratch rather than tidy up and refactor the existing code with its inevitable fumbling and half-baked ideas. What a shame that technology is now so good that developers rarely experience the cleansing shock of losing one’s code and having to rewrite it from scratch.  If you’ve never accidentally lost  your code, then it is worth doing it deliberately once for the experience. Creative people have, until Technology mistakenly prevented it, torn up their drafts or sketches, threw them in the bin, and started again from scratch.  Leonardo’s obsessive reworking of the Mona Lisa was renowned because it was so unusual:  Most artists have been utterly ruthless in destroying work that didn’t quite make it. Authors are particularly keen on writing afresh, and the results are generally positive. Lawrence of Arabia actually lost the entire 250,000 word manuscript of ‘The Seven Pillars of Wisdom’ by accidentally leaving it on a train at Reading station, before rewriting a much better version.  Now, any writer or artist is seduced by technology into altering or refining their work rather than casting it dramatically in the bin or setting a light to it on a bonfire, and rewriting it from the blank page.  It is easy to pick away at a flawed work, but the real creative process is far more brutal. Once, many years ago whilst running a software house that supplied commercial software to local businesses, I’d been supervising an accounting system for a farming cooperative. No packaged system met their needs, and it was all hand-cut code.  For us, it represented a breakthrough as it was for a government organisation, and success would guarantee more contracts. As you’ve probably guessed, the code got mangled in a disk crash just a week before the deadline for delivery, and the many backups all proved to be entirely corrupted by a faulty tape drive.  There were some fragments left on individual machines, but they were all of different versions.  The developers were in despair.  Strangely, I managed to re-write the bulk of a three-month project in a manic and caffeine-soaked weekend.  Sure, that elegant universally-applicable input-form routine was‘nt quite so elegant, but it didn’t really need to be as we knew what forms it needed to support.  Yes, the code lacked architectural elegance and reusability. By dawn on Monday, the application passed its integration tests. The developers rose to the occasion after I’d collapsed, and tidied up what I’d done, though they were reproachful that some of the style and elegance had gone out of the application. By the delivery date, we were able to install it. It was a smaller, faster application than the beta they’d seen and the user-interface had a new, rather Spartan, appearance that we swore was done to conform to the latest in user-interface guidelines. (we switched to Helvetica font to look more ‘Bauhaus’ ). The client was so delighted that he forgave the new bugs that had crept in. I still have the disk that crashed, up in the attic. In IT, we have had mixed experiences from complete re-writes. Lotus 123 never really recovered from a complete rewrite from assembler into C, Borland made the mistake with Arago and Quattro Pro  and Netscape’s complete rewrite of their Navigator 4 browser was a white-knuckle ride. In all cases, the decision to rewrite was a result of extreme circumstances where no other course of action seemed possible.   The rewrite didn’t come out of the blue. I prefer to remember the rewrite of Minix by young Linus Torvalds, or the rewrite of Bitkeeper by a slightly older Linus.  The rewrite of CP/M didn’t do too badly either, did it? Come to think of it, the guy who decided to rewrite the windowing system of the Xerox Star never regretted the decision. I’ll agree that one should often resist calls for a rewrite. One of the worst habits of the more inexperienced programmer is to denigrate whatever code he or she inherits, and then call loudly for a complete rewrite. They are buoyed up by the mistaken belief that they can do better. This, however, is a different psychological phenomenon, more related to the idea of some motorcyclists that they are operating on infinite lives, or the occasional squaddies that if they charge the machine-guns determinedly enough all will be well. Grim experience brings out the humility in any experienced programmer.  I’m referring to quite different circumstances here. Where a team knows the requirements perfectly, are of one mind on methodology and coding standards, and they already have a solution, then what is wrong with considering  a complete rewrite? Rewrites are so painful in the early stages, until that point where one realises the payoff, that even I quail at the thought. One needs a natural disaster to push one over the edge. The trouble is that source-control systems, and disaster recovery systems, are just too good nowadays.   If I were to lose this draft of this very blog post, I know I’d rewrite it much better. However, if you read this, you’ll know I didn’t have the nerve to delete it and start again.  There was a time that one prayed that unreliable hardware would deliver you from an unmaintainable mess of a codebase, but now technology has made us almost entirely immune to such a merciful act of God. An old friend of mine with long experience in the software industry has long had the idea of the ‘source-control wet-work’,  where one hires a malicious hacker in some wild eastern country to hack into one’s own  source control system to destroy all trace of the source to an application. Alas, backup systems are just too good to make this any more than a pipedream. Somehow, it would be difficult to promote the idea. As an alternative, could one construct a source control system that, on doing all the code-quality metrics, would systematically destroy all trace of source code that failed the quality test? Alas, I can’t see many managers buying into the idea. In reading the full story of the near-loss of Toy Story 2, it set me thinking. It turned out that the lucky restoration of the code wasn’t the happy ending one first imagined it to be, because they eventually came to the conclusion that the plot was fundamentally flawed and it all had to be rewritten anyway.  Was this an early  case of the ‘source-control wet-job’?’ It is very hard nowadays to do a rapid U-turn in a development project because we are far too prone to cling to our existing source-code.

