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  • boost::python string-convertible properties

    - by Checkers
    I have a C++ class, which has the following methods: class Bar { ... const Foo& getFoo() const; void setFoo(const Foo&); }; where class Foo is convertible to std::string (it has an implicit constructor from std::string and an std::string cast operator). I define a Boost.Python wrapper class, which, among other things, defines a property based on previous two functions: class_<Bar>("Bar") ... .add_property( "foo", make_function( &Bar::getFoo, return_value_policy<return_by_value>()), &Bar::setFoo) ... I also mark the class as convertible to/from std::string. implicitly_convertible<std::string, Foo>(); implicitly_convertible<Foo, std::string>(); But at runtime I still get a conversion error trying to access this property: TypeError: No to_python (by-value) converter found for C++ type: Foo How to achieve the conversion without too much boilerplate of wrapper functions? (I already have all the conversion functions in class Foo, so duplication is undesirable.

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  • Return lines in input code causing gaps/whitespace between elements in output?

    - by Jenny Zhang
    I am trying to put images next to each other on a webpage. Here is my HTML: <img class="pt" src="Yellow Tulip.jpg" title="Yellow Tulip" alt="Yellow Tulip" /> <img class="pt" src="Pink Tulip.jpg" title="Pink Tulip" alt="Pink Tulip" /> <img class="pt" src="Purple Tulip.jpg" title="Purple Tulip" alt="Purple Tulip" /> However, on my webpage, this shows a gap between each image. I've noticed that once I remove the return line that makes the elements separate and readable and instead just put all the elements on one line, the gaps go away. <img class="pt" src="Yellow Tulip.jpg" title="Yellow Tulip" alt="Yellow Tulip" /><img class="pt" src="Pink Tulip.jpg" title="Pink Tulip" alt="Pink Tulip" /><img class="pt" src="Purple Tulip.jpg" title="Purple Tulip" alt="Purple Tulip" /> Is there anyway I can achieve the output of the latter but still have the code/input look like the former? I really like the readability that the return lines (enter spaces) bring to the code, but I don't want the whitespace it creates on the actual page. If someone could explain why this is and/or how to fix it, I'd be really grateful! :)

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  • Why is this ajax call being made even though it shouldn't be

    - by user2921557
    i have this validation script im working on but cant see why im having an issue. You can see that i have a check = false / true, check before it runs the ajax call. However, even if a field is empty and check is set to false, it is still running the call. so: // JavaScript - Update Password AJAX $(document).ready(function () { // When the form is submitted $('.updatepasswordform').submit(function () { var check = true; // Get the values var password1 = $("input[name=password1]").val(); var password2 = $("input[name=password2]").val(); var newpassword = $("input[name=newpassword]").val(); /* Password Validation */ // If fields are empty if (password1 === '') { check = false; $("input[name=password1]").css('border', 'solid 2px red'); } // If fields are empty if (password2 === '') { check = false; $("input[name=password2]").css('border', 'solid 2px red'); } // If fields are empty if (newpassword === '') { check = false; $("input[name=newpassword]").css('border', 'solid 2px red'); } if (check = true) { $.ajax({ type: "POST", url: "process/updatepassword.php", data: $(".updatepasswordform").serialize(), dataType: "json", success: function (response) { /* Checks for database validation, removed for space saving */ } }); } return false; }); });

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  • jquery .on() toggle div

    - by lollo
    i'm developing a blog with dynamic content loaded via ajax request and i'm trying to hide/show the "post comment" form, of the article, with a button : <div id="post"> ... <ol id="update" class="timeline"> <!-- comments here --> </ol> <button class="mybutton Bhome">Commenta</button><!-- hide/show button --> <div class="mycomment"><!-- div to hide/show --> <form action="#" method="post"> Nome: <input type="text" size="12" id="name" /><br /> Email: <input type="text" size="12" id="email" /><br /> <textarea rows="10" cols="50" class="mytext" id="commentArea"></textarea><br /> <input type="submit" class="Bhome" value=" Post " /> </form> </div><!-- mycomment --> </div><!-- post --> This jquery code works well but has effect on All the posts... $("div").on("click", ".mybutton", function(e){ $(".mycomment").slideToggle("slow"); e.stopPropagation(); }); I want that only the clicked hide/show button has effect on the related article but f i have more than one article on my page the button with .mybutton class hides or shows all the comment form of all the articles.

