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  • Reference properteries declared in a protocol and implemented in the anonymous category?

    - by Heath Borders
    I have the following protocol: @protocol MyProtocol @property (nonatomic, retain) NSObject *myProtocolProperty; -(void) myProtocolMethod; @end and I have the following class: @interface MyClass : NSObject { } @end I have a class extension declared, I have to redeclare my protocol properties here or else I can't implement them with the rest of my class. @interface()<MyProtocol> @property (nonatomic, retain) NSObject *myExtensionProperty; /* * This redeclaration is required or my @synthesize myProtocolProperty fails */ @property (nonatomic, retain) NSObject *myProtocolProperty; - (void) myExtensionMethod; @end @implementation MyClass @synthesize myProtocolProperty = _myProtocolProperty; @synthesize myExtensionProperty = _myExtensionProperty; - (void) myProtocolMethod { } - (void) myExtensionMethod { } @end In a consumer method, I can call my protocol methods and properties just fine. Calling my extension methods and properties produces a warning and an error respectively. - (void) consumeMyClassWithMyProtocol: (MyClass<MyProtocol> *) myClassWithMyProtocol { myClassWithMyProtocol.myProtocolProperty; // works, yay! [myClassWithMyProtocol myProtocolMethod]; // works, yay! myClassWithMyProtocol.myExtensionProperty; // compiler error, yay! [myClassWithMyProtocol myExtensionMethod]; // compiler warning, yay! } Is there any way I can avoid redeclaring the properties in MyProtocol within my class extension in order to implement MyProtocol privately?

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  • MySQL datetime fields and daylight savings time -- how do I reference the "extra" hour?

    - by Aaron
    I'm using the America/New York timezone. In the Fall we "fall back" an hour -- effectively "gaining" one hour at 2am. At the transition point the following happens: it's 01:59:00 -04:00 then 1 minute later it becomes: 01:00:00 -05:00 So if you simply say "1:30am" it's ambiguous as to whether or not you're referring to the first time 1:30 rolls around or the second. I'm trying to save scheduling data to a MySQL database and can't determine how to save the times properly. Here's the problem: "2009-11-01 00:30:00" is stored internally as 2009-11-01 00:30:00 -04:00 "2009-11-01 01:30:00" is stored internally as 2009-11-01 01:30:00 -05:00 This is fine and fairly expected. But how do I save anything to 01:30:00 -04:00? The documentation does not show any support for specifying the offset and, accordingly, when I've tried specifying the offset it's been duly ignored. The only solutions I've thought of involve setting the server to a timezone that doesn't use daylight savings time and doing the necessary transformations in my scripts (I'm using PHP for this). But that doesn't seem like it should be necessary. Many thanks for any suggestions.

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  • Is this a safe way to reference objects in JavaScript?

    - by John
    If I were to define two objects myDataStore and myDrawer something like this: var myDataStore = function(myObjectRef) { this.myInternalObject = myObjectRef; }; var myDrawer = function(myObjRef) { this.myInternalObject = myObjectRef; }; And if I were to create an object like so: (function(){ var myObject = window.myObject = function(){ this.dataStore = new myDataStore(this); this.drawer = new myDrawer(this); } })(); Then myObject.dataStore.myInternalObject, and myObject.drawer.myInternalObject, would simply be pointers back to the original 'myObject' - not taking up any additional memory in the browser. Yes? I am interested in implementing techniques like this - as it makes it easy for objects to communicate with each other.

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  • Java: If I overwrite the .equals method, can I still test for reference equality with ==?

    - by shots fired
    I have the following situation: I need to sort trees based by height, so I made the Tree's comparable using the height attribute. However, I was also told to overwrite the equals and hashCode methods to avoid unpredictable behaviour. Still, sometimes I may want to compare the references of the roots or something along those lines using ==. Is that still possible or does the == comparison call the equals method?

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  • How do I reference a control in a different thread?

    - by Testifier
    //button is clicked //worker starts private void processWorker_DoWork(object sender, DoWorkEventArgs e) { string code = DoLongWorkAndReturnCode(); if (code != 0) { MessageBox.Show("Error!"); EnableAllButtons(); // this is defined in the other thread and it's where i run into the error. } else { string code = DoAnotherLongProcessAndReturnCode(); if (code != 0) { MessageBox.Show("Error 2!"); EnableAllButtons(); // again, this is defined in the other thread } } } I'm running into a cross threading error because "EnableAllButtons()" is defined in a different thread. How do I go about enabling all buttons in one thread, from a different thread?

