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  • C++ Changing a class in a dll where a pointer to that class is returned to other dlls...

    - by Patrick
    Hello, Horrible title I know, horrible question too. I'm working with a bit of software where a dll returns a ptr to an internal class. Other dlls (calling dlls) then use this pointer to call methods of that class directly: //dll 1 internalclass m_class; internalclass* getInternalObject() { return &m_class; } //dll 2 internalclass* classptr = getInternalObject(); classptr->method(); This smells pretty bad to me but it's what I've got... I want to add a new method to internalclass as one of the calling dlls needs additional functionality. I'm certain that all dlls that access this class will need to be rebuilt after the new method is included but I can't work out the logic of why. My thinking is it's something to do with the already compiled calling dll having the physical address of each function within internalclass in the other dll but I don't really understand it; is anyone here able to provide a concise explanation of how the dlls (new internal class dll, rebuilt calling dll and calling dll built with previous version of the internal class dll) would fit together? Thanks, Patrick

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  • XSLT 1.0: restrict entries in a nodeset

    - by Mike
    Hi, Being relatively new to XSLT I have what I hope is a simple question. I have some flat XML files, which can be pretty big (eg. 7MB) that I need to make 'more hierarchical'. For example, the flat XML might look like this: <D0011> .... .... and it should end up looking like this: <D0011> .... .... I have a working XSLT for this, and it essentially gets a nodeset of all the b elements and then uses the 'following-sibling' axis to get a nodeset of the nodes following the current b node (ie. following-sibling::*[position() =$nodePos]). Then recursion is used to add the siblings into the result tree until another b element is found (I have parameterised it of course, to make it more generic). I also have a solution that just sends the position in the XML of the next b node and selects the nodes after that one after the other (using recursion) via a *[position() = $nodePos] selection. The problem is that the time to execute the transformation increases unacceptably with the size of the XML file. Looking into it with XML Spy it seems that it is the 'following-sibling' and 'position()=' that take the time in the two respective methods. What I really need is a way of restricting the number of nodes in the above selections, so fewer comparisons are performed: every time the position is tested, every node in the nodeset is tested to see if its position is the right one. Is there a way to do that ? Any other suggestions ? Thanks, Mike

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  • Does F# documentation have a way to search for functions by their types?

    - by Nathan Sanders
    Say I want to know if F# has a library function of type ('T -> bool) -> 'T list -> int ie, something that counts how many items of a list that a function returns true for. (or returns the index of the first item that returns true) I used to use the big list at the MSR site for F# before the documentation on MSDN was ready. I could just search the page for the above text because the types were listed. But now the MSDN documentation only lists types on the individual pages--the module page is a mush of descriptive text. Google kinda-sorta works, but it can't help with // compatible interfaces ('T -> bool) -> Seq<'T> -> int // argument-swaps Seq<'T> -> ('T -> bool) -> int // type-variable names ('a -> bool) -> Seq<'a> -> int // wrappers ('a -> bool) -> 'a list -> option<int> // uncurried versions ('T -> bool) * 'T list -> int // .NET generic syntax ('T -> bool) -> List<'T> -> int // methods List<'T> member : ('T -> bool) -> int Haskell has a standalone program for this called Hoogle. Does F# have an equivalent, like Fing or something?

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  • How can I limit asp.net control actions based on user role?

    - by Duke
    I have several pages or views in my application which are essentially the same for both authenticated users and anonymous users. I'd like to limit the insert/update/delete actions in formviews and gridviews to authenticated users only, and allow read access for both authed and anon users. I'm using the asp.net configuration system for handling authentication and roles. This system limits access based on path so I've been creating duplicate pages for authed and anon paths. The solution that comes to mind immediately is to check roles in the appropriate event handlers, limiting what possible actions are displayed (insert/update/delete buttons) and also limiting what actions are performed (for users that may know how to perform an action in the absence of a button.) However, this solution doesn't eliminate duplication - I'd be duplicating security code on a series of pages rather than duplicating pages and limiting access based on path; the latter would be significantly less complicated. I could always build some controls that offered role-based configuration, but I don't think I have time for that kind of commitment right now. Is there a relatively easy way to do this (do such controls exist?) or should I just stick to path-based access and duplicate pages? Does it even make sense to use two methods of authorization? There are still some pages which are strictly for either role so I'll be making use of path-based authorization anyway. Finally, would using something other than path-based authorization be contrary to typical asp.net design practices, at least in the context of using the asp.net configuration system?

