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  • C++ return a "NULL" object if search result not found

    - by aduric
    I'm pretty new to C++ so I tend to design with a lot of Java-isms while I'm learning. Anyway, in Java, if I had class with a 'search' method that would return an object T from a Collection< T that matched a specific parameter, I would return that object and if the object was not found in the collection, I would return a NULL. Then in my calling function I would just check if(T != NULL) { ... } In C++, I'm finding out that I can't return a NULL if the object doesn't exist. I just want to return an 'indicator' of type T that notifies the calling function that no object has been found. I don't want to throw an exception because it's not really an exceptional circumstance. class Node { .... Attr& getAttribute(const string& attribute_name) const { //search collection //if found at i return attributes[i]; //if not found return NULL; } private: vector<Attr> attributes; }

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  • What is the easiest way to add compression to WCF in Silverlight?

    - by caryden
    I have a silverlight 2 beta 2 application that accesses a WCF web service. Because of this, it currently can only use basicHttp binding. The webservice will return fairly large amounts of XML data. This seems fairly wasteful from a bandwidth usage standpoint as the response, if zipped, would be smaller by a factor of 5 (I actually pasted the response into a txt file and zipped it.). The request does have the "Accept-Encoding: gzip, deflate" - Is there any way have the WCF service gzip (or otherwise compress) the response? I did find this link but it sure seems a bit complex for functionality that should be handled out-of-the-box IMHO. OK - at first I marked the solution using the System.IO.Compression as the answer as I could never "seem" to get the IIS7 dynamic compression to work. Well, as it turns out: Dynamic Compression on IIS7 was working al along. It is just that Nikhil's Web Developer Helper plugin for IE did not show it working. My guess is that since SL hands the web service call off to the browser, that the browser handles it "under the covers" and Nikhil's tool never sees the compressed response. I was able to confirm this by using Fiddler which monitors traffic external to the browser application. In fiddler, the response was, in fact, gzip compressed!! The other problem with the System.IO.Compression solution is that System.IO.Compression does not exist in the Silverlight CLR. So from my perspective, the EASIEST way to enable WCF compression in Silverlight is to enable Dynamic Compression in IIS7 and write no code at all.

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  • Mapping Vectors

    - by Dan Snyder
    Is there a good way to map vectors? Here's an example of what I mean: vec0 = [0,0,0,0,0,0,0,0,0,0,0] vec1 = [1,4,2,7,3,2] vec2 = [0,0,0,0,0,0,0,0,0] vec2 = [7,2,7,9,9,6,1,0,4] vec4 = [0,0,0,0,0,0] mainvec = [0,0,0,0,0,0,0,0,0,0,0,1,4,2,7,3,2,0,0,0,0,0,0,0,0,0,7,2,7,9,9,6,1,0,4,0,0,0,0,0,0] Lets say mainvec doesn't exist (I'm just showing it to you so you can see the general data structure in mind. Now say I want mainvec(12) which would be 4. Is there a good way to map the call of these vectors without just stitching them together into a mainvec? I realize I could make a bunch of if statements that test the index of mainvec and I can then offset each call depending on where the call is within one of the vectors, so for instance: mainvec(12) = vec1(1) which I could do by: mainvec(index) if (index >=13) vect1(index-11); I wonder if there's a concise way of doing this without if statements. Any Ideas?

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  • unable to set fields of a collection-property elements after changing their order (elements becoming