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  • Decimal problem in Java

    - by Jerome
    I am experimenting with writing a java class for financial engineering (hobby of mine). The algorithm that I desire to implement is: 100 / 0.05 = 2000 Instead I get: 100 / 0.05 = 2000.9999999999998 I understand the problem to be one with converting from binary numbers to decimals (float -- int). I have looked at the BigDecimal class on the web but have not quite found what I am looking for. Attached is the program and a class that I wrote: // DCF class public class DCF { double rate; double principle; int period; public DCF(double $rate, double $principle, int $period) { rate = $rate; principle = $principle; period = $period; } // returns the console value public double consol() { return principle/rate; } // to string Method public String toString() { return "(" + rate + "," + principle + "," + period + ")"; } } Now the actual program: // consol program public class DCFmain { public static void main(String[] args) { // create new DCF DCF abacus = new DCF(0.05, 100.05, 5); System.out.println(abacus); System.out.println("Console value= " + abacus.consol() ); } } Output: (0.05,100.05,5) Console value= 2000.9999999999998 Thanks!

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  • JavaScript - Efficiently find all elements containing one of a large set of strings

    - by noah
    I have a set of strings and I need to find all all of the occurrences in an HTML document. Where the string occurs is important because I need to handle each case differently: String is all or part of an attribute. e.g., the string is foo: <input value="foo"> - Add class ATTR to the element. String is the full text of an element. e.g., <button>foo</button> - Add class TEXT to the element. String is inline in the text of an element. e.g., <p>I love foo</p> - Wrap the text in a span tag with class TEXT. Also, I need to match the longest string first. e.g., if I have foo and foobar, then <p>I love foobar</p> should become <p>I love <span class="TEXT">foobar</span></p>, not <p>I love <span class="TEXT">foo</span>bar</p>. The inline text is easy enough: Sort the strings descending by length and find and replace each in document.body.innerHTML with <span class="TEXT">$1</span>, although I'm not sure if that is the most efficient way to go. For the attributes, I can do something like this: sortedStrings.each(function(it) { document.body.innerHTML.replace(new RegExp('(\S+?)="[^"]*'+escapeRegExChars(it)+'[^"]*"','g'),function(s,attr) { $('[+attr+'*='+it+']').addClass('ATTR'); }); }); Again, that seems inefficient. Lastly, for the full text elements, a depth first search of the document that compares the innerHTML to each string will work, but for a large number of strings, it seems very inefficient. Any answer that offers performance improvements gets an upvote :)

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  • MVC3 View For Loop values initialization

    - by Ryan
    So I have a for loop in my View that is supposed to render out the input boxes. Now inside these input boxes I want to put lables that disappear when you click on them. This is all simple. Now it's probably because my brain was wired for php first, and it has been difficult to get it to think in lambdas and object orientation, but I can't figure out how to do this: @{ for (int i = 0; i < 3; i++) { <div class="editor-label grid_2">User</div> Model.Users[i].UserFirstName = "First Name"; Model.Users[i].UserLastName = "Last Name"; Model.Users[i].UserEmailAddress = "Email Address"; <div class="grid_10"> @Html.TextBoxFor(m => Model.Users[i].UserFirstName, new { @class = "user-input" }) @Html.TextBoxFor(m => Model.Users[i].UserLastName, new { @class = "user-input" }) @Html.TextBoxFor(m => Model.Users[i].UserEmailAddress, new { @class = "user-input-long" }) @Html.CheckBoxFor(m => Model.Users[i].IsUserAdmin) <span>&nbsp;admin?</span> </div> <div class="clear"> </div> } } And initialize the values for the users. And you're probably thinking "Of course that won't work. You're going to get a Null Reference Exception", and you would be correct. I might need to initialize them somewhere else and I don't realize it but I'm just not sure. I've tried the [DefaultValue("First Name")] route and that doesn't work. I'm probably thinking about this wrong, but my brain is already shot from trying to figure out how to wire up these events to the controller, so any help would be appreciated!

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  • When using a repository is it possible for a type to return a Func that the repository uses to test for existing entities?

