Search Results

Search found 8576 results on 344 pages for 'named constructor'.

Page 275/344 | < Previous Page | 271 272 273 274 275 276 277 278 279 280 281 282  | Next Page >

• Handling selection and deselection of objects in a user interface

  - by Dennis

  I'm writing a small audio application (in Silverlight, but that's not really relevant I suppose), and I'm a struggling with a problem I've faced before and never solved properly. This time I want to get it right. In the application there is one Arrangement control, which contains several Track controls, and every Track can contain AudioObject controls (these are all custom user controls). The user needs to be able to select audio objects, and when these objects are selected they are rendered differently. I can make this happen by hooking into the MouseDown event of the AudioObject control and setting state accordingly. So far so good, but when an audio object is selected, all other audio objects need to be deselected (well, unless the user holds the shift key). Audio objects don't know about other audio objects though, so they have no way to tell the rest to deselect themselves. Now if I would approach this problem like I did the last time I would pass a reference to the Arrangement control in the constructor of the AudioObject control and give the Arrangement control a DeselectAll() method or something like that, which would tell all Track controls to deselect all their AudioObject controls. This feels wrong, and if I apply this strategy to similar issues I'm afraid I will soon end up with every object having a reference to every other object, creating one big tightly coupled mess. It feels like opening the floodgates for poorly designed code. Is there a better way to handle this?

  Read the article

• C# ref Confusion

  - by Rahat

  I have a confusion that when i pass a variable by refrence in the constructor of another class and after passing that object by refrence i recreate the refrence object with the new keyword. Now the class in which i have passed the refrenced object dosen't reflect the updated data. An exabple of the above problem is shown below: Object to be passed by Refrence: public class DummyObject { public string Name = "My Name"; public DummyObject() { } } Class which is passing the Refrence: public partial class Form1 : Form { // Object to be passed as refrence DummyObject dummyObject = new DummyObject(); public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { // assigning value dummyObject.Name = "I am Dummy"; // Passing object Form2 frm = new Form2(ref dummyObject); frm.Show(); } private void button2_Click(object sender, EventArgs e) { // Displaying Name MessageBox.Show(this.dummyObject.Name); } private void button3_Click(object sender, EventArgs e) { // Assigning new object this.dummyObject = new DummyObject(); // Changing Name Variable this.dummyObject.Name = "I am Rechanged"; // Displaying Name MessageBox.Show(this.dummyObject.Name); } } Class to which Object is passed by Reference: public partial class Form2 : Form { private DummyObject dummyObject = null; public Form2(ref DummyObject DummyObject) { InitializeComponent(); this.dummyObject = DummyObject; this.dummyObject.Name = "I am Changed"; } private void button2_Click(object sender, EventArgs e) { MessageBox.Show(this.dummyObject.Name); } } whn i reaasign the object in Form 1 and cdisplay its value in form 2 it still displays "I am Changed" instead of "I am Rechanged". How to keep the data synchronized?

  Read the article

• Initializing objects on the fly

  - by pocoa

  I have a vector called players and a class called Player. And what I'm trying to do is to write: players.push_back(Player(name, Weapon(bullets))); So I want to be able to create players in a loop. But I see an error message says "no matching function for call Player::Player..." Then I've changed that to: Weapon w(bullets); Player p(name, w); players.push_back(p); Here is my Player definition: class Player { public: Player(string &name, Weapon &weapon); private string name; Weapon weapon; } I'm just trying to learn what is the difference between these definitions. And is this the right way to pass an object to an object constructor. Note: These are not my actual class definitions. I'm just trying to learn something about object oriented programming in C++ with coding it. I mean I know that Weapon should be initialized in Player :)

  Read the article

• Question about decorator pattern and the abstract decorator class?