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  • Mr Flibble: As Seen Through a Lens, Darkly

    - by Phil Factor
    One of the rewarding things about getting involved with Simple-Talk has been in meeting and working with some pretty daunting talents. I’d like to say that Dom Reed’s talents are at the end of the visible spectrum, but then there is Richard, who pops up on national radio occasionally, presenting intellectual programs, Andrew, master of the ukulele, with his pioneering local history work, and Tony with marathon running and his past as a university lecturer. However, Dom, who is Red Gate’s head of creative design and who did the preliminary design work for Simple-Talk, has taken the art photography to an extreme that was impossible before Photoshop. He’s not the first person to take a photograph of himself every day for two years, but he is definitely the first to weave the results into a frightening narrative that veers from comedy to pathos, using all the arts of Photoshop to create a fictional character, Mr Flibble.   Have a look at some of the Flickr pages. Uncle Spike The B-Men – Woolverine The 2011 BoyZ iN Sink reunion tour turned out to be their last Error 404 – Flibble not found Mr Flibble is not a normal type of alter-ego. We generally prefer to choose bronze age warriors of impossibly magnificent physique and stamina; superheroes who bestride the world, scorning the forces of evil and anarchy in a series noble and righteous quests. Not so Dom, whose Mr Flibble is vulnerable, and laid low by an addiction to toxic substances. His work has gained an international cult following and is used as course material by several courses in photography. Although his work was for a while ignored by the more conventional world of ‘art’ photography they became famous through the internet. His photos have received well over a million views on Flickr. It was definitely time to turn this work into a book, because the whole sequence of images has its maximum effect when seen in sequence. He has a Kickstarter project page, one of the first following the recent UK launch of the crowdfunding platform. The publication of the book should be a major event and the £45 I shall divvy up will be one of the securest investments I shall ever make. The local news in Cambridge picked up on the project and I can quote from the report by the excellent Cabume website , the source of Tech news from the ‘Cambridge cluster’ Put really simply Mr Flibble likes to dress up and take pictures of himself. One of the benefits of a split personality, however is that Mr Flibble is supported in his endeavour by Reed’s top notch photography skills, supreme mastery of Photoshop and unflinching dedication to the cause. The duo have collaborated to take a picture every day for the past 730-plus days. It is not a big surprise that neither Mr Flibble nor Reed watches any TV: In addition to his full-time role at Cambridge software house,Red Gate Software as head of creativity and the two to five hours a day he spends taking the Mr Flibble shots, Reed also helps organise the . And now Reed is using Kickstarter to see if the world is ready for a Mr Flibble coffee table book. Judging by the early response it is. At the time of writing, just a few days after it went live, ‘I Drink Lead Paint: An absurd photography book by Mr Flibble’ had raised £1,545 of the £10,000 target it needs to raise by the Friday 30 November deadline from 37 backers. Following the standard Kickstarter template, Reed is offering a series of rewards based on the amount pledged, ranging from a Mr Flibble desktop wallpaper for pledges of £5 or more to a signed copy of the book for pledges of £45 or more, right up to a starring role in the book for £1,500. Mr Flibble is unquestionably one of the more deranged Kickstarter hopefuls, but don’t think for a second that he doesn’t have a firm grasp on the challenges he faces on the road to immortalisation on 150 gsm stock. Under the section ‘risks and challenges’ on his Kickstarter page his statement begins: “An angry horde of telepathic iguanas discover the world’s last remaining stock of vintage lead paint and hold me to ransom. Gosh how I love to guzzle lead paint. Anyway… faced with such brazen bravado, I cower at the thought of taking on their combined might and die a sad and lonely Flibble deprived of my one and only true liquid love.” At which point, Reed manages to wrestle away the keyboard, giving him the opportunity to present slightly more cogent analysis of the obstacles the project must still overcome. We asked Reed a few questions about Mr Flibble’s Kickstarter adventure and felt that his responses were worth publishing in full: Firstly, how did you manage it – holding down a full time job and also conceiving and executing these ideas on a daily basis? I employed a small team of ferocious gerbils to feed me ideas on a daily basis. Whilst most of their ideas were incomprehensibly rubbish and usually revolved around food, just occasionally they’d give me an idea like my B-Men series. As a backup plan though, I found that the best way to generate ideas was to actually start taking photos. If I were to stand in front of the camera, pull a silly face, place a vegetable on my head or something else equally stupid, the resulting photo of that would typically spark an idea when I came to look at it. Sitting around idly trying to think of an idea was doomed to result in no ideas. I admit that I really struggled with time. I’m proud that I never missed a day, but it was definitely hard when you were late from work, tired or doing something socially on the same day. I don’t watch TV, which I guess really helps, because I’d frequently be spending 2-5 hours taking and processing the photos every day. Are there any overlaps between software development and creative thinking? Software is an inherently creative business and the speed that it moves ensures you always have to find solutions to new things. Everyone in the team needs to be a problem solver. Has it helped me specifically with my photography? Probably. Working within teams that continually need to figure out new stuff keeps the brain feisty I suppose, and I guess I’m continually exposed to a lot of possible sources of inspiration. How specifically will this Kickstarter project allow you to test the commercial appeal of your work and do you plan to get the book into shops? It’s taken a while to be confident saying it, but I know that people like the work that I do. I’ve had well over a million views of my pictures, many humbling comments and I know I’ve garnered some loyal fans out there who anticipate my next photo. For me, this Kickstarter is about seeing if there’s worth to my work beyond just making people smile. In an online world where there’s an abundance of freely available content, can you hope to receive anything from what you do, or would people just move onto the next piece of content if you happen to ask for some support? A book has been the single-most requested thing that people have asked me to produce and it’s something that I feel would showcase my work well. It’s just hard to convince people in the publishing industry just now to take any kind of risk – they’ve been hit hard. If I can show that people would like my work enough to buy a book, then it sends a pretty clear picture that publishers might hear, or it gives me the confidence enough to invest in myself a bit more – hard to do when you’re riddled with self-doubt! I’d love to see my work in the shops, yes. I could see it being the thing that someone flips through idly as they’re Christmas shopping and recognizing that it’d be just the perfect gift for their difficult to buy for friend or relative. That said, working in the software industry means I’m clearly aware of how I could use technology to distribute my work, but I can’t deny that there’s something very appealing to having a physical thing to hold in your hands. If the project is successful is there a chance that it could become a full-time job? At the moment that seems like a distant dream, as should this be successful, there are many more steps I’d need to take to reach any kind of business viability. Kickstarter seems exactly that – a way for people to help kick start me into something that could take off. If people like my work and want me to succeed with it, then taking a look at my Kickstarter page (and hopefully pledging a bit of support) would make my elbows blush considerably. So there is is. An opportunity to open the wallet just a bit to ensure that one of the more unusual talents sees the light in the format it deserves.  