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  • SQL Server error handling: exceptions and the database-client contract

    - by gbn
    We’re a team of SQL Servers database developers. Our clients are a mixed bag of C#/ASP.NET, C# and Java web services, Java/Unix services and some Excel. Our client developers only use stored procedures that we provide and we expect that (where sensible, of course) they treat them like web service methods. Some our client developers don’t like SQL exceptions. They understand them in their languages but they don’t appreciate that the SQL is limited in how we can communicate issues. I don’t just mean SQL errors, such as trying to insert “bob” into a int column. I also mean exceptions such as telling them that a reference value is wrong, or that data has already changed, or they can’t do this because his aggregate is not zero. They’d don’t really have any concrete alternatives: they’ve mentioned that we should output parameters, but we assume an exception means “processing stopped/rolled back. How do folks here handle the database-client contract? Either generally or where there is separation between the DB and client code monkeys. Edits: we use SQL Server 2005 TRY/CATCH exclusively we log all errors after the rollback to an exception table already we're concerned that some of our clients won't check output paramaters and assume everything is OK. We need errors flagged up for support to look at. everything is an exception... the clients are expected to do some message parsing to separate information vs errors. To separate our exceptions from DB engine and calling errors, they should use the error number (ours are all 50,000 of course)

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  • PHP static objects giving a fatal error

    - by Webbo
    I have the following PHP code; <?php component_customer_init(); component_customer_go(); function component_customer_init() { $customer = Customer::getInstance(); $customer->set(1); } function component_customer_go() { $customer = Customer::getInstance(); $customer->get(); } class Customer { public $id; static $class = false; static function getInstance() { if(self::$class == false) { self::$class = new Customer; } else { return self::$class; } } public function set($id) { $this->id = $id; } public function get() { print $this->id; } } ?> I get the following error; Fatal error: Call to a member function set() on a non-object in ....../classes/customer.php on line 9 Can anyone tell me why I get this error? I know this code might look strange, but it's based on a component system that I'm writing for a CMS. The aim is to be able to replace HTML tags in the template e.g.; <!-- component:customer-login --> with; <?php component_customer_login(); ?> I also need to call pre-render methods of the "Customer" class to validate forms before output is made etc. If anyone can think of a better way, please let me know but in the first instance, I'd like to know why I get the "Fatal error" mentioned above. Cheers

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  • Java Function Analysis

    - by khan
    Okay..I am a total Python guy and have very rarely worked with Java and its methods. The condition is that I have a got a Java function that I have to explain to my instructor and I have got no clue about how to do so..so if one of you can read this properly, kindly help me out in breaking it down and explaining it. Also, i need to find out any flaw in its operation (i.e. usage of loops, etc.) if there is any. Finally, what is the difference between 'string' and 'string[]' types? public static void search(String findfrom, String[] thething){ if(thething.length > 5){ System.err.println("The thing is quite long"); } else{ int[] rescount = new int[thething.length]; for(int i = 0; i < thething.length; i++){ String[] characs = findfrom.split("[ \"\'\t\n\b\f\r]", 0); for(int j = 0; j < characs.length; j++){ if(characs[j].compareTo(thething[i]) == 0){ rescount[i]++; } } } for (int j = 0; j < thething.length; j++) { System.out.println(thething[j] + ": " + rescount[j]); } } }

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  • Custom Android control with children

