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  • How do I construct a Django form with model objects in a Select widget?

    - by Thierry Lam
    Let's say I'm using the Django Site model: class Site(models.Model): name = models.CharField(max_length=50) My Site values are (key, value): 1. Stackoverflow 2. Serverfault 3. Superuser I want to construct a form with an html select widget with the above values: <select> <option value="1">Stackoverflow</option> <option value="2">Serverfault</option> <option value="3">Superuser</option> </select> I'm thinking of starting with the following code but it's incomplete: class SiteForm(forms.Form): site = forms.IntegerField(widget=forms.Select()) Any ideas how I can achieve that with Django form?

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  • How does object of sub-class record information about its super-class the in a Virtual Inheritance

    - by Summer_More_More_Tea
    Hi there: I encounter this problem when tackling with virtual inheritance. I remember that in a non-virtual inheritance hierarchy, object of sub-class hold an object of its direct super-class. What about virtual inheritance? In this situation, does object of sub-class hold an object of its super-class directly or just hold a pointer pointing to an object of its super-class? By the way, why the output of the following code is: sizeof(A): 8 sizeof(B): 20 sizeof(C): 32 Code: #include <iostream> using namespace std; class A{ char k[ 3 ]; public: virtual void a(){}; }; class B : public virtual A{ char j[ 3 ]; public: virtual void b(){}; }; class C : public virtual B{ char i[ 3 ]; public: virtual void c(){}; }; int main( int argc, char *argv[] ){ cout << "sizeof(A): " << sizeof( A ) << endl; cout << "sizeof(B): " << sizeof( B ) << endl; cout << "sizeof(C): " << sizeof( C ) << endl; return 0; } Thanks in advance. Kind regards.

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  • Where could I get the information about the in-memory layout info of .NET Object Model?

    - by smwikipedia
    I want to know the in-memory representation of .NET constructs such as "interface", "class", "struct", etc. There's an excellent book for C++ object model - <Inside the C++ Object Model by Stanley. Lippman, I want a similar book for .NET and C#. Could someone provide some hints about books and articles? I have read about the "Drill Into .NET Framework Internals to See How the CLR Creates Runtime Objects" Anything more? If this info is not publicly avaialble. Shared source one like Mono or Shared Source CLI could be an option. Many thanks.

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  • Showing custom model validation exceptions in the Django admin site.

    - by Guy Bowden
    I have a booking model that needs to check if the item being booked out is available. I would like to have the logic behind figuring out if the item is available centralised so that no matter where I save the instance this code validates that it can be saved. At the moment I have this code in a custom save function of my model class: def save(self): if self.is_available(): # my custom check availability function super(MyObj, self).save() else: # this is the bit I'm stuck with.. raise forms.ValidationError('Item already booked for those dates') This works fine - the error is raised if the item is unavailable, and my item is not saved. I can capture the exception from my front end form code, but what about the Django admin site? How can I get my exception to be displayed like any other validation error in the admin site?

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  • Where is the best place to call the .tolist(); inside my controller classes or inside my model repository classes

    - by john G
    I have the following action method, inside my asp.net mvc web application:- public JsonResult LoadZoneByDataCenter(string id) { var zonelist = repository.getrealtedzone(Convert.ToInt32(id)).ToList(); //code goes here Which calls the following model repository method:- public IQueryable<Zone> getrealtedzone(int? dcid) { return tms.Zones.Where(a=> a.DataCenterID == dcid || dcid == null); } Currently I am calling the .tolist() which will interpret the Database from my action method, but my question is where is the best place to call the .tolist() inside the controller or inside the model classes and why ? thanks

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  • How can i implement the NULL Object Design Pattern in a generic form?

    - by Colour Blend
    Is there a way to implement the null object design pattern in a generic form so that i don't need to implement it for every buisness object. For me, there are two high level classes you'll need for every business class. One for a single record and another for a list. So i think there should be a way to implement the NULL Object design pattern at a high level and not have to implement it for every class. Is there a way and how please?

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  • Why would it be necessary to subclass from object in Python?

    - by rmh
    I've been using Python for quite a while now, and I'm still unsure as to why you would subclass from object. What is the difference between this: class MyClass(): pass And this: class MyClass(object): pass As far as I understand, object is the base class for all classes and the subclassing is implied. Do you get anything from explicitly subclassing from it? What is the most "Pythonic" thing to do?