    - by Jaroslav Záruba
    Hello I want to change order of objects in a collection, and then to access+modify fields of those items. Unfortunately the items somehow become 'deleted'. This is what I do... if(someCondition) { MainEvent mainEvent = pm.getObjectById(MainEvent.class, mainEventKey); /* * events in the original order * MainEvent.subEvents field is not in default fetch group, * therefore I also tried to add the named group into the * persistenceManeger fetch plan, no difference * (mainEvent is not instance of the Event sub/class BTW) */ List<Event> subEvents = mainEvent.getSubEvents(); // re-arrange the events according to keysOrdered { Map<Key, Event> eventMap = new HashMap<Key, Event>(); for(Event event : subEvents) eventMap.put(event.getKey(), event); List<Event> eventsOrdered = new LinkedList<Event>(); for(Key eventKey : keysOrdered) eventsOrdered.add(eventMap.put(eventKey, eventMap.get(eventKey))); // } // put the re-arranged items back into the collection property { subEvents.clear(); subEvents.addAll(eventsOrdered); // } pm.makePersistent(mainEvent); eventsOrdered = subEvents; } else eventsOrdered = getEventsUsingAlternateApproach(); /* * so by now the mainEvent variable does not exist; * could it be this lead the persistence manager to mark * my events as abandoned/obsolete/invalid/deleted...? */ for(Event event : eventsOrdered) event.setDate(new Date()); // -> "Cannot write fields to a deleted object" What am I doing wrong please?

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  • iPhone: Does it ever make sense for an object to retain its delegate?

    - by randombits
    According to the rules of memory management in a non garbage collected world, one is not supposed to retain a the calling object in a delegate. Scenario goes like this: I have a class that inherits from UITableViewController and contains a search bar. I run expensive search operations in a secondary thread. This is all done with an NSOperationQueue and subclasses NSOperation instances. I pass the controller as a delegate that adheres to a callback protocol into the NSOperation. There are edge cases when the application crashes because once an item is selected from the UITableViewController, I dismiss it and thus its retain count goes to 0 and dealloc gets invoked on it. The delegate didn't get to send its message in time as the results are being passed at about the same time the dealloc happens. Should I design this differently? Should I call retain on my controller from the delegate to ensure it exists until the NSOperation itself is dealloc'd? Will this cause a memory leak? Right now if I put a retain on the controller, the crashes goes away. I don't want to leak memory though and need to understand if there are cases where retaining the delegate makes sense. Just to recap. UITableViewController creates an NSOperationQueue and NSOperation that gets embedded into the queue. The UITableViewController passes itself as a delegate to NSOperation. NSOperation calls a method on UITableViewController when it's ready. If I retain the UITableViewController, I guarantee it's there, but I'm not sure if I'm leaking memory. If I only use an assign property, edge cases occur where the UITableViewController gets dealloc'd and objc_msgSend() gets called on an object that doesn't exist in memory and a crash is imminent.

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  • Disable validation in an object in Ruby on Rails

    - by J. Pablo Fernández
    I have an object which whether validation happens or not should depend on a boolean, or in another way, validation is optional. I haven't found a clean way to do it. What I'm currently doing is this (disclaimer: you cannot unsee, leave this page if you are too sensitive): def valid? if perform_validation super else super # Call valid? so that callbacks get called and things like encrypting passwords and generating salt in before_validation actually happen errors.clear # but then clear the errors true # and claim ourselves to be valid. This is super hacky! end end Any better ways? Before you point to the :if argument of many validations, this is for a user model which is using authlogic so it has a lot of validation rules. You can stop reading here if you belive me. If you don't, authlogic already sets some :ifs like: :if => :email_changed? which I have to turn into :if => Proc.new {|user| user.email_changed? and user.perform_validation} and in some other cases, since I'm also using authlogic-oid (OpenID) I just don't have control over the :if, authlogic-oid sets it in a way I cannot change it (in time) without further monkey patching. So I have to override seemingly unrelated functions, catch exceptions if a method doesn't exist, etc. The previous hacky solution if the best of my two attempts.

