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  • Which Code Should Go Where in MVC Structure

    - by Oguz
    My problem is in somewhere between model and controller.Everything works perfect for me when I use MVC just for crud (create, read, update, delete).I have separate models for each database table .I access these models from controller , to crud them . For example , in contacts application,I have actions (create, read, update, delete) in controller(contact) to use model's (contact) methods (create, read, update, delete). The problem starts when I try to do something more complicated. There are some complex processes which I do not know where should I put them. For example , in registering user process. I can not just finish this process in user model because , I have to use other models too (sending mails , creating other records for user via other models) and do lots of complex validations via other models. For example , in some complex searching processes , I have to access lots of models (articles, videos, images etc.) Or, sometimes , I have to use apis to decide what I will do next or which database model I will use to record data So where is the place to do this complicated processes. I do not want to do them in controllers , Because sometimes I should use these processes in other controllers too. And I do not want to put these process in models because , I use models as database access layers .May be I am wrong,I want to know . Thank you for your answer .

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  • How can I create a horizontal table in a single foreach loop in MVC?

    - by GenericTypeTea
    Is there any way, in ASP.Net MVC, to condense the following code to a single foreach loop? <table class="table"> <tr> <td> Name </td> <% foreach (var item in Model) { %> <td> <%= item.Name %> </td> <% } %> </tr> <tr> <td> Item </td> <% foreach (var item in Model) { %> <td> <%= item.Company %> </td> <% } %> </tr> </table> Where model is a simple object: public class SomeObject { public virtual Name {get;set;} public virtual Company {get;set;} } This would output a table as follows: Name | Bob | Sam | Bill | Steve | Company | Builder | Fireman | MS | Apple | I know I could probably use an extension method to write out each row, but is it possible to build all rows using a single iteration over the model? This is a follow on from this question as I'm unhappy with my accepted answer and cannot believe I've provided the best solution.

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  • edmx - The operation could not be completed - When adding Inheritance

    - by vdh_ant
    Hey guys I have an edmx model which I have draged 2 tables onto - One called 'File' and the other 'ApplicaitonFile'. These two tables have a 1 to 1 relationship in the database. If I stop here everything works fine. But in my model, I want 'ApplicaitonFile' to inherit from 'File'. So I delete the 1 to 1 relationship then configure 'ApplicaitonFile' from 'File' and then remove the FileId from 'ApplicaitonFile' which was the primary key. (Note I am following the instructions from here). If I leave the model open at this point everything is fine, but as soon as I close it, if I try and reopen it again I get the following error "The operation could not be completed". I have been searching for a solution and found this - http://stackoverflow.com/questions/944050/entity-model-does-not-load but as far as I can tell I don't have a duplicate InheritanceConnectors (although I don't know exactly what I'm looking for but I can't see anything out of the ordinary - like 2 connectors with the same name) and the relationship I originally have is a 1 to 1 not a 1 to 0..1 Any ideas??? this is driving me crazy...

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  • Trouble accessing data in relationships in Ember

    - by user3618430
    I'm having trouble saving data in this model relationship. My models are as follows: App.Flow = DS.Model.extend({ title: DS.attr('string'), content: DS.attr('string'), isCustom: DS.attr('boolean'), params: DS.hasMany('parameter', {async: true}) }); App.Parameter = DS.Model.extend({ flow: DS.belongsTo('flow'), param: DS.attr('string'), param_tooltip: DS.attr('string'), param_value: DS.attr('string') }); As you can see, I want Flows to have multiple Parameters. I have a rudimentary setup using Flow and Parameter fixtures, which behave as expected in the templates. However, when I try to create new ones in the controller, I have trouble setting the flow and parameter values correctly. var p = this.store.createRecord('parameter', { param: "foo", param_tooltip: "world", param_value: "hello" }); var f = this.store.createRecord('flow', { title: 'job', content: title, isCustom: true, params: [p] // doesn't seem to work }); f.set('params', [p]); // doesn't seem to work p.set('flow', f); // also doesn't seem to work // Save the new model p.save(); f.save(); I've tried a lot of solutions after staring at this and StackOverflow for a while (not just the ones listed). I'm not really sure what to try next. One thing that I noticed in the Ember inspector was that the ids of these created elements were not integers (they were something like the string 'fixture_0'), but I'm not really sure why that would be, whether its related, or how to fix it. Thanks!