    - by Gromix
    Hi, I'm trying to create a custom Android control that contains a LinearLayout. You can think of it as an extended LinearLayout with fancy borders, a background, an image on the left... I could do it all in XML (works great) but since I have dozens of occurences in my app it's getting hard to maintain. I thought it would be nicer to have something like this: /* Main.xml */ <MyFancyLayout> <TextView /> /* what goes inside my control's linear layout */ </MyfancyLayout> How would you approach this? I'd like to avoid re-writing the whole linear layout onMeasure / onLayout methods. This is what I have for the moment: /* MyFancyLayout.xml */ <TableLayout> <ImageView /> <LinearLayout id="container" /> /* where I want the real content to go */ </TableLayout> and /* MyFancyLayout.java */ public class MyFancyLayout extends LinearLayout { public MyFancyLayout(Context context) { super(context); View.inflate(context, R.layout.my_fancy_layout, this); } } How would you go about inserting the user-specified content (the TextView in main.xml) in the right place (id=container)? Cheers! Romain ----- edit ------- Still no luck on this, so I changed my design to use a simpler layout and decided to live with a bit of repeated XML. Still very interested in anyone knows how to do this though!

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  • How do you keep application logic separate from UI when UI components have built-in functionality?

    - by Al C
    I know it's important to keep user interface code separated from domain code--the application is easier to understand, maintain, change, and (sometimes) isolate bugs. But here's my mental block ... Delphi comes with components with methods that do what I want, e.g., a RichText Memo component lets me work with rich text. Other components, like TMS's string grid not only do what I want, but I paid extra for the functionality. These features put the R in RAD. It seems illogical to write my own classes to do things somebody else has already done for me. It's reinventing the wheel [ever tried working directly with rich text? :-) ] But if I use the functionality built into components like these, then I will end up with lots of intermingled UI and domain code--I'll have a form with most of my code built into its event handlers. How do you deal with this issue? ... Or, if I want to continue using the code others have already written for me, how would you suggest I deal with the issue?

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  • What Test Environment Setup do Committers Use in the Ruby Community?

    - by viatropos
    Today I am going to get as far as I can setting up my testing environment and workflow. I'm looking for practical advice on how to setup the test environment from you guys who are very passionate and versed in Ruby Testing. By the end of the day (6am PST?) I would like to be able to: Type one 1-command to run test suites for ANY project I find on Github. Run autotest for ANY Github project so I can fork and make TESTABLE contributions. Build gems from the ground up with Autotest and Shoulda. For one reason or another, I hardly ever run tests for projects I clone from Github. The major reason is because unless they're using RSpec and have a Rake task to run the tests, I don't see the common pattern behind it all. I have built 3 or 4 gems writing tests with RSpec, and while I find the DSL fun, it's less than ideal because it just adds another layer/language of methods I have to learn and remember. So I'm going with Shoulda. But this isn't a question about which testing framework to choose. So the questions are: What is your, the SO reader and Github project committer, test environment setup using autotest so that whenever you git clone a gem, you can run the tests and autotest-develop them if desired? What are the guys who are writing the Paperclip Tests and Authlogic Tests doing? What is their setup? Thanks for the insight. Looking for answers that will make me a more effective tester.

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  • deleting object with template for int and object

    - by Yokhen
    Alright so Say I have a class with all its definition, bla bla bla... template <class DT> class Foo{ private: DT* _data; //other stuff; public: Foo(DT* data){ _data = data } virtual ~Foo(){ delete _data } //other methods }; And then I have in the main method: int main(){ int number = 12; Foo<anyRandomClass>* noPrimitiveDataObject = new Foo<anyRandomClass>(new anyRandomClass()); Foo<int>* intObject = new Foo<int>(number); delete noPrimitiveDataObject; //Everything goes just fine. delete intObject; //It messes up here, I think because primitive data types such as int are allocated in a different way. return 0; } My question is: What could I do to have both delete statements in the main method work just fine? P.S.: Although I have not actually compiled/tested this specific code, I have reviewed it extensively (as well as indented. You're welcome.), so if you find a mistake, please be nice. Thank you.

