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  • If I select from an IQueryable then the Include is lost

    - by Connor Murphy
    The include does not work after I perform a select on the IQueryable query. Is there a way arround this? My query is public IQueryable<Network> GetAllNetworks() { var query = (from n in _db.NetworkSet .Include("NetworkContacts.Contact") .Include("NetworkContacts.Contact.RelationshipSource.Target") .Include("NetworkContacts.Contact.RelationshipSource.Source") select (n)); return query;; } I then try to populate mya ViewModel in my WebUI layer using the following code var projectedNetworks = from n in GetAllNetworks() select new NetworkViewModel { Name = n.Name, Contacts = from contact in networkList .SelectMany(nc => nc.NetworkContacts) .Where(nc => nc.Member == true) .Where(nc => nc.NetworkId == n.ID) .Select(c => c.Contact) select contact, }; return projectedNetworks; The problem now occurs in my newly createdNetworkViewModel The Contacts object does include any loaded data for RelationshipSource.Target or RelationshipSource.Source The data should is there when run from the original Repository IQueryable object. However the related include data does not seem to get transferred into the new Contacts collection that is created from this IQueryable using the Select New {} code above. Is there a way to preserve this Include data when it gets passed into a new object?

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  • C++ Returning Multiple Items

    - by Travis Parks
    I am designing a class in C++ that extracts URLs from an HTML page. I am using Boost's Regex library to do the heavy lifting for me. I started designing a class and realized that I didn't want to tie down how the URLs are stored. One option would be to accept a std::vector<Url> by reference and just call push_back on it. I'd like to avoid forcing consumers of my class to use std::vector. So, I created a member template that took a destination iterator. It looks like this: template <typename TForwardIterator, typename TOutputIterator> TOutputIterator UrlExtractor::get_urls( TForwardIterator begin, TForwardIterator end, TOutputIterator dest); I feel like I am overcomplicating things. I like to write fairly generic code in C++, and I struggle to lock down my interfaces. But then I get into these predicaments where I am trying to templatize everything. At this point, someone reading the code doesn't realize that TForwardIterator is iterating over a std::string. In my particular situation, I am wondering if being this generic is a good thing. At what point do you start making code more explicit? Is there a standard approach to getting values out of a function generically?

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  • How do I prevent a C# method from executing using an attribute validator?

    - by Boydski
    I'd like to create an attribute-based validator that goes a few steps beyond what I've seen in examples. It'll basically prevent methods or other functionality from executing. Please be aware that I'm having to use AzMan since I have no availability to Active Directory in this scenario. Here's some pseudo code of what what I'm looking for: // Attribute validator class AttributeUsage is arbitrary at this point and may include other items [AttributeUsage( AttributeTargets.Method | AttributeTargets.Property, AllowMultiple = true, Inherited = true )] public class PermissionsValidatorAttribute : Attribute { public PermissionsValidatorAttribute(PermissionEnumeration permission){...} public bool UserCanCreateAndEdit(){...} public bool UserCanDelete(){...} public bool UserCanUpload(){...} } Here's a sample of a class/member that'll be decorated. The method will not be executed at all if the PermissionValidator.UserCanDelete() doesn't return true from wherever it's executed: public class DoStuffNeedingPermissions { [PermissionValidator(PermissionEnumeration.MustHaveDeletePermission)] public void DeleteSomething(){...} } I know this is a simple, incomplete example. But you should get the gist of what I'm needing. Make the assumption that DeleteSomething() already exists and I'm preferring to NOT modify the code within the method at all. I'm currently looking at things like the Validation Application Block and am messing with custom attribute POC's. But I'd love to hear opinions with code samples from everyone out there. I'm also certainly not opposed to other methods of accomplishing the same thing such as extension methods or whatever may work to accomplish the same thing. Please remember I'm making the attempt to minimize changes to existing DoStuffNeedingPermissions code. Thanks everyone!

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  • Should I release NSString before assigning a new value to it?