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  • How to determine the type of object in blackberry application?

    - by SIA
    Hi Everybody On my screen i have ButtonField and CustomButtonField. Both have been added to Listner of my screen. myScreen.add(new ButtonField("click me")); myScreen.add(new CustomButtonField("click me Again")); Now i want to know which button is clicked and type of object in fieldChanged function. public void fieldChanged(Field field, int context) { //Here- how to determine the type of object //which object has been clicked //ButtonField or CustomButtonField???? } Kindly Help Thanks SIA

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  • How to proprely remove a flash object from a HTML page.

    - by Niklaos
    Hi guys. I made a website using AJAX (with jquery) for the navigation. The pages of the site are sliding and I use remove() to destroy the old page. Every thing seems alright, but some times the browser crashes when he tries to remove the old page containing a Flash object. I suppose this is because Flash is still executing the Flash object. My question is simple. How do i remove this Flash's object for my page without having the browser crashing on my face ? Is there a way to stop the Flash execution before removing the object ? Thanks for your help.

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  • When Creating a Reference for an Object Where from where that class is Loaded?

    - by asela38
    When doing some sample codings with Java I came crosss ClassCast Exception, from where I cast the object to StaticClass. Can any explaing the what has happened here. public void test5() throws Exception { System.out.println(StaticClass.obj); Object newInstance = ClassLoader.getSystemClassLoader().loadClass("com.StaticClass").newInstance(); System.out.println(newInstance.getClass().getDeclaredField("obj").get(newInstance)); Object newInstance2 = new ILoader().loadClass("com//StaticClass.class").newInstance(); System.out.println(newInstance2.getClass().getDeclaredField("obj").get(newInstance2)); StaticClass s = (StaticClass)newInstance2; System.out.println(s.obj); System.out.println(newInstance.getClass().getClassLoader()); System.out.println(newInstance2.getClass().getClassLoader()); } package com; public class StaticClass { public static final Object obj = new Object(); } package com; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; public class ILoader extends ClassLoader { public ILoader() { super(null); } @Override protected Class<?> findClass(String name) throws ClassNotFoundException { File file = new File(name); byte[] bytes = new byte[(int)file.length()]; try { new FileInputStream(file).read(bytes); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return super.defineClass("com.StaticClass",bytes, 0, bytes.length); } } output which was given by last sysout's when the casting part of the code not existed is as belows. sun.misc.Launcher$AppClassLoader@133056f com.ILoader@1ac3c08

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  • How do I release an object allocated in a different AutoReleasePool ?

    - by ajcaruana
    Hi, I have a problem with the memory management in Objective-C. Say I have a method that allocates an object and stores the reference to this object as a member of the class. If I run through the same function a second time, I need to release this first object before creating a new one to replace it. Supposing that the first line of the function is: NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; This means that a different auto-release pool will be in place. The code to allocate the object is as follows: if (m_object != nil) [m_object release]; m_object = [[MyClass alloc] init]; [m_object retain]; The problem is that the program crashes when running the last line of the method: [pool release]; What am I doing wrong ? How can I fix this ? Regards Alan

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  • MVC 3 Nested EditorFor Templates

