Search Results

Search found 8692 results on 348 pages for 'patterns and practices'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 154/348 | < Previous Page | 150 151 152 153 154 155 156 157 158 159 160 161  | Next Page >

  • wpf command pattern

    - by evan
    I have a wpf gui which displays a list of information in separate window and in a separate thread from the main application. As the user performs actions in the main window the side window is updated. (For example if you clicked page down in the main window a listbox in the side window would page down). Right now the architecture for this application feels very messy and I'm sure there is a cleaner way to do it. It looks like this: Main Window contains a singleton SideWindowControl which communicates with an instance of the SideWindowDisplay using events - so, for example, the pagedown button would work like: 1) the event handler of the button on the main window calls SideWindowControl.PageDown() 2) in the PageDown() function a event is created and thrown. 3) finally the gui, ShowSideWindowDisplay is subscribing to the SideWindowControl.Actions event handles the event and actually scrolls the listbox down - note because it is in a different thread it has to do that by running the command via Dispatcher.Invoke() This just seems like a very messy way to this and there must be a clearer way (The only part that can't change is that the main window and the side window must be on different threads). Perhaps using WPF commands? I'd really appreciate any suggestions!! Thanks

    Read the article

  • Visitor Pattern can be replaced with Callback functions?

    - by getit
    Is there any significant benefit to using either technique? In case there are variations, the Visitor Pattern I mean is this: http://en.wikipedia.org/wiki/Visitor_pattern And below is an example of using a delegate to achieve the same effect (at least I think it is the same) Say there is a collection of nested elements: Schools contain Departments which contain Students Instead of using the Visitor pattern to perform something on each collection item, why not use a simple callback (Action delegate in C#) Say something like this class Department { List Students; } class School { List Departments; VisitStudents(Action<Student> actionDelegate) { foreach(var dep in this.Departments) { foreach(var stu in dep.Students) { actionDelegate(stu); } } } } School A = new School(); ...//populate collections A.Visit((student)=> { ...Do Something with student... }); *EDIT Example with delegate accepting multiple params Say I wanted to pass both the student and department, I could modify the Action definition like so: Action class School { List Departments; VisitStudents(Action<Student, Department> actionDelegate, Action<Department> d2) { foreach(var dep in this.Departments) { d2(dep); //This performs a different process. //Using Visitor pattern would avoid having to keep adding new delegates. //This looks like the main benefit so far foreach(var stu in dep.Students) { actionDelegate(stu, dep); } } } }

    Read the article

  • Using switch and enumerations as substitute for named methods

    - by MatthewMartin
    This pattern pops up a lot. It looks like a very verbose way to move what would otherwise be separate named methods into a single method and then distinguished by a parameter. Is there any good reason to have this pattern over just having two methods Method1() and Method2() ? The real kicker is that this pattern tends to be invoked only with constants at runtime-- i.e. the arguments are all known before compiling is done. public enum Commands { Method1, Method2 } public void ClientCode() { //Always invoked with constants! Never user input. RunCommands(Commands.Method1); RunCommands(Commands.Method2); } public void RunCommands(Commands currentCommand) { switch (currentCommand) { case Commands.Method1: // Stuff happens break; case Commands.Method2: // Other stuff happens break; default: throw new ArgumentOutOfRangeException("currentCommand"); } }

    Read the article

  • Best way to unit test Collection?

    - by limc
    I'm just wondering how folks unit test and assert that the "expected" collection is the same/similar as the "actual" collection (order is not important). To perform this assertion, I wrote my simple assert API:- public void assertCollection(Collection<?> expectedCollection, Collection<?> actualCollection) { assertNotNull(expectedCollection); assertNotNull(actualCollection); assertEquals(expectedCollection.size(), actualCollection.size()); assertTrue(expectedCollection.containsAll(actualCollection)); assertTrue(actualCollection.containsAll(expectedCollection)); } Well, it works. It's pretty simple if I'm asserting just bunch of Integers or Strings. It can also be pretty painful if I'm trying to assert a collection of Hibernate domains, say for example. The collection.containsAll(..) relies on the equals(..) to perform the check, but I always override the equals(..) in my Hibernate domains to check only the business keys (which is the best practice stated in the Hibernate website) and not all the fields of that domain. Sure, it makes sense to check just against the business keys, but there are times I really want to make sure all the fields are correct, not just the business keys (for example, new data entry record). So, in this case, I can't mess around with the domain.equals(..) and it almost seems like I need to implement some comparators for just unit testing purposes instead of relying on collection.containsAll(..). Are there some testing libraries I could leverage here? How do you test your collection? Thanks.