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  • Modeling Buyers & Sellers in a Rails Ecommerce App

    - by MikeH
    I'm building a Rails app that has Etsy.com style functionality. In other words, it's like a mall. There are many buyers and many sellers. I'm torn about how to model the sellers. Key facts: There won't be many sellers. Perhaps less than 20 sellers in total. There will be many buyers. Hopefully many thousands :) I already have a standard user model in place with account creation and roles. I've created a 'role' of 'seller', which the admin will manually apply to the proper users. Since we'll have very few sellers, this is not an issue. I'm considering two approaches: (1) Create a 'store' model, which will contain all the relevant store information. Products would :belong_to :store, rather than belonging to the seller. The relationship between the user and store models would be: user :has_one store. My main problem with this is that I've always found has_one associations to be a little funky, and I usually try to avoid them. The app is fairly complex, and I'm worried about running into a cascade of problems connected to the has_one association as I get further along into development. (2) Simply include the relevant 'store' information as part of the user model. But in this case, the store-related db columns would only apply to a very small percentage of users since very few users will also be sellers. I'm not sure if this is a valid concern or not. It's very possible that I'm thinking about this incorrectly. I appreciate any thoughts. Thanks.

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  • Generating alerts from ossec ( server- agent ) model

    - by batman
    I'm very new to OSSEC. I use a server-agent model. I wish to generate alert for the following actions ( in agent side ): 1) Sample Alert for delation of logs I added the rules for these in agent's ossec.conf using <localfile> tags. Like this : <localfile> <log_format>syslog</log_format> <location>/var/log/syslog</location> </localfile> In my server's ossec.conf. I added the following : <global> <email_notification>yes</email_notification> <email_to>xxxx@xxxxxx</email_to> <smtp_server>smtp.gmail.com</smtp_server> <email_from>xxxx@xxx</email_from> </global> And I restarted my server. Now I tried to delete the agents syslog file using rm syslog. But no alerts has been triggered. Where I'm making the mistake?

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  • asp.net MVC 1.0 and 2.0 currency model binding

    - by David Liddle
    I would like to create model binding functionality so a user can enter ',' '.' etc for currency values which bind to a double value of my ViewModel. I was able to do this in MVC 1.0 by creating a custom model binder, however since upgrading to MVC 2.0 this functionality no longer works. Does anyone have any ideas or better solutions for performing this functionality? A better solution would be to use some data annotation or custom attribute. public class MyViewModel { public double MyCurrencyValue { get; set; } } A preferred solution would be something like this... public class MyViewModel { [CurrencyAttribute] public double MyCurrencyValue { get; set; } } Below is my solution for model binding in MVC 1.0. public class MyCustomModelBinder : DefaultModelBinder { public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) { object result = null; ValueProviderResult valueResult; bindingContext.ValueProvider.TryGetValue(bindingContext.ModelName, out valueResult); bindingContext.ModelState.SetModelValue(bindingContext.ModelName, valueResult); if (bindingContext.ModelType == typeof(double)) { string modelName = bindingContext.ModelName; string attemptedValue = bindingContext.ValueProvider[modelName].AttemptedValue; string wantedSeperator = NumberFormatInfo.CurrentInfo.NumberDecimalSeparator; string alternateSeperator = (wantedSeperator == "," ? "." : ","); try { result = double.Parse(attemptedValue, NumberStyles.Any); } catch (FormatException e) { bindingContext.ModelState.AddModelError(modelName, e); } } else { result = base.BindModel(controllerContext, bindingContext); } return result; } }

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  • Explicit casting doesn't work in default model binding

    - by Felix
    I am using ASP.NET MVC2 and Entity Framework. I am going to simplify the situation a little; hopefully it will make it clearer, not more confusing! I have a controller action to create address, and the country is a lookup table (in other words, there is a one-to-many relationship between Country and Address classes). Let's say for clarity that the field in the Address class is called Address.Land. And, for the purposes of the dropdown list, I am getting Country.CountryID and Country.Name. I am aware of Model vs. Input validation. So, if I call the dropdown field formLand - I can make it work. But if I call the field Land (that is, matching the variable in Address class) - I am getting the following error: "The parameter conversion from type 'System.String' to type 'App.Country' failed because no type converter can convert between these types." OK, this makes sense. A string (CountryID) comes from the form and the binder doesn't know how to convert it to Country type. So, I wrote the converter: namespace App { public partial class Country { public static explicit operator Country(string countryID) { AppEntities context = new AppEntities(); Country country = (Country) context.GetObjectByKey( new EntityKey("AppEntities.Countries", "CountryID", countryID)); return country; } } } FWIW, I tried both explicit and implicit. I tested it from the controller - Country c = (Country)"fr" - and it works fine. However, it never got invoked when the View is posted. I am getting the same "no type converter" error in the model. Any ideas how to hint to the model binder that there is a type converter? Thanks