    - by Scott Rickman
    For example given a Factory with a method public static T Save<T>(T item) where T : Base, new() { /* item.Id == Guid.Empty therefore item is new */ if (item.Id == Guid.Empty && repository.GetAll<T>(t => t.Name == item.Name)) { throw new Exception("Name is not unique"); } } how do I create a property of Base (say MustNotAlreadyExist) so that I can change the method above to public static T Save<T>(T item) where T : Base, new() { /* item.Id == Guid.Empty therefore item is new */ if (item.Id == Guid.Empty && repository.GetAll<T>(t.MustNotAlreadyExist)) { throw new Exception("Name is not unique"); } } public class Base { ... public virtual Expression<Func<T, bool>> MustNotAlreadyExist() { return (b => b.Name == name); /* <- this clearly doesn't work */ } } and then how can I override MustNotAlreadyExist in Account : Base public class Account : Base { ... public override Expression<Func<T, bool>> MustNotAlreadyExist() { return (b => b.Name == name && b.AccountCode == accountCode); /* <- this doesn't work */ } ... }

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  • How do I DRY up business logic between sever-side Ruby and client-side Javascript?

    - by James A. Rosen
    I have a Widget model with inheritance (I'm using Single-Table Inheritance, but it's equally valid for Class-per-Table). Some of the subclasses require a particular field; others do not. class Widget < ActiveRecord ALL_WIDGET_TYPES = [FooWidget, BarWidget, BazWidget] end class FooWidget < Widget validates_presence_of :color end class BarWidget < Widget # no color field end class BazWidget < Widget validates_presence_of :color end I'm building a "New Widget" form (app/views/widgets/new.html.erb) and would like to dynamically show/hide the color field based on a <select> for widget_type. <% form_for @widget do |f| %> <%= f.select :type, Widget::ALL_WIDGET_TYPES %> <div class='hiddenUnlessWidgetTypeIsFooOrBaz'> <%= f.label :color %> <%= f.text_field :color %> </div> <% end %> I can easily write some jQuery to watch for onChange events on widget_type, but that would mean putting some sort of WidgetTypesThatRequireColor constant in my Javascript. Easy enough to do manually, but it is likely to get disconnected from the Widget model classes. I would prefer not to output Javascript directly in my view, though I have considered using content_for(:js) and have a yield :js in my template footer. Any better ideas?

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  • How do I structure my tests with Python unittest module?

    - by persepolis
    I'm trying to build a test framework for automated webtesting in selenium and unittest, and I want to structure my tests into distinct scripts. So I've organised it as following: base.py - This will contain, for now, the base selenium test case class for setting up a session. import unittest from selenium import webdriver # Base Selenium Test class from which all test cases inherit. class BaseSeleniumTest(unittest.TestCase): def setUp(self): self.browser = webdriver.Firefox() def tearDown(self): self.browser.close() main.py - I want this to be the overall test suite from which all the individual tests are run. import unittest import test_example if __name__ == "__main__": SeTestSuite = test_example.TitleSpelling() unittest.TextTestRunner(verbosity=2).run(SeTestSuite) test_example.py - An example test case, it might be nice to make these run on their own too. from base import BaseSeleniumTest # Test the spelling of the title class TitleSpelling(BaseSeleniumTest): def test_a(self): self.assertTrue(False) def test_b(self): self.assertTrue(True) The problem is that when I run main.py I get the following error: Traceback (most recent call last): File "H:\Python\testframework\main.py", line 5, in <module> SeTestSuite = test_example.TitleSpelling() File "C:\Python27\lib\unittest\case.py", line 191, in __init__ (self.__class__, methodName)) ValueError: no such test method in <class 'test_example.TitleSpelling'>: runTest I suspect this is due to the very special way in which unittest runs and I must have missed a trick on how the docs expect me to structure my tests. Any pointers?

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  • Working with libpath with java reflection.

