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  • how can I get instance from the property.

    - by viky
    In my application I have a class which has properties of user-defined types like this: class MyType { public A MyProperty { get; set; } } class A { .....some methods and proeprties } for some operations that I need to perform from my main program, I create a List of MyProperty whenever creating object of MyType and pass it to my main program and there I perform different operation on these properties which reflects in there instances also. Is there any way by which I could get the object instance for any particular MyProperty from that property in the list.

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  • How can I make my tableview enter editing mode?

    - by Jake
    Hi, for some reason I can't get my tableview to enter editing mode. It's a little harder than it might seem because I'm using some open source code to make a calendar (iCal esque) with a tableview under it, and it's not quite as straightforward as just using a regular tableview. Basically, I have two classes. One (let's say Class A) is a UIViewController and the other (Class B) is that viewController's datasource and tableview delegate. In Class B, I've implemented -(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath; which works fine, but if I put an edit nav bar item in Class A (the view controller), nothing happens. Am I forgetting certain protocols, or certain special methods that I need to write? Thanks for any help, and apologies if I'm missing something, I'm just learning to work with other people's code.

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  • javascript hide/show tabs using JQuery

    - by JohnMerlino
    Hey all, I have a quick question of how I can use jquery tabs (you click on link button to display/hide certain divs). The div id matches the href of the link: HTML links: <table class='layout tabs'> <tr> <td><a href="#site">Site</a></td> <td><a href="#siteno">Number</a></td> </tr> <tr> <td><a href="#student">Student</a></td> <td><a href="#school">School</a></td> </tr> </table> </div> div that needs to display/hide: <div id="site"> <table class='explore'> <thead class='ui-widget-header'> <tr> <th class=' sortable'> Site </th> <th class=' sortable'> Number </th> </tr> </thead> </table> </div> Thanks for any response.

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  • Can JMX operations take interfaces as parameters?

    - by Thor84no
    I'm having problems with an MBean that takes a Map<String, Object> as a parameter. If I try to execute it via JMX using a proxy object, I get an Exception: Caused by: javax.management.ReflectionException at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:231) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:668) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) Caused by: java.lang.IllegalArgumentException: Unable to find operation updateProperties(java.util.HashMap) It appears that it attempts to use the actual implementation class rather than the interface, and doesn't check if this is a child of the required interface. The same thing happens for extended classes (for example declare HashMap, pass in LinkedHashMap). Does this mean it's impossible to use an interface for such methods? At the moment I'm getting around it by changing the method signature to accept a HashMap, but it seems odd that I wouldn't be able to use interfaces (or extended classes) in my MBeans. Edit: The proxy object is being created by an in-house utility class called JmxInvocationHandler. The (hopefully) relevant parts of it are as follows: public class JmxInvocationHandler implements InvocationHandler { ... public static <T> T createMBean(final Class<T> iface, SFSTestProperties properties, String mbean, int shHostID) { T newProxyInstance = (T) Proxy.newProxyInstance(iface.getClassLoader(), new Class[] { iface }, (InvocationHandler) new JmxInvocationHandler(properties, mbean, shHostID)); return newProxyInstance; } ... private JmxInvocationHandler(SFSTestProperties properties, String mbean, int shHostID) { this.mbeanName = mbean + MBEAN_SUFFIX + shHostID; msConfig = new MsConfiguration(properties.getHost(0), properties.getMSAdminPort(), properties.getMSUser(), properties.getMSPassword()); } ... public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { if (management == null) { management = ManagementClientStore.getInstance().getManagementClient(msConfig.getHost(), msConfig.getAdminPort(), msConfig.getUser(), msConfig.getPassword(), false); } final Object result = management.methodCall(mbeanName, method.getName(), args == null? new Object[] {} : args); return result; } }

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  • Is there a way to create a python object that will be not sortable?

    - by Graf
    Is there a possibility to create any python object that will be not sortable? So that will be an exception when trying to sort a list of that objects? I created a very simple class, didn't define any comparison methods, but still instances of this class are comparable and thus sortable. Maybe, my class inherits comparison methods from somewhere. But I don't want this behaviour.