  Read the article

• Sweet and Sour Source Control

  - by Tony Davis

  Most database developers don't use Source Control. A recent anonymous poll on SQL Server Central asked its readers "Which Version Control system do you currently use to store you database scripts?" The winner, with almost 30% of the vote was...none: "We don't use source control for database scripts". In second place with almost 28% of the vote was Microsoft's VSS. VSS? Given its reputation for being buggy, unstable and lacking most of the basic features required of a proper source control system, answering VSS is really just another way of saying "I don't use Source Control". At first glance, it's a surprising thought. You wonder how database developers can work in a team and find out what changed, when the system worked before but is now broken; to work out what happened to their changes that now seem to have vanished; to roll-back a mistake quickly so that the rest of the team have a functioning build; to find instantly whether a suspect change has been deployed to production. Unfortunately, the survey didn't ask about the scale of the database development, and correlate the two questions. If there is only one database developer within a schema, who has an automated approach to regular generation of build scripts, then the need for a formal source control system is questionable. After all, a database stores far more about its metadata than a traditional compiled application. However, what is meat for a small development is poison for a team-based development. Here, we need a form of Source Control that can reconcile simultaneous changes, store the history of changes, derive versions and builds and that can cope with forks and merges. The problem comes when one borrows a solution that was designed for conventional programming. A database is not thought of as a "file", but a vast, interdependent and intricate matrix of tables, indexes, constraints, triggers, enumerations, static data and so on, all subtly interconnected. It is an awkward fit. Subversion with its support for merges and forks, and the tolerance of different work practices, can be made to work well, if used carefully. It has a standards-based architecture that allows it to be used on all platforms such as Windows Mac, and Linux. In the words of Erland Sommerskog, developers should "just do it". What's in a database is akin to a "binary file", and the developer must work only from the file. You check out the file, edit it, and save it to disk to compile it. Dependencies are validated at this point and if you've broken anything (e.g. you renamed a column and broke all the objects that reference the column), you'll find out about it right away, and you'll be forced to fix it. Nevertheless, for many this is an alien way of working with SQL Server. Subversion is the powerhouse, not the GUI. It doesn't work seamlessly with your existing IDE, and that usually means SSMS. So the question then becomes more subtle. Would developers be less reluctant to use a fully-featured source (revision) control system for a team database development if they had a turn-key, reliable system that fitted in with their existing work-practices? I'd love to hear what you think. Cheers, Tony.