    - by C. Ross
    I'm dynamically loading a class and calling a method on it. This class does JNI. When I call the class, java attempts to load the library. This causes an error because the library is not on the libpath. I'm calling from instead a jar so I can't easily change the libpath (especially since the library is not in the same directory or a sub directory of the jar). I do know the path of the library, but how can I load it before I load the class. Current code: public Class<?> loadClass(String name) throws ClassNotFoundException { if(!CLASS_NAME.equals(name)) return super.loadClass(name); try { URL myUrl = new URL(classFileUrl); URLConnection connection = myUrl.openConnection(); InputStream input = connection.getInputStream(); byte[] classData = readConnectionToArray(input); return defineClass(CLASS_NAME, classData, 0, classData.length); } catch (MalformedURLException e) { throw new UndeclaredThrowableException(e); } catch (IOException e) { throw new UndeclaredThrowableException(e); } } Exception: Can't find library libvcommon.so java.lang.UnsatisfiedLinkError: vcommon (A file or directory in the path name does not exist.) at java.lang.ClassLoader.loadLibraryWithPath(ClassLoader.java:998) at java.lang.ClassLoader.loadLibraryWithClassLoader(ClassLoader.java:962) at java.lang.System.loadLibrary(System.java:465) at vcommon.(vcommon.java:103) at java.lang.J9VMInternals.initializeImpl(Native Method) at java.lang.J9VMInternals.initialize(J9VMInternals.java:200) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37) at java.lang.reflect.Method.invoke(Method.java:599) at com.fortune500.fin.v.vunit.reflection.ReflectionvProcessor.calculateV(ReflectionvProcessor.java:36) at com.fortune500.fin.v.vunit.UTLTestCase.execute(UTLTestCase.java:42) at com.fortune500.fin.v.vunit.TestSuite.execute(TestSuite.java:15) at com.fortune500.fin.v.vunit.batch.Testvendor.execute(Testvendor.java:101) at com.fortune500.fin.v.vunit.batch.Testvendor.main(Testvendor.java:58) Related: Dynamic loading a class in java with a different package name

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  • Is it possible to parameterize a MEF import?

    - by Josh Einstein
    I am relatively new to MEF so I don't fully understand the capabilities. I'm trying to achieve something similar to Unity's InjectionMember. Let's say I have a class that imports MEF parts. For the sake of simplicity, let's take the following class as an example of the exported part. [Export] [PartCreationPolicy(CreationPolicy.NonShared)] public class Logger { public string Category { get; set; } public void Write(string text) { } } public class MyViewModel { [Import] public Logger Log { get; set; } } Now what I'm trying to figure out is if it's possible to specify a value for the Category property at the import. Something like: public class MyViewModel { [MyImportAttribute(Category="MyCategory")] public Logger Log { get; set; } } public class MyOtherViewModel { [MyImportAttribute(Category="MyOtherCategory")] public Logger Log { get; set; } } For the time being, what I'm doing is implementing IPartImportsSatisfiedNotification and setting the Category in code. But obviously I would rather keep everything neatly in one place.

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  • How to add a new entry to a multiple has_many association?

    - by siulamvictor
    I am not sure am I doing these correct. I have 3 models, Account, User, and Event. Account contains a group of Users. Each User have its own username and password for login, but they can access the same Account data under the same Account. Events is create by a User, which other Users in the same Account can also read or edit it. I created the following migrations and models. User migration class CreateUsers < ActiveRecord::Migration def self.up create_table :users do |t| t.integer :account_id t.string :username t.string :password t.timestamps end end def self.down drop_table :users end end Account migration class CreateAccounts < ActiveRecord::Migration def self.up create_table :accounts do |t| t.string :name t.timestamps end end def self.down drop_table :accounts end end Event migration class CreateEvents < ActiveRecord::Migration def self.up create_table :events do |t| t.integer :account_id t.integer :user_id t.string :name t.string :location t.timestamps end end def self.down drop_table :events end end Account model class Account < ActiveRecord::Base has_many :users has_many :events end User model class User < ActiveRecord::Base belongs_to :account end Event model class Event < ActiveRecord::Base belongs_to :account belongs_to :user end so.... Is this setting correct? Every time when a user create a new account, the system will ask for the user information, e.g. username and password. How can I add them into correct tables? How can I add a new event? I am sorry for such a long question. I am not very understand the rails way in handling such data structure. Thank you guys for answering me. :)

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  • Jquery Append() and remove() element