    Read the article

  • how to share a variable between two threads

    - by prmatta
    I just inherited some code, two threads within this code need to perform a system task. One thread should do the system task before the other thread. They should not be performing the system task together. The two threads do not have references to each other. Now, I know I can use some sort of a semaphore to achieve this. But my question is what is the right way to get both threads to access this semaphore. I could create a static variable/method a new class : public class SharedSemaphore { private static Semaphore s = new Semaphore (1, true); public static void performSystemTask () { s.acquire(); } public static void donePerformingSystemTask() { s.release(); } } This would work (right?) but this doesn't seem like the right thing to do. Because, the threads now have access to a semaphore, without ever having a reference to it. This sort of thing doesn't seem like a good programming practice. Am I wrong?

    Read the article

  • What is the best Design/Way to keep user connected ?

    - by Fasih Hansmukh
    Am working on a POC for self learning in which I want to keep my user connected in LIVE pattern. For example, A game in which 4 user can play at a time , here I need to keep this user connected to my game . M not good at Socket type of programming and love to do that in Services way.What i wana know is 'What is the best way of doing this'. According to my initial Brain Storming, I have decided that I will use SilverLight(In Browser Or Out of Browser) as Front end [I have no issue in that]. I m more concern in back end. Either I make an handler or make a WCF service or use full duplex service and use pooling mechanism for that. As a random thought I come up with a Timer type logic that will fire every after 10 seconds at clients end and get status like Is it now Its turn to roll a dice Home many user left (in case if some of them left) What are connected user status in game like there score/points ect and update game view according to this at his end Kindly place your best answers here that will help me to learn this. Regards and thanks in Advance EDIT: Starting Bounty as i need more feedback. FH

    Read the article

  • Routing redirection decision

    - by programming late night
    I have really no idea why I'm asking this as this a really completely irrelevant question for which I should have figured out an answer within milliseconds, yet I'm doing it. So in my project I have a Router class which splits up the request and selects the right page to be loaded. Fine so far. Now I have a page displayed when the user requests a page that doesn't exist, you know, 404. So theoretically, if the user entered mydomain.com/404 (I use mod_rewrite with a requests collector via index.php?req=*) the 404 error would be shown to him, but in fact there was no error - the 404 page would be displayed as a perfectly normal page. So if someone would try out requesting the 404 page via /404, he would be shown the page but he can't tell if the 404 page he requested doesn't exist and he is actually getting a, you guessed it, 404 error or if he actually found some flaw in the system that makes him able to see an error page when there is no error. I don't know how dumb this whole thing here is but I'm sure some of you have in fact ran into this problem already. Short version: If the user enters mydomain.com/404 the 404 page is shown even though there is no 404 error. I know this is a completely irrelevant question, please don't tell me, but I just spontaneously wanted to hear your thoughts on it. Strange eh? Should I redirect direct access to my 404-page to the home page? Should I do nothing? Should I just go to bed and stop asking irrelevant stuff?

    Read the article

  • Robust Large File Transfer with WCF

    - by Sharov
    I want to transfer big files (1GB) over unreliable transport channels. When connection is interrupted, I don't want start file transfering from the begining. I can partially store it in a temp table and store last readed position, so when connection is reestablished I can request continue uploading of file from this position. Is there any best-practice for such kind of things. I'm currently use chunking channel.

    Read the article

  • What is the recommended way of parsing an XML feed with multiple namespaces with ActionScript 3.0?