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  • callbacks via objective-c selectors

    - by codemonkey
    I have a "BSjax" class that I wrote that lets me make async calls to our server to get json result sets, etc using the ASIHTTPRequest class. I set it up so that the BSjax class parses my server's json response, then passes control back to the calling view controller via this call: [[self delegate] performSelectorOnMainThread:@selector(bsRequestFinished:) withObject:self waitUntilDone:YES]; ... where "bsRequestFinished" is the callback method in the calling view controller. This all worked fine and well until I realized that some pages are going to need to make different types of requests... i.e. I'll want to do different types of things in that callback function depending on which type of request was made. To me it seems like being able to pass different callback function names to my BSjax class would be the cleanest fix... but I'm having trouble (and am not even sure if it's possible) to pass in a variable that holds the callback function name and then replace the call above with something like this: [[self delegate] performSelectorOnMainThread:@selector(self.variableCallbackFunctionName) withObject:self waitUntilDone:YES]; ... where "self.variableCallbackFunctionName" is set by the calling view controller when it calls BSjax to make a new request. Is this even possible? If so, advisable? If not, alternatives? EDIT: Note that whatever fix I arrive at will need to take into account the reality that this class is making async requests... so I need to make sure that the callback function processing is correctly tied to the specific requests... as I can't rely on FIFO processing sequence.

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  • how to upload a audio file using REST webservice in Google App Engine for Java

    - by sathya
    Am using google app engine with eclipse IDE and trying to upload a audio file. I used the File Upload in Google App Engine For Java and can able to upload the file successfully. Now am planning to use REST web service for it. I had analyzed in developers.google but i failed. Can anyone suggest me how to implement REST Web services in google app engine using Eclipse. The code google provided is shown below, // file Upload.java public class Upload extends HttpServlet { private BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService(); public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { Map<String, BlobKey> blobs = blobstoreService.getUploadedBlobs(req); BlobKey blobKey = blobs.get("myFile"); if (blobKey == null) { res.sendRedirect("/"); } else { res.sendRedirect("/serve?blob-key=" + blobKey.getKeyString()); }}} // file Serve.java public class Serve extends HttpServlet { private BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService(); public void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException { BlobKey blobKey = new BlobKey(req.getParameter("blob-key")); blobstoreService.serve(blobKey, res); }} // file index.jsp <%@ page import="com.google.appengine.api.blobstore.BlobstoreServiceFactory" %> <%@ page import="com.google.appengine.api.blobstore.BlobstoreService" %> <% BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService(); %> <form action="<%= blobstoreService.createUploadUrl("/upload") %>" method="post" enctype="multipart/form-data"> <input type="file" name="myFile"> <input type="submit" value="Submit"> </form> // web.xml <servlet> <servlet-name>Upload</servlet-name> <servlet-class>Upload</servlet-class> </servlet> <servlet> <servlet-name>Serve</servlet-name> <servlet-class>Serve</servlet-class> </servlet> <servlet-mapping> <servlet-name>Upload</servlet-name> <url-pattern>/upload</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>Serve</servlet-name> <url-pattern>/serve</url-pattern> </servlet-mapping> Now how to provide a rest web service for the above code. Kindly suggest me an idea.

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  • Validating an Autocomplete field in Django

    - by anonymous coward
    I have models similar to the following: class Band(models.Model): name = models.CharField(unique=True) class Event(models.Model): name = models.CharField(max_length=50, unique=True) bands = models.ManyToManyField(Band) and essentially I want to use the validation capability offered by a ModelForm that already exists for Event, but I do not want to show the default Multi-Select list (for 'bands') on the page, because the potential length of the related models is extremely long. I have the following form defined: class AddEventForm(ModelForm): class Meta: model = Event fields = ('name', ) Which does what is expected for the Model, but of course, validation could care less about the 'bands' field. I've got it working enough to add bands correctly, but there's no correct validation, and it will simply drop bad band IDs. What should I do so that I can ensure that at least one (correct) band ID has been sent along with my form? For how I'm sending the band-IDs with auto-complete, see this related question: http://stackoverflow.com/questions/1528059/