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  • Using named_scopes on the join model of a has_many :through

    - by uberllama
    Hi folks. I've been beating my head against the wall on something that on the surface should be very simple. Lets say I have the following simplified models: user.rb has_many :memberships has_many :groups, :through => :memberships membership.rb belongs_to :group belongs_to :user STATUS_CODES = {:admin => 1, :member => 2, :invited => 3} named_scope :active, :conditions => {:status => [[STATUS_CODES[:admin], STATUS_CODES[:member]]} group.rb has_many :memberships has_many :users, :through => :memberships Simple, right? So what I want to do is get a collection of all the groups a user is active in, using the existing named scope on the join model. Something along the lines of User.find(1).groups.active. Obviously this doesn't work. But as it stands, I need to do something like User.find(1).membrships.active.all(:include => :group) which returns a collection of memberships plus groups. I don't want that. I know I can add another has_many on the User model with conditions that duplicate the :active named_scope on the Membership model, but that's gross. has_many :active_groups, :through => :memberships, :source => :group, :conditions => ... So my question: is there a way of using intermediary named scopes when traversing directly between models? Many thanks.

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  • model not showing up in django admin.

    - by Zayatzz
    Hi. I have ceated several django apps and stuffs for my own fund and so far everything has been working fine. Now i just created new project (django 1.2.1) and have run into trouble from 1st moments. I created new app - game and new model Game. i created admin.py and put related stuff into it. Ran syncdb and went to check into admin. Model did not show up there. I proceeded to check and doublecheck and read through previous similar threads: http://stackoverflow.com/questions/1839927/registered-models-do-not-show-up-in-admin http://stackoverflow.com/questions/1694259/django-app-not-showing-up-in-admin-interface But as far as i can tell, they dont help me either. Perhaps someone else can point this out for me. models.py in game app: # -*- coding: utf-8 -*- from django.db import models class Game(models.Model): type = models.IntegerField(blank=False, null=False, default=1) teamone = models.CharField(max_length=100, blank=False, null=False) teamtwo = models.CharField(max_length=100, blank=False, null=False) gametime = models.DateTimeField(blank=False, null=False) admin.py in game app: # -*- coding: utf-8 -*- from jalka.game.models import Game from django.contrib import admin class GameAdmin(admin.ModelAdmin): list_display = ['type', 'teamone', 'teamtwo', 'gametime'] admin.site.register(Game, GameAdmin) project settings.py: MIDDLEWARE_CLASSES = ( 'django.middleware.common.CommonMiddleware', 'django.contrib.sessions.middleware.SessionMiddleware', 'django.middleware.csrf.CsrfViewMiddleware', 'django.contrib.auth.middleware.AuthenticationMiddleware', 'django.contrib.messages.middleware.MessageMiddleware', ) ROOT_URLCONF = 'jalka.urls' TEMPLATE_DIRS = ( "/home/projects/jalka/templates/" ) INSTALLED_APPS = ( 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.sites', 'django.contrib.messages', 'django.contrib.admin', 'game', ) urls.py: from django.conf.urls.defaults import * # Uncomment the next two lines to enable the admin: from django.contrib import admin admin.autodiscover() urlpatterns = patterns('', # Example: # (r'^jalka/', include('jalka.foo.urls')), (r'^admin/', include(admin.site.urls)), ) Alan.