  - by es11

  This question was asked already here, but rather than answering the specific question, descriptions of how the decorator pattern works were given instead. I'd like to ask it again because the answer is not immediately evident to me just by reading how the decorator pattern works (I've read the wikipedia article and the section in the book Head First Design Patterns). Basically, I want to know why an abstract decorator class must be created which implements (or extends) some interface (or abstract class). Why can't all the new "decorated classes" simply implement (or extend) the base abstract object themselves (instead of extending the abstract decorator class)? To make this more concrete I'll use the example from the design patterns book dealing with coffee beverages: There is an abstract component class called Beverage Simple beverage types such as HouseBlend simply extend Beverage To decorate beverage, an abstract CondimentDecorator class is created which extends Beverage and has an instance of Beverage Say we want to add a "milk" condiment, a class Milk is created which extends CondimentDecorator I'd like to understand why we needed the CondimentDecorator class and why the class Milk couldn't have simply extended the Beverage class itself and been passed an instance of Beverage in its constructor. Hopefully this is clear...if not I'd simply like to know why is the abstract decorator class necessary for this pattern? Thanks. Edit: I tried to implement this, omitting the abstract decorator class, and it seems to still work. Is this abstract class present in all descriptions of this pattern simply because it provides a standard interface for all of the new decorated classes?

  Read the article

• Data Structures for Junior Java Developer

  - by user1639637

  Ok,still learning Arrays. I wrote this code which fills the array named "rand" with random numbers between 0 and 1( exclusive). I want to start learning Complexity. the For loop executes n times (100 times) ,every time it takes O(1) time,so the worse case scenario is O(n),am I right? Also,I used ArrayList to store the 100 elements and I imported "Collections" and used Collections.sort() method to sort the elements. import java.util.Arrays; public class random { public static void main(String args[]) { double[] rand=new double[10]; for(int i=0;i<rand.length;i++) { rand[i]=(double) Math.random(); System.out.println(rand[i]); } Arrays.sort(rand); System.out.println(Arrays.toString(rand)); } } ArrayList: import java.util.ArrayList; import java.util.Collections; public class random { public static void main(String args[]) { ArrayList<Double> MyArrayList=new ArrayList<Double>(); for(int i=0;i<100;i++) { MyArrayList.add(Math.random()); } Collections.sort(MyArrayList); for(int j=0;j<MyArrayList.size();j++) { System.out.println(MyArrayList.get(j)); } } }

  Read the article

• Weird camera Intent behavior

  - by David Erosa

  Hi all. I'm invoking the MediaStore.ACTION_IMAGE_CAPTURE intent with the MediaStore.EXTRA_OUTPUT extra so that it does save the image to that file. On the onActivityResult I can check that the image is being saved in the intended file, which is correct. The weird thing is that anyhow, the image is also saved in a file named something like "/sdcard/Pictures/Camera/1298041488657.jpg" (epoch time in which the image was taken). I've checked the Camera app source (froyo-release branch) and I'm almost sure that the code path is correct and wouldn't have to save the image, but I'm a noob and I'm not completly sure. AFAIK, the image saving process starts with this callback (comments are mine): private final class JpegPictureCallback implements PictureCallback { ... public void onPictureTaken(...){ ... // This is where the image is passed back to the invoking activity. mImageCapture.storeImage(jpegData, camera, mLocation); ... public void storeImage(final byte[] data, android.hardware.Camera camera, Location loc) { if (!mIsImageCaptureIntent) { // Am i an intent? int degree = storeImage(data, loc); // THIS SHOULD NOT BE CALLED WITHIN THE CAPTURE INTENT!! ....... // An finally: private int storeImage(byte[] data, Location loc) { try { long dateTaken = System.currentTimeMillis(); String title = createName(dateTaken); String filename = title + ".jpg"; // Eureka, timestamp filename! ... So, I'm receiving the correct data, but it's also being saved in the "storeImage(data, loc);" method call, which should not be called... It'd not be a problem if I could get the newly created filename from the intent result data, but I can't. When I found this out, I found about 20 image files from my tests that I didn't know were on my sdcard :) I'm getting this behavior both with my Nexus One with Froyo and my Huawei U8110 with Eclair. Could please anyone enlight me? Thanks a lot.

  Read the article

• Set title and (title) icon for a custom alert dialog

  - by Ecki

  I don't manage to set a neither a title nor a (title) icon to my custom alert dialog. My code: public class AddingFavoriteDialog extends AlertDialog { . . . private OnAddingFavoriteListener onAddingFavoriteListener; private Context context; private GeocodingManager geocodingManager; private FavoritesActivity favoritesActivity; public AddingFavoriteDialog(Context context, OnAddingFavoriteListener onAddingFavoriteListener) { super(context, android.R.style.Theme_Dialog); this.context = context; this.onAddingFavoriteListener = onAddingFavoriteListener; this.geocodingManager = new GeocodingManager(context); this.favoritesActivity = (FavoritesActivity) context; } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.adding_favorite_dialog2); setTitle("MYTITLE"); setIcon(R.drawable.star_gold); . . . } What am i doing wrong? I also tried to set it by calling super.setTitle("MYTITLE"); in onCreate() as well as in the constructor.