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  • XML Document Depth?

    - by CrazyNick
    How to find the depth of the xml file using powershell/xpath? consider the below xml: <?xml version="1.0" encoding="ISO-8859-1"?> <bookstore> <book> <title>Harry Potter</title> <price>25.99</price> </book> <book> <title>Learning XML</title> <price>49.95</price> </book> </bookstore> depth of the above xml document is 3 (bookstore - book - title/price).

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  • Rails: link_to with block and GET params?

    - by bobthabuilda
    How can I achieve query string and URL parameters in a link_to block declaration? Right now, I have this, which works: <%= link_to 'Edit', :edit, :type => 'book', :id => book %> The above works, and outputs: http://localhost:3000/books/edit/1?type=book What I want to do is something like this: <% link_to :edit, :type => 'book', :id => book do %> ... <% end %> But the above format outputs: http://localhost:3000/books/edit/ Which isn't what I'm looking for... I want it to output a URL like the previous example. How can I achieve this?

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  • Setting a property value on each of the results in a FetchedResults set

    - by RickiG
    Hi On my Core Data Entity "Book" i have a boolean property, 'wasViewed' (NSNumber numberWithBool) that tells me if the Book was "viewed". I would like to implement a sort of "reset" this property for all my NSManagedObjects "Book". So that I can set them all to NO between sessions. I use an NSPredicate to retrieve all the Books like this: NSPredicate *predicate = [NSPredicate predicateWithFormat:@"wasViewed == %@", [NSNumber numberWithBool:YES]]; // code for setting entity, request etc... NSMutableArray *mutableFetchResults = [[[managedObjectContext executeFetchRequest:request error:&error] mutableCopy] autorelease]; This is working just fine, however, now I need to set up a loop, go through each Book object, something like this: for(Book *b in mutableFetchResults) { [b setWasViewed:NO] } Is there a way to perform an action on each element that fits the predicate instead of retrieving it? So instead of executeFetchRequest on a managedObjectContext it could be executeOperationOnFetchRequestResults or something along those lines. Thanks for any input given:)

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  • Model Binding to a List using non-sequential indexes. Can I access the index later?