    - by Gordon Hickley
    I am working with MVC 3, Razor views and EditorFor templates. I have three simple nested models:- public class BillingMatrixViewModel { public ICollection<BillingRateRowViewModel> BillingRateRows { get; set; } public BillingMatrixViewModel() { BillingRateRows = new Collection<BillingRateRowViewModel>(); } } public class BillingRateRowViewModel { public ICollection<BillingRate> BillingRates { get; set; } public BillingRateRowViewModel() { BillingRates = new Collection<BillingRate>(); } } public class BillingRate { public int Id { get; set; } public int Rate { get; set; } } The BillingMatrixViewModel has a view:- @using System.Collections @using WIP_Data_Migration.Models.ViewModels @model WIP_Data_Migration.Models.ViewModels.BillingMatrixViewModel <table class="matrix" id="matrix"> <tbody> <tr> @Html.EditorFor(model => Model.BillingRateRows, "BillingRateRow") </tr> </tbody> </table> The BillingRateRow has an Editor Template called BillingRateRow:- @using System.Collections @model IEnumerable<WIP_Data_Migration.Models.ViewModels.BillingRateRowViewModel> @foreach (var item in Model) { <tr> <td> @item.BillingRates.First().LabourClass.Name </td> @Html.EditorFor(m => item.BillingRates) </tr> } The BillingRate has an Editor Template:- @model WIP_Data_Migration.Models.BillingRate <td> @Html.TextBoxFor(model => model.Rate, new {style = "width: 20px"}) </td> The markup produced for each input is:- <input name="BillingMatrix.BillingRateRows.item.BillingRates[0].Rate" id="BillingMatrix_BillingRateRows_item_BillingRates_0__Rate" style="width: 20px;" type="text" value="0"/> Notice the name and ID attributes the BillingRate indexes are handled nicely but the BillingRateRows has no index instead '.item.'. From my reasearch this is because the context has been pulled out due to the foreach loop, the loop shouldn't be necessary. I want to achieve:- <input name="BillingMatrix.BillingRateRows[0].BillingRates[0].Rate" id="BillingMatrix_BillingRateRows_0_BillingRates_0__Rate" style="width: 20px;" type="text" value="0"/> If I change the BillingRateRow View to:- @model WIP_Data_Migration.Models.ViewModels.BillingRateRowViewModel <tr> @Html.EditorFor(m => Model.BillingRates) </tr> It will throw an InvalidOperationException, 'model item passed into the dictionary is of type System.Collections.ObjectModel.Collection [BillingRateRowViewModel] but this dictionary required a type of BillingRateRowViewModel. Can anyone shed any light on this?

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  • What do you name the "other" kind of view-model in an MVVM project?

    - by DanM
    With MVVM, I think of a view-model as a class that provides all the data and commands that a view needs to bind to. But what happens when I have a database entity object, say a Customer, and I want to build a class that shapes or flattens the Customer class for use in a data grid. For example, maybe this special Customer object would have a property TotalOrders, which is actually calculated using a join with a collection of Order entities. My question is, what do I call this special Customer class? In other situations, I'd be tempted to call it a CustomerViewModel, but I feel like "overloading" the notion of a view-model like this would be confusing in an MVVM project. What would you suggest?

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  • asp.net mvc. Inserting string data from model into javascript. best-practice

    - by Andrew Florko
    Hello everybody, I have to populate javascript code in html layout (hidden fields, method params) with string data from model. Html.Encode is not appropriate for my task because it encodes ' symbol, bypass : (that ruines object attributes declaration) and so on. I wrote static helper class that is used from View like this: alert('<%=ViewHelper.MakeJavaScriptSafe(Model.Message)%>'); I hope there is asp.net in-built function I don't know about for this task. Does it exist really? Thank you in advance.

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  • How to declare and use the name of a function from a json object?

    - by Sebastian
    Hello, I have a json object collection of geo locations that I build in the server. Each of those objects has two properties: "marker" and "onClick". Marker is for storing a Google Maps marker object and the onClick stores the name of the function to be called when that marker is clicked on the map. When I'm pushing the location objects into an array using javascript in the client side, I create the markers and assign them to each location object within the array. My problem is that when I bind the marker with the onClick property, the function won't be found in the DOM and get an error. Is there a way to declare a property in a json object for using it on an event binding? Hope I could explain it clearly, if not, please let me know. Thanks!

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  • Assigning function within function object without invoking the function itself.

    - by webzide
    Dear experts, I am trying to assign an function within an function object property without actually invoking then function itself. for instance, I have the following function object class definition function objectOne(name, value, id){ this.name=name; this.value=value; this.id=id; this.methodOne=methodFunction(this); } the last line this.methodOne=methodFunction(this); I want to pass the current object to the function but at the same time i don't want to execute the function right now. But if I do it this way without the bracket this.methodOne=methodFunction then the argument of this object would not be passed as a parameter to the function. Is there a way to work through this. Thank you in advance

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  • How to pass an object from a Frame to another Frame in a Windows 8 Style App

