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  • LINQ - Select Statement - The null value cannot be assigned to a member with type System.Int32 which

    - by thiag0
    I am trying to achieve the following... _4S.NJB_Request request = (from r in db.NJB_Requests where r.RequestId == referenceId select r).Take(1).SingleOrDefault(); Getting the following exception... Message: The null value cannot be assigned to a member with type System.Int32 which is a non-nullable value type. StackTrace: at System.Data.Linq.SqlClient.SqlProvider.Execute(Expression query, QueryInfo queryInfo, IObjectReaderFactory factory, Object[] parentArgs, Object[] userArgs, ICompiledSubQuery[] subQueries, Object lastResult) at System.Data.Linq.SqlClient.SqlProvider.ExecuteAll(Expression query, QueryInfo[] queryInfos, IObjectReaderFactory factory, Object[] userArguments, ICompiledSubQuery[] subQueries) at System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) at System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute[S](Expression expression) at System.Linq.Queryable.SingleOrDefault[TSource](IQueryable`1 source) at DAL.SqlDataProvider.MarkNJBPCRequestAsComplete(Int32 referenceId, Int32 processState) I have verified that 'referenceId' does have a value. Anyone know why this would happen in a select statement? Thanks!

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  • Random record in ActiveRecord

    - by astrofoo
    I'm in need of getting a random record from a table via ActiveRecord. I've followed the example from Jamis Buck from 2006. However, I've also come across another way via a Google search (can't attribute with a link due to new user restrictions): rand_id = rand(Model.count) rand_record = Model.first(:conditions => [ "id >= ?", rand_id]) I'm curious how others on here have done it or if anyone knows what way would be more efficient.

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  • Django: Is there any way to have "unique for date range"?

    - by tomwolber
    If my model for Items is: class Item(models.Model): name = models.CharField(max_length=500) startDate = models.DateField("Start Date", unique="true") endDate = models.DateField("End Date") Each Item needs to have a unique date range. for example, if i create an Item that has a date range of June 1st to June 8th, how can I keep and Item with a date range of June 3rd to June 5th from being created (or render an error with template logic)?

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  • Modelview navigation problem

    - by Allen
    i have a navigation controller displaying as a modelview controller. That model view controller calling from another view controller. In that modelview controller im navigating to different controllers and its working fine. but when i return to that model view controller the navigfation is not smooth and i can see space between that controllers while navigating. what is the reason?

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  • What does the "=>" mean in asp.net mvc?

    - by quakkels
    Hey SO, I've got a pretty noob question for ya. I keep seeing this syntax: <%= Html.LabelFor(model => model.Email) %> ...and I have no idea what the = means. I thought it was syntax for linq2sql or ado.net entity framework but I'm just using straight ado.net. I don't understand why the VWD used that syntax when generating the Create form. What does = mean?

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  • Django approximate matching of unicode strings with ascii equivalents

    - by c
    I have the following model and instance: class Bashable(models.Model): name = models.CharField(max_length=100) >>> foo = Bashable.objects.create(name=u"piñata") Now I want to be able to search for objects, but using ascii characters rather than unicode, something like this: >>> Bashable.objects.filter(name__lookslike="pinata") Is there a way in Django to do this sort of approximate string matching, using ascii stand-ins for the unicode characters in the database? Here is a related question, but for Apple's Core Data.

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  • Multithread Communication

    - by Robert
    I'm creating a WPF application that uses a custom object to populate all the controls. The constructor of that object is initiated by an EventHandler that waits for an API. The problem I'm having is when I try to access any information from that object using a button for example, it returns an error saying "The calling thread cannot access this object because a different thread owns it". I'm assuming this is because the EventHandler creates a new thread which doesn't allow the MainThread to have access to it. Any ideas on how to get around this?

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  • What database systems should an startup company consider?

    - by Am
    Right now I'm developing the prototype of a web application that aggregates large number of text entries from a large number of users. This data must be frequently displayed back and often updated. At the moment I store the content inside a MySQL database and use NHibernate ORM layer to interact with the DB. I've got a table defined for users, roles, submissions, tags, notifications and etc. I like this solution because it works well and my code looks nice and sane, but I'm also worried about how MySQL will perform once the size of our database reaches a significant number. I feel that it may struggle performing join operations fast enough. This has made me think about non-relational database system such as MongoDB, CouchDB, Cassandra or Hadoop. Unfortunately I have no experience with either. I've read some good reviews on MongoDB and it looks interesting. I'm happy to spend the time and learn if one turns out to be the way to go. I'd much appreciate any one offering points or issues to consider when going with none relational dbms?