  Read the article

• What Counts For A DBA: ESP

  - by Louis Davidson

  Now I don’t want to get religious here, and I’m not going to, but what I’m going to describe in this ‘What Counts for a DBA’ installment sometimes feels like magic. Often  I will spend hours thinking about the solution to a design issue or coding problem, working diligently to try to come up with a solution and then finally just give up with the feeling that I’m not even qualified to be a data entry clerk, much less a data architect.  At this point I often take a walk (or sometimes a nap), and then it hits me. I realize that I have the answer just sitting in my brain, ready to implement.  This phenomenon is not limited to walks either; it can happen almost any time after I stop my obsession about a problem. I call this phenomena ESP (or Extra-Sensory Programming.)  Another term for this could be ‘sleeping on it’, and while the idiom tends to mean to let time pass to actively think about a problem, sleeping on a problem also lets you relax and let your brain do the work. I first noticed this back in my college days when I would play video games for hours on end. We would get stuck deep in some dungeon unable to find a way out, playing for days on end until we were beaten down tired. Once we gave up and walked away, the solution would usually be there waiting for one of us before we came back to play the next day.  Sometimes it would be in the form of a dream, and sometimes it would just be that the problem was now easy to solve when we started to play again.  While it worked great for video games, it never occurred when I studied English Literature for hours on end, or even when I worked for the same sort of frustrating hours attempting to solve a homework problem in Calculus.  I believe that the difference was that I was passionate about the video game, and certainly far less so about homework where people used the word “thou” instead of “you” or x to represent a number. This phenomenon occurs somewhat more often in my current work as a professional data programmer, because I am very passionate about SQL and love those aspects of my career choice.  Every day that I get to draw a new data model to solve a customer issue, or write a complex SELECT statement to ferret out the answer to a complex data question, is a great day. I hope it is the same for any reader of this blog.  But, unfortunately, while the day on a whole is great, a heck of a lot of noise is generated in work life. There are the typical project deadlines, along with the requisite project manager sitting on your shoulders shouting slogans to try to make you to go faster: Add in office politics, and the occasional family issues that permeate the mind, and you lose the ability to think deeply about any problem, not to mention occasionally forgetting your own name.  These office realities coupled with a difficult SQL problem staring at you from your widescreen monitor will slowly suck the life force out of your body, making it seem impossible to solve the problem This is when the walk starts; or a nap. Maybe you hide from the madness under your desk like George Costanza hides from Steinbrenner on Seinfeld.  Forget about the problem. Free your mind from the insanity of the problem and your surroundings. Then let your training and education deep in your brain take over and see if it will passively do the rest for you. If you don’t end up with a solution, the worst case scenario is that you have a bit of exercise or rest, and you won’t have heard the phrase “better is the enemy of good enough” even once…which certainly will do your brain some good. Once you stop expecting whipping your brain for information, inspiration may just strike and instead of a humdrum solution you find a solution you hadn’t even considered, almost magically. So, my beloved manager, next time you have an urgent deadline and you come across me taking a nap, creep away quietly because I’m working, doing some extra-sensory programming.

  Read the article

• New database profiling support in ANTS Performance Profiler

  - by Ben Emmett

  In May last year, the ANTS Performance Profiler team added the ability to profile database requests your application makes to SQL Server or Oracle. The really cool thing is that you’re shown those requests in the application’s call tree, so you can see what .NET code caused those queries to run. It’s particularly helpful if you’re using an ORM which automagically generates and runs queries for you, but which doesn’t necessarily do it in the most efficient way possible. Now by popular demand, we’ve added support for profiling MySQL (or MariaDB) and PostgreSQL, so you can see queries run against those databases too. Some of you have also said that you’re using the Devart dotConnect data providers instead of the native .NET ones, so we’ve added support for those drivers too. Hope it helps! For the record, here’s a list of supported connectors (ones in bold are new): SQL Server .NET Framework Data Provider Devart dotConnect for SQL Server Oracle .NET Framework Data Provider Oracle Data Provider for .NET Devart dotConnect for Oracle MySQL / MariaDB MySQL Connector/Net Devart dotConnect for MySQL PostgreSQL Npgsql .NET Data Provider for PostgreSQL Devart dotConnect for PostgreSQL SQL Server Compact Edition .NET Framework Data Provider for SQL Server Compact Edition Devart dotConnect for SQL Server Pro Have we missed a connector or database which you’d find useful? Tell us about it in the comments or by emailing [email protected]. Ben

  Read the article

• 4 Geek Excuses for Bad Presentations

  Frustrated by technically interesting yet agonizing conferences, Dr. Masha Petrova leaves geeks with no excuses for making bad presentations, and begins her campaign ensure that the people with good ideas also have good presentation skills to back them up, and get them noticed.