    - by Elliot Chen
    Hi, Please give me some suggestions about how to change a NSString variable. At my class, I set a member var: NSString *m_movieName; ... @property(nonatomic, retain) NSString *m_movieName; At viewDidLoad method, I assign a default name to this var: -(void)viewDidLoad{ NSString *s1 = [[NSString alloc] initWithFormat:@"Forrest Gump"]; self.m_movieName = s1; ... [s1 release]; [super viewDidLoad] } At some function, I want to give a new name to this var, so I did like: -(void)SomeFunc{ NSString *s2 = [[NSString alloc] initWithFormat:@"Brave Heart"]; //[self.movieName release]; // ??????? Should perform here? self.m_moiveName = s2; [s2 release]; } I know, NSString* var is just a pointer to an allocated memory block, and 'assign' operation will increment this memory block's using count. For my situation, should I release m_movieName before assigning a value to it? If I do not release it (via [self.movieName release]), when and where will the previous block be released? Thanks for your help very much!

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  • UISlider how to set the initial value

    - by slim
    I'm pretty new at this iphone dev stuff and i'm working on some existing code at a company. The uislider i'm trying to set the initial value on is actually in a UITableViewCell and is a custom control. I was thinking in the cell init cell = (QuantitiesCell *)[self loadCellWithNibName:@"QuantitiesCell" forTableView:ltableView withStyle:UITableViewCellStyleDefault]; i could just call something like ((QuantitiesCell *)cell).value = 5; The actual QuantitiesCell class has the member value and the following functions -(void)initCell;{ if (listOfValues == nil) { [self initListOfValues]; } quantitiesSLider.maximumValue = [listOfValues count]-1; quantitiesSLider.minimumValue = 0; quantitiesSLider.value = self.value; } -(void)initListOfValues;{ listOfValues = [[NSMutableArray alloc] initWithCapacity:10]; int j =0; for (float i = minValue; i <= maxValue+increment; i=i+increment) { [listOfValues addObject:[NSNumber numberWithFloat: i]]; if (i == value) { quantitiesSLider.value = j; } j++; } } like i said, i'm pretty new at this so if i need to post more of the code to show whats going to get help, let me know, This slider always is defaulting to 1, the slider ranges usually from 1-10, and i want to set it to a specific value of the item i'm trying to edit.

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  • Serialize Object

    - by Mark Pearl
    Hi.. I am new to serialization and I cannot for the life of me figure out how to fix this exception I am getting... I have an object that has the following structure [XmlRoot("MaxCut2")] public class MaxCut2File : IFile { public MaxCut2File() { MyJob = new Job(); Job.Reference = "MyRef"; } [XmlElement("JobDetails", typeof(Job))] public IJob MyJob { get; set; } } An inteferface... public interface IJob { string Reference { get; set; } } And an class [Serializable()] public class Job : IJob { [XmlElement("Reference")] public string Reference { get; set; } } When I try to serialize an instance of the MaxCut2File object I get an error {"Cannot serialize member 'MaxCut2File.MaxCut2File.MyJob' of type 'MaxCut2BL.Interfaces.IJob', see inner exception for more details."} "There was an error reflecting type 'MaxCut2File.MaxCut2File'." However if I change my property MyJob from the IJob type to the Job type it works fine... Any ideas?

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  • initialising a 2-dim Array in Scala