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  • SFINAE + sizeof = detect if expression compiles

    - by FredOverflow
    I just found out how to check if operator<< is provided for a type. template<class T> T& lvalue_of_type(); template<class T> T rvalue_of_type(); template<class T> struct is_printable { template<class U> static char test(char(*)[sizeof( lvalue_of_type<std::ostream>() << rvalue_of_type<U>() )]); template<class U> static long test(...); enum { value = 1 == sizeof test<T>(0) }; typedef boost::integral_constant<bool, value> type; }; Is this trick well-known, or have I just won the metaprogramming Nobel prize? ;) EDIT: I made the code simpler to understand and easier to adapt with two global function template declarations lvalue_of_type and rvalue_of_type.

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  • sqlalchemy: what is the difference between declaring the cascade within the foreign key vs relation?

    - by steve
    what is the difference between declaring the cascade within a foreign key vs relations? class Contact(Base): __tablename__ = 'contacts' id = Column(Integer, primary_key=True) addresses = relation("Address", backref="contact") class Address(Base): __tablename__ = 'addresses' id = Column(Integer, primary_key=True) contact_id = Column(Integer, ForeignKey('contact.id', onupdate="CASCADE", ondelete="CASCADE"))) vs class Contact(Base): __tablename__ = 'contacts' id = Column(Integer, primary_key=True) addresses = relation("Address", backref="contact", cascade="all, delete-orphan") class Address(Base): __tablename__ = 'addresses' id = Column(Integer, primary_key=True) contact_id = Column(Integer, ForeignKey('contact.id')) with the foreign key declaration, it seems like the cascade is enforced at the database level. how does the relations approach work? thanks!

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  • Accessing data entered into multiple Django forms and generating them onto a new URL

    - by pedjk
    I have a projects page where users can start up new projects. Each project has two forms. The two forms are: class ProjectForm(forms.Form): Title = forms.CharField(max_length=100, widget=_hfill) class SsdForm(forms.Form): Status = forms.ModelChoiceField(queryset=P.ProjectStatus.objects.all()) With their respective models as follows: class Project(DeleteFlagModel): Title = models.CharField(max_length=100) class Ssd(models.Model): Status = models.ForeignKey(ProjectStatus) Now when a user fills out these two forms, the data is saved into the database. What I want to do is access this data and generate it onto a new URL. So I want to get the "Title" and the "Status" from these two forms and then show them on a new page for that one project. I don't want the "Title" and "Status" from all the projects to show up, just for one project at a time. If this makes sense, how would I do this? I'm very new to Django and Python (though I've read the Django tutorials) so I need as much help as possible. Thanks in advance Edit: The ProjectStatus code is (under models): class ProjectStatus(models.Model): Name = models.CharField(max_length=30) def __unicode__(self): return self.Name

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  • I am confused about how to use @SessionAttributes

    - by yusaku
    I am trying to understand architecture of Spring MVC. However, I am completely confused by behavior of @SessionAttributes. Please look at SampleController below , it is handling post method by SuperForm class. In fact, just field of SuperForm class is only binding as I expected. However, After I put @SessionAttributes in Controller, handling method is binding as SubAForm. Can anybody explain me what happened in this binding. ------------------------------------------------------- @Controller @SessionAttributes("form") @RequestMapping(value = "/sample") public class SampleController { @RequestMapping(method = RequestMethod.GET) public String getCreateForm(Model model) { model.addAttribute("form", new SubAForm()); return "sample/input"; } @RequestMapping(method = RequestMethod.POST) public String register(@ModelAttribute("form") SuperForm form, Model model) { return "sample/input"; } } ------------------------------------------------------- public class SuperForm { private Long superId; public Long getSuperId() { return superId; } public void setSuperId(Long superId) { this.superId = superId; } } ------------------------------------------------------- public class SubAForm extends SuperForm { private Long subAId; public Long getSubAId() { return subAId; } public void setSubAId(Long subAId) { this.subAId = subAId; } } ------------------------------------------------------- <form:form modelAttribute="form" method="post"> <fieldset> <legend>SUPER FIELD</legend> <p> SUPER ID:<form:input path="superId" /> </p> </fieldset> <fieldset> <legend>SUB A FIELD</legend> <p> SUB A ID:<form:input path="subAId" /> </p> </fieldset> <p> <input type="submit" value="register" /> </p> </form:form>