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  • Multiple exports with MEF does some really heinous stuff -- why, and why is it allowed?

    - by Dave
    I have an interesting situation where I need to do something like this: [Export[typeof(ICandy1)] [Export[typeof(ICandy2)] public class Candy : ICandy2 { ... } where public interface ICandy1 { ... } public interface ICandy2 : ICandy1 { ... } I couldn't find any posts anywhere regarding using multiple [Export] attributes, so I figured, what the hell, might as well try it. At first glance, it actually seemed to work. I have a couple of methods that call into both interfaces of a Candy instance, and it was fine. However, as I started to test the app, I saw that the behavior wasn't right, and when looking at the Output window, I saw that I was getting tons of COMExceptions. I couldn't track down where they were all coming from, but they always occurred when a worker thread was sleeping. I figured that it had to be from the main thread, then, but didn't know how to debug this at all. Nothing should have been going on in the GUI, and I disabled my DispatchTimers just in case -- same thing. Even more strange than the COMExceptions was the really, really erratic behavior when stepping through code. About 30% of the time, when I single stepped, it would pop out of the method, or it would single step over two lines of code! Totally weird stuff that I am not used to seeing. The only thing that changed between working and non-working code was the introduction of MEF through my plugin loading code. So as a test, I changed my plugin assembly to only export one interface, and I hardcoded everything in the app that relied on the other (now not-implemented) interface. And now the COMExceptions are gone, and the weird debugging behavior is gone. Is this something people here have seen before? If MEF is not expected to allow a class to Export multiple interfaces, then shouldn't a CompositionException get raised when composing the parts? Can anyone explain why MEF would cause these weird problems???

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  • WCF Multiple contracts with duplicate method names

    - by haxelit
    Hello, I have a service with multiple contracts like so. [ServiceContract] public partial interface IBusinessFunctionDAO { [OperationContract] BusinessFunction GetBusinessFunction(Int32 businessFunctionRefID); [OperationContract] IEnumerable<Project> GetProjects(Int32 businessFunctionRefID); } [ServiceContract] public partial interface IBusinessUnitDAO { [OperationContract] BusinessUnit GetBusinessUnit(Int32 businessUnitRefID); [OperationContract] IEnumerable<Project> GetProjects(Int32 businessUnitRefID); } I then explicitly implemented each one of the interfaces like so. public class TrackingTool : IBusinessFunctionDAO, IBusinessUnitDAO { BusinessFunction IBusinessFunctionDAO.GetBusinessFunction(Int32 businessFunctionRefID) { // implementation } IEnumerable<Project> IBusinessFunctionDAO.GetProjects(Int32 businessFunctionRefID) { // implementation } BusinessUnit IBusinessUnitDAO.GetBusinessUnit(Int32 businessUnitRefID) { // implementation } IEnumerable<Project> IBusinessUnitDAO.GetProjects(Int32 businessUnitRefID) { // implementation } } As you can see I have two GetProjects(int) methods, but each one is implemented explicitly so this compiles just fine and is perfectly valid. The problem arises when I actually start this as a service. It gives me an error staying that TrackingTool already contains a definition GetProject. While it is true, it is part of a different service contract. Does WCF not distinguish between service contracts when generating the method names ? Is there a way to get it to distinguish between the service contracts ? My App.Config looks like this <service name="TrackingTool"> <endpoint address="BusinessUnit" contract="IBusinessUnitDAO" /> <endpoint address="BusinessFunction" contract="IBusinessFunctionDAO" /> </service> Any help would be appreciated. Thanks, Raul

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  • In M-V-VM where does my code go?