  Read the article

• nhibernate : Repository Session Management

  - by frosty

  At the moment my repository has 2 constructors. When i call these from my mvc website i am alway calling first constructor and thus opening a new session. Should i been passing in the session. How should i be doing this. public CompanyRepository() { _session = NHibernateHelper.OpenSession(); } public CompanyRepository(ISession session) { _session = session; } public class NHibernateHelper { private static ISessionFactory _sessionFactory; private static ISessionFactory SessionFactory { get { if (_sessionFactory == null) { var configuration = new Configuration(); configuration.Configure(); configuration.AddAssembly(typeof(UserProfile).Assembly); configuration.SetProperty(NHibernate.Cfg.Environment.ConnectionStringName, System.Environment.MachineName); _sessionFactory = configuration.BuildSessionFactory(); } return _sessionFactory; } } public static ISession OpenSession() { return SessionFactory.OpenSession(); } } I'm using the Ninject IOC container ( very new to me ). I have the following container. How would i bind the ISession to the CompanyRepository. private class EStoreDependencies : NinjectModule { public override void Load() { Bind<ICompanyRepository>().To<CompanyRepository>(); Bind<IUserProfileRepository>().To<UserProfileRepository>(); Bind<IAddressRepository>().To<AddressRepository>(); Bind<IRolesService>().To<AspNetRoleProviderWrapper>(); Bind<IUserService>().To<AspNetMembershipProviderWrapper>(); Bind<ICurrentUserSerivce>().To<DefaultCurrentUserSerivce>(); Bind<IPasswordService>().To<AspNetMembershipProviderWrapper>(); Bind<IStatusResponseRepository>().To<StatusResponseRepository>(); Bind<ICategoryRepository>().To<CategoryRepository>(); Bind<IProductRepository>().To<ProductRepository>(); } }

  Read the article

• Cannot call DLL import entry in C# from C++ project. EntryPointNotFoundException

  - by kriau

  I'm trying to call from C# a function in a custom DLL written in C++. However I'm getting the warning during code analysis and the error at runtime: Warning: CA1400 : Microsoft.Interoperability : Correct the declaration of 'SafeNativeMethods.SetHook()' so that it correctly points to an existing entry point in 'wi.dll'. The unmanaged entry point name currently linked to is SetHook. Error: System.EntryPointNotFoundException was unhandled. Unable to find an entry point named 'SetHook' in DLL 'wi.dll'. Both projects wi.dll and C# exe has been compiled in to the same DEBUG folder, both files reside here. There is only one file with the name wi.dll in the whole file system. C++ function definition looks like: #define WI_API __declspec(dllexport) bool WI_API SetHook(); I can see exported function using Dependency Walker: as decorated: bool SetHook(void) as undecorated: ?SetHook@@YA_NXZ C# DLL import looks like (I've defined these lines using CLRInsideOut from MSDN magazine): [DllImport("wi.dll", EntryPoint = "SetHook", CallingConvention = CallingConvention.Cdecl)] [return: MarshalAsAttribute(UnmanagedType.I1)] internal static extern bool SetHook(); I've tried without EntryPoint and CallingConvention definitions as well. Both projects are 32-bits, I'm using W7 64 bits, VS 2010 RC. I believe that I simply have overlooked something.... Thanks in advance.