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  • How do I get events to execute on the "main thread"

    - by William DiStefano
    I have 2 classes, one is frmMain a windows form and the other is a class in vb.NET 2003. frmMain contains a start button which executes the monitor function in the other class. My question is, I am manually adding the event handlers -- when the events are executed how do I get them to excute on the "main thread". Because when the tooltip balloon pops up at the tray icon it displays a second tray icon instead of popping up at the existing tray icon. I can confirm that this is because the events are firing on new threads because if I try to display a balloon tooltip from frmMain it will display on the existing tray icon. Here is a part of the second class (not the entire thing): Friend Class monitorFolders Private _watchFolder As System.IO.FileSystemWatcher = New System.IO.FileSystemWatcher Private _eType As evtType Private Enum evtType changed created deleted renamed End Enum Friend Sub monitor(ByVal path As String) _watchFolder.Path = path 'Add a list of Filter to specify _watchFolder.NotifyFilter = IO.NotifyFilters.DirectoryName _watchFolder.NotifyFilter = _watchFolder.NotifyFilter Or IO.NotifyFilters.FileName _watchFolder.NotifyFilter = _watchFolder.NotifyFilter Or IO.NotifyFilters.Attributes 'Add event handlers for each type of event that can occur AddHandler _watchFolder.Changed, AddressOf change AddHandler _watchFolder.Created, AddressOf change AddHandler _watchFolder.Deleted, AddressOf change AddHandler _watchFolder.Renamed, AddressOf Rename 'Start watching for events _watchFolder.EnableRaisingEvents = True End Sub Private Sub change(ByVal source As Object, ByVal e As System.IO.FileSystemEventArgs) If e.ChangeType = IO.WatcherChangeTypes.Changed Then _eType = evtType.changed notification() End If If e.ChangeType = IO.WatcherChangeTypes.Created Then _eType = evtType.created notification() End If If e.ChangeType = IO.WatcherChangeTypes.Deleted Then _eType = evtType.deleted notification() End If End Sub Private Sub notification() _mainForm.NotifyIcon1.ShowBalloonTip(500, "Folder Monitor", "A file has been " + [Enum].GetName(GetType(evtType), _eType), ToolTipIcon.Info) End Sub End Class

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  • Jquery Select Problem

    - by oraclee
    Hi; Jquery Code: $("[id$=mytable] tr").click(function() { alert($(this).html()); }); Html: <table id="mytable"> <tr> <td class="locked">1</td> <td>2</td> <td>3</td> </tr> <tr> <td class="locked">a</td> <td>b</td> <td>c</td> </tr> </table> i need only "td class='locked'" click return this click: <td class="locked">1</td> output: <tr> <td class="locked">1</td> <td>2</td> <td>3</td> </tr>

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  • How to make Date locale-independent?

    - by folone
    I have a db, that stores dates in OleDateTime format, in GMT timezone. I've implemented a class, extending Date in java to represent that in classic date format. But my class is locale-dependent (I'm in GMT+2). Therefore, it converts the date in the db as date - 2 hours. How do I make it convert the date correctly? I want my class to be locale-independent, always using GMT timezone. Actually, the question is: class MyOleDateTime extends Date { static { Locale.setDefault(WhatGoesHere?) } // ... some constructors // ... some methods }

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  • [PHP] Weird problem with dynamic method invocation

    - by Rolf
    Hi everyone, this time, I'm facing a really weird problem. I've the following code: $xml = simplexml_load_file($this->interception_file); foreach($xml->children() as $class) { $path = str_replace('__CLASS_DIR__',CLASS_DIR,$class['path']); if(!is_file($path)) { throw new Exception('Bad configuration: file '.$path.' not found'); } $className = pathinfo($path,PATHINFO_FILENAME); foreach($class as $method) { $method_name = $method['name']; $obj = new $className(); var_dump(in_array($method_name,get_class_methods($className)));exit; echo $obj->$method_name();### not a method ??? } } As you can see, I get the class name and method name from an XML file. I can create an instance of the class without any problem. The var_dump at the end returns true, that means $method_name (which has 2 optional parameters) is a method of $className. BUT, and I am pretty sure the syntax is correct, when I try: $obj-$method_name() I get: Fatal error: Method name must be a string If you have any ideas, pleaaaaase tell me :) Thanks in advance, Rolf