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  • Initialize child models at model creation

    - by Antoine
    I have a model Entree which belongs to a model Vin, which itself belongs to a model Producteur. On the form for Entree creation/edition, I want to allow the user to define the attributes for parent Vin and Producteur to create them, or retrieve them if they exist (retrieval based on user input). For now I do the following in Entree new and edit actions: @entree = Entree.new @entree.vin = Vin.new @entree.vin.producteur = Producteur.new and use fields_for helper in the form,and that works. But I intend to have much more dependencies with more models, so I want to keep it DRY. I defined a after_initialize callback in Vin model which does the producteur initialization: class Vin < ActiveRecord::Base after_initialize :vin_setup def vin_setup producteur = Producteur.new end end and remove the producteur.new from the controller. However, get an error on new action: undefined method `model_name' for NilClass:Class for the line in the form that says <%= fields_for @entree.vin.producteur do |producteur| %> I guess that means the after_initialize callback doesn't act as I expect it. Is there something I'm missing? Also, I get the same error if I define a after_initialize method in the Vin model instead of definiing a callback.

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  • Simple way of getting the Last.fm artist image for recently listened songs?

    - by animuson
    On the Last.fm website, your recently listened track include the 34x34 (or whatever size) image at the left of each song. However, in the RSS feed that they give you, no image URLs are provided for the songs. I was wondering if there was a good way of figuring out the ID for the image that needs to be used for that artist and displaying it based on the data that we're given. I know it is possible to load the artist page from their website and then grab the image values from JavaScript, but that seems overly complicated and would probably take quite some time to do. What we're given: <item> <title>Owl City – Rainbow Veins</title> <link>http://www.last.fm/music/Owl+City/_/Rainbow+Veins</link> <pubDate>Thu, 20 May 2010 18:15:29 +0000</pubDate> <guid>http://www.last.fm/user/animuson#1274379329</guid> <description>http://www.last.fm/music/Owl+City</description> </item> and the 34x34 image for this song would be here (ID# 37056785). Does anything like this exist? I've considered storing the ID number in a cache of some sort once it has been checked once, but what if the image changes?

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  • Pro ASP.Net MVC 3 Entity Framework Sports Store tutorial

    - by gary7
    Following the tutorial in the book "Pro ASP.Net MVC 3 Entity Framework" in Chapter 9 - Image Uploads section; asks that the Product class be updated with two new columns - public byte ImageData, and public string ImageType. It also directs that the database be updated with these two columns via the server explorer. After these updates, the discussion directs that the Entity Framework Conceptual Model be updated via the SportsStore.EDMX file. This file does not exist in the source code for the project, and was not used in the project to begin with. Obvious errata for the book. Adding the ADO.NET Entity Data Model to the Project then overrides the EFProduct reposistory (conceptual model used throughout the project) which inherits from the interface IProductsRepository; and results in errors within the mapping. If the project is debugged after the columns are added, an error is thrown related to the new added columns. Has anyone resolved this issue in the project? I haven't found any solutions so far. Thanks!

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  • Are there any libraries for parsing "number expressions" like 1,2-9,33- in Java

    - by mihi
    Hi, I don't think it is hard, just tedious to write: Some small free (as in beer) library where I can put in a String like 1,2-9,33- and it can tell me whether a given number matches that expression. Just like most programs have in their print range dialogs. Special functions for matching odd or even numbers only, or matching every number that is 2 mod 5 (or something like that) would be nice, but not needed. The only operation I have to perform on this list is whether the range contains a given (nonnegative) integer value; more operations like max/min value (if they exist) or an iterator would be nice, of course. What would be needed that it does not occupy lots of RAM if anyone enters 1-10000000 but the only number I will ever query is 12345 :-) (To implement it, I would parse a list into several (min/max/value/mod) pairs, like 1,10,0,1 for 1-10 or 11,33,1,2 for 1-33odd, or 12,62,2,10 for 12-62/10 (i. e. 12, 22, 32, ..., 62) and then check each number for all the intervals. Open intervals by using Integer.MaxValue etc. If there are no libs, any ideas to do it better/more efficient?)