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  • Inheriting from ViewPage forces explicit casting of model in view

    - by Martin Hansen
    I try to inhering from ViewPage as shown in this question http://stackoverflow.com/questions/370500/inheriting-from-viewpage But I get a Compiler Error Message: CS1061: 'object' does not contain a definition for 'Spot' and no extension method 'Spot' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?) My viewpage, normally I can do Model.ChildProperty(Spot) when I inherit from ViewPage directly, so I do that here too. But it fails. <%@ Page Language="C#" Inherits="Company.Site.ViewPageBase<WebSite.Models.SpotEntity>" %> <h1><%= Html.Encode(Model.Spot.Title) %></h1> To get it working correctly I have to do like this: <%@ Page Language="C#" Inherits="Company.Site.ViewPageBase<WebSite.Models.SpotEntity>" %> <h1><%= Html.Encode(((WebSite.Models.SpotEntity)Model).Spot.Title) %></h1> Here is my classes: namespace Company.Site { public class ViewPageBase<TModel> : Company.Site.ViewPageBase where TModel:class { private ViewDataDictionary<TModel> _viewData; [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")] public new ViewDataDictionary<TModel> ViewData { get { if (_viewData == null) { SetViewData(new ViewDataDictionary<TModel>()); } return _viewData; } set { SetViewData(value); } } protected override void SetViewData(ViewDataDictionary viewData) { _viewData = new ViewDataDictionary<TModel>(viewData); base.SetViewData(_viewData); } } public class ViewPageBase : System.Web.Mvc.ViewPage { } } So how do I get it to work without the explicit cast?

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  • nested attributes with polymorphic has_one model

    - by Millisami
    I am using accepts_nested_attributes_for with the has_one polymorphic model in rails 2.3.5 Following are the models and its associations: class Address < ActiveRecord::Base attr_accessible :city, :address1, :address2 belongs_to :addressable, :polymorphic => true validates_presence_of :address1, :address2, :city end class Vendor < ActiveRecord::Base attr_accessible :name, :address_attributes has_one :address, :as => :addressable, :dependent => :destroy accepts_nested_attributes_for :address end This is the view: - form_for @vendor do |f| = f.error_messages %p = f.label :name %br = f.text_field :name - f.fields_for :address_attributes do |address| = render "shared/address_fields", :f => address %p = f.submit "Create" This is the partial shared/address_fields.html.haml %p = f.label :city %br= f.text_field :city %span City/Town name like Dharan, Butwal, Kathmandu, .. %p = f.label :address1 %br= f.text_field :address1 %span City Street name like Lazimpat, New Road, .. %p = f.label :address2 %br= f.text_field :address2 %span Tole, Marg, Chowk name like Pokhrel Tole, Shanti Marg, Pako, .. And this is the controller: class VendorsController < ApplicationController def new @vendor = Vendor.new end def create @vendor = Vendor.new(params[:vendor]) if @vendor.save flash[:notice] = "Vendor created successfully!" redirect_to @vendor else render :action => 'new' end end end The problem is when I fill in all the fileds, the record gets save on both tables as expected. But when I just the name and city or address1 filed, the validation works, error message shown, but the value I put in the city or address1, is not persisted or not displayed inside the address form fields? This is the same case with edit action too. Though the record is saved, the address doesn't show up on the edit form. Only the name of the Client model is shown. Actually, when I look at the log, the address model SQL is not queried even at all.

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  • .net MVC RenderPartial renders information that is not in the model

    - by Andreas
    Hi, I have a usercontrol that is rendering a list of items. Each row contains a unique id in a hidden field, a text and a delete button. When clicking on the delete button I use jquery ajax to call the controller method DeleteCA (seen below). DeleteCA returns a new list of items that replaces the old list. [HttpPost] public PartialViewResult DeleteCA(CAsViewModel CAs, Guid CAIdToDelete) { int indexToRemove = CAs.CAList.IndexOf(CAs.CAList.Single(m => m.Id == CAIdToDelete)); CAs.CAList.RemoveAt(indexToRemove); return PartialView("EditorTemplates/CAs", CAs); } I have checked that DeleteCA is really removing the correct item. The modified list of CAs passed to PartialView no longer contains the deleted item. Something weird happens when the partial view is rendered. The number of items in the list is reduced but it is always the last element that is removed from the list. The rendered items does not correspond to the items in the list/model sent to PartialView. In the usercontrol file (ascx) I'm using both Model.CAList and lambda expression m = m.CAList. How is it possible for the usercontrol to render stuff that is not in the model sent to PartialView? Thanx Andreas

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  • Online voice chat: Why client-server model vs. peer-to-peer model?