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  • What is the purpose of unit testing an interface repository

    - by ahsteele
    I am unit testing an ICustomerRepository interface used for retrieving objects of type Customer. As a unit test what value am I gaining by testing the ICustomerRepository in this manner? Under what conditions would the below test fail? For tests of this nature is it advisable to do tests that I know should fail? i.e. look for id 4 when I know I've only placed 5 in the repository I am probably missing something obvious but it seems the integration tests of the class that implements ICustomerRepository will be of more value. [TestClass] public class CustomerTests : TestClassBase { private Customer SetUpCustomerForRepository() { return new Customer() { CustId = 5, DifId = "55", CustLookupName = "The Dude", LoginList = new[] { new Login { LoginCustId = 5, LoginName = "tdude" }, new Login { LoginCustId = 5, LoginName = "tdude2" } } }; } [TestMethod] public void CanGetCustomerById() { // arrange var customer = SetUpCustomerForRepository(); var repository = Stub<ICustomerRepository>(); // act repository.Stub(rep => rep.GetById(5)).Return(customer); // assert Assert.AreEqual(customer, repository.GetById(5)); } } Test Base Class public class TestClassBase { protected T Stub<T>() where T : class { return MockRepository.GenerateStub<T>(); } } ICustomerRepository and IRepository public interface ICustomerRepository : IRepository<Customer> { IList<Customer> FindCustomers(string q); Customer GetCustomerByDifID(string difId); Customer GetCustomerByLogin(string loginName); } public interface IRepository<T> { void Save(T entity); void Save(List<T> entity); bool Save(T entity, out string message); void Delete(T entity); T GetById(int id); ICollection<T> FindAll(); }

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  • Slide navigation problem multiple div movement

    - by littleMan
    I have almost figured it out but still doesn't quite work the way i want it to. my problem is this part. It scrolls the first element to the left but the second element just appears and doesn't scroll does anyone know what todo here. var i = jQuery('.wikiform .wizard .view').size(); jQuery('.wikiform .navigation input[name^=Next]').click(function () { jQuery('.wikiform .wizard .view').each(function (j) { jQuery(this).animate({ marginLeft: -(current.next().width() * (i - j)) }, 750); /*line above Im having problems with ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ */ current = current.next(); j++; }); }); my complete code down below test it out and see what Im doing wrong (function ($) { $.fn.WikiForm = function (options) { this.Mode = options.mode || 'CancelOk' || 'Ok' || 'Wizard'; var current = jQuery('.wikiform .view:first'); function positionForm() { jQuery('body') .css('overflow-y', 'hidden'); jQuery('<div id="overlay"></div>') .insertBefore('.wikiform') .css('top', jQuery(document).scrollTop()) .animate({ 'opacity': '0.8' }, 'slow'); jQuery('.wikiform') .css('height', jQuery('.wikiform .wizard .view:first').height() + jQuery('.wikiform .navigation').height()) .css('top', window.screen.availHeight / 2 - jQuery('.wikiform').height() / 2) .css('width', jQuery('.wikiform .wizard .view:first').width()) .css('left', -jQuery('.wikiform').width()) .animate({ marginLeft: jQuery(document).width() / 2 + jQuery('.wikiform').width() / 2 }, 750); jQuery('.wikiform .wizard') .css('overflow', 'hidden') .css('height', jQuery('.wikiform .wizard .view:first').height()); } if (this.Mode == "Wizard") { return this.each(function () { positionForm(); //alert(current.next().width()); var i = jQuery('.wikiform .wizard .view').size(); jQuery('.wikiform .navigation input[name^=Next]').click(function () { jQuery('.wikiform .wizard .view').each(function (j) { jQuery(this).animate({ marginLeft: -(current.next().width() * (i - j)) }, 750); current = current.next(); j++; }); }); jQuery('.wikiform .navigation input[name^=Back]').click(function () { }); }); } else if (this.Mode == "CancelOk") { return this.each(function () { }); } else { return this.each(function () { }); } }; })(jQuery); $(document).ready(function () { jQuery(window).bind("load", function () { jQuery(".wikiform").WikiForm({ mode: 'Wizard', speed:750, ease:"expoinout" }); }); }); <style type="text/css"> body { margin:0px; } #overlay { background-color:Black; position:absolute; top:0; left:0; height:100%; width:100%; } .wikiform { background-color:Green; position:absolute; } .wikiform .wizard { clear: both; } .wizard { position: relative; left: 0; top: 0; width: 100%; list-style-type: none; } .wizard .view { float:left; } .view .form { } .navigation { float:right; clear:left } #view1 { background-color:Aqua; width:300px; height:300px; } #view2 { background-color:Fuchsia; width:300px; height:300px; } </style> <title></title></head><body><form action="" method=""><div id="layout"><div id="header"> Header </div> <div id="content" style="height:2000px"> Content </div> <div id="footer"> Footer </div> </div> <div id="formView1" class="wikiform"> <div class="wizard"> <div id="view1" class="view"> <div class="form"> Content 1 </div> </div> <div id="view2" class="view"> <div class="form"> Content 2 </div> </div> </div> <div class="navigation"> <input type="button" name="Back" value=" Back " /> <input type="button" name="Next " class="Next" value=" Next " /> <input type="button" name="Cancel" value="Cancel" /> </div> </div>