    - by Mythul
    I have problem that i just cant figure out right now. I am trying to develop a Windows-8 style app and im stuck implementing this functionality. I have a MainWindow which contains a ListBox and a Button (lets say addButton). When i click the button i navigate to a new page, lets say AddCustomerPage with this.Frame.Navigate(typeof (AddCustomerPage)); AddCustomerPage has 1 textBox and 1 button (lets say doneButton. When i click the button i want the string in the textBox to be added to the ListBox on the previous page. This is my current functionality: 1. MainWindow is created. Click addButton AddCustomer page is created. MainWindow is destroyed(problem). Click doneButton A MainWindow object is created with a ListBox with 1 item. Repeat the add process, i always get a MainWindow with a ListBox with 1 item. Thanks for the help. Here is the code: public sealed partial class MainPage : Page { public MainPage() { this.InitializeComponent(); this.brainPageController = new PageController(); // add items from the List<String> to the listBox listGoals.ItemsSource = brainPageController.GetListGoals(); } protected override void OnNavigatedTo(NavigationEventArgs e) { var parameter = e.Parameter as String; // a simple controller that adds a string to a List<string> brainPageController.AddGoal(parameter); } private void addButton_Click(object sender, RoutedEventArgs e) { this.Frame.Navigate(typeof (GoalsInfo)); } // VARIABLES DECLARATION private PageController brainPageController; } public sealed partial class GoalsInfo : WinGoalsWIP.Common.LayoutAwarePage { public GoalsInfo() { this.InitializeComponent(); this.brainPageController = new PageController(); } protected override void LoadState(Object navigationParameter, Dictionary<String, Object> pageState) { } protected override void SaveState(Dictionary<String, Object> pageState) { } private void Button_Click_1(object sender, RoutedEventArgs e) { brainPageController.AddGoal(nameTextBox.Text); this.Frame.Navigate(typeof(MainPage), nameTextBox.Text); } // VARIABLES DECLARATION PageController brainPageController; }

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  • How do I delete an object from an Entity Framework model without first loading it?

    - by Tomas Lycken
    I am quite sure I've seen the answer to this question somewhere, but as I couldn't find it with a couple of searches on SO or google, I ask it again anyway... In Entity Framework, the only way to delete a data object seems to be MyEntityModel ent = new MyEntityModel(); ent.DeleteObject(theObjectToDelete); ent.SaveChanges(); However, this approach requires the object to be loaded to, in this case, the Controller first, just to delete it. Is there a way to delete a business object referencing only for instance its ID? If there is a smarter way using Linq or Lambda expressions, that is fine too. The main objective, though, is to avoid loading data just to delete it.

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  • Excel I have a .Net object compiled as a tlb but cant not access any methods apart from Dispose.

    - by Mark O'Grady
    Hi This is ongoing issue to something I posted yesterday. I have a .net object that I want to use in Excel. I have an existing VBA script that i need to alter to call this the object from. I have then converted the object to a TLB. I've not really touched on this area before so any help will be appreciated. I have created an interface [Guid("0F700B48-E0CA-446b-B87E-555BCC317D74"),InterfaceType(ComInterfaceType.InterfaceIsDual)] [ComVisible(true)] public interface IOfficeCOMInterface { [DispId(1)] void ResetOrder(); [DispId(2)] void SetDeliveryAddress(string PostalName, string AddressLine1, string AddressLine2, string AddressLine3, string AddressLine4, string PostCode, string CountryCode, string TelephoneNo, string FaxNo, string EmailAddress); } I have also created an class that inherits that object. [ClassInterface(ClassInterfaceType.None), ProgId("NAMESPACE.OfficeCOMInterface"), Guid("9D9723F9-8CF1-4834-BE69-C3FEAAAAB530"), ComVisible(true)] public class OfficeCOMInterface : IOfficeCOMInterface, IDisposable { public void ResetSOPOrder() { } public void SetDeliveryAddress(string PostalName, string AddressLine1, string AddressLine2, string AddressLine3, string AddressLine4, string PostCode, string CountryCode, string TelephoneNo, string FaxNo, string EmailAddress) { try { SalesOrder.AmendDeliveryAddress(PostalName, AddressLine1, AddressLine2, AddressLine3, AddressLine4, PostCode); MessageBox.Show("Delivery address set"); } catch (Exception ex) { throw ex; } } } I can't access the object methods apart from dispose, I guess IDisposable is working fine. Is there anything I need to my Interface?

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  • How could I know if an object is derived from a specific generic class?

    - by Edison Chuang
    Suppose that I have an object then how could I know if the object is derived from a specific generic class. For example: public class GenericClass<T> { } public bool IsDeriveFrom(object o) { return o.GetType().IsSubclassOf(typeof(GenericClass)); //will throw exception here } please notice that the code above will throw an exception. The type of the generic class cannot be retrieved directly because there is no type for a generic class without a type parameter provided.

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