    - by Nate Bross
    So, this is a pretty basic question I hope. I have a web service that I've added through Add Service Reference. It has some methods to get list and get detail of a perticular table in my database. What I'm trying to do is setup a UI as follows: App Load Load service proxy Call the GetList(); method display the results in a ListBox control User Double Clicks item in ListBox, display a modal dialog with a "detail" view I'm extremely new to using MVVM, so any help would be greatly appreciated. Additional information: // Service Interface (simplification): interface IService { IEnumerable<MyObject> GetList(); MyObject GetDetail(int id); } // Data object (simplification) class MyObject { public int ID { get; set; } public string Name { get; set; } } I'm thinking I should have something like this: MainWindow MyObjectViewUserControl Displays list Opens modal window on double click Specific Questions: What would my ViewModel class look like? Where does the code to handle the double click go? Inside the UserControl? Sorry for the long details, but I'm very new to the whole thing and I'm not educated enough to ask the right questions. I checked out the MVVM Sample from wpf.codeplex.com and something isn't quite clicking for me yet, because it seems very confusing.

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  • Javascript Closures, Callbacks, This and That

    - by nazbot
    I am having some trouble getting a callback function to work. Here is my code: SomeObject.prototype.refreshData = function() { var read_obj = new SomeAjaxCall("read_some_data", { }, this.readSuccess, this.readFail); } SomeObject.prototype.readSuccess = function(response) { this.data = response; this.someList = []; for (var i = 0; i < this.data.length; i++) { var systemData = this.data[i]; var system = new SomeSystem(systemData); this.someList.push(system); } this.refreshList(); } Basically SomeAjaxCall is making an ajax request for data. If it works we use the callback 'this.readSuccess' and if it fails 'this.readFail'. I have figured out that 'this' in the SomeObject.readSuccess is the global this (aka the window object) because my callbacks are being called as functions and not member methods. My understanding is that I need to use closures to keep the 'this' around, however, I have not been able to get this to work. If someone is able show me what I should be doing I would appreciate it greatly. I am still wrapping my head around how closures work and specifically how they would work in this situation. Thanks!

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  • Different approaches for finding users within Active Directory

    - by EvilDr
    I'm a newbie to AD programming, but after a couple of weeks of research have found the following three ways to search for users in Active Directory using the account name as the search parameter: Option 1 - FindByIdentity Dim ctx As New PrincipalContext(ContextType.Domain, Environment.MachineName) Dim u As UserPrincipal = UserPrincipal.FindByIdentity(ctx, IdentityType.SamAccountName, "MYDOMAIN\Administrator") If u Is Nothing Then Trace.Warn("No user found.") Else Trace.Warn("Name=" & u.Name) Trace.Warn("DisplayName=" & u.DisplayName) Trace.Warn("DistinguishedName=" & u.DistinguishedName) Trace.Warn("EmployeeId=" & u.EmployeeId) Trace.Warn("EmailAddress=" & u.EmailAddress) End If Option 2 - DirectorySearcher Dim connPath As String = "LDAP://" & Environment.MachineName Dim de As New DirectoryEntry(connPath) Dim ds As New DirectorySearcher(de) ds.Filter = String.Format("(&(objectClass=user)(anr={0}))", Split(User.Identity.Name, "\")(1)) ds.PropertiesToLoad.Add("name") ds.PropertiesToLoad.Add("displayName") ds.PropertiesToLoad.Add("distinguishedName") ds.PropertiesToLoad.Add("employeeId") ds.PropertiesToLoad.Add("mail") Dim src As SearchResult = ds.FindOne() If src Is Nothing Then Trace.Warn("No user found.") Else For Each propertyKey As String In src.Properties.PropertyNames Dim valueCollection As ResultPropertyValueCollection = src.Properties(propertyKey) For Each propertyValue As Object In valueCollection Trace.Warn(propertyKey & "=" & propertyValue.ToString) Next Next End If Option 3 - PrincipalSearcher Dim ctx2 As New PrincipalContext(ContextType.Domain, Environment.MachineName) Dim sp As New UserPrincipal(ctx2) sp.SamAccountName = "MYDOMAIN\Administrator" Dim s As New PrincipalSearcher s.QueryFilter = sp Dim p2 As UserPrincipal = s.FindOne() If p2 Is Nothing Then Trace.Warn("No user found.") Else Trace.Warn(p2.Name) Trace.Warn(p2.DisplayName) Trace.Warn(p2.DistinguishedName) Trace.Warn(p2.EmployeeId) Trace.Warn(p2.EmailAddress) End If All three of these methods return the same results, but I was wondering if any particular method is better or worse than the others? Option 1 or 3 seem to be the best as they provide strongly-typed property names, but I might be wrong? My overall objective is to find a single user within AD based on the user principal value passed via the web browser when using Windows Authentication on a site (e.g. "MYDOMAIN\MyUserAccountName")