  Read the article

• Sharing configuration settings between Windows Azure roles

  - by theo.spears

  If you are working on a medium-large Windows Azure project it's likely it will involve more than one role, for example separate web and worker roles. Unfortunately although all the windows azure configuration settings are stored in a single cscfg file, there is no way to share configuration settings between multiple roles. This means you have to duplicate common settings like connection strings across all your roles. There is an open Connect issue about this topic, but Microsoft have not said when they will fix it. In the mean time I've put together a dirty dirty hack cunning workaround that creates a fake role containing your shared configuration settings, and copies it to all roles as part of the build process. Here's how you set it up: 1. Download the zip file attached to this post, and unzip it into the folder containing your Azure project (not your solution folder). 2. Edit your csdef and cscfg files to include the placeholder project ServiceDefinition.csdef<?xml version="1.0" encoding="utf-8"?> <ServiceDefinition name="AzureSpendNotifier" http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceDefinition%22"http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceDefinition"> <WorkerRole name="GLOBAL"> <ConfigurationSettings> <Setting name="ExampleSetting" /> </ConfigurationSettings> </WorkerRole> <WorkerRole name="MyWorker"> <ConfigurationSettings> </ConfigurationSettings> </WorkerRole> <WebRole name="MyWeb"> <Sites> <Site name="Web"> <Bindings> <Binding name="WebEndpoint" endpointName="WebEndpoint" /> </Bindings> </Site> </Sites> <ConfigurationSettings> </ConfigurationSettings> </WebRole> </ServiceDefinition> ServiceConfiguration.cscfg<?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="AzureSpendNotifier" xmlns=http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration osFamily="1" osVersion="*"> <Role name="GLOBAL"> <ConfigurationSettings> <Setting name="ExampleSetting" value="Hello World" /> </ConfigurationSettings> <Instances count="1" /> </Role> <Role name="MyWorker"> <Instances count="1" /> <ConfigurationSettings> </ConfigurationSettings> </Role> <Role name="MyWeb"> <Instances count="1" /> <ConfigurationSettings> </ConfigurationSettings> </Role> </ServiceConfiguration> It is important that all your roles contain a ConfigurationSettings entry in both cscfg and csdef files, even if it's empty- otherwise the shared configuration settings will not be inserted. 3. Open your azure deployment (.ccproj) project in notepad, and add the highlighted line below: ... <Import Project="$(CloudExtensionsDir)Microsoft.CloudService.targets" /> <Import Project="globalsettings/globalsettings.targets" /> </Project> It is important you add this below the Microsoft.CloudService.targets import line, as it replaces some of the rules defined in that file. Visual studio will prompt you to reload the project, say yes. At this point you will have a new Azure role called 'GLOBAL' with settings you can edit through the visual studio properties panel as normal. This role will never be deployed, but any settings you add to it will be copied to all your other roles when deployed or tested locally within visual studio.