    - by Stefan W.
    (Scala 2.7.7:) I don't get used to 2d-Arrays. Arrays are mutable, but how do I specify a 2d-Array which is - let's say of size 3x4. The dimension (2D) is fixed, but the size per dimension shall be initializable. I tried this: class Field (val rows: Int, val cols: Int, sc: java.util.Scanner) { var field = new Array [Char](rows)(cols) for (r <- (1 to rows)) { val line = sc.nextLine () val spl = line.split (" ") field (r) = spl.map (_.charAt (0)) } def put (val rows: Int, val cols: Int, c: Char) = todo () } I get this error: :11: error: value update is not a member of Char field (r) = spl.map (_.charAt (0)) If it would be Java, it would be much more code, but I would know how to do it, so I show what I mean: public class Field { private char[][] field; public Field (int rows, int cols, java.util.Scanner sc) { field = new char [rows][cols]; for (int r = 0; r < rows; ++r) { String line = sc.nextLine (); String[] spl = line.split (" "); for (int c = 0; c < cols; ++c) field [r][c] = spl[c].charAt (0); } } public static void main (String args[]) { new Field (3, 4, new java.util.Scanner ("fraese.fld")); } } and fraese.fld would look, for example, like that: M M M M . M I get some steps wide with val field = new Array Array [Char] but how would I then implement 'put'? Or is there a better way to implement the 2D-Array. Yes, I could use a one-dim-Array, and work with put (y, x, c) = field (y * width + x) = c but I would prefer a notation which looks more 2d-ish.

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  • Concurrency and Coordination Runtime (CCR) Learning Resources

    - by Harry
    I have recently been learning the in's and out's of the Concurrency and Coordination Runtime (CCR). Finding good learning resources for this relatively new technology has been quite difficult. (A quick google search brings up "Creedence Clearwater Revival" as the top result!) Some of the resources I have found: Free e-book chapter from WROX on the Robotics Developer Studio Good Article/post on InfoQ Robotic's Member blog Very active MSDN CCR Forum - Got plenty of help from here! Great MSDN Magazine by Jeffrey Richter Official CCR User Guide - Didn't find this very helpful Great blogging series on CCR iodyner CCR Related Blog - Update: Moved to here Eight or so Videos on Channel9.msdn.com CCR Patterns page on MS Robotics Studio - I haven't read this yet 4 x CCR Questions on Stackoverflow - Most of the questions have been Mine! LOL CCR and DSS toolkit has now been released to MSDN Members Do you have any good learning resources for the CCR? I really hope that Microsoft will publish more material, so far it has been too Robotics specific. I believe that MS needs to acknowledge that most people are using the CCR in issolation from the DSS and Robotics Studio. Update The Mix 2010 conference had a presentation by Myspace about how they have used the CCR framework in their middle tier. They also open sourced the code base. MySpace DataRelay Mix Video Presentation

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  • Vim + OmniCppComplete and completing members of class members

    - by Robert S. Barnes
    I've noticed that I can't seem to complete members of class members using OmniCppComplete. For example, given the following files: // foo.h #include <string> class foo { public: void set_str(const std::string &); std::string get_str_reverse( void ); private: std::string str; }; // foo.cpp #include "foo.h" using std::string; string foo::get_str_reverse ( void ) { string temp; temp.assign(str); reverse(temp.begin(), temp.end()); return temp; } /* ----- end of method foo::get_str ----- */ void foo::set_str ( const string &s ) { str.assign(s); } /* ----- end of method foo::set_str ----- */ I've set up tags for stdlibc++ and generated the tags for these two files using: ctags -R --c++-kinds=+pl --fields=+iaS --extra=+q . When I type temp. in the cpp I get a list of string member functions as expected. But if I type str. omnicomplete spits out "Pattern Not Found". I've noticed that the temp. completion only works if I have the using std::string; declaration. How do I get completion to work on my class members?

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  • Codeigniter: db data in controller

    - by Kevin Brown
    I'm confused about what to do... I'm working on a user's page where they can view certain things only if their supervisor has given them "money" or "credits". I need a simple way to get the person that is their supervisor by doing something like: $data['employer'] = $this->home_model->getEmployees(array('user_id'=>$manager_id)); Basically, get the user information about a person who's user_id matches the manager_id of the currently logged in member. I don't know how to set the variable $manager_id. Additional Information: The current user has an id, and a manager_id. I need the id of the manager. So, I need to grab the manager_id of the logged-in user and find the manager who's user_id is that of the manager_id. What's the process to do this? I can get each individually, but I don't know how to use one to get the other... I know it is confusing, but I'm confused! Thanks for the help!