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  • Simulating a contains If-Else using RewriteCond

    - by hlissner
    Hi! I'm trying to get my head around RewriteCond, and want to rewrite any requests either to a static html page (if it exists), or to a specific index.php (so long as the requested file doesn't exist). To illustrate the logic: if HTTP_HOST is '(www\.)?mydomain.com' if file exists: "/default/static/{REQUEST_URI}.html", then rewrite .* to /default/static/{REQUEST_URI}.html else if file exists: {REQUEST_FILENAME}, then do not rewrite else rewrite .* to /default/index.php I don't seem to have much trouble doing it when I don't need to test for the HTTP_HOST. Ultimately, this one .htaccess file will be handling requests for several domains. I know I could get around this with vhosts, but I'd like to figure out how to do it this way. Here's where I am at now: RewriteCond %{HTTP_HOST} ^(www\.)?mydomain\.com$ [NC] RewriteCond /default/static/%{REQUEST_URI}.html -f RewriteRule . /default/static/%{REQUEST_URI}.html [L,NC] RewriteCond %{REQUEST_FILENAME} !-f RewriteRule . /default/index.php [L,QSA] I'm not too familiar with some of the other flags, will any of them be of use here (like chain|C, next|N or skip|S)? Thanks in advance!

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  • How do I keep from running out of memory on graphics for an Android app?

    - by user279112
    I've been working on an Android app in Eclipse, and so far, my program hasn't really grown past midget size. However I've already run into an issue with an Out of Memory error. You see, I've been using graphics comprised solely of bitmaps and PNGs in this program, and recently, when I tried to add a little bit more functionality to the program (mainly including a few more bitmaps and causing an extra sprite to be created), it started crashing in the graphics thread's constructor - sprite's constructor. When I tracked the problem down, it turned out to be an Out of Memory error that is seemingly caused by adding too many picture files to the program and creating Drawables out of them. This would be a problem, as I really don't have that many picture resources worked into that program...maybe 20 or so. I haven't even started to include sound yet. These images aren't all that fancy. My questions are this: 1) Are programs for the Android phone really that limited on how much memory they can employ, or is it probably something other than the 20-30 resource pictures causing that error? 2) If the memory for Android apps is so awful it can't even handle 20-30 picture resources being loaded into Drawables that exist at the same time, then how in the world are you supposed to make decent graphics and sound for that thing? Thanks.

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  • Carbon, LSUIElement, and showing a window

    - by James Turner
    I have a Carbon LSUIElement application, which runs in the background (possibly with an icon in the menubar, depending on a pref) and occasionally needs to show a dialog to the user - sometimes in response to a user event, but sometimes in response to a background task failing or similar. (I'm using Qt 4.5, so the application is Carbon based; With Qt 4.6 things will be Cocoa based, but it sounds as if the problem may exist there too). The problem is that when I open a window, and show it, it doesn't get brought to the front. I assume this is an artefect of being an LSUIElement app. Qt uses SelectWindow in Carbon, and [makeKeyAndOrderFront] in Cocoa, to bring a window (and the app) to the front. To work around the problem, I tried going direct to the window server: (the first few steps are to get the WindowID, this will be simpler with Qt-Cocoa, since I can use NSWindow:nativeWindow) WindowRef ref = HIViewGetWindow((HIViewRef) aWidget->winId()); CGSWindow wid = GetNativeWindowFromWindowRef(ref); CGSConnection cid =_CGSDefaultConnection(); CGSOrderWindow(cid, wid, 1 /* above everything */, 0 /* NULL */); This works, sort of - the window comes to the front, but it's not highlighted or keyboard focused. Are there additional steps to fix those issues, or is there a simpler solution to the whole problem?

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  • Conditional column values in NSTableView?

    - by velocityb0y
    I have an NSTableView that binds via an NSArrayController to an NSMutableArray. What's in the array are derived classes; the first few columns of the table are bound to properties that exist on the base class. That all works fine. Where I'm running into problem is a column that should only be populated if the row maps to one specific subclass. The property that column is meant to display only exists in that subclass, since it makes no sense in terms of the base class. The user will know, from the first two columns, why the third column's cell is populated/editable or not. The binding on the third column's value is on arrangedObjects, with a model path of something like "foo.name" where foo is the property on the subclass. However, this doesn't work, as the other subclasses in the hierarchy are not key-value compliant for foo. It seems like my only choice is to have foo be a property on the base class so everybody responds to it, but this clutters up the interfaces of the model objects. Has anyone come up with a clean design for this situation? It can't be uncommon (I'm a relative newcomer to Cocoa and I'm just learning the ins and outs of bindings.)