  Read the article

• Using generics in F# to create an EnumArray type

  - by Matthew

  I've created an F# class to represent an array that allocates one element for each value of a specific enum. I'm using an explicit constructor that creates a dictionary from enum values to array indices, and an Item property so that you can write expressions like: let my_array = new EnumArray<EnumType, int> my_array.[EnumType.enum_value] <- 5 However, I'm getting the following obscure compilation error at the line marked with '// FS0670' below. error FS0670: This code is not sufficiently generic. The type variable ^e when ^e : enum<int> and ^e : equality and ^e : (static member op_Explicit : ^e -> int) could not be generalized because it would escape its scope. I'm at a loss - can anyone explain this error? type EnumArray< 'e, 'v when 'e : enum<int> and 'e : equality and ^e : (static member op_Explicit : ^e -> int) > = val enum_to_int : Dictionary<'e, int> val a : 'v array new() as this = { enum_to_int = new Dictionary<'e, int>() a = Array.zeroCreate (Enum.GetValues(typeof<'e>).Length) } then for (e : obj) in Enum.GetValues(typeof<'e>) do this.enum_to_int.Add(e :?> 'e, int(e :?> 'e)) member this.Item with get (idx : 'e) : 'v = this.a.[this.enum_to_int.[idx]] // FS0670 and set (idx : 'e) (c : 'v) = this.a.[this.enum_to_int.[idx]] <- c

  Read the article

• Indexing community images for google image search

  - by Vittorio Vittori

  Hi, I'm trying to understand how can I do to let my site be reachable from google image search spiders. I like how last.fm solution, and I thought to use a technique like his staff do to let google find artists images on their pages. When I'm looking for an artist and I search it on google image search, as often as not I find an image from last.fm artists page, I make an example: If I search the band Pure Reason Revolution It brings me here, the artist's image page http://www.last.fm/music/Pure+Reason+Revolution/+images/4284073 Now if I take a look to the image file, i can see it's named: http://userserve-ak.last.fm/serve/500/4284073/Pure+Reason+Revolution+4.jpg so if I try to undertand how the service works I can try to say: http://userserve-ak.last.fm/serve/ the server who serve the images 500/ the selected size for the image 4284073/ the image id for database Pure+Reason+Revolution+4.jpg the image name I thought it's difficult to think the real filename for the image is Pure+Reason+Revolution+4.jpg for image overwrite problems when an user upload it, in fact if I digit: http://userserve-ak.last.fm/serve/500/4284073.jpg I probably find the real image location and filename With this tecnique the image is highly reachable from search engines and easily archived. My question is, does exist some guide or tutorial to approach on this kind of tecniques, or something similar?

  Read the article

• Adding a block of XML as child of a SimpleXMLElement object

  - by miCRoSCoPiC_eaRthLinG

  Hey all, I have this SimpleXMLElement object with a XML setup similar to the following... $xml <<< EOX <books> <book> <name>ABCD</name> </book> </books> EOX; $sx = new SimpleXMLElement( $xml ); Now I have a class named Book that contains info. about each book. The same class can also spit out the book info. in XML format akin the the above (the nested block).. example, $book = new Book( 'EFGH' ); $book->genXML(); ... will generate <book> <name>EFGH</name> </book> Now I'm trying to figure out a way by which I can use this generated XML block and append as a child of so that now it looks like... for example.. // Non-existent member method. For illustration purposes only. $sx->addXMLChild( $book->genXML() ); ...XML tree now looks like: <books> <book> <name>ABCD</name> </book> <book> <name>EFGH</name> </book> </books> From what documentation I have read on SimpleXMLElement, addChild() won't get this done for you as it doesn't support XML data as tag value. Any ideas on how I should go about this ? Thanks, m^e

  Read the article

• capturing CMD batch file parameter list; write to file for later processing

  - by BobB

  I have written a batch file that is launched as a post processing utility by a program. The batch file reads ~24 parameters supplied by the calling program, stores them into variables, and then writes them to various text files. Since the max input variable in CMD is %9, it's necessary to use the 'shift' command to repeatedly read and store these individually to named variables. Because the program outputs several similar batch files, the result is opening several CMD windows sequentially, assigning variables and writing data files. This ties up the calling program for too long. It occurs to me that I could free up the calling program much faster if maybe there's a way to write a very simple batch file that can write all the command parameters to a text file, where I can process them later. Basically, just grab the parameter list, write it and done. Q: Is there some way to treat an entire series of parameter data as one big text string and write it to one big variable... and then echo the whole big thing to one text file? Then later read the string into %n variables when there's no program waiting to resume? Parameter list is something like 25 - 30 words, less than 200 characters. Sample parameter list: "First Name" "Lastname" "123 Steet Name Way" "Cityname" ST 12345 1004968 06/01/2010 "Firstname+Lastname" 101738 "On Account" 20.67 xy-1z 1 8.95 3.00 1.39 0 0 239 8.95 Items in quotes are processed as string variables. List is space delimited. Any suggestions?