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  • Weird bug with C++ lambda expressions in VS2010

    - by Andrei Tita
    In a couple of my projects, the following code: class SmallClass { public: int x1, y1; void TestFunc() { auto BadLambda = [&]() { int g = x1 + 1; //ok int h = y1 + 1; //c2296 int l = static_cast<int>(y1); //c2440 }; int y1_copy = y1; //it works if you create a local copy auto GoodLambda = [&]() { int h = y1_copy + 1; //ok int l = this->y1 + 1; //ok }; } }; generates error C2296: '+' : illegal, left operand has type 'double (__cdecl *)(double)' or alternatively error C2440: 'static_cast' : cannot convert from 'double (__cdecl *)(double)' to 'int' You get the picture. It also happens if catching by value. The error seems to be tied to the member name "y1". It happened in different classes, different projects and with (seemingly) any type for y1; for example, this code: [...] MyClass y1; void TestFunc() { auto BadLambda = [&]()->void { int l = static_cast<int>(y1); //c2440 }; } generates both these errors: error C2440: 'static_cast' : cannot convert from 'MyClass' to 'int' No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called error C2440: 'static_cast' : cannot convert from 'double (__cdecl *)(double)' to 'int' There is no context in which this conversion is possible It didn't, however, happen in a completely new project. I thought maybe it was related to Lua (the projects where I managed to reproduce this bug both used Lua), but I did not manage to reproduce it in a new project linking Lua. It doesn't seem to be a known bug, and I'm at a loss. Any ideas as to why this happens? (I don't need a workaround; there are a few in the code already). Using Visual Studio 2010 Express version 10.0.40219.1 Sp1Rel.

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  • Asp.Net Login Control very slow initial connection to Non-Trusted AD Domain

    - by Eric Brown - Cal
    ASP.NET Login control is very slow making the initial connection to AD when authenticating to a different domain than the domain the web server is a member of. Problem occurs for the IIS server and when using with the Visual Studio's built in web server. It takes about 30 seconds the first time when attempting to use the control to connect against another domain. There is no trust relationship bewteen the web server's domain and the other domains (attempted connecting to several different domains). Subsequent connections execute quickly until the connection times out. Using Systernals Process Monitor to troubleshoot, there are two OpenQuery operations right before the delay to "C:\WINDOWS\asembly\GAC_MSIL\System.DirectoryServices\2.0.0.0_b03f5f7f11d50a3a\Netapi32.dll with a result NAME NOT FOUND" and right after the 30 second delay the TCP Send and TCP Recieves indicate communication begins with the AD server. Things we have tried: Impersonating an administrator on the web server in the web.config; Granting permissions to the CryptoKeys to the NetworkService and ASPNET; Specifying by IP instead of DNS name; Multiple variations of specifying the name and ldap server with domains and OU's; Local host entries; Looked for ports being blocked (SYN_SENT) with netstat -an. Nslookup resolves all the domains and systems involved correectly. TraceRt shows the Correct routes Any Idea or hints are greately appreicated.

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  • How do determine what is *really* causing your compiler error

    - by ML
    Hi All, I am porting a very large code base and I am having more difficulty with old code. For example, this causes a compiler error: inline CP_M_ReferenceCounted * FrAssignRef(CP_M_ReferenceCounted * & to, CP_M_ReferenceCounted * from) { if (from) from->AddReference(); if (to) to->RemoveReference(); to = from; return to; } The error is: error: expected initializer before '*' token. How do I know what this is. I looked up inline member functions to be sure I understood and I dont think the inlining is the cause but I am not sure what is. Another example: template <class eachClass> eachClass FrReferenceIfClass(FxRC * ptr) { eachClass getObject = dynamic_cast<eachClass>(ptr); if (getObject) getObject->AddReference(); return getObject; } The error is: error: template declaration of 'eachClass FrReferenceIfClass' That is all. How do I decide what this is?. I am admittedly rusty with templates.