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  • multi-shop orders table and sequential order numbers based on shop

    - by imanc
    Hey, I am looking at building a shop solution that needs to be scalable. Currently it retrieves 1-2000 orders on average per day across multiple country based shops (e.g. uk, us, de, dk, es etc.) but this order could be 10x this amount in two years. I am looking at either using separate country-shop databases to store the orders tables, or looking to combine all into one order table. If all orders exist in one table with a global ID (auto num) and country ID (e.g uk,de,dk etc.), each countries orders would also need to have sequential ordering. So in essence, we'd have to have a global ID and a country order ID, with the country order ID being sequential for countries only, e.g. global ID = 1000, country = UK, country order ID = 1000 global ID = 1001, country = DE, country order ID = 1000 global ID = 1002, country = DE, country order ID = 1001 global ID = 1003, country = DE, country order ID = 1002 global ID = 1004, country = UK, country order ID = 1001 THe global ID would be DB generated and not something I would need to worry about. But I am thinking that I'd have to do a query to get the current country order based ID+1 to find the next sequential number. Two things concern me about this: 1) query times when the table has potentially millions of rows of data and I'm doing a read before a write, 2) the potential for ID number clashes due to simultaneous writes/reads. With a MyISAM table the entire table could be locked whilst the last country order + 1 is retrieved, to prevent ID number clashes. I am wondering if anyone knows of a more elegant solution? Cheers, imanc

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  • Rails 3) Delete, Destory, and Routing

    - by Maximus S
    The problem is the code below <%= button_to t('.delete'), @post, :method => :delete, :class => :destroy %> My Post model has many relations that are dependent on delete. However, the code above will only remove the post, leaving its relations intact. The problem is that methods delete and destroy are different in that method delete doesn't instantiate the object. So I need to use "destroy" instead of "delete" my post. <%= button_to t('.delete'), @post, :method => :destroy %> gives me routing error. No route matches [POST] "/posts/2" <%= button_to t('.delete'), @post, Post.destroy(@post) %> deletes the post without clicking the button. Could anyone help me with this? UPDATE: application.js //= require jquery //= require jquery-ui //= require jquery_ujs //= require bootstrap-modal //= require bootstrap-typeahead //= require_tree . rake routes DELETE (/:locale)/posts/:id(.:format) posts#destroy Post model has_many :tag_links, :dependent => :destroy has_many :tags, :through => :tag_links Tag model has_many :tag_links, :dependent => :destroy has_many :posts, :through => :tag_links Problem: When I delete a post, all the tag_links are destroyed but tags still exist.

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  • How do I create a class repository in Java and do I really need it?

    - by Roman
    I have a large number of objects which are identified by names (strings). So, I would like to have a kind of mapping from object name to the class instances. I was told that in this situation I can use a "repository" class which works like that: Server myServer = ServerRepository.getServer("NameOfServer"); So, if there is already an object (sever) with the "NameOfServer" it will be returned by the "getServer". If such an object does not exist yet, it will be created and returned by the "getServer". So, my question is how to program such a "repository" class? In this class I have to be able to check if there is an instance of a given class such that it has a given value of a given field. How can I do it? I need to have a kind of loop over all existing object of a given class? Another part of my question is why I cannot use associative arrays (associative container, map, mapping, dictionary, finite map)? (I am not sure how do you call it in Java) In more details, I have an "array" which maps names of objects to objects. So, whenever I create a new object, I add a new element to the array: myArray["NameOfServer"] = new Server("NameOfServer").