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  • DRYing out implementation of ICloneable in several classes

    - by Sarah Vessels
    I have several different classes that I want to be cloneable: GenericRow, GenericRows, ParticularRow, and ParticularRows. There is the following class hierarchy: GenericRow is the parent of ParticularRow, and GenericRows is the parent of ParticularRows. Each class implements ICloneable because I want to be able to create deep copies of instances of each. I find myself writing the exact same code for Clone() in each class: object ICloneable.Clone() { object clone; using (var stream = new MemoryStream()) { var formatter = new BinaryFormatter(); // Serialize this object formatter.Serialize(stream, this); stream.Position = 0; // Deserialize to another object clone = formatter.Deserialize(stream); } return clone; } I then provide a convenience wrapper method, for example in GenericRows: public GenericRows Clone() { return (GenericRows)((ICloneable)this).Clone(); } I am fine with the convenience wrapper methods looking about the same in each class because it's very little code and it does differ from class to class by return type, cast, etc. However, ICloneable.Clone() is identical in all four classes. Can I abstract this somehow so it is only defined in one place? My concern was that if I made some utility class/object extension method, it would not correctly make a deep copy of the particular instance I want copied. Is this a good idea anyway?

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  • Design Patterns: What is a type

    - by contactmatt
    A very basic question, but after reading the "Design Patterns: Elements of reusable OO Software" book, I'm a little confused. The book states, "An object's type only refers to its interface-the set of request to which it can respond. An object can have many types, and objects of different classes can have the same type." Could someone please better explain what a Type is? I also don't understand how one object can have multiple types...unless the book is speaking of polymorphism....

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  • Executing logic before save or validation with EF Code-First Models

    - by Ryan Norbauer
    I'm still getting accustomed to EF Code First, having spent years working with the Ruby ORM, ActiveRecord. ActiveRecord used to have all sorts of callbacks like before_validation and before_save, where it was possible to modify the object before it would be sent off to the data layer. I am wondering if there is an equivalent technique in EF Code First object modeling. I know how to set object members at the time of instantiation, of course, (to set default values and so forth) but sometimes you need to intervene at different moments in the object lifecycle. To use a slightly contrived example, say I have a join table linking Authors and Plays, represented with a corresponding Authoring object: public class Authoring { public int ID { get; set; } [Required] public int Position { get; set; } [Required] public virtual Play Play { get; set; } [Required] public virtual Author Author { get; set; } } where Position represents a zero-indexed ordering of the Authors associated to a given Play. (You might have a single "South Pacific" Play with two authors: a "Rodgers" author with a Position 0 and a "Hammerstein" author with a Position 1.) Let's say I wanted to create a method that, before saving away an Authoring record, it checked to see if there were any existing authors for the Play to which it was associated. If no, it set the Position to 0. If yes, it would find set the Position of the highest value associated with that Play and increment by one. Where would I implement such logic within an EF code first model layer? And, in other cases, what if I wanted to massage data in code before it is checked for validation errors? Basically, I'm looking for an equivalent to the Rails lifecycle hooks mentioned above, or some way to fake it at least. :)

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  • Get Specific Data From Array, Based On Another Value

    - by A Smith
    I have an array that outputs these values: Array ( [0] => stdClass Object ( [ID] => 6585 [COLOR] => red [Name] => steve ) [1] => stdClass Object ( [ID] => 5476 [COLOR] => blue [Name] => sol ) [2] => stdClass Object ( [ID] => 7564 [COLOR] => yellow [Name] => jake ) [3] => stdClass Object ( [ID] => 3465 [COLOR] => green [Name] => helen ) ) Now, I will know the ID of the person, and I need the get the COLOR value for that specific value set. How is this best achieved please?

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  • rails, activerecord callbacks not saving

    - by Joseph Silvashy
    I have a model with a callback that runs after_update: after_update :set_state protected def set_state if self.valid? self.state = 'complete' else self.state = 'in_progress' end end But it doesn't actually save those values, why not? Regardless of if the model is valid or not it won't even write anything, even if i remove the if self.valid? condition, I can't seem to save the state. Um, this might sound dumb, do I need to run save on it?

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  • Rectangles Covering

    - by den bardadym
    I have N rectangles with sides parallel Ox and Oy. Exists another rectangele (model). I need create algorithm, which can tell: is model covered by N rectangles? and code him. I have some ideas. First I think need sort rectangles by left side (it can be done by O(n log n)). Then I think need use vertical sweeping line. Thanks.