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  • What are possible/good ways to prototype iPhone applications?

    - by Ted Johnson
    This is intentionally left broad. If you wanted to show users what iPhone/mobile applications could to for them. The more interactive the better, but it must be quick to build as you can't code up every idea. Let us assume real-time games are out of scope. Throw out ideas or state which approach would be best. Here are some of my ideas, what are yours? Hack a app that loads mostly web or image content, but has hyperlinks to get around in. This would mean static data. Build screens which look great but can only be navigated in a story board type fashion. Load the web version or equivalent on the iPhone and say: now image the buttons and navigation is better. A paper based prototype. Flash or video walk through running on the phone. String existing iPhone apps and web pages together with minimal glue just to convey the idea. Can anyone share prototyping methods for other mobile devices? Ex: The palm prototype was just a block of wood and note pad that was carried around.

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  • In-order tree traversal

    - by Chris S
    I have the following text from an academic course I took a while ago about in-order traversal (they also call it pancaking) of a binary tree (not BST): In-order tree traversal Draw a line around the outside of the tree. Start to the left of the root, and go around the outside of the tree, to end up to the right of the root. Stay as close to the tree as possible, but do not cross the tree. (Think of the tree — its branches and nodes — as a solid barrier.) The order of the nodes is the order in which this line passes underneath them. If you are unsure as to when you go “underneath” a node, remember that a node “to the left” always comes first. Here's the example used (slightly different tree from below) However when I do a search on google, I get a conflicting definition. For example the wikipedia example: Inorder traversal sequence: A, B, C, D, E, F, G, H, I (leftchild,rootnode,right node) But according to (my understanding of) definition #1, this should be A, B, D, C, E, F, G, I, H Can anyone clarify which definition is correct? They might be both describing different traversal methods, but happen to be using the same name. I'm having trouble believing the peer-reviewed academic text is wrong, but can't be certain.

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  • Reference to the Main Form whilst trying to Serialize objects in C#

    - by Paul Matthews
    I have a button on my main form which calls a method to serialize some objects to disk. I am trying to add these objects to an ArrayList and then serialize them using a BinaryFormatter and a FileStream. public void SerializeGAToDisk(string GenAlgName) { // Let's make a list that includes all the objects we // need to store a GA instance ArrayList GAContents = new ArrayList(); GAContents.Add(GenAlgInstances[GenAlgName]); // Structure and info for a GA GAContents.Add(RunningGAs[GenAlgName]); // There may be several running GA's using (FileStream fStream = new FileStream(GenAlgName + ".ga", FileMode.Create, FileAccess.Write, FileShare.None)) { BinaryFormatter binFormat = new BinaryFormatter(); binFormat.Serialize(fStream, GAContents); } } When running the above code I get the following exception: System.Runtime.Serialization.SerializationException was unhandled Message=Type 'WindowsFormsApplication1.Form1' in Assembly 'GeneticAlgApp, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' is not marked as serializable. So that means that somewhere in the objects I'm trying to save there must be a reference to the main form. The only possible references I can see are 3 delegates which all point to methods in the main form code. Do delegates get serialized as well? I can't seem to apply the [NonSerialized] attribute to them. Is there anything else I might be missing? Even better, is there a quick method to find the reference(s) that are causing the problem?