    - by Kid A
    I'm following Phil's great tutorial on model binding to a list. I use input names like this: book[5804].title book[5804].author book[1234].title book[1234].author This works well and the data gets back to the model just fine, populating a list of books. What I'm looking for is a way to get access in the model to the index that was used to send the books. I'd like to get that number, "5804." This is because the index is of semantic importance. If I can access it, it saves me from setting another property on the object (book ID). Is there a way to see, either on the FormCollection or on the model after UpdateModel is called, what the index was when it was sent up?

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  • Deserialize array values to .NET properties using DataContractJsonSerializer

    - by James Cadd
    I'm working with the DataContractJsonSerializer in Silverlight 4 and would like to deserialize the following JSON: { "collectionname":"Books", "collectionitems": [ ["12345-67890",201, "Book One"], ["09876-54321",45, "Book Two"] ] } Into classes like the following: class BookCollection { public string collectionname { get; set; } public List<Book> collectionitems { get; set; } } class Book { public string Id { get; set; } public int NumberOfPages { get; set; } public string Title { get; set; } } What's the proper place to extend DataContractJsonSerializer to map the unnamed first array element in "collectionitems" to the Id property of the Book class, the second element to the NumberOfPages property and the final element to Title? I don't have control over the JSON generation in this instance and would like the solution to work with the Silverlight subset of .NET. It would be great if the solution could perform the reverse for serialization as well.

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  • selecting a range of verses from a database

    - by Noam Smadja
    i have a database, with verses from the bible, with those fields: book (book number), chapter (chapter number), verse (verse number), text (the verse) example: 1 1 1 In the beginning God created the heaven and the earth. first 1 is for Genesis, second 1 is for chapter 1, third 1 is for verse 1 user gives me something like 1 1:1 - 1 1:4 which means he wants to show Genesis 1:1-4. what i want to do is something like SELECT book*100000+chapter*1000+verse AS index FROM bible WHERE index >= 1001001 AND index <=1001004 or WHERE book*100000+chapter*1000+verse >= 1001001 AND book*100000+chapter*1000+verse <= 1001004

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  • SQL Syntax Error 1064

    - by 01010011
    Hi, I keep getting the following error message ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right systax to use near ''isbn10','isbn13','title','edition','author_f_name','author_m_name','author_l_na' at line 1 when trying to populate my MySQL database from the command line with the following command: source C:\myFilePath\myFileName.sql Here is an excerpt from my mysqldump (showing the table structure for book). Where did I go wrong? Any assistance will be appreciated: -- -- Table structure for table book DROP TABLE IF EXISTS book; /*!40101 SET @saved_cs_client = @@character_set_client /; /!40101 SET character_set_client = utf8 */; CREATE TABLE book ( book_id int(11) NOT NULL AUTO_INCREMENT, isbn10 char(20) DEFAULT NULL, isbn13 char(20) DEFAULT NULL, title char(20) DEFAULT NULL, edition char(20) DEFAULT NULL, author_f_name char(20) DEFAULT NULL, author_m_name char(20) DEFAULT NULL, author_l_name char(20) DEFAULT NULL, cond enum('as new','very good','good','fair','poor') DEFAULT NULL, price decimal(8,2) DEFAULT NULL, genre char(20) DEFAULT NULL, PRIMARY KEY (book_id) ) ENGINE=MyISAM DEFAULT CHARSET=latin1; /*!40101 SET character_set_client = @saved_cs_client */; -- -- Dumping data for table book

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  • Select an entity according to a list of associated entities

    - by Maverickch
    I have the following database schema : Two tables, books and tags, with n-m relationship. Books - Tags We can have for example the book 1, with tags {A,B,C}, and book 2, with tags {A}. I would like to select the books according to a list of tags. For example : selected tags list : {A,B} - book 1 My idea was to use the MINUS SQL function, to subtract book tags list to the selected tags list, and return the book if the list was empty. Unfortunately, this SQL function is not supported by HQL. Any idea about that ?