  Read the article

• SQL query recursion for a web-like structure

  - by MickeyD

  I have a table here, named "Foo". The data is set up something like this. ID TableReference DataId0 DataId1 DataId2 -- -------------- ------- ------- ------- 1 Prize 3 4 5 2 Prize 4 5 NULL 3 Cash 1 NULL NULL 4 Prize 8 NULL 12 5 Foo 2 3 NULL 6 Cash 8 1 10 7 Foo 5 1 2 Etc. The data is horribly set up, I know, but I didn't set it up that way. :) I'm only dealing with the after effect. I'm trying to come up with a way to essentially "flatten" the table; that is, to display all the data to a point where the table "Foo" does not reference itself. I'm trying to figure out a sql query that I can do to get there. Usually when I deal with recursion, I have (or can establish) parent IDs and set it up that way, but for this table there are seemingly multiple child and parent IDs creating a web-like structure instead of a hierarchy. So I'm at a loss where to even begin to write a sql query for something like this. Note: There is no infinite looping (where one Foo points to another Foo, which points back to the original Foo) from what I've found. Using t-sql. Thanks for any assistance, if at all possible.

  Read the article

• How do I copy files repository to new folder with PHP

  - by dcp3450

  I have a folder named "repository" in my admin folders. This folder holds 2 files: index.html and content.php. When a user creates a new page the php creates a new folder specified by the user then will need to copy the two files into that folder while leaving them in the repository. copy(file,dest) does not work. rename(file,dest) moves the files to the new folder but I lose them in the repository. How do I copy the files in one folder to the new folder without losing the files in the original folder? $dest = '../'.$menuLocation.'/'.$pageName; $file1= "repository/index.html"; $file2= "repository/content.php"; mkdir($dest,0777); rename($file1,$dest.'/index.html'); rename($file2,$dest.'/content.php'); $menuLocation and $pageName are supplied by the user. The files are there, file_exists returns back true. Also, the directory is created with no issues. rename() also works I just lose the files in repository.

  Read the article

• How can I strip Python logging calls without commenting them out?

  - by cdleary

  Today I was thinking about a Python project I wrote about a year back where I used logging pretty extensively. I remember having to comment out a lot of logging calls in inner-loop-like scenarios (the 90% code) because of the overhead (hotshot indicated it was one of my biggest bottlenecks). I wonder now if there's some canonical way to programmatically strip out logging calls in Python applications without commenting and uncommenting all the time. I'd think you could use inspection/recompilation or bytecode manipulation to do something like this and target only the code objects that are causing bottlenecks. This way, you could add a manipulator as a post-compilation step and use a centralized configuration file, like so: [Leave ERROR and above] my_module.SomeClass.method_with_lots_of_warn_calls [Leave WARN and above] my_module.SomeOtherClass.method_with_lots_of_info_calls [Leave INFO and above] my_module.SomeWeirdClass.method_with_lots_of_debug_calls Of course, you'd want to use it sparingly and probably with per-function granularity -- only for code objects that have shown logging to be a bottleneck. Anybody know of anything like this? Note: There are a few things that make this more difficult to do in a performant manner because of dynamic typing and late binding. For example, any calls to a method named debug may have to be wrapped with an if not isinstance(log, Logger). In any case, I'm assuming all of the minor details can be overcome, either by a gentleman's agreement or some run-time checking. :-)

  Read the article

• [JAX-B] How can I ignore a superclass?

  - by MrSpandex

  I'm trying to write a web service for the java.util.logging api. So I wrote a class MyLogRecord that inherits from LogRecord. I annotated this class with JAX-B annotations, including @XmlAccessorType(XmlAccessType.NONE) so it would ignore non-annotated fields and properties. When I start up tomcat, I get errors that java.util.logging.Level and other java.util.logging classes do not have a default constructor, but none of my annotated methods make any reference to the Level class or any of the other java.util.logging classes. These are referenced by the parent class. My sub-class has everything it needs defined. How can I get JAX-B to ignore the parent class completely? Update: I found another post on this, which suggests modifying the parent class. This is obviously not possible because I am extending a java.util class. IS there any way to do this without modifying the superclass? Update2: I found a thread on java.net for a similar problem. That thread resulted in an enhancement request, which was marked as a duplicate of another issue, which resulted in the @XmlTransient annotation. The comments on these bug reports lead me to believe this is impossible in the current spec.