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  • ASP.Net Problem with Event Handlers and Control Creation Timing

    - by Oliver Weichhold
    What I am trying to achieve here is to display a number of LinkButtons in a RadGrid Column. The buttons are generated from a collection property member of the bound grid row item. The CollectionLinkButton control is nothing more than a asp:Panel derived control that populates its Child Controls from "DataItem.SomeCollection" and this is working fine. The problem I am facing is with this part: Collection='<%# DataBinder.Eval(Container, "DataItem.SomeCollection") %' This is because databound Collection Property is populated so late in the lifecycle of the page that the LinkButton Controls that the CollectionLinkButton class creates from the collection are not available yet during Postback when the Click event Handler is supposed to fire and I have currently no idea how to solve this problem. <radG:RadGrid ID="grid" runat="server" DataSourceID="ds_AB"> <MasterTableView> <Columns> <radG:GridTemplateColumn> <ItemTemplate> <local:CollectionLinkButton ID="LinkButton1" runat="server" CssClass="EntityLinkButton" Collection='<%# DataBinder.Eval(Container, "DataItem.SomeCollection") %>' CollectionProperty="Id" CollectionDisplayProperty="Name" Text='<%# DataBinder.Eval(Container, "DataItem.Name") %>'</local:CollectionLinkButton> </ItemTemplate> </radG:GridTemplateColumn>

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  • Getting bizarre "expected primary-expression" error.

    - by Fecal Brunch
    Hi, I'm getting a really strange error when making a method call: /* input.cpp */ #include <ncurses/ncurses.h> #include "input.h" #include "command.h" Input::Input () { raw (); noecho (); } Command Input::next () { char input = getch (); Command nextCommand; switch (input) { case 'h': nextCommand.setAction (ACTION_MOVELEFT); break; case 'j': nextCommand.setAction (ACTION_MOVEDOWN); break; case 'k': nextCommand.setAction (ACTION_MOVEUP); break; case 'l': nextCommand.setAction (ACTION_MOVERIGHT); break; case 'y': nextCommand.setAction (ACTION_MOVEUPLEFT); break; case 'u': nextCommand.setAction (ACTION_MOVEUPRIGHT); break; case 'n': nextCommand.setAction (ACTION_MOVEDOWNLEFT); break; case 'm': nextCommand.setAction (ACTION_MOVEDOWNRIGHT); break; case '.': nextCommand.setAction (ACTION_WAIT); break; } return nextCommand; } and the error: Administrator@RHYS ~/code/rogue2 $ make g++ -c -Wall -pedantic -g3 -O0 input.cpp input.cpp: In member function `Command Input::next()': input.cpp:21: error: expected primary-expression before '=' token input.cpp:24: error: expected primary-expression before '=' token input.cpp:27: error: expected primary-expression before '=' token input.cpp:30: error: expected primary-expression before '=' token input.cpp:33: error: expected primary-expression before '=' token input.cpp:36: error: expected primary-expression before '=' token input.cpp:39: error: expected primary-expression before '=' token input.cpp:42: error: expected primary-expression before '=' token input.cpp:45: error: expected primary-expression before '=' token make: *** [input.o] Error 1 Sorry about the lack of linenumbers, the errors occur on the lines "nextCommand.setAction(...)", which is totally bizarre considering that they don't contain a '='. Any ideas? Thanks, Rhys

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  • asyncronous call doesn't return json

    - by Rebecca
    I am running wamp on an xp box. I am fairly new to web programming, this is for a student project, and have run out of avenues to try to solve this problem. Problem We have client side JavaScript code that uses GDownloadUrl- from the Google api- to wrap xmlHttpRequest calls to a php server side program that is accessing our database. In my callback program, the result of this call is always " ". However, if I use an alert to display the http:// call, with the arguments, and cut and paste that into my browser, the json I expected is displayed. I zipped my dir containing all the files, and tried it out on another team member's computer, and they were able to get the json in the callback function. Note this is exactly the same code and structure I was using, he just unzipped and ran. So now I'm thinking this is something about Firefox or Wamp? Would this be a config problem? I'm running wamp server 2.0, and Firefox 3.5.8. I have no problems with syncronous php, or reading in files asyncronously. Any help would be greatly appreciated. Rebecca