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  • The question about the basics of LINQ to SQL working

    - by Alex
    I just started learning LINQ to SQL, and so far I'm impressed with the easy of use and good performance. I used to think that when doing LINQ queries like from Customer in DB.Customers where Customer.Age > 30 select Customer Get all customers from the database ("SELECT * FROM Customers"), move them to the Customers array and then make a search in that Array using .NET methods. This is very inefficient, what if there are hundreds of thousands of customers in the database? Making such big SELECT queries would kill the web application. Now after experiencing how actually fast LINQ to SQL is, I start to suspect that when doing that query I just wrote, LINQ somehow converts it to a SQL Query string SELECT * FROM Customers WHERE Age > 30 And only when necessary it will run the query. So my question is: am I right? And when is the query actually run? The reason why I'm asking is not only because I want to understand how it works in order to build good optimized applications, but because I came across the following problem. I have 2 tables, one of them is Books, the other has information on how many books were sold on certain days. My goal is to select books that had at least 50 sales/day in past 10 days. It's done with this simple query: from Book in DB.Books where (from Sale in DB.Sales where Sale.SalesAmount >= 50 and Sale.DateOfSale >= DateTime.Now.AddDays(-10) select Sale.BookID).Contains(Book.ID) select Book The point is, I have to use the checking part in several queries and I decided to create an array with IDs of all popular books: var popularBooksIDs = from Sale in DB.Sales where Sale.SalesAmount >= 50 and Sale.DateOfSale >= DateTime.Now.AddDays(-10) select Sale.BookID; BUT when I try to do the query now: from Book in DB.Books where popularBooksIDs.Contains(Book.ID) select Book It doesn't work! That's why I think that we can't use thins kinds of shortcuts in LINQ to SQL queries, like we can't use them in real SQL. We have to create straightforward queries, am I right?

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  • Compact data structure for storing a large set of integral values

    - by Odrade
    I'm working on an application that needs to pass around large sets of Int32 values. The sets are expected to contain ~1,000,000-50,000,000 items, where each item is a database key in the range 0-50,000,000. I expect distribution of ids in any given set to be effectively random over this range. The operations I need on the set are dirt simple: Add a new value Iterate over all of the values. There is a serious concern about the memory usage of these sets, so I'm looking for a data structure that can store the ids more efficiently than a simple List<int>or HashSet<int>. I've looked at BitArray, but that can be wasteful depending on how sparse the ids are. I've also considered a bitwise trie, but I'm unsure how to calculate the space efficiency of that solution for the expected data. A Bloom Filter would be great, if only I could tolerate the false negatives. I would appreciate any suggestions of data structures suitable for this purpose. I'm interested in both out-of-the-box and custom solutions. EDIT: To answer your questions: No, the items don't need to be sorted By "pass around" I mean both pass between methods and serialize and send over the wire. I clearly should have mentioned this. There could be a decent number of these sets in memory at once (~100).

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  • Is there a way to automatically load navigational property using the .NET Entity Framework?

    - by René Wolferink
    Stepping away more and more from writing SQL for my applications, I decided to give the Entity Framework a try. However, I've run into something I believe is causing me to write more code than I think is strictly necessary. When I accessed some navigational properties, I discovered that all many-to-one relations (simple references) were null and all one-to-many and many-to-many relations (EntityCollections) were empty. For example: I have a User with a reference to a Group. When I have retieved a User, by using a simple select-by-id, the Group property is null. If I want to access the Group I have to manually load it (using User.GroupReference.Load()). So I added a GetGroup() method in User which checks whether the Group is loaded already and, if not, does so and then returns the Group. Now this will result in a lot of highly similar methods for all navigational properties. And it all results in the navigational properties not being used, only my custom-made Get"PropertyName"() method's are now being used. I don't want to expand my queries (linq to entities) to immediately load all these properties, because it's not always known at first what is needed. And besides, it would cause a lot of queries to have to be made. Is there a way to configure the Entity Framework to load these objects when they happen to not be present? So when I access User.Group and the group is not loaded yet, it is loaded automatically? Or am I stuck using my own Get"PropertyName"() method's as long as I'm trying to load objects only on demand (or "just-in-time")? Some extra info: I'm using VS2008 SP1 with .NET 3.5 SP1. The Entity Framework I'm using is the one that got shipped with it.