  Read the article

• Generate a merge statement from table structure

  - by Nigel Rivett

  This code generates a merge statement joining on he natural key and checking all other columns to see if they have changed. The full version deals with type 2 processing and an audit trail but this version is useful. Just the insert or update part is handy too. Change the table at the top (spt_values in master in the version) and the join columns for the merge in @nk. The output generated is at the top and the code to run to generate it below. Output merge spt_values a using spt_values b on a.name = b.name and a.number = b.number and a.type = b.type when matched and (1=0 or (a.low b.low) or (a.low is null and b.low is not null) or (a.low is not null and b.low is null) or (a.high b.high) or (a.high is null and b.high is not null) or (a.high is not null and b.high is null) or (a.status b.status) or (a.status is null and b.status is not null) or (a.status is not null and b.status is null) ) then update set low = b.low , high = b.high , status = b.status when not matched by target then insert ( name , number , type , low , high , status ) values ( b.name , b.number , b.type , b.low , b.high , b.status ); Generator set nocount on declare @t varchar(128) = 'spt_values' declare @i int = 0 -- this is the natural key on the table used for the merge statement join declare @nk table (ColName varchar(128)) insert @nk select 'Number' insert @nk select 'Name' insert @nk select 'Type' declare @cols table (seq int, nkseq int, type int, colname varchar(128)) ;with cte as ( select ordinal_position, type = case when columnproperty(object_id(@t), COLUMN_NAME,'IsIdentity') = 1 then 3 when nk.ColName is not null then 1 else 0 end, COLUMN_NAME from information_schema.columns c left join @nk nk on c.column_name = nk.ColName where table_name = @t ) insert @cols (seq, nkseq, type, colname) select ordinal_position, row_number() over (partition by type order by ordinal_position) , type, COLUMN_NAME from cte declare @result table (i int, j int, k int, data varchar(500)) select @i = @i + 1 insert @result (i, data) select @i, 'merge ' + @t + ' a' select @i = @i + 1 insert @result (i, data) select @i, ' using cte b' select @i = @i + 1 insert @result (i, j, data) select @i, nkseq, ' ' + case when nkseq = 1 then 'on' else 'and' end + ' a.' + ColName + ' = b.' + ColName from @cols where type = 1 select @i = @i + 1 insert @result (i, data) select @i, ' when matched and (1=0' select @i = @i + 1 insert @result (i, j, k, data) select @i, seq, 1, ' or (a.' + ColName + ' b.' + ColName + ')' + ' or (a.' + ColName + ' is null and b.' + ColName + ' is not null)' + ' or (a.' + ColName + ' is not null and b.' + ColName + ' is null)' from @cols where type 1 select @i = @i + 1 insert @result (i, data) select @i, ' )' select @i = @i + 1 insert @result (i, data) select @i, ' then update set' select @i = @i + 1 insert @result (i, j, data) select @i, nkseq, ' ' + case when nkseq = 1 then ' ' else ', ' end + colname + ' = b.' + colname from @cols where type = 0 select @i = @i + 1 insert @result (i, data) select @i, ' when not matched by target then insert' select @i = @i + 1 insert @result (i, data) select @i, ' (' select @i = @i + 1 insert @result (i, j, data) select @i, seq, ' ' + case when seq = 1 then ' ' else ', ' end + colname from @cols where type 3 select @i = @i + 1 insert @result (i, data) select @i, ' )' select @i = @i + 1 insert @result (i, data) select @i, ' values' select @i = @i + 1 insert @result (i, data) select @i, ' (' select @i = @i + 1 insert @result (i, j, data) select @i, seq, ' ' + case when seq = 1 then ' ' else ', ' end + 'b.' + colname from @cols where type 3 select @i = @i + 1 insert @result (i, data) select @i, ' );' select data from @result order by i,j,k,data

  Read the article

• Conference networking for the socially awkward

  - by Melanie Townsend

  Do you approach a room full of strangers with excitement at all the new people you’re going to chat to over coffee and a muffin as you swap tales of how you convinced your manager to give you the day “off”? Or, do you find rooms full of strangers intimidating and begin by scouting out a place you can stand quietly and not be in someone’s way until the next session begins? If you’re on the train to extrovert city, that’s great, well done, move along. If, on the other hand, a room full of strangers who all seem to inexplicably know each other already is more challenge than opportunity, then making those connections with other professionals can be more difficult. So, here’s some advice, some gleaned from other things I’ve read online when trying to overcome my own discomfort in large groups (hopefully minus the infuriating condescension), others are just things I’ve found helpful over the years. Start small Smaller groups are less intimidating, and, now that you’ve taken the plunge to show up, it’s harder to remain inconspicuous. I find it’s easier to speak to new people once the option NOT to has been taken away. You’re there now, smile through the awkward and you’ll be forever grateful when the three people you’ve met and gotten to know here are also at that gigantic conference later on (ideally, introducing you to other people). Smile, or at the very least, stop scowling You probably don’t even know you’re doing it. If your resting face doesn’t come across as manically happy, tinge that with some social anxiety and you become one great ball of unapproachable. Normally, I wouldn’t suggest this as a problem that needs fixing, I have personally honed this face to use while travelling alone all the time. However, if you are indeed hoping to meet some useful people and get the most out of this conference, you may need to remind yourself to smile. Prepare some ice breakers This is going to sound stupid, like “no one does this right?” stupid, but, just, trust me a minute. It’s okay to prepare. You don’t need to write word-for-word questions to ask people and practice them in a mirror – that would be strange. I’m suggesting to just have an arsenal of questions to ask people if you get stuck, what session has been your favorite, which ones are you most looking forward to, have you heard X presenter speak before, what did you think of them? Even just thinking about these things in advance can help, and, as a bonus, while the other person is answering it gives you a moment to tamp down that panic, I mean breathe, I mean get to know them. You’re not alone (in the least creepy way possible) See that person in the corner clutching their phone with a mild deer in the headlights look?  That is potentially your new conference buddy. Starting with something along the lines of: I don’t know about you, the sessions here are great but I find the crowds a little tough to deal with. Mind if I park here for a second? is a decent opener. Just walking around and looking at exhibitors (if applicable) is fine, but it’s a little too easy to wander about and not actually speak to anyone if that’s all you’re doing. If joining a group of people talking is too much to start with, one-on-one can be easier. Have goals Are there people in particular you wanted to speak to? Did you have a personal goal of speaking to at least “x” new people? Are you trying to get a contact in a specific company because you want to work with them on something? Does the business have vague goals as well that you may or may not be judged on later? Making specific goals you can accomplish lets you know whether you’ve actually succeeded in your “networking pursuits” or what you need to work on more for next time. Everyone’s got their own coping technique. Some people are able to remind themselves that “humans are fundamentally social creatures” and somehow that helps them, others drink which is not really something I recommend for professional conferences but to each their own, and some focus on the fact that networking can play a big role in their career path. Just do what works for you, and if there’re any tricks you’ve found helpful over the years, please share em.