    - by dafko
    I have seen the following methods to be used in several online examples, but haven't found any documentation on the recommended way of parsing an XML feed. Method 1: protected function xmlResponseHandler(event:ResultEvent):void { var atom:Namespace = new Namespace("http://www.w3.org/2005/Atom"); var microsoftData:Namespace = new Namespace("http://schemas.microsoft.com/ado/2007/08/dataservices"); var microsoftMetadata:Namespace = new Namespace("http://schemas.microsoft.com/ado/2007/08/dataservices/metadata"); var ac:ArrayCollection = new ArrayCollection(); var keyValuePairs:KeyValuePair; var propertyList:XMLList = (event.result as XML)..atom::entry.atom::content.microsoftMetadata::properties; for each (var properties:XML in propertyList) { keyValuePairs = new KeyValuePair(properties.microsoftData::FieldLocation, properties.microsoftData::Locationid); ac.addItem(keyValuePairs); } cb.dataProvider = ac; } Method 2: protected function xmlResponseHandler(event:ResultEvent):void { namespace atom = "http://www.w3.org/2005/Atom"; namespace d = "http://schemas.microsoft.com/ado/2007/08/dataservices"; namespace m = "http://schemas.microsoft.com/ado/2007/08/dataservices/metadata"; use namespace d; use namespace m; use namespace atom; var ac:ArrayCollection = new ArrayCollection(); var keyValuePairs:KeyValuePair; var propertyList:XMLList = (event.result as XML)..entry.content.properties; for each (var properties:XML in propertyList) { keyValuePairs = new KeyValuePair(properties.FieldLocation, properties.Locationid); ac.addItem(keyValuePairs); } cb.dataProvider = ac; } Sample XML feed: <?xml version="1.0" encoding="iso-8859-1" standalone="yes"?> <feed xml:base="http://www.test.com/Test/my.svc/" xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns="http://www.w3.org/2005/Atom"> <title type="text">Test_Locations</title> <id>http://www.test.com/test/my.svc/Test_Locations</id> <updated>2010-04-27T20:41:23Z</updated> <link rel="self" title="Test_Locations" href="Test_Locations" /> <entry> <id>1</id> <title type="text"></title> <updated>2010-04-27T20:41:23Z</updated> <author> <name /> </author> <link rel="edit" title="Test_Locations" href="http://www.test.com/id=1" /> <category term="MySQLModel.Test_Locations" scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme" /> <content type="application/xml"> <m:properties> <d:FieldLocation>Test Location</d:FieldLocation> <d:Locationid>test0129</d:Locationid> </m:properties> </content> </entry> <entry> <id>2</id> <title type="text"></title> <updated>2010-04-27T20:41:23Z</updated> <author> <name /> </author> <link rel="edit" title="Test_Locations" href="http://www.test.com/id=2" /> <category term="MySQLModel.Test_Locations" scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme" /> <content type="application/xml"> <m:properties> <d:FieldLocation>Yet Another Test Location</d:FieldLocation> <d:Locationid>test25</d:Locationid> </m:properties> </content> </entry> </feed>

    Read the article

  • Unit Testing User Interface. What is an effective way ?

    - by pierocampanelli
    I have an accounting & payroll client/server application where there are several input form with complex data validation rules. I am finding an effective way to perform unit testing of user interface. For complex validation rules I mean: "Disable button X if I Insert a value in textfield Y" "Enable a combobox if I insert a value in a textfield" ...... ...... Most promising pattern i have found is suggested by M. Fowler (http://martinfowler.com/eaaDev/ModelViewPresenter.html). Have you any experience about Unit Testing of User Interface? As technology stack I am using: .NET 3.5 & Windows Forms Widget Library.

    Read the article

  • What Getters and Setters should and shouldn't do.

    - by cyclotis04
    I've run into a lot of differing opinions on Getters and Setters lately, so I figured I should make it into it's own question. A previous question of mine received an immediate comment (later deleted) that stated setters shouldn't have any side effects, and a SetProperty method would be a better choice. Indeed, this seems to be Microsoft's opinion as well. However, their properties often raise events, such as Resized when a form's Width or Height property is set. OwenP also states "you shouldn't let a property throw exceptions, properties shouldn't have side effects, order shouldn't matter, and properties should return relatively quickly." Yet Michael Stum states that exceptions should be thrown while validating data within a setter. If your setter doesn't throw an exception, how could you effectively validate data, as so many of the answers to this question suggest? What about when you need to raise an event, like nearly all of Microsoft's Control's do? Aren't you then at the mercy of whomever subscribed to your event? If their handler performs a massive amount of information, or throws an error itself, what happens to your setter? Finally, what about lazy loading within the getter? This too could violate the previous guidelines. What is acceptable to place in a getter or setter, and what should be kept in only accessor methods?