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  • Javascript Cookie Function not working for Domain

    - by danit
    Here are the functions Im using: Set Cookie: function set_cookie ( name, value, exp_y, exp_m, exp_d, path, domain, secure ) { var cookie_string = name + "=" + escape ( value ); if ( exp_y ) { var expires = new Date ( exp_y, exp_m, exp_d ); cookie_string += "; expires=" + expires.toGMTString(); } if ( path ) cookie_string += "; path=" + escape ( path ); if ( domain ) cookie_string += "; domain=" + escape ( domain ); if ( secure ) cookie_string += "; secure"; document.cookie = cookie_string; } Read Cookie: function get_cookie ( cookie_name ) { var results = document.cookie.match ( '(^|;) ?' + cookie_name + '=([^;]*)(;|$)' ); if ( results ) return ( unescape ( results[2] ) ); else return null; } Delete Cookie: function delete_cookie ( cookie_name ) { var cookie_date = new Date ( ); // current date & time cookie_date.setTime ( cookie_date.getTime() - 1 ); document.cookie = cookie_name += "=; expires=" + cookie_date.toGMTString(); } The Jquery I use to construct the cookie: if(get_cookie('visible')== 'no') { $("#wrapper").hide(); $(".help").hide(); $("#slid .show").show(); $("#slid .hide").hide(); } else { $("#slid .show").hide(); $("#slid .hide").show(); } $("#slider").click(function() { if(get_cookie('visible')== null) { set_cookie('visible','no', 2020, 01,01, '/', 'domain.com'); } else { delete_cookie('visible'); } $(".help").slideToggle(); $("#wrapper").animate({ opacity: 1.0 },200).slideToggle(200, function() { $("#slid img").toggle(); }); }); Im trying to set the cookie for all pages that exist under domain.com with the path '/'. However using these functions and jQuery it doesn't appear to be working, any anyone give me an idea of where im going wrong?

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  • Scheduling algorithm optimized to execute during low usage periods.

    - by The Rook
    Lets say there is a Web Application serving mostly one country. Because of normal sleep habits website traffic follows a Sine wave, where 1 period lasts 24 hours and the lowest part of the wave is at about midnight. Is there a scheduling algorithm optimized to execute during low usage periods? I am thinking of this as a liquid that is "pored into" this sine wave to flatten out resource usage. A ideal algorithm would take the integral of this empty space. If the same tasks need to be run daily the amount of resources consumed by previous executions could be used to predict future usage by looking at the rate in which resource usage is increasing. By knowing the amount of resources required this algorithm could fill in this empty space while leaving as much buffer as possible on either side such that its interference was reduced as much as possible. It would also be possible to detect if there isn't enough resources before execution begins, this opens the door for a cloud to help out. Does anything like this exist? Or should I build it into an existing scheduler like quartz and make it open source?

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  • How to use MySQL geospatial extensions with spherical geometries

    - by Joshua
    Hi Everyone, I would like to store thousands of latitude/longitude points in a MySQL db. I was successful at setting up the tables and adding the data using the geospatial extensions where the column 'coord' is a Point(lat, lng). Problem: I want to quickly find the 'N' closest entries to latitude 'X' degrees and longitude 'Y' degrees. Since the Distance() function has not yet been implemented, I used GLength() function to calculate the distance between (X,Y) and each of the entries, sorting by ascending distance, and limiting to 'N' results. The problem is that this is not calculating shortest distance with spherical geometry. Which means if Y = 179.9 degrees, the list of closest entries will only include longitudes of starting at 179.9 and decreasing even though closer entries exist with longitudes increasing from -179.9. How does one typically handle the discontinuity in longitude when working with spherical geometries in databases? There has to be an easy solution to this, but I must just be searching for the wrong thing because I have not found anything helpful. Should I just forget the GLength() function and create my own function for calculating angular separation? If I do this, will it still be fast and take advantage of the geospatial extensions? Thanks! josh UPDATE: This is exactly what I am describing above. However, it is only for SQL Server. Apparently SQL Server has a Geometry and Geography datatypes. The geography does exactly what I need. Is there something similar in MySQL?