  Read the article

• How do I mock a method with an open array parameter in PascalMock?

  - by Oliver Giesen

  I'm currently in the process of getting started with unit testing and mocking for good and I stumbled over the following method that I can't seem to fabricate a working mock implementation for: function GetInstance(const AIID: TGUID; out AInstance; const AArgs: array of const; const AContextID: TImplContextID = CID_DEFAULT): Boolean; (TImplContextID is just an alias for Integer) I thought it would have to look something like this: function TImplementationProviderMock.GetInstance( const AIID: TGUID; out AInstance; const AArgs: array of const; const AContextID: TImplContextID): Boolean; begin Result := AddCall('GetInstance') .WithParams([@AIID, AContextID]) .ReturnsOutParams([AInstance]) .ReturnValue; end; But the compiler complains about the .ReturnsOutParams([AInstance]) saying "Bad argument type in variable type array constructor.". Also I haven't found a way to specify the open array parameter AArgs at all. Also, is using the @-notation for the TGUID-typed parameter the right way to go? Is it possible to mock this method with the current version of PascalMock at all? Update: I now realize I got the purpose of ReturnsOutParams completely wrong: It's intended to be used for populating the values to be returned when defining the expectations rather than for mocking the call itself. I now think the correct syntax for mocking the out parameter would probably have to look more like this: function TImplementationProviderMock.GetInstance( const AIID: TGUID; out AInstance; const AArgs: array of const; const AContextID: TImplContextID): Boolean; var lCall: TMockMethod; begin lCall := AddCall('GetInstance').WithParams([@AIID, AContextID]); Pointer(AInstance) := lCall.OutParams[0]; Result := lCall.ReturnValue; end; The questions that remain are how to mock the open array parameter AArgs and whether passing the TGUID argument (i.e. a value type) by address will work out...

  Read the article

• PHP Form Validation

  - by JM4

  This question will undoubtedly be difficult to answer and ask in a way that makes sense but I'll try my best: I have a form which uses PHP to display certain sections of the form such as: <?php if ($_SESSION['EnrType'] == "Individual") { display only form information for individual enrollment } ?> and <?php if ($_SESSION['Num_Enrs'] > 6) { display only form information for 7 total members enrollment } ?> In each form piece, unique information is collected about each enrollee but the basic criteria for each enrollee is the same, i.e. All enrollee's must use have a value in the FirstName field. Each field is named according to the enrollee number, i.e. Num1FirstName; Num2FirstName. I have a PHP validation script which is absolutely fantastic and am not looking to change it but the issue I am running into is duplication of the script in order to validate ALL fields in one swoop. On submission, all POSTED items are run through my validation script and based on the rules set return an error if they do not equal true. Sample code: if (isset($_POST['submit'])) { // import the validation library require("validation.php"); $rules = array(); // stores the validation rules //All Enrollee Rules $rules[] = "required,Num1FirstName,Num2FirstName,The First Name field is required."; The script above does the following, $rules[] ="REQUIREMENT,fieldname,error message" where requirement gives criteria (in this case, simply that a value is passed), fieldname is the name of the field being validated, and error message returns the error used. My Goal is to use the same formula above and have $rules[] run through ALL firstnames and return the error posted ONLY if they exist (i.e. dont check for member #7's first name if it doesnt exist on the screen). If I simply put a comma between the 'fieldnames' this only checks for the first, then second, and so on so this wont work. Any ideas?

  Read the article

• What's the most efficient query?