    - by sstallings
    I am adding online voice chat to a Silverlight app. I've been reviewing current apps, services and SDKs found thru online searches and forums. I'm finding that the majority of these implement a client-server (C/S) model and I'm trying to understand why that model versus a peer-to-peer (PTP) model. To me PTP would be preferable because going direct between peers would be more efficient (fewer IP hops and no processing along the way by a server computer) and no need for a server and its costs and dependencies. I found some products offer the ability to switch from PTP to C/S if the PTP proves insufficient. As I thought more about it, I could see that C/S could be better if there are more than two peers involved in a conversation, then the server (supposedly with more bandwidth) could do a better job of relaying each peers outgoing traffic to the multiple other peers. In C/S many-to-many voice chatting, each peer's upstream broadband (which is where the bottleneck inherently is) would only have to carry each item of voice traffic once, then the server would use its superior bandwidth to relay the message to the multiple other peers. But, in a situation with one-on-one voice chatting it seems that PTP would be best. A server would not reduce each of the two peer's bandwidth requirements and would only add unnecessary overhead, dependency and cost. In one-on-one voice chatting: Am I mistaken on anything above? Would peer-to-peer be best? Would a server provide anything of value that could not be provided by a client-only program? Is there anything else that I should be taking into consideration? And lastly, can you recommend any Silverlight PTP or C/S voice chat products? Thanks in advance for any info.

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  • Django Cannot set values on a ManyToManyField which specifies an intermediary model

    - by dana
    i am using a m2m and a through table, and when i was trying to save, my error was: Cannot set values on a ManyToManyField which specifies an intermediary model so, i've modified my code, so that when i save the form, to insert data into the 'through' table too.But now, i'm having another error. (i've bolded the lines where i think i am wrong) i have in models.py: class Classroom(models.Model): user = models.ForeignKey(User, related_name = 'classroom_creator') classname = models.CharField(max_length=140, unique = True) date = models.DateTimeField(auto_now=True) open_class = models.BooleanField(default=True) members = models.ManyToManyField(User,related_name="list of invited members", through = 'Membership') class Membership(models.Model): accept = models.BooleanField(User) date = models.DateTimeField(auto_now = True) classroom = models.ForeignKey(Classroom, related_name = 'classroom_membership') member = models.ForeignKey(User, related_name = 'user_membership') and in def save_classroom(request): if request.method == 'POST': form = ClassroomForm(request.POST, request.FILES, user = request.user) **classroom_instance = Classroom member_instance = Membership** if form.is_valid(): new_obj = form.save(commit=False) new_obj.user = request.user r = Relations.objects.filter(initiated_by = request.user) membership = Membership.objects.create(**classroom = classroom_instance, member = member_instance,date=datetime.datetime.now())** new_obj.save() form.save_m2m() return HttpResponseRedirect('/classroom/classroom_view/{{user}}/') else: form = ClassroomForm(user = request.user) return render_to_response('classroom/classroom_form.html', { 'form': form, }, context_instance=RequestContext(request)) but i don't seem to initialise okay the classroom_instance and menber_instance.My error os: Cannot assign "": "Membership.classroom" must be a "Classroom" instance. Thanks!

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  • Proper way to validate model in ASP.NET MVC 2 and ViewModel apporach

    - by adrin
    I am writing an ASP.NET MVC 2 application using NHibernate and repository pattern. I have an assembly that contains my model (business entities), moreover in my web project I want to use flattened objects (possibly with additional properties/logic) as ViewModels. These VMs contain UI-specific metadata (eg. DisplayAttribute used by Html.LabelFor() method). The problem is that I don't know how to implement validation so that I don't repeat myself throughout various tiers (specifically validation rules are written once in Model and propagated to ViewModel). I am using DataAnnotations on my ViewModel but this means no validation rules are imposed on the Model itself. One approach I am considering is deriving ViewModel objects from business entities adding new properties/overriding old ones, thus preserving validation metadata between the two however this is an ugly workaround. I have seen Automapper project which helps to map properties, but I am not sure if it can handle ASP.NET MVC 2 validation metadata properly. Is it difficult to use custom validation framework in asp.net mvc 2? Do you have any patterns that help to preserve DRY in regard to validation?