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  • Dynamic TextBox on LinkButton click

    - by Alex Peta
    I am creating dynamic TextBoxes in a page by clicking a LinkButton. However, after that, if the page is submitted, I can't find the items created dynamically, thus, can't send the information to the database. protected void lbAddTag_Click(object sender, EventArgs e) { for (int i = 0; i < 3;i++ ) { CreateTextBox("txtTag-" + i.ToString()); } } private void CreateTextBox(string ID) { TextBox txt = new TextBox(); txt.ID = ID; txt.Width = Unit.Pixel(300); //txt.TextChanged += new EventHandler(OnTextChanged); txt.AutoPostBack = false; tagsPanel.Controls.Add(txt); Literal lt = new Literal(); lt.Text = "<br /><br />"; tagsPanel.Controls.Add(lt); } If I put: foreach (Control c in tagsPanel.Controls) { if (c is TextBox) { lblError.Text += c.ClientID + " , "; } } in the lbAddTag_Click method I can see the items, and they exist, but if I submit the page and try to insert the values in the database nothing... Any hint is much appreciated.

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  • Testing approach for multi-threaded software

    - by Shane MacLaughlin
    I have a piece of mature geospatial software that has recently had areas rewritten to take better advantage of the multiple processors available in modern PCs. Specifically, display, GUI, spatial searching, and main processing have all been hived off to seperate threads. The software has a pretty sizeable GUI automation suite for functional regression, and another smaller one for performance regression. While all automated tests are passing, I'm not convinced that they provide nearly enough coverage in terms of finding bugs relating race conditions, deadlocks, and other nasties associated with multi-threading. What techniques would you use to see if such bugs exist? What techniques would you advocate for rooting them out, assuming there are some in there to root out? What I'm doing so far is running the GUI functional automation on the app running under a debugger, such that I can break out of deadlocks and catch crashes, and plan to make a bounds checker build and repeat the tests against that version. I've also carried out a static analysis of the source via PC-Lint with the hope of locating potential dead locks, but not had any worthwhile results. The application is C++, MFC, mulitple document/view, with a number of threads per doc. The locking mechanism I'm using is based on an object that includes a pointer to a CMutex, which is locked in the ctor and freed in the dtor. I use local variables of this object to lock various bits of code as required, and my mutex has a time out that fires my a warning if the timeout is reached. I avoid locking where possible, using resource copies where possible instead. What other tests would you carry out?

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  • Object Oriented Programming Problem

    - by Danny Love
    I'm designing a little CMS using PHP whilst putting OOP into practice. I've hit a problem though. I have a page class, whos constructor accepts a UID and a slug. This is then used to set the properties (unless the page don't exist in which case it would fail). Anyway, I wanted to implement a function to create a page, and I thought ... what's the best way to do this without overloading the constructor. What would the correct way, or more conventional method, of doing this be? My code is below: <?php class Page { private $dbc; private $title; private $description; private $image; private $tags; private $owner; private $timestamp; private $views; public function __construct($uid, $slug) { } public function getTitle() { return $this->title; } public function getDescription() { if($this->description != NULL) { return $this->description; } else { return false; } } public function getImage() { if($this->image != NULL) { return $this->image; } else { return false; } } public function getTags() { if($this->tags != NULL) { return $this->tags; } else { return false; } } public function getOwner() { return $this->owner; } public function getTimestamp() { return $this->timestamp; } public function getViews() { return $this->views; } public function createPage() { // Stuck? } }

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  • Association Mapping Details confusion?