  - by Aaron Carlino

  I have a table named Projects that has the following relationships: has many Contributions has many Payments In my result set, I need the following aggregate values: Number of unique contributors (DonorID on the Contribution table) Total contributed (SUM of Amount on Contribution table) Total paid (SUM of PaymentAmount on Payment table) Because there are so many aggregate functions and multiple joins, it gets messy do use standard aggregate functions the the GROUP BY clause. I also need the ability to sort and filter these fields. So I've come up with two options: Using subqueries: SELECT Project.ID AS PROJECT_ID, (SELECT SUM(PaymentAmount) FROM Payment WHERE ProjectID = PROJECT_ID) AS TotalPaidBack, (SELECT COUNT(DISTINCT DonorID) FROM Contribution WHERE RecipientID = PROJECT_ID) AS ContributorCount, (SELECT SUM(Amount) FROM Contribution WHERE RecipientID = PROJECT_ID) AS TotalReceived FROM Project; Using a temporary table: DROP TABLE IF EXISTS Project_Temp; CREATE TEMPORARY TABLE Project_Temp (project_id INT NOT NULL, total_payments INT, total_donors INT, total_received INT, PRIMARY KEY(project_id)) ENGINE=MEMORY; INSERT INTO Project_Temp (project_id,total_payments) SELECT `Project`.ID, IFNULL(SUM(PaymentAmount),0) FROM `Project` LEFT JOIN `Payment` ON ProjectID = `Project`.ID GROUP BY 1; INSERT INTO Project_Temp (project_id,total_donors,total_received) SELECT `Project`.ID, IFNULL(COUNT(DISTINCT DonorID),0), IFNULL(SUM(Amount),0) FROM `Project` LEFT JOIN `Contribution` ON RecipientID = `Project`.ID GROUP BY 1 ON DUPLICATE KEY UPDATE total_donors = VALUES(total_donors), total_received = VALUES(total_received); SELECT * FROM Project_Temp; Tests for both are pretty comparable, in the 0.7 - 0.8 seconds range with 1,000 rows. But I'm really concerned about scalability, and I don't want to have to re-engineer everything as my tables grow. What's the best approach?

  Read the article

• What happens when we combine RAII and GOTO ?

  - by Robert Gould

  I'm wondering, for no other purpose than pure curiosity (because no one SHOULD EVER write code like this!) about how the behavior of RAII meshes with the use of Goto (lovely idea isn't it). class Two { public: ~Two() { printf("2,"); } }; class Ghost { public: ~Ghost() { printf(" BOO! "); } }; void foo() { { Two t; printf("1,"); goto JUMP; } Ghost g; JUMP: printf("3"); } int main() { foo(); } When running the following code in VS2005 I get the following output: 1,2,3 BOO! However I imagined, guessed, hoped that 'BOO!' wouldn't actually appear as the Ghost should have never been instantiated (IMHO, because I don't know the actual expected behavior of this code). Any Guru out there knows what's up? Just realized that if I instantiate an explicit constructor for Ghost the code doesn't compile... class Ghost { public: Ghost() { printf(" HAHAHA! "); } ~Ghost() { printf(" BOO! "); } }; Ah, the mystery ...

  Read the article

• Can I get rid of this read lock?

  - by Pieter

  I have the following helper class (simplified): public static class Cache { private static readonly object _syncRoot = new object(); private static Dictionary<Type, string> _lookup = new Dictionary<Type, string>(); public static void Add(Type type, string value) { lock (_syncRoot) { _lookup.Add(type, value); } } public static string Lookup(Type type) { string result; lock (_syncRoot) { _lookup.TryGetValue(type, out result); } return result; } } Add will be called roughly 10/100 times in the application and Lookup will be called by many threads, many of thousands of times. What I would like is to get rid of the read lock. How do you normally get rid of the read lock in this situation? I have the following ideas: Require that _lookup is stable before the application starts operation. The could be build up from an Attribute. This is done automatically through the static constructor the attribute is assigned to. Requiring the above would require me to go through all types that could have the attribute and calling RuntimeHelpers.RunClassConstructor which is an expensive operation; Move to COW semantics. public static void Add(Type type, string value) { lock (_syncRoot) { var lookup = new Dictionary<Type, string>(_lookup); lookup.Add(type, value); _lookup = lookup; } } (With the lock (_syncRoot) removed in the Lookup method.) The problem with this is that this uses an unnecessary amount of memory (which might not be a problem) and I would probably make _lookup volatile, but I'm not sure how this should be applied. (John Skeets' comment here gives me pause.) Using ReaderWriterLock. I believe this would make things worse since the region being locked is small. Suggestions are very welcome.