    - by BandonRandon
    Hi, I have a form where I'm dynamically adding the ability to upload files with the append function but I would also like to be able to remove unused fields. Here is the html markup <span class="inputname">Project Images: <a href="#" class="add_project_file"><img src="images/add_small.gif" border="0"></a></span> <span class="project_images"> <input name="upload_project_images[]" type="file" /><br/> </span> Right now if they click on the "add" gif a new row is added with this jquery $('a.add_project_file').click(function() { $(".project_images").append('<input name="upload_project_images[]" type="file" class="new_project_image" /> <a href="#" class="remove_project_file" border="2"><img src="images/delete.gif"></a><br/>'); return false; }); To remove the input box i've tried to add the class "remove_project_file" then add this function. $('a.remove_project_file').click(function() { $('.project_images').remove(); return false;}); I think there should be a much easier way to do this. Maybe i need to use the $(this) function for the remove. Another possible solution would be to expand the "add project file" to do both adding and removing fields. Any of you JQuery wizards have any ideas that would be great

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  • adding a div with data()

    - by Dizzy Bryan High
    Hi people am generating a list of flash swfs, the information comes from an ajax call which returns a json object which i loop through to create the rows of data using my makeAppRow function. makeAppRow = function(myData){ var myStr = '<div class="fileEntry">' myStr = myStr +'<div class="appDate">'+dateFormat(myData.date_swf, "dS mmmm, yyyy, h:MM TT")+'</div>' myStr = myStr +'<div class="appName">'+myData.name_swf+'</div>' myStr = myStr +'<div class="appOptions" data>' myStr = myStr +'<div class="gotoAppBtn" data-options="'+myData+'">Open App</div>' myStr = myStr +'</div>' myStr = myStr +'</div>' $('#appData').append(myStr); } I need the json data to be attached to the gotoAppBtn so that when its clicked i can read in the data from the attached json object and use it in my click function, as you can see ive been trying to embed the data using the html5 data but i cant get it to work. <div class="gotoAppBtn" data-options="'+myData+'">Open App</div> i have a function so that when the button is clicked it loads in an swf. $('.gotoAppBtn').live('click', function(){ //alert('button clicked') var myData = $(this).data("options") alert('../userfiles/'+myData.id_ugp+'/'+myData.id_swf+'/'+myData.launchfile_swf+'') console.log(myData); var flashvars = {}; var params = {}; params.menu = "false"; params.quality = "best"; params.scale = "noscale"; var attributes = {}; attributes.id = "flashAppDisplay"; attributes.name = "flashAppDisplay"; swfobject.embedSWF( '../userfiles/'+myData.id_ugp+'/'+myData.id_swf+'/'+myData.launchfile_swf+'', 'flashAppDisplay', myData.width_swf, myData.height_swf, myData.version_swf ,"../FAVideo/expressInstall.swf", flashvars, params, attributes) }); but the data does not seem to be there, any pointers on where i am going wrong, or a better way to achive this???

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  • Partial slideDown with jQuery

    - by Jon
    I have some buttons that have drawer menus and what I'd like to do is add a state so that when the user hovers over the button, the drawer bumps out slightly (maybe with a little wiggle/rubber-banding) so that they know that there's a drawer with more information. I have the sliding working and a hover function set up, but I don't know how to implement a partial slideDown. Any ideas? FIDDLE. Code: <div class="clause"> <div class="icon"><img src="http://i.imgur.com/rTu40.png"/></div> <div class="label">Location</div> <div class="info">Midwest > Indiana, Kentucky; Southwest > Texas, Nevada, Utah; Pacific > California, Hawaii</div> </div> <div class="drawer">Info 1<br/><br/></div> <div class="drawerBottom"></div> $(".clause").click(function() { var tmp = $(this).next("div.drawer"); if(tmp.is(":hidden")) tmp.slideDown('3s'); else tmp.slideUp('3s'); }); $(".clause").hover(function() { });

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  • php oop and mysql

    - by gloris
    I need to get data, to check and send to db. Programming with PHP OOP. Could you tell me if my class structure is good and how dislpay all data?. Thanks <?php class Database{ private $DBhost = 'localhost'; private $DBuser = 'root'; private $DBpass = 'root'; private $DBname = 'blog'; public function connect(){ //Connect to mysql db } public function select($rows){ //select data from db } public function insert($rows){ //Insert data to db } public function delete($rows){ //Delete data from db } } class CheckData{ public $number1; public $number2; public function __construct(){ $this->number1 = $_POST['number1']; $this->number2 = $_POST['number2']; } function ISempty(){ if(!empty($this->$number1)){ echo "Not Empty"; $data = new Database(); $data->insert($this->$number1); } else{ echo "Empty1"; } if(!empty($this->$number2)){ echo "Not Empty"; $data = new Database(); $data->insert($this->$number2); } else{ echo "Empty2"; } } } class DisplayData{ //How print all data? function DisplayNumber(){ $data = new Database(); $data->select(); } } $check = new CheckData(); $check->ISempty(); $display = new DisplayData() $display->DisplayNumber(); ?>