  Read the article

• Good questions to ask a potential new boss?

  - by David Johnstone

  I first asked this question on Stack Overflow, but it turns out this is a better place for it. Imagine you were working as a software developer. Imagine that the manager of your team leaves and your company is looking for a replacement. Imagine that as part of the hiring process you had the opportunity to talk with him. You are not the only person doing an interview, and while it is not ultimately your decision whether or not to hire him, you do have an influence. What questions would you ask? What would you talk with him about?

  Read the article

• Taking our Friendships to the next level.

  - by RedAndTheCommunity

  Red Gate have been running the Friends of Red Gate program for years now, and over that time we've built some great relationships with some truly awesome members of the SQL and .NET communities. When I took over the running of the program from Annabel in 2011, I was overwhelmed by the enthusiasm and commitment of our Friends. There were just so many of them, however, that it was hard to make the most of the relationships we had with people, and I wanted to fix that. I decided to survey all our Friends, to find out what they wanted to get out of, and put into, being in the Friends of Red Gate (FoRG) program. From the results of that survey, I identified 30 FoRGs that were really willing and able to go that step further to help Red Gate improve their tools, improve their relationship with the community, and improve the Friends of Red Gate program. Those 30 Friends of Red Gate have been awarded 'FoRG+' status. That means they'll: Have a closer relationship with the product teams, by getting involved in projects Have even more access to the inside track about the tools they're interested in Get the opportunity to come visit us at the Red Gate office and really influence the development of the tools. Plus more, depending on how the individual FoRG+ wants to work with us. This doesn't mean I've forgotten our other Friends; I'm working on ways to improve their experience of the Friends of Red Gate program. I'll write about them in another post. If you're an existing Friend of Red Gate, and you're interested in finding out how to get involved in the FoRG+ program, then I'd love to chat to you. For anyone that's interested in joining the Friend of Red Gate program, take a look at the web page dedicated to the program, and get in touch at [email protected] to be put on the waiting list for our 2013 program.

  Read the article

• .NET Demon 1.0 Released

  - by theo.spears

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

  Read the article

• How to learn programming for a medium scale project form a beginner? [closed]

  - by Lin Xiangyu

  I study programming by myself.I have learn servel programming languages. but I never write a project more than 1000 lines. I know the best way to improve programming skills is practise. The problem is many books, just talk about the programming language, or talk about build a project from a high level. Fews of books will teach how to build a middle scale project. For example, I want to build a simple HTTP Server(Nor like Apache or just a simple listenr to a port), a Markdown Parser, or a download tools just like emule or wget. I don't know what to do. I may found peaces of code in the web, or found familiar project in the Github. I don't know how to read the code. I want to some tutorial that can told me how to build the project step by step, teacher me how to write thousands lines of code. Any suggest?