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  • ASP.NET MVC & Web Services

    - by ANaimi
    Hello, Does adding a Web Service to my ASP.NET MVC project break the whole concept of MVC? That Web Service (WCF) depends on the Model layer from my MVC project to communicate with the back-end (so it looks to me like it needs to be part of the MVC solution). Should I add this to the Controller or Model layer?

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  • ajaxSubmit options success & error functions aren't fired

    - by Thommy Tomka
    jQuery 1.7.2 jQuery Validate 1.1.0 jQuery Form 3.18 Wordpress 3.4.2 I am trying to code a contact/ mail form in above environment/ with above jQuery libs. Now I am having a problem with the jQuery Form JS: I have taken the original code from the developers page for ajaxSubmit and only altered the target option to an ID which exists in my HTML source and replaced $ with jQuery in function showRequest. The problem is, that the function namend after success: does not fire. I tried the same with error: and again nothing fired. Only complete: did and the function I placed there alerted the responseText from the receiving script. Does anyone has an idea whats going wrong? Thanks in advance! Thomas jQuery(document).ready(function() { var options = { target: '#mail-status', // target element(s) to be updated with server response beforeSubmit: showRequest, // pre-submit callback success: showResponse, // post-submit callback // other available options: //url: url // override for form's 'action' attribute //type: type // 'get' or 'post', override for form's 'method' attribute //dataType: null // 'xml', 'script', or 'json' (expected server response type) //clearForm: true // clear all form fields after successful submit //resetForm: true // reset the form after successful submit // $.ajax options can be used here too, for example: //timeout: 3000 }; jQuery("#mailform").validate( { submitHandler: function(form) { jQuery(form).ajaxSubmit(options); }, errorPlacement: function(error, element) { }, rules: { author: { minlength: 2, required: true }, email: { required: true, email: true }, comment: { minlength: 2, required: true } }, highlight: function(element) { jQuery(element).addClass("e"); jQuery(element.form).find("label[for=" + element.id + "]").addClass("e"); }, unhighlight: function(element) { jQuery(element).removeClass("e"); jQuery(element.form).find("label[for=" + element.id + "]").removeClass("e"); } }); }); // pre-submit callback function showRequest(formData, jqForm, options) { // formData is an array; here we use $.param to convert it to a string to display it // but the form plugin does this for you automatically when it submits the data var queryString = jQuery.param(formData); // jqForm is a jQuery object encapsulating the form element. To access the // DOM element for the form do this: // var formElement = jqForm[0]; alert('About to submit: \n\n' + queryString); // here we could return false to prevent the form from being submitted; // returning anything other than false will allow the form submit to continue return true; } // post-submit callback function showResponse(responseText, statusText, xhr, $form) { // for normal html responses, the first argument to the success callback // is the XMLHttpRequest object's responseText property // if the ajaxSubmit method was passed an Options Object with the dataType // property set to 'xml' then the first argument to the success callback // is the XMLHttpRequest object's responseXML property // if the ajaxSubmit method was passed an Options Object with the dataType // property set to 'json' then the first argument to the success callback // is the json data object returned by the server alert('status: ' + statusText + '\n\nresponseText: \n' + responseText + '\n\nThe output div should have already been updated with the responseText.'); }

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  • How do I write a powershell script that gets the file with the most recent last write time from a fo

    - by Shoko
    The subject line says it all. I'd also like to do this using pipes. I figured that I could use Get-ChildItem, Measure-Object and Where-Object, but Measure-Object doesn't like dates. Should I have a script block which loops through each item returned from Get-ChildItem and does a comparison to see if it's the most recent? I thought that there should be a handy PS cmdlet for that.

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  • Is Dynamic Casting Possible in Java

    - by Tom Tucker
    So I have a class of overloaded methods like this: class Foo { public void test(Object value) { ... } public void test(String value) { ... } } I need to pass a property value of a bean to one of these methods depending on its type, but I don't know the actual property type until the runtime. e.g. public void run(Object bean, String propertyName) { Foo foo = new Foo(); foo.test(PropertyUtils.getProperty(bean, propertyName)); } BTW, PropertyUtils.getProperty() is a helper method that returns a value of the specified property on a bean. PropertyUtils.getProperty() returns an Object, so that test(Object value) will be always called and the actual property type will be ignored. I can figure out the propery type in the runtime, even if its value is null. Is there such a thing as dynamic casting in Java? If not, is there a way to have an overloaded method with the correct parameter type called?