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  • accessing private variable from member function in PHP

    - by Carson Myers
    I have derived a class from Exception, basically like so: class MyException extends Exception { private $_type; public function type() { return $this->_type; //line 74 } public function __toString() { include "sometemplate.php"; return ""; } } Then, I derived from MyException like so: class SpecialException extends MyException { private $_type = "superspecial"; } If I throw new SpecialException("bla") from a function, catch it, and go echo $e, then the __toString function should load a template, display that, and then not actually return anything to echo. This is basically what's in the template file <div class="<?php echo $this->type(); ?>class"> <p> <?php echo $this->message; ?> </p> </div> in my mind, this should definitely work. However, I get the following error when an exception is thrown and I try to display it: Fatal error: Cannot access private property SpecialException::$_type in C:\path\to\exceptions.php on line 74 Can anyone explain why I am breaking the rules here? Am I doing something horribly witty with this code? Is there a much more idiomatic way to handle this situation? The point of the $_type variable is (as shown) that I want a different div class to be used depending on the type of exception caught.

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  • Service reference not generating client types

    - by Cranialsurge
    I am trying to consume a WCF service in a class library by adding a service reference to it. In one of the class libraries it gets consumed properly and I can access the client types in order to generate a proxy off of them. However in my second class library (or even in a console test app), when i add the same service reference, it only exposes the types that are involved in the contract operations and not the client type for me to generate a proxy against. e.g. Endpoint has 2 services exposed - ISvc1 and ISvc2. When I add a service reference to this endpoint in the first class library I get ISvc1Client andf ISvc2Client to generate proxies off of in order to use the operations exposed via those 2 contracts. In addition to these clients the service reference also exposes the types involved in the operations like (type 1, type 2 etc.) this is what I need. However when i try to add a service reference to the same endpoing in another console application or class library only Type 1, Type 2 etc. are exposed and not ISvc1Client and ISvc2Client because of which I cannot generate a proxy to access the operations I need. I am unable to determine why the service reference gets properly generated in one class library but not in the other or the test console app.

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  • Floating not right in ie ?

    - by Tom
    Hi, i want to do like the following format: So this is what i did : <style> .toptitle{ font-size:14px; } .toprating{ background:yellow; float:left; font-size:12px; } .topcontainer{ border-bottom:1px #CCCCCC solid; } </style> <div class="topcontainer"> <div class="toprating">256</div> <div class="toptitle">Lorem Ipsum...</div> </div> <br> <div class="topcontainer"> <div class="toprating">256</div> <div class="toptitle">Lorem Ipsum...</div> </div> Now, in firefox,chrome,safari, this works perfectly, but in IE the title goes about 30 px down. Is there a mistake in the code, or is there any better code to do this?

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  • Retaining Managed objects - more general retaining objects

    - by Luuk D. Jansen
    A quick question regarding Managed Objects. I created an Array with Managed Objects (in Object 1: TableViewConbtroller), and pass one of those objects to another class/object (object 2: TableCell). The original array should still be retained in the original caller class. Then Object 2 is released, does that mean that that particular item in the array is released as well, as the reference to it in Object 2 was released? I am trying to better understand how to work with ManagedObjects as I get 'Object was released' errors. [EDIT] After some experimenting I came across the following scenario: I have the main AppDelegate. In a different class I create an AppDelegate to obtain the ManagedObjectContext. appDelegate = (iDomsAppDelegate *)[[UIApplication sharedApplication] delegate]; [self setContext:[appDelegate managedObjectContext]]; When the class is finished, and I release it, the variable in the class 'appDelegate' is also released. But then the ManagedObjectContext is closed, and obvious any future attempt to use it will cause a crash. So should I leave the appDelegate unreleased? This comes to the same question as the above about when and how to release in those situations where an objects is used from another class. I think a way of putting it is, how to know when you own an object and when not.