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  • Load some data from database and hide it somewhere in a web page

    - by kwokwai
    Hi all, I am trying to load some data (which may be up to a few thousands words) from the database, and store the data somewhere in a html web page for comparing the data input by users. I am thinking to load the data to a Textarea under Div tag and hide the the data: <Div id="reference" style="Display:none;"> <textarea rows="2" cols="20" id="database"> html, htm, php, asp, jsp, aspx, ctp, thtml, xml, xsl... </textarea> </Div> <table border=0 width="100%"> <tr> <td>Username</td> <td> <div id="username"> <input type="text" name="data" id="data"> </div> </td> </tr> </table> <script> $(document).ready(function(){ //comparing the data loaded from database with the user's input if($("#data").val()==$("#database").val()) {alert("error");} }); </script> I am not sure if this is the best way to do it, so could you give me some advice and suggest your methods please.

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  • Should conditional expressions go inside or outside of classes?

    - by Rupert
    It seems that often I will want to execute some methods from a Class when I call it and choosing which function will depend on some condition. This leads me to write classes like in Case 1 because it allows me to rapidly include their functionality. The alternative would be Case 2 which can take a lot of time if there is a lot of code and also means more code being written twice when I drop the Class into different pages. Having said that, Case 1 feels very wrong for some reason that I can't quite put my finger on. I haven't really seen any classes written like this, I suppose. Is there anything wrong with writing classes like in Case 1 or is Case 2 superior? Or is there a better way? What the advantages and disadvantages of each? Case 1 class Foo { public function __construct($bar) { if($bar = 'action1') $this->method1(); else if($bar = 'action2') $this->method2(); else $this->method1(); } public function method1() { } public function method2() { } } $bar = 'action1' $foo = new Foo($bar); Case 2 class Foo { public function __construct() { } public function method1() { } public function method2() { } } $foo = new Foo; $bar = 'action1'; if($bar == 'action1') $foo->method1(); else if($bar == 'action2') $foo->method2(); else $foo->method1();

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  • C++ design related question

    - by Kotti
    Hi! Here is the question's plot: suppose I have some abstract classes for objects, let's call it Object. It's definition would include 2D position and dimensions. Let it also have some virtual void Render(Backend& backend) const = 0 method used for rendering. Now I specialize my inheritance tree and add Rectangle and Ellipse class. Guess they won't have their own properties, but they will have their own virtual void Render method. Let's say I implemented these methods, so that Render for Rectangle actually draws some rectangle, and the same for ellipse. Now, I add some object called Plane, which is defined as class Plane : public Rectangle and has a private member of std::vector<Object*> plane_objects; Right after that I add a method to add some object to my plane. And here comes the question. If I design this method as void AddObject(Object& object) I would face trouble like I won't be able to call virtual functions, because I would have to do something like plane_objects.push_back(new Object(object)); and this should be push_back(new Rectangle(object)) for rectangles and new Circle(...) for circles. If I implement this method as void AddObject(Object* object), it looks good, but then somewhere else this means making call like plane.AddObject(new Rectangle(params)); and this is generally a mess because then it's not clear which part of my program should free the allocated memory. ["when destroying the plane? why? are we sure that calls to AddObject were only done as AddObject(new something).] I guess the problems caused by using the second approach could be solved using smart pointers, but I am sure there have to be something better. Any ideas?

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