    Read the article

  • Preprocessor "macro function" vs. function pointer - best practice?

    - by Dustin
    I recently started a small personal project (RGB value to BGR value conversion program) in C, and I realised that a function that converts from RGB to BGR can not only perform the conversion but also the inversion. Obviously that means I don't really need two functions rgb2bgr and bgr2rgb. However, does it matter whether I use a function pointer instead of a macro? For example: int rgb2bgr (const int rgb); /* * Should I do this because it allows the compiler to issue * appropriate error messages using the proper function name, * not to mention possible debugging benefits? */ int (*bgr2rgb) (const int bgr) = rgb2bgr; /* * Or should I do this since it is merely a convenience * and they're really the same function anyway? */ #define bgr2rgb(bgr) (rgb2bgr (bgr)) I'm not necessarily looking for a change in execution efficiency as it's more of a subjective question out of curiosity. I am well aware of the fact that type safety is neither lost nor gained using either method. Would the function pointer merely be a convenience or are there more practical benefits to be gained of which I am unaware?

    Read the article

  • Is it good practice to put private API in the .m files and public API in .h files in Cocoa?

    - by Paperflyer
    Many of my classes in my current project have several properties and methods that are only ever called from within the class itself. Also, they might mess with the working of the class depending on the current state of the class. Currently, all these interfaces are defined in the main interface declaration in the .h files. Is it considered good practice to put the “private” methods and properties at the top of the .m files? This won't ever affect anything since I am very likely the only person ever to look at this source code, but of course it would be interesting to know for future projects.

    Read the article

  • How to Communicate between minifb and a GAE-Hosted Silverlight Client

    - by Nick Gotch
    I have a minifb app (technically gminifb) running on Google App Engine with a bunch of handlers for processing all kinds of requests from a Silverlight client. What's the recommended approach for adding the FB GET variables, such as fb_sig, to the HTTP requests? I believe I can technically pass the session key and uid directly and get things to work but it seems there's probably a much better way to do this. I was reading about FBJS AJAX and I'm trying to figure out how I can use it to proxy the HTTP requests from the Silverlight client through it. Is this a good way to do it? And if so, how would I go about doing so? Any other recommendations would be appreciated too. Thanks,

    Read the article

  • objectWithFieldNAme Best Practice for CoreData

    - by Rafael
    Hello, I'm trying to implements some methods for my CoreData models and I'm wonndering if the way I'm doing it is a good practice. I want to implement methods of the type getObjectsWithFieldName. This methods could be used by severals views. So the way I'm doing it is implementing a Class method in the model in the following way: +(NSArray *)getObjectWithFieldName:(NSString *)fieldName andContext:(NSManagedObjectContext *) context; Is this a good practice? Or there is another way to do it for iPhone Development? Thanks in advanced.

    Read the article

  • Why is using a common-lookup table to restrict the status of entity wrong?

    - by FreshCode
    According to Five Simple Database Design Errors You Should Avoid by Anith Sen, using a common-lookup table to store the possible statuses for an entity is a common mistake. Why is this wrong? I disagree that it's wrong, citing the example of jobs at a repair service with many possible statuses that generally have a natural flow, eg.: Booked In Assigned to Technician Diagnosing problem Waiting for Client Confirmation Repaired & Ready for Pickup Repaired & Couriered Irreparable & Ready for Pickup Quote Rejected Arguably, some of these statuses can be normalised to tables like Couriered Items, Completed Jobs and Quotes (with Pending/Accepted/Rejected statuses), but that feels like unnecessary schema complication. Another common example would be order statuses that restrict the status of an order, eg: Pending Completed Shipped Cancelled Refunded The status titles and descriptions are in one place for editing and are easy to scaffold as a drop-down with a foreign key for dynamic data applications. This has worked well for me in the past. If the business rules dictate the creation of a new order status, I can just add it to OrderStatus table, without rebuilding my code.