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  • How do virtual destructors work?

    - by Prabhu
    Few hours back I was fiddling with a Memory Leak issue and it turned out that I really got some basic stuff about virtual destructors wrong! Let me put explain my class design. class Base { virtual push_elements() {} }; class Derived:public Base { vector<int> x; public: void push_elements(){ for(int i=0;i <5;i++) x.push_back(i); } }; void main() { Base* b = new Derived(); b->push_elements(); delete b; } The bounds checker tool reported a memory leak in the derived class vector. And I figured out that the destructor is not virtual and the derived class destructor is not called. And it surprisingly got fixed when I made the destructor virtual. Isn't the vector deallocated automatically even if the derived class destructor is not called? Is that a quirk in BoundsChecker tool or is my understanding of virtual destructor wrong?

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  • Use properties or methods to expose business rules in C#?

    - by Val
    I'm writing a class to encapsulate some business rules, each of which is represented by a boolean value. The class will be used in processing an InfoPath form, so the rules get the current program state by looking up values in a global XML data structure using XPath operations. What's the best (most idiomatic) way to expose these rules to callers -- properties or public methods? Call using properties Rules rules = new Rules(); if ( rules.ProjectRequiresApproval ) { // get approval } else { // skip approval } Call using methods Rules rules = new Rules(); if ( rules.ProjectRequiresApproval() ) { // get approval } else { // skip approval } Rules class exposing rules as properties public class Rules() { private int _amount; private int threshold = 100; public Rules() { _amount = someExpensiveXpathOperation; } // rule property public bool ProjectRequiresApproval { get { return _amount < threshold } } } Rules class exposing rules as methods public class Rules() { private int _amount; private int threshold = 100; public Rules() { _amount = someExpensiveXpathOperation; } // rule method public bool ProjectRequiresApproval() { return _amount < threshold; } } What are the pros and cons of one over the other?

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  • Is context:annotation-config an alternative to @AutoWired?

    - by Antacid
    Is it correct that I can put context:annotation-config in my XML config and it will automatically inject the bean class without needing any annotations? So instead of using these annotation types: public class Mailman { private String name; @Autowired private Parcel Parcel; public Mailman(String name) { this.name = name; } @Autowired public void setParcel(Parcel Parcel) { this.Parcel = Parcel; } @Autowired public void directionsToParcel(Parcel Parcel) { this.Parcel = Parcel; } } I would just need to write this: <beans ... > <bean id="mailMan" class="MailMan"> <constructor-arg value="John Doe"/> </bean> <bean id="parcel" class="Parcel" /> <context:annotation-config /> </beans> and then my MailMan class would look a lot simpler without the need for annotations: public class Mailman { private String name; private Parcel Parcel; public Mailman(String name) { this.name = name; } }

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  • OO model for nsxmlparser when delegate is not self

    - by richard
    Hi, I am struggling with the correct design for the delegates of nsxmlparser. In order to build my table of Foos, I need to make two types of webservice calls; one for the whole table and one for each row. It's essentially a master-query then detail-query, except the master-query-result-xml doesn't return enough information so i then need to query the detail for each row. I'm not dealing with enormous amounts of data. Anyway - previously I've just used NSXMLParser *parser = [[NSXMLParser alloc]init]; [parser setDelegate:self]; [parser parse]; and implemented all the appropriate delegate methods in whatever class i'm in. In attempt at cleanliness, I've now created two separate delegate classes and done something like: NSXMLParser *xp = [[NSXMLParser alloc]init]; MyMasterXMLParserDelegate *masterParserDelegate = [[MyMasterXMLParser]alloc]init]; [xp setDelegate:masterParserDelegate]; [xp parse]; In addition to being cleaner (in my opinion, at least), it also means each of the -parser:didStartElement implementations don't spend most of the time trying to figure out which xml they're parsing. So now the real crux of the problem. Before i split out the delegates, i had in the main class that was also implementing the delegate methods, a class-level NSMutableArray that I would just put my objects-created-from-xml in when -parser:didEndElement found the 'end' of each record. Now the delegates are in separate classes, I can't figure out how to have the -parser:didEndElement in the 'detail' delegate class "return" the created object to the calling class. At least, not in a clean OO way. I'm sure i could do it with all sorts of nasty class methods. Does the question make sense? Thanks.

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