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  • how to made one-to-one bidirectional relationships in grails?

    - by user369759
    I have two domain classes and want to have one-to-one BIDIRECTIONAL relation between them. I write: class Person { Book book; String name Integer age Date lastVisit static constraints = { book unique: true // "one-to-one". Without that = "Many-to-one". } } class Book { String title Date releaseDate String ISBN static belongsTo = [person:Person] // it makes relationship bi-directional regarding the grails-docs } So, i want to have bi-directional, i could NOT find link from Book to Person in generated SQL: CREATE TABLE `book` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `version` bigint(20) NOT NULL, `isbn` varchar(255) NOT NULL, `release_date` datetime NOT NULL, `title` varchar(255) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM AUTO_INCREMENT=2 DEFAULT CHARSET=latin1 So then it means it is not bidirectional then? How to make bidirectional?

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  • JQuery: Remove duplicate elements?

    - by Keith Donegan
    Say I have a list of links with duplicate values as below: <a href="#">Book</a> <a href="#">Magazine</a> <a href="#">Book</a> <a href="#">Book</a> <a href="#">DVD</a> <a href="#">DVD</a> <a href="#">DVD</a> <a href="#">Book</a> How would I, using JQuery, remove the dups and be left with the following for example: <a href="#">Book</a> <a href="#">Magazine</a> <a href="#">DVD</a> Basically I am looking for a way to remove any duplicate values found and show 1 of each link.

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  • Sampler referencing in HLSL - Sampler parameter must come from a literal expression

    - by user1423893
    The following method works fine when referencing a sampler in HLSL float3 P = lightScreenPos; sampler ShadowSampler = DPFrontShadowSampler; float depth; if (alpha >= 0.5f) { // Reference the correct sampler ShadowSampler = DPFrontShadowSampler; // Front hemisphere 'P0' P.z = P.z + 1.0; P.x = P.x / P.z; P.y = P.y / P.z; P.z = lightLength / LightAttenuation.z; // Rescale viewport to be [0, 1] (texture coordinate space) P.x = 0.5f * P.x + 0.5f; P.y = -0.5f * P.y + 0.5f; depth = tex2D(ShadowSampler, P.xy).x; depth = 1.0 - depth; } else { // Reference the correct sampler ShadowSampler = DPBackShadowSampler; // Back hemisphere 'P1' P.z = 1.0 - P.z; P.x = P.x / P.z; P.y = P.y / P.z; P.z = lightLength / LightAttenuation.z; // Rescale viewport to be [0, 1] (texture coordinate space) P.x = 0.5f * P.x + 0.5f; P.y = -0.5f * P.y + 0.5f; depth = tex2D(ShadowSampler, P.xy).x; depth = 1.0 - depth; } // [Standard Depth Calculation] float mydepth = P.z; shadow = depth + Bias.x < mydepth ? 0.0f : 1.0f; If I try and do anything with the sampler reference outside the if statement then I get the following error: Sampler parameter must come from a literal expression This code demonstrates that float3 P = lightScreenPos; sampler ShadowSampler = DPFrontShadowSampler; if (alpha >= 0.5f) { // Reference the correct sampler ShadowSampler = DPFrontShadowSampler; // Front hemisphere 'P0' P.z = P.z + 1.0; P.x = P.x / P.z; P.y = P.y / P.z; P.z = lightLength / LightAttenuation.z; } else { // Reference the correct sampler ShadowSampler = DPBackShadowSampler; // Back hemisphere 'P1' P.z = 1.0 - P.z; P.x = P.x / P.z; P.y = P.y / P.z; P.z = lightLength / LightAttenuation.z; } // Rescale viewport to be [0, 1] (texture coordinate space) P.x = 0.5f * P.x + 0.5f; P.y = -0.5f * P.y + 0.5f; // [Standard Depth Calculation] float depth = tex2D(ShadowSampler, P.xy).x; depth = 1.0 - depth; float mydepth = P.z; shadow = depth + Bias.x < mydepth ? 0.0f : 1.0f; How can I reference the sampler in this manner without triggering the error?