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  • Visual Studio - easy way to bring up type definition as source code

    - by Igor Zevaka
    Oftentimes I want to bring up a system class in a source view, so that I can browse the properties and methods exposed by the class in a source view. Below is the screenshot of what I mean: Usually I do this by selecting the class name and pressing F12 (or right clickGo To Definition). However, if I haven't got it anywhere ready, i have type it up and then do Go To Definition. Most of the time I have to delete what I typed later on. Is there a way to bring up this view without having to type the class name? The VS2010 Navigate To dialog doesn't support this.

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  • FieldError when annotating over foreign keys

    - by X_9
    I have a models file that looks similar to the following: class WithDate(models.Model): adddedDate = models.DateTimeField(auto_now_add=True) modifiedDate = models.DateTimeField(auto_now=True) class Meta: abstract = True class Match(WithDate): ... class Notify(WithDate): matchId = models.ForeignKey(Match) headline = models.CharField(null=True, blank=True, max_length=10) For each Match I'm trying to get a count of notify records that have a headline. So my call looks like matchObjs = Match.objects.annotate(notifies_made=Count('notify__headline__isnull')) This keeps throwing a FieldError. I've simplified the query down to matchObjs = Match.objects.annotate(notifies_made=Count('notify')) And I still get the same FieldError... I've seen this work in other cases (other documentation, other SO questions like this one) but I can't figure out why I'm getting an error. The specific error that is returned is as follows: Cannot resolve keyword 'notify' into field. Choices are: (all fields from Match model) Does anyone have a clue as to why I can't get this annotation to work across tables? I'm baffled after looking at the other SO question and various Django docs where I've seen this done. Edit: I am using Django 1.1.1

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  • How to create a generic list in this wierd case in c#

    - by Marc Bettex
    Hello, In my program, I have a class A which is extended by B, C and many more classes. I have a method GetInstance() which returns a instance of B or C (or of one of the other child), but I don't know which one, so the return type of the method is A. In the method CreateGenericList(), I have a variable v of type A, which is in fact either a B, a C or another child type and I want to create a generic list of the proper type, i.e. List<B> if v is a B or List<C> if v is a C, ... Currently I do it by using reflection, which works, but this is extremely slow. I wanted to know if there is another way to to it, which doesn't use reflection. Here is an example of the code of my problem: class A { } class B : A { } class C : A { } // More childs of A. class Program { static A GetInstance() { // returns an instance of B or C } static void CreateGenericList() { A v = Program.GetInstance(); IList genericList = // Here I want an instance of List<B> or List<C> or ... depending of the real type of v, not a List<A>. } } I tried the following hack. I call the following method, hoping the type inferencer will guess the type of model, but it doesn't work and return a List<A>. I believe that because c# is statically typed, T is resolved as A and not as the real type of model at runtime. static List<T> CreateGenericListFromModel<T>(T model) where T : A { return new List<T> (); } Does anybody have a solution to that problem that doesn't use reflection or that it is impossible to solve that problem without reflection? Thank you very much, Marc

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  • Error in connection in ruby.