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  • Why do not C++11's move constructor/assignment operator act as expected

    - by xmllmx
    #include <iostream> using namespace std; struct A { A() { cout << "A()" << endl; } ~A() { cout << "~A()" << endl; } A(A&&) { cout << "A(A&&)" << endl; } A& operator =(A&&) { cout << "A& operator =(A&&)" << endl; return *this; } }; struct B { // According to the C++11, the move ctor/assignment operator // should be implicitly declared and defined. The move ctor // /assignment operator should implicitly call class A's move // ctor/assignment operator to move member a. A a; }; B f() { B b; // The compiler knows b is a temporary object, so implicitly // defined move ctor/assignment operator of class B should be // called here. Which will cause A's move ctor is called. return b; } int main() { f(); return 0; } My expected output should be: A() A(A&&) ~A() ~A() However, the actual output is: (The C++ compiler is: Visual Studio 2012) A() ~A() ~A() Is this a bug of VC++? or just my misunderstanding?

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  • How does jquery display an image received from an ajax request?

    - by Gnee
    I have this working great, but I'd like a deeper understanding of what is actually going on behind the scenes. I am using Jquery's Ajax method to pull 5 blog posts (returning only the title and first photo). A PHP script grabs the blog posts' title and first photo and sticks it in an array and sends it back to my browser as JSON. Upon receiving the JSON object, Jquery grabs the first member of the JSON object and displays it's title and photo. In a gallery I made, using buttons – the user can iterate the 1-5 posts. So the actual AJAX call happens right away, and only once. I am basically using this kind of setup: $('my_div').html(json_obj[i]) and each click does a i++. So jquery is plucking these blog posts from my computers memory, my web browsers cache, or some kind of cache in the Javascript engine? One of the things it's returning is a pretty gnarly animated gif. I just wonder if it constantly running in the background (but not visible), stealing processing cycles...etc. Or Javascript just inserting (say a flash movie) into the DOM, but before hand does nothing but take up a little memory (no processing). Anyway, I'm just curious. If someone is a guru on this, I'd love to hear your take. Thanks!!

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  • Search Form in Responsive Design - Remove Search button on Mobile

    - by Kevin
    I'm working with a search box in the header of a responsive website. On desktop/tablet widths, there's a search input field and a styled 'search' button to the right. You can type in a search term and either click 'SEARCH' button or just hit enter on the keyboard with the same result. When you scale down to mobile widths, the search input field fills the width of the screen. The submit button falls below it. On a desktop, clicking the button or hitting enter activate the search. On an actual iphone phone, you can hit the 'SEARCH' button, but the native mobile keyboard that rises from the bottom of the screen has a search button where the enter/return key would normally be. It seems to know I'm in a form and the keyboard automatically gives me the option to kick off the search by basically hitting the ENTER key location....but it says SEARCH. So far so good. I figure I don't need the button in the header on mobile since it's already in the keyboard. Therefore, I'll hide the button on mobile widths and everything will be tighter and look better. So I added this to my CSS to hide it in mobile: #search-button {display: none;} But now the search doesn't work at all. On mobile, I don't get the option in the keyboard that showed up before and if I just hit enter, it doesn't work at all. On desktop at mobile width, hitting enter also not longer works. So clearly by hiding the submit/search button, the phone no longer gave me the native option to run the search. In addition, on the desktop at mobile width, even hitting enter inside the search input box also fails to launch the the search. Here's my search box: <form id="search-form" method="get" accept-charset="UTF-8, utf-8" action="search.php"> <fieldset> <div id="search-wrapper"> <label id="search-label" for="search">Item:</label> <input id="search" class="placeholder-color" name="item" type="text" placeholder="Item Number or Description" /> <button id="search-button" title="Go" type="submit"><span class="search-icon"></span></button> </div> </fieldset> </form> Here's what my CSS looks like: #search-wrapper { float: left; display: inline-block; position: relative; white-space: nowrap; } #search-button { display: inline-block; cursor: pointer; vertical-align: top; height: 30px; width: 40px; } @media only screen and (max-width: 639px) { #search-wrapper { display: block; margin-bottom: 7px; } #search-button { /* this didn't work....it hid the button but the search failed to load */ display: none;*/ } } So.....how can I hide this submit button when I'm on a mobile screen, but still let the search run from the mobile keyboard or just run by hitting enter when in the search input box. I was sure that putting display:none on the search button at mobile width would do the trick, but apparently not. Thanks...