  Read the article

• Returning object from function

  - by brainydexter

  I am really confused now on how and which method to use to return object from a function. I want some feedback on the solutions for the given requirements. Scenario A: The returned object is to be stored in a variable which need not be modified during its lifetime. Thus, const Foo SomeClass::GetFoo() { return Foo(); } invoked as: someMethod() { const Foo& l_Foo = someClassPInstance->GetFoo(); //... } Scneraio B: The returned object is to be stored in a variable which will be modified during its lifetime. Thus, void SomeClass::GetFoo(Foo& a_Foo_ref) { a_Foo_ref = Foo(); } invoked as: someMethod() { Foo l_Foo; someClassPInstance-GetFoo(l_Foo); //... } I have one question here: Lets say that Foo cannot have a default constructor. Then how would you deal with that in this situation, since we cant write this anymore: Foo l_Foo Scenario C: Foo SomeClass::GetFoo() { return Foo(); } invoked as: someMethod() { Foo l_Foo = someClassPInstance->GetFoo(); //... } I think this is not the recommended approach since it would incur constructing extra temporaries. What do you think ? Also, do you recommend a better way to handle this instead ?

  Read the article

• Windows Azure: Creating a subdirectories inside the blob

  - by veda

  I wanted to create some subdirectories inside my blob. But it is not working out well Here is my code protected void ButUpload_click(object sender, EventArgs e) { // store upladed file as a blob storage if (uplFileUpload.HasFile) { name = uplFileUpload.FileName; // get refernce to the cloud blob container CloudBlobContainer blobContainer = cloudBlobClient.GetContainerReference("documents"); if (textbox.Text != "") { name = textbox.Text + "/" + name; } // set the name for the uploading files string UploadDocName = name; // get the blob reference and set the metadata properties CloudBlockBlob blob = blobContainer.GetBlockBlobReference(UploadDocName); blob.Metadata["FILETYPE"] = "text"; blob.Properties.ContentType = uplFileUpload.PostedFile.ContentType; // upload the blob to the storage blob.UploadFromStream(uplFileUpload.FileContent); } } What I did is that, If I have to create a sub directory, I will enter the name of the sub directory in the textbox. for example, if I need to create a file named "test.txt" inside the sub directory "files" Then, my textbox.text = files and uplFileUpload.FileName = test.txt Now I will concatenate them and upload to the blob.. But it is not working well.. I am getting just https://test.core.windows.net/documents/files/ I am not getting the entire thing I was expecting https://test.core.windows.net/documents/files/test.txt What am I doing wrong... How to create sub directories inside the blob.

  Read the article

• Sql server query using function and view is slower

  - by Lieven Cardoen

  I have a table with a xml column named Data: CREATE TABLE [dbo].[Users]( [UserId] [int] IDENTITY(1,1) NOT NULL, [FirstName] [nvarchar](max) NOT NULL, [LastName] [nvarchar](max) NOT NULL, [Email] [nvarchar](250) NOT NULL, [Password] [nvarchar](max) NULL, [UserName] [nvarchar](250) NOT NULL, [LanguageId] [int] NOT NULL, [Data] [xml] NULL, [IsDeleted] [bit] NOT NULL,... In the Data column there's this xml <data> <RRN>...</RRN> <DateOfBirth>...</DateOfBirth> <Gender>...</Gender> </data> Now, executing this query: SELECT UserId FROM Users WHERE data.value('(/data/RRN)[1]', 'nvarchar(max)') = @RRN after clearing the cache takes (if I execute it a couple of times after each other) 910, 739, 630, 635, ... ms. Now, a db specialist told me that adding a function, a view and changing the query would make it much more faster to search a user with a given RRN. But, instead, these are the results when I execute with the changes from the db specialist: 2584, 2342, 2322, 2383, ... This is the added function: CREATE FUNCTION dbo.fn_Users_RRN(@data xml) RETURNS varchar(100) WITH SCHEMABINDING AS BEGIN RETURN @data.value('(/data/RRN)[1]', 'varchar(max)'); END; The added view: CREATE VIEW vwi_Users WITH SCHEMABINDING AS SELECT UserId, dbo.fn_Users_RRN(Data) AS RRN from dbo.Users Indexes: CREATE UNIQUE CLUSTERED INDEX cx_vwi_Users ON vwi_Users(UserId) CREATE NONCLUSTERED INDEX cx_vwi_Users__RRN ON vwi_Users(RRN) And then the changed query: SELECT UserId FROM Users WHERE dbo.fn_Users_RRN(Data) = '59021626919-61861855-S_FA1E11' Why is the solution with a function and a view going slower?

  Read the article

< Previous Page | 271 272 273 274 275 276 277 278 279 280 281 282  | Next Page >