    - by piemesons
    require 'rubygems' require 'mysql' db = Mysql.connect('localhost', 'root', '', 'mohit') //db.rb:4: undefined method `connect' for Mysql:Class (NoMethodError) //undefined method `real_connect' for Mysql:Class (NoMethodError) db.query("CREATE TABLE people ( id integer primary key, name varchar(50), age integer)") db.query("INSERT INTO people (name, age) VALUES('Chris', 25)") begin query = db.query('SELECT * FROM people') puts "There were #{query.num_rows} rows returned" query.each_hash do |h| puts h.inspect end rescue puts db.errno puts db.error end error i am geting is: undefined method `connect' for Mysql:Class (NoMethodError) OR undefined method `real_connect' for Mysql:Class (NoMethodError) EDIT return value of Mysql.methods ["private_class_method", "inspect", "name", "tap", "clone", "public_methods", "object_id", "__send__", "method_defined?", "instance_variable_defined?", "equal?", "freeze", "extend", "send", "const_defined?", "methods", "ancestors", "module_eval", "instance_method", "hash", "autoload?", "dup", "to_enum", "instance_methods", "public_method_defined?", "instance_variables", "class_variable_defined?", "eql?", "constants", "id", "instance_eval", "singleton_methods", "module_exec", "const_missing", "taint", "instance_variable_get", "frozen?", "enum_for", "private_method_defined?", "public_instance_methods", "display", "instance_of?", "superclass", "method", "to_a", "included_modules", "const_get", "instance_exec", "type", "<", "protected_methods", "<=>", "class_eval", "==", "class_variables", ">", "===", "instance_variable_set", "protected_instance_methods", "protected_method_defined?", "respond_to?", "kind_of?", ">=", "public_class_method", "to_s", "<=", "const_set", "allocate", "class", "new", "private_methods", "=~", "tainted?", "__id__", "class_exec", "autoload", "untaint", "nil?", "private_instance_methods", "include?", "is_a?"] return value of Mysql.methods(false) is []... blank array

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  • How to accomplish covariant return types when returning a shared_ptr?

    - by Kyle
    using namespace boost; class A {}; class B : public A {}; class X { virtual shared_ptr<A> foo(); }; class Y : public X { virtual shared_ptr<B> foo(); }; The return types aren't covariant (nor are they, therefore, legal), but they would be if I was using raw pointers instead. What's the commonly accepted idiom to work around this, if there is one?

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  • Python hash() can't handle long integer?

    - by Xie
    I defined a class: class A: ''' hash test class a = A(9, 1196833379, 1, 1773396906) hash(a) -340004569 This is weird, 12544897317L expected. ''' def __init__(self, a, b, c, d): self.a = a self.b = b self.c = c self.d = d def __hash__(self): return self.a * self.b + self.c * self.d Why, in the doctest, hash() function gives a negative integer?

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  • How do I restrict foreign keys choices to related objects only in django

    - by Jeff Mc
    I have a two way foreign relation similar to the following class Parent(models.Model): name = models.CharField(max_length=255) favoritechild = models.ForeignKey("Child", blank=True, null=True) class Child(models.Model): name = models.CharField(max_length=255) myparent = models.ForeignKey(Parent) How do I restrict the choices for Parent.favoritechild to only children whose parent is itself? I tried class Parent(models.Model): name = models.CharField(max_length=255) favoritechild = models.ForeignKey("Child", blank=True, null=True, limit_choices_to = {"myparent": "self"}) but that causes the admin interface to not list any children.

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