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  • Returning the same type the function was passed

    - by Ken Bloom
    I have the following code implementation of Breadth-First search. trait State{ def successors:Seq[State] def isSuccess:Boolean = false def admissableHeuristic:Double } def breadthFirstSearch(initial:State):Option[List[State]] = { val open= new scala.collection.mutable.Queue[List[State]] val closed = new scala.collection.mutable.HashSet[State] open.enqueue(initial::Nil) while (!open.isEmpty){ val path:List[State]=open.dequeue() if(path.head.isSuccess) return Some(path.reverse) closed += path.head for (x <- path.head.successors) if (!closed.contains(x)) open.enqueue(x::path) } return None } If I define a subtype of State for my particular problem class CannibalsState extends State { //... } What's the best way to make breadthFirstSearch return the same subtype as it was passed? Supposing I change this so that there are 3 different state classes for my particular problem and they share a common supertype: abstract class CannibalsState extends State { //... } class LeftSideOfRiver extends CannibalsState { //... } class InTransit extends CannibalsState { //... } class RightSideOfRiver extends CannibalsState { //... } How can I make the types work out so that breadthFirstSearch infers that the correct return type is CannibalsState when it's passed an instance of LeftSideOfRiver? Can this be done with an abstract type member, or must it be done with generics?

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  • Potential g++ template bug?

    - by Evan Teran
    I've encountered some code which I think should compile, but doesn't. So I'm hoping some of the local standards experts here at SO can help :-). I basically have some code which resembles this: #include <iostream> template <class T = int> class A { public: class U { }; public: U f() const { return U(); } }; // test either the work around or the code I want... #ifndef USE_FIX template <class T> bool operator==(const typename A<T>::U &x, int y) { return true; } #else typedef A<int> AI; bool operator==(const AI::U &x, int y) { return true; } #endif int main() { A<int> a; std::cout << (a.f() == 1) << std::endl; } So, to describe what is going on here. I have a class template (A) which has an internal class (U) and at least one member function which can return an instance of that internal class (f()). Then I am attempting to create an operator== function which compares this internal type to some other type (in this case an int, but it doesn't seem to matter). When USE_FIX is not defined I get the following error: test.cc: In function 'int main()': test.cc:27:25: error: no match for 'operator==' in 'a.A<T>::f [with T = int]() == 1' Which seems odd, because I am clearly (I think) defining a templated operator== which should cover this, in fact if I just do a little of the work for the compiler (enable USE_FIX), then I no longer get an error. Unfortunately, the "fix" doesn't work generically, only for a specific instantiation of the template. Is this supposed to work as I expected? Or is this simply not allowed? BTW: if it matters I am using gcc 4.5.2.

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  • How to get the title and subtitle for a pin when we are implementing the MKAnnotation?