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  • ASP.net MVC Linq-To-SQL Many-To-Many Field Binding

    - by user336858
    Hi there, The short version of this question is "Is there a way to gracefully handle database insertion for an object that has a many-to-many field that has been set up in a partial class?" Apologies if it's been asked before. Example Suppose I have a typical MVC setup with the tables: Posts {PostID, ...} Categories {CategoryID, ...} A post can have more than one category, and a category can identify more than one post. Thus suppose further that I need an extra table: PostCategories {PostID, CategoryID, ...} This handles the many-to-many relationship between posts and categories. As far as I know, there's no way to do this in Linq-to-SQL right now so I have to shoehorn it in by adding a partial Post class to the project to add that functionality. Something like: public partial class Post { public IEnumerable<Category> Categories{ get { ... } set { ... } } } So I can now create a "Create" view that automatically populates a "Categories" UI item. This is where the trouble starts. So here's my question: How do you get automatic object model binding to work cleanly with an object that has a many-to-many relationship to control? The workaround that makes many-to-many relationships possible relies on the Post object having a PostID in order to be associated with CategoryID(s), which is only issued after the Post object has been submitted for validation and insertion. Bit of a Catch22 here. Any terminology, links, or tips you can provide would be tremendously helpful!

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  • Design: How to declare a specialized memory handler class

    - by Michael Dorgan
    On an embedded type system, I have created a Small Object Allocator that piggy backs on top of a standard memory allocation system. This allocator is a Boost::simple_segregated_storage< class and it does exactly what I need - O(1) alloc/dealloc time on small objects at the cost of a touch of internal fragmentation. My question is how best to declare it. Right now, it's scope static declared in our mem code module, which is probably fine, but it feels a bit exposed there and is also now linked to that module forever. Normally, I declare it as a monostate or a singleton, but this uses the dynamic memory allocator (where this is located.) Furthermore, our dynamic memory allocator is being initialized and used before static object initialization occurs on our system (as again, the memory manager is pretty much the most fundamental component of an engine.) To get around this catch 22, I added an extra 'if the small memory allocator exists' to see if the small object allocator exists yet. That if that now must be run on every small object allocation. In the scheme of things, this is nearly negligable, but it still bothers me. So the question is, is there a better way to declare this portion of the memory manager that helps decouple it from the memory module and perhaps not costing that extra isinitialized() if statement? If this method uses dynamic memory, please explain how to get around lack of initialization of the small object portion of the manager.

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  • Creating a generic NotFound View in ASP.MVC

    - by George
    Hello guys, I'm having a problem to create a generic View to represent NotFound pages. The view is created and it's fine. I need to know how i can direct the user to the NotFound view in my Controllers and how to render a specific "Return to Index" in each controller. Here is some code: public class NotFoundModel { private string _contentName; private string _notFoundTitle; private string _apologiesMessage; public string ContentName { get; private set; } public string NotFoundTitle { get; private set; } public string ApologiesMessage { get; private set; } public NotFoundModel(string contentName, string notFoundTitle, string apologiesMessage) { this._contentName = contentName; this._notFoundTitle = notFoundTitle; this._apologiesMessage = apologiesMessage; } } // NotFound View <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<Geographika.Models.NotFoundModel>" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server"> <%= Html.Encode(Model.ContentName) %> </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <h2><%= Html.Encode(Model.NotFoundTitle) %></h2> <p><%= Html.Encode(Model.ApologiesMessage) %></p> <!-- How can i render here a specific "BackToIndexView", but that it's not bound to my NotFoundModel? --> </asp:Content> // Controller piece of code // // GET: /Term/Details/2 public ActionResult Details(int id) { Term term = termRepository.SingleOrDefault(t => t.TermId == id); if (term == null) return View("NotFound"); // how can i return the specific view that its not bound to Term Model? // the idea here would be something like: // return View("NotFound",new NotFoundModel("a","b","c")); else return View("Details", term); } I'm not sure how to redirect to a whole different page. Can anyone give me any pointers? Thanks

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  • Using a NullTempDataProvider crashes at PossiblyLoadTempData()

    - by Jova
    I'm trying to use a dummy TempDataProvider for some of my controllers. The provider looks like this. public class NullTempDataProvider : ITempDataProvider { public IDictionary<string, object> LoadTempData(ControllerContext controllerContext) { return new TempDataDictionary(); } public void SaveTempData(ControllerContext controllerContext, IDictionary<string, object> values) { } } But I'm getting an error that says System.NullReferenceException: Object reference not set to an instance of an object. at System.Web.Mvc.Controller.PossiblyLoadTempData() Any help for figuring out the reason for it is much appreciated.

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