    Read the article

  • Looking for design help

    - by jess
    I have this scenario in most of the WindowsForms having grids I have a sequence of code which is similar - AddNewRow(in grid),CreateNewEntity,notifyUser,few other steps Now, I want to use a template kind of pattern.But,my issue is with CreateEntity method since sometimes it is passed a parameter which is different depending on the type of object being created.Should I make createentity accept an "object" type,and cast when the parameter is to be used.What other way can I tackle this design issue? Also,CreateEntity returns the object being created.

    Read the article

  • standard debugging way for javascript/jquery

    - by ZX12R
    This is my usual way to debug javascript. Include alert(0); to break the flow and find out what is happening. sometimes when i need multiple check points i do alert('the flow is now in function 1'); alert('the flow is now in function 2'); or sometimes just alert('success'); i would like to know if there is any standard way for debugging adopted as i am finding my current method very intrusive. thanks in advance..:)

    Read the article

  • UX Design Question: Should a multi step wizard save the form contents when the user clicks 'go back'

    - by Ashwin Prabhu
    I am developing a web application that collects data over multiple steps through a wizard. Steps are generally not interdependent, in that data input at each step has little or no effect on the consequent steps. However each step may have a set of validations which determine whether the user can progress to the next step by clicking 'continue' What should be the behavior when the user clicks previous? a Quickly move to the previous page, thus losing all the unsaved data in the form. Prompting the user with a warning is an option, but it can become irritating quite soon. b Move to the previous page saving all the data in the current step - without triggering validations, so that when the user comes back she sees the form in the same state that she left it in. c any other behaviour All opinions are welcome :)

    Read the article

  • php form submit and the resend infromation screen

    - by Para
    Hello, I want to ask a best practice question. Suppose I have a form in php with 3 fields say name, email and comment. I submit the form via POST. In PHP I try and insert the date into the database. Suppose the insertion fails. I should now show the user an error and display the form filled in with the data he previously inserted so he can correct his error. Showing the form in it's initial state won't do. So I display the form and the 3 fields are now filled in from PHP with echo or such. Now if I click refresh I get a message saying "Are you sure you want to resend information?". OK. Suppose after I insert the data I don't carry on but I redirect to the same page but with the necessary parameters in the query string. This makes the message go away but I have to carry 3 parameters in the query string. So my question is: How is it better to do this? I want to not carry around lots of parameters in the query string but also not get that error. How can this be done? Should I use cookies to store the form information.

    Read the article

  • .net design pattern question

    - by user359562
    Hi. I am trying to understand design pattern problems. I am trying to modify the code like this in winforms and trying to see if any design pattern suits my requirement. Please suggest which is the best design pattern in this scenario. This is very basic code containing 2 tab pages which might have different controls can be added dynamically and read out different files on click of particular tab. To elaborate more... I have written this code to learn and understand design pattern. This is just a scenario where user click on a particular tab which will show dynamic controls generated. public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void tabControl1_SelectedIndexChanged(object sender, EventArgs e) { if (tabControl1.SelectedTab.Name.Equals("tabPage1")) { GeneratedynamicControlsForTab1(); } else if (tabControl1.SelectedTab.Name.Equals("tabPage2")) { GeneratedynamicControlsForTab2(); } } private void GeneratedynamicControlsForTab1() { Label label1 = new Label(); label1.Text = "Label1"; tabPage1.Controls.Add(label1); ReadCSVFile(); } private void GeneratedynamicControlsForTab2() { tabPage1.Controls.Clear(); Label label2 = new Label(); label2.Text = "Label2"; tabPage2.Controls.Add(label2); ReadTextFile(); } private void ReadCSVFile() { } private void ReadTextFile() { } }

    Read the article

  • How can I handle multiple views of a data object? Which design pattern is acceptable?

    - by tranquil.byte
    I have a person object. class Person { private $name; ... } I need to be able to change how they are displayed on the front-end ( visitors have control ). They can choose list view, grid view, photo view for example. class PersonDisplay { public function displayList() { // Query database // Output html to display in list mode } public function displayPhoto() { // Query database // Output html to display in photo mode } } Is this an acceptable way to handle the presentation of the items on the front-end or is there a specific design pattern I should be researching to help me with this task? Does anyone have any suggestions or ideas where this could go wrong or if this could potentially make maintenance a nightmare? The Person object was just an example very similiar to what I am using.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 150 151 152 153 154 155 156 157 158 159 160 161  | Next Page >