    - by wolverine
    I have implemented the MKAnnotation as below. I will put a lot of pins and the information for each of those pins are stored in an array. Each member of this array is an object whose properties will give the values for the title and subtitle of the pin. Each object corresponds to a pin. But how can I display these values for the pin when I click a pin?? @interface UserAnnotation : NSObject <MKAnnotation> { CLLocationCoordinate2D coordinate; NSString *title; NSString *subtitle; NSString *city; NSString *province; } @property (nonatomic, assign) CLLocationCoordinate2D coordinate; @property (nonatomic, retain) NSString *title; @property (nonatomic, retain) NSString *subtitle; @property (nonatomic, retain) NSString *city; @property (nonatomic, retain) NSString *province; -(id)initWithCoordinate:(CLLocationCoordinate2D)c; And .m is @implementation UserAnnotation @synthesize coordinate, title, subtitle, city, province; - (NSString *)title { return title; } - (NSString *)subtitle { return subtitle; } - (NSString *)city { return city; } - (NSString *)province { return province; } -(id)initWithCoordinate:(CLLocationCoordinate2D)c { coordinate=c; NSLog(@"%f,%f",c.latitude,c.longitude); return self; } @end

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  • How to initialize audio with Vala/SDL

    - by ioev
    I've been trying to figure this out for a few hours now. In order to start up the audio, I need to create an SDL.AudioSpec object and pass it to SDL.Audio.Open. The problem is, AudioSpec is a class with a private constructor, so when I try to create one I get: sdl.vala:18.25-18.43: error: `SDL.AudioSpec' does not have a default constructor AudioSpec audiospec = new SDL.AudioSpec(); ^^^^^^^^^^^^^^^^^^^ And if I try to just assign values to it's member vars like a struct (it's a struct in normal sdl) I get: sdl.vala:20.3-20.25: error: use of possibly unassigned local variable `audiospec' audiospec.freq = 22050; ^^^^^^^^^^^^^^^^^^^^^^^ I found the valac doc here: http://valadoc.org/sdl/SDL.AudioSpec.html But it isn't much help at all. The offending code block looks like this: // setup the audio configuration AudioSpec audiospec; AudioSpec specback; audiospec.freq = 22050; audiospec.format = SDL.AudioFormat.S16LSB; audiospec.channels = 2; audiospec.samples = 512; // try to initialize sound with these values if (SDL.Audio.open(audiospec, specback) < 0) { stdout.printf("ERROR! Check audio settings!\n"); return 1; } Any help would be greatly appreciated!

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  • lambda traits inconsistency across C++0x compilers

    - by Sumant
    I observed some inconsistency between two compilers (g++ 4.5, VS2010 RC) in the way they match lambdas with partial specializations of class templates. I was trying to implement something like boost::function_types for lambdas to extract type traits. Check this for more details. In g++ 4.5, the type of the operator() of a lambda appears to be like that of a free standing function (R (*)(...)) whereas in VS2010 RC, it appears to be like that of a member function (R (C::*)(...)). So the question is are compiler writers free to interpret any way they want? If not, which compiler is correct? See the details below. template <typename T> struct function_traits : function_traits<decltype(&T::operator())> { // This generic template is instantiated on both the compilers as expected. }; template <typename R, typename C> struct function_traits<R (C::*)() const> { // inherits from this one on VS2010 RC typedef R result_type; }; template <typename R> struct function_traits<R (*)()> { // // inherits from this one g++ 4.5 typedef R result_type; }; int main(void) { auto lambda = []{}; function_traits<decltype(lambda)>::result_type *r; // void * } This program compiles on both g++ 4.5 and VS2010 but the function_traits that are instantiated are different as noted in the code.

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  • super light software development process

    - by Walty
    hi, For the development process I have involved so far, most have teams of SINGLE member, or occasionally two. We used python + django for the major development, the development process is actually very fast, and we do have code reviews, design pattern discussions, and constant refactoring. Though team size is small, I do think there are some development processes / best practices that could be enforced. For example, using svn would be definitely better than regular copy backup. I did read some articles & books about Agile, XP & continuous integration, I think they are nice, but still too heavy for this case (team of 1 or 2, and fast coding). For example, IMHO, with nice design pattern, and iterative development + refactoring, the TDD MIGHT be an overkill, or at least the overhead does not out-weight the advantages. And so is the pair programming. The automated testing is a nice idea, but it seems not technically feasible for every project. our current practices are: svn + milestone + code review I wonder if there are development processes / best practices specifically targeted on such super light teams? thanks.

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