  Read the article

• Why you shouldn't add methods to interfaces in APIs

  - by Simon Cooper

  It is an oft-repeated maxim that you shouldn't add methods to a publically-released interface in an API. Recently, I was hit hard when this wasn't followed. As part of the work on ApplicationMetrics, I've been implementing auto-reporting of MVC action methods; whenever an action was called on a controller, ApplicationMetrics would automatically report it without the developer needing to add manual ReportEvent calls. Fortunately, MVC provides easy hook when a controller is created, letting me log when it happens - the IControllerFactory interface. Now, the dll we provide to instrument an MVC webapp has to be compiled against .NET 3.5 and MVC 1, as the lowest common denominator. This MVC 1 dll will still work when used in an MVC 2, 3 or 4 webapp because all MVC 2+ webapps have a binding redirect redirecting all references to previous versions of System.Web.Mvc to the correct version, and type forwards taking care of any moved types in the new assemblies. Or at least, it should. IControllerFactory In MVC 1 and 2, IControllerFactory was defined as follows: public interface IControllerFactory { IController CreateController(RequestContext requestContext, string controllerName); void ReleaseController(IController controller); } So, to implement the logging controller factory, we simply wrap the existing controller factory: internal sealed class LoggingControllerFactory : IControllerFactory { private readonly IControllerFactory m_CurrentController; public LoggingControllerFactory(IControllerFactory currentController) { m_CurrentController = currentController; } public IController CreateController( RequestContext requestContext, string controllerName) { // log the controller being used FeatureSessionData.ReportEvent("Controller used:", controllerName); return m_CurrentController.CreateController(requestContext, controllerName); } public void ReleaseController(IController controller) { m_CurrentController.ReleaseController(controller); } } Easy. This works as expected in MVC 1 and 2. However, in MVC 3 this type was throwing a TypeLoadException, saying a method wasn't implemented. It turns out that, in MVC 3, the definition of IControllerFactory was changed to this: public interface IControllerFactory { IController CreateController(RequestContext requestContext, string controllerName); SessionStateBehavior GetControllerSessionBehavior( RequestContext requestContext, string controllerName); void ReleaseController(IController controller); } There's a new method in the interface. So when our MVC 1 dll was redirected to reference System.Web.Mvc v3, LoggingControllerFactory tried to implement version 3 of IControllerFactory, was missing the GetControllerSessionBehaviour method, and so couldn't be loaded by the CLR. Implementing the new method Fortunately, there was a workaround. Because interface methods are normally implemented implicitly in the CLR, if we simply declare a virtual method matching the signature of the new method in MVC 3, then it will be ignored in MVC 1 and 2 and implement the extra method in MVC 3: internal sealed class LoggingControllerFactory : IControllerFactory { ... public virtual SessionStateBehaviour GetControllerSessionBehaviour( RequestContext requestContext, string controllerName) {} ... } However, this also has problems - the SessionStateBehaviour type only exists in .NET 4, and we're limited to .NET 3.5 by support for MVC 1 and 2. This means that the only solutions to support all MVC versions are: Construct the LoggingControllerFactory type at runtime using reflection Produce entirely separate dlls for MVC 1&2 and MVC 3. Ugh. And all because of that blasted extra method! Another solution? Fortunately, in this case, there is a third option - System.Web.Mvc also provides a DefaultControllerFactory type that can provide the implementation of GetControllerSessionBehaviour for us in MVC 3, while still allowing us to override CreateController and ReleaseController. However, this does mean that LoggingControllerFactory won't be able to wrap any calls to GetControllerSessionBehaviour. This is an acceptable bug, given the other options, as very few developers will be overriding GetControllerSessionBehaviour in their own custom controller factory. So, if you're providing an interface as part of an API, then please please please don't add methods to it. Especially if you don't provide a 'default' implementing type. Any code compiled against the previous version that can't be updated will have some very tough decisions to make to support both versions.

  Read the article

< Previous Page | 120 121 122 123 124 125 126 127 128 129 130 131  | Next Page >