    - by AaronLS
    I have never understood why the associations in EntityFramework look the way they do in the Mapping Details window. When I select the line between 2 tables for an association, for example FK_ApplicationSectionsNodes_FormItems, it shows this: Association Maps to ApplicationSectionNodes FormItems (key symbol) FormItemId:Int32 <--> FormItemId:int ApplicationSectionNodes (key symbol) NodeId:Int32 <--> (key symbol) NodeId : int Fortunately this one was create automatically for me based on the foreign key constraints in my database, but whenever no constraints exist, I have a hard to creating associations manually(when the database doesn't have a diagram setup) because I don't understand the mapping details for associations. FormItems table has a primary key identity column FormItemId, and ApplicationSectionNodes contains a FormItemId column that is the foreign key and has NodeId as a primary key identity column. What really makes no sense to me is why the association has anything listed about the NodeId, when NodeId doesn't have anything to do with the foreign key relationship? (It's even more confusing with self referencing relationships, but maybe if I could understand the above case I'd have a better handle). CREATE TABLE [dbo].[ApplicationSectionNodes]( [NodeID] [int] IDENTITY(1,1) NOT NULL, [OutlineText] [varchar](5000) NULL, [ParentNodeID] [int] NULL, [FormItemId] [int] NULL, CONSTRAINT [PK_ApplicationSectionNodes] PRIMARY KEY CLUSTERED ( [NodeID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY], CONSTRAINT [UQ_ApplicationSectionNodesFormItemId] UNIQUE NONCLUSTERED ( [FormItemId] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO ALTER TABLE [dbo].[ApplicationSectionNodes] WITH NOCHECK ADD CONSTRAINT [FK_ApplicationSectionNodes_ApplicationSectionNodes] FOREIGN KEY([ParentNodeID]) REFERENCES [dbo].[ApplicationSectionNodes] ([NodeID]) GO ALTER TABLE [dbo].[ApplicationSectionNodes] NOCHECK CONSTRAINT [FK_ApplicationSectionNodes_ApplicationSectionNodes] GO ALTER TABLE [dbo].[ApplicationSectionNodes] WITH NOCHECK ADD CONSTRAINT [FK_ApplicationSectionNodes_FormItems] FOREIGN KEY([FormItemId]) REFERENCES [dbo].[FormItems] ([FormItemId]) GO ALTER TABLE [dbo].[ApplicationSectionNodes] NOCHECK CONSTRAINT [FK_ApplicationSectionNodes_FormItems] GO FormItems Table: CREATE TABLE [dbo].[FormItems]( [FormItemId] [int] IDENTITY(1,1) NOT NULL, [FormItemType] [int] NULL, CONSTRAINT [PK_FormItems] PRIMARY KEY CLUSTERED ( [FormItemId] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO ALTER TABLE [dbo].[FormItems] WITH NOCHECK ADD CONSTRAINT [FK_FormItems_FormItemTypes] FOREIGN KEY([FormItemType]) REFERENCES [dbo].[FormItemTypes] ([FormItemTypeId]) GO ALTER TABLE [dbo].[FormItems] NOCHECK CONSTRAINT [FK_FormItems_FormItemTypes] GO

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  • Drag Drop copy file

    - by Graham Warrender
    I've perhaps done something marginally stupid, but can't see what it is!! string pegasusKey = @"HKEY_LOCAL_MACHINE\SOFTWARE\Pegasus\"; string opera2ServerPath = @"Server VFP\"; string opera3ServerPath = @"O3 Client VFP\"; string opera2InstallationPath = null; string opera3InstallationPath = null; //Gets the opera Installtion paths and reads to the string opera*InstallationPath opera2InstallationPath = (string)Registry.GetValue(pegasusKey + opera2ServerPath + "System", "PathToServerDynamic", null); opera3InstallationPath = (string)Registry.GetValue(pegasusKey + opera3ServerPath + "System", "PathToServerDynamic", null); string Filesource = null; string[] FileList = (string[])e.Data.GetData(DataFormats.FileDrop, false); foreach (string File in FileList) Filesource = File; label.Text = Filesource; if (System.IO.Directory.Exists(opera3InstallationPath)) { System.IO.File.Copy(Filesource, opera3InstallationPath); MessageBox.Show("File Copied from" + Filesource + "\n to" + opera3InstallationPath); } else { MessageBox.Show("Directory Doesn't Exist"); } The user drags the file onto the window, I then get the installation path of an application which is then used as the destination for the source file.. When the application is runs, it throws the error directory not found. But surely if the directory doesn't exists is should step into the else statement? a simple application that is becoming a headache!!

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