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  • SQLAuthority News – Microsoft SQL Server Protocol Documentation Download

    - by pinaldave
    The Microsoft SQL Server protocol documentation provides detailed technical specifications for Microsoft proprietary protocols (including extensions to industry-standard or other published protocols) that are implemented and used in Microsoft SQL Server to interoperate or communicate with Microsoft products. The documentation includes a set of companion overview and reference documents that supplement the technical specifications with conceptual background, overviews of inter-protocol relationships and interactions, and technical reference information. Microsoft SQL Server Protocol Documentation Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Back to Basics: When does a .NET Assembly Dependency get loaded

    - by Rick Strahl
    When we work on typical day to day applications, it's easy to forget some of the core features of the .NET framework. For me personally it's been a long time since I've learned about some of the underlying CLR system level services even though I rely on them on a daily basis. I often think only about high level application constructs and/or high level framework functionality, but the low level stuff is often just taken for granted. Over the last week at DevConnections I had all sorts of low level discussions with other developers about the inner workings of this or that technology (especially in light of my Low Level ASP.NET Architecture talk and the Razor Hosting talk). One topic that came up a couple of times and ended up a point of confusion even amongst some seasoned developers (including some folks from Microsoft <snicker>) is when assemblies actually load into a .NET process. There are a number of different ways that assemblies are loaded in .NET. When you create a typical project assemblies usually come from: The Assembly reference list of the top level 'executable' project The Assembly references of referenced projects Dynamically loaded at runtime via AppDomain/Reflection loading In addition .NET automatically loads mscorlib (most of the System namespace) the boot process that hosts the .NET runtime in EXE apps, or some other kind of runtime hosting environment (runtime hosting in servers like IIS, SQL Server or COM Interop). In hosting environments the runtime host may also pre-load a bunch of assemblies on its own (for example the ASP.NET host requires all sorts of assemblies just to run itself, before ever routing into your user specific code). Assembly Loading The most obvious source of loaded assemblies is the top level application's assembly reference list. You can add assembly references to a top level application and those assembly references are then available to the application. In a nutshell, referenced assemblies are not immediately loaded - they are loaded on the fly as needed. So regardless of whether you have an assembly reference in a top level project, or a dependent assembly assemblies typically load on an as needed basis, unless explicitly loaded by user code. The same is true of dependent assemblies. To check this out I ran a simple test: I have a utility assembly Westwind.Utilities which is a general purpose library that can work in any type of project. Due to a couple of small requirements for encoding and a logging piece that allows logging Web content (dependency on HttpContext.Current) this utility library has a dependency on System.Web. Now System.Web is a pretty large assembly and generally you'd want to avoid adding it to a non-Web project if it can be helped. So I created a Console Application that loads my utility library: You can see that the top level Console app a reference to Westwind.Utilities and System.Data (beyond the core .NET libs). The Westwind.Utilities project on the other hand has quite a few dependencies including System.Web. I then add a main program that accesses only a simple utillity method in the Westwind.Utilities library that doesn't require any of the classes that access System.Web: static void Main(string[] args) { Console.WriteLine(StringUtils.NewStringId()); Console.ReadLine(); } StringUtils.NewStringId() calls into Westwind.Utilities, but it doesn't rely on System.Web. Any guesses what the assembly list looks like when I stop the code on the ReadLine() command? I'll wait here while you think about it… … … So, when I stop on ReadLine() and then fire up Process Explorer and check the assembly list I get: We can see here that .NET has not actually loaded any of the dependencies of the Westwind.Utilities assembly. Also not loaded is the top level System.Data reference even though it's in the dependent assembly list of the top level project. Since this particular function I called only uses core System functionality (contained in mscorlib) there's in fact nothing else loaded beyond the main application and my Westwind.Utilities assembly that contains the method accessed. None of the dependencies of Westwind.Utilities loaded. If you were to open the assembly in a disassembler like Reflector or ILSpy, you would however see all the compiled in dependencies. The referenced assemblies are in the dependency list and they are loadable, but they are not immediately loaded by the application. In other words the C# compiler and .NET linker are smart enough to figure out the dependencies based on the code that actually is referenced from your application and any dependencies cascading down into the dependencies from your top level application into the referenced assemblies. In the example above the usage requirement is pretty obvious since I'm only calling a single static method and then exiting the app, but in more complex applications these dependency relationships become very complicated - however it's all taken care of by the compiler and linker figuring out what types and members are actually referenced and including only those assemblies that are in fact referenced in your code or required by any of your dependencies. The good news here is: That if you are referencing an assembly that has a dependency on something like System.Web in a few places that are not actually accessed by any of your code or any dependent assembly code that you are calling, that assembly is never loaded into memory! Some Hosting Environments pre-load Assemblies The load behavior can vary however. In Console and desktop applications we have full control over assembly loading so we see the core CLR behavior. However other environments like ASP.NET for example will preload referenced assemblies explicitly as part of the startup process - primarily to minimize load conflicts. Specifically ASP.NET pre-loads all assemblies referenced in the assembly list and the /bin folder. So in Web applications it definitely pays to minimize your top level assemblies if they are not used. Understanding when Assemblies Load To clarify and see it actually happen what I described in the first example , let's look at a couple of other scenarios. To see assemblies loading at runtime in real time lets create a utility function to print out loaded assemblies to the console: public static void PrintAssemblies() { var assemblies = AppDomain.CurrentDomain.GetAssemblies(); foreach (var assembly in assemblies) { Console.WriteLine(assembly.GetName()); } } Now let's look at the first scenario where I have class method that references internally uses System.Web. In the first scenario lets add a method to my main program like this: static void Main(string[] args) { Console.WriteLine(StringUtils.NewStringId()); Console.ReadLine(); PrintAssemblies(); } public static void WebLogEntry() { var entry = new WebLogEntry(); entry.UpdateFromRequest(); Console.WriteLine(entry.QueryString); } UpdateFromWebRequest() internally accesses HttpContext.Current to read some information of the ASP.NET Request object so it clearly needs a reference System.Web to work. In this first example, the method that holds the calling code is never called, but exists as a static method that can potentially be called externally at some point. What do you think will happen here with the assembly loading? Will System.Web load in this example? No - it doesn't. Because the WebLogEntry() method is never called by the mainline application (or anywhere else) System.Web is not loaded. .NET dynamically loads assemblies as code that needs it is called. No code references the WebLogEntry() method and so System.Web is never loaded. Next, let's add the call to this method, which should trigger System.Web to be loaded because a dependency exists. Let's change the code to: static void Main(string[] args) { Console.WriteLine(StringUtils.NewStringId()); Console.WriteLine("--- Before:"); PrintAssemblies(); WebLogEntry(); Console.WriteLine("--- After:"); PrintAssemblies(); Console.ReadLine(); } public static void WebLogEntry() { var entry = new WebLogEntry(); entry.UpdateFromRequest(); Console.WriteLine(entry.QueryString); } Looking at the code now, when do you think System.Web will be loaded? Will the before list include it? Yup System.Web gets loaded, but only after it's actually referenced. In fact, just until before the call to UpdateFromRequest() System.Web is not loaded - it only loads when the method is actually called and requires the reference in the executing code. Moral of the Story So what have we learned - or maybe remembered again? Dependent Assembly References are not pre-loaded when an application starts (by default) Dependent Assemblies that are not referenced by executing code are never loaded Dependent Assemblies are just in time loaded when first referenced in code All of this is nothing new - .NET has always worked like this. But it's good to have a refresher now and then and go through the exercise of seeing it work in action. It's not one of those things we think about everyday, and as I found out last week, I couldn't remember exactly how it worked since it's been so long since I've learned about this. And apparently I'm not the only one as several other people I had discussions with in relation to loaded assemblies also didn't recall exactly what should happen or assumed incorrectly that just having a reference automatically loads the assembly. The moral of the story for me is: Trying at all costs to eliminate an assembly reference from a component is not quite as important as it's often made out to be. For example, the Westwind.Utilities module described above has a logging component, including a Web specific logging entry that supports pulling information from the active HTTP Context. Adding that feature requires a reference to System.Web. Should I worry about this in the scope of this library? Probably not, because if I don't use that one class of nearly a hundred, System.Web never gets pulled into the parent process. IOW, System.Web only loads when I use that specific feature and if I am, well I clearly have to be running in a Web environment anyway to use it realistically. The alternative would be considerably uglier: Pulling out the WebLogEntry class and sticking it into another assembly and breaking up the logging code. In this case - definitely not worth it. So, .NET definitely goes through some pretty nifty optimizations to ensure that it loads only what it needs and in most cases you can just rely on .NET to do the right thing. Sometimes though assembly loading can go wrong (especially when signed and versioned local assemblies are involved), but that's subject for a whole other post…© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET  CSharp   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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