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  • ViewModel updates after Model server roundtrip

    - by Pavel Savara
    I have stateless services and anemic domain objects on server side. Model between server and client is POCO DTO. The client should become MVVM. The model could be graph of about 100 instances of 20 different classes. The client editor contains diverse tab-pages all of them live-connected to model/viewmodel. My problem is how to propagate changes after server round-trip nice way. It's quite easy to propagate changes from ViewModel to DTO. For way back it would be possible to throw away old DTO and replace it whole with new one, but it will cause lot of redrawing for lists/DataTemplates. I could gather the server side changes and transmit them to client side. But the names of fields changed would be domain/DTO specific, not ViewModel specific. And the mapping seems nontrivial to me. If I should do it imperative way after round-trip, it would break SOC/modularity of viewModels. I'm thinking about some kind of mapping rule engine, something like automappper or emit mapper. But it solves just very plain use-cases. I don't see how it would map/propagate/convert adding items to list or removal. How to identify instances in collections so it could merge values to existing instances. As well it should propagate validation/error info. Maybe I should implement INotifyPropertyChanged on DTO and try to replay server side events on it ? And then bind ViewModel to it ? Would binding solve the problems with collection merges nice way ? Is EventAgregator from PRISM useful for that ? Is there any event record-replay component ? Is there better client side pattern for architecture with server side logic ?

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  • Creating form using Generic_inlineformset_factory from the Model Form

    - by Prateek
    hello dear all, I wanted to create a edit form with the help of ModelForm. and my models contain a Generic relation b/w classes, so if any one could suggest me the view and a bit of template for the purpose I would be very thankful, as I am new to the language. My models look like:- class Employee(Person): nickname = models.CharField(_('nickname'), max_length=25, null=True, blank=True) blood_type = models.CharField(_('blood group'), max_length=3, null=True, blank=True, choices=BLOOD_TYPE_CHOICES) marital_status = models.CharField(_('marital status'), max_length=1, null=True, blank=True, choices=MARITAL_STATUS_CHOICES) nationality = CountryField(_('nationality'), default='IN', null=True, blank=True) about = models.TextField(_('about'), blank=True, null=True) dependent = models.ManyToManyField(Dependent, through='DependentRelationship') pan_card_number = models.CharField(_('PAN card number'), max_length=50, blank=True, null=True) policy_number = models.CharField(_('policy number'), max_length=50, null=True, blank=True) # code specific details user = models.OneToOneField(User, blank=True, null=True, verbose_name=_('user')) class Person(models.Model): """Person model""" title = models.CharField(_('title'), max_length=20, null=True, blank=True) first_name = models.CharField(_('first name'), max_length=100) middle_name = models.CharField(_('middle name'), max_length=100, null=True, blank=True) last_name = models.CharField(_('last name'), max_length=100, null=True, blank=True) suffix = models.CharField(_('suffix'), max_length=20, null=True, blank=True) slug = models.SlugField(_('slug'), max_length=50, unique=True) class PhoneNumber(models.Model) : phone_number = generic.GenericRelation('PhoneNumber') email_address = generic.GenericRelation('EmailAddress') address = generic.GenericRelation('Address') date_of_birth = models.DateField(_('date of birth'), null=True, blank=True) gender = models.CharField(_('gender'), max_length=1, null=True, blank=True, choices=GENDER_CHOICES) content_type = models.ForeignKey(ContentType, If anyone could suggest me a link or so. it would be a great help........

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  • MVVM pattern: ViewModel updates after Model server roundtrip

    - by Pavel Savara
    I have stateless services and anemic domain objects on server side. Model between server and client is POCO DTO. The client should become MVVM. The model could be graph of about 100 instances of 20 different classes. The client editor contains diverse tab-pages all of them live-connected to model/viewmodel. My problem is how to propagate changes after server round-trip nice way. It's quite easy to propagate changes from ViewModel to DTO. For way back it would be possible to throw away old DTO and replace it whole with new one, but it will cause lot of redrawing for lists/DataTemplates. I could gather the server side changes and transmit them to client side. But the names of fields changed would be domain/DTO specific, not ViewModel specific. And the mapping seems nontrivial to me. If I should do it imperative way after round-trip, it would break SOC/modularity of viewModels. I'm thinking about some kind of mapping rule engine, something like automappper or emit mapper. But it solves just very plain use-cases. I don't see how it would map/propagate/convert adding items to list or removal. How to identify instances in collections so it could merge values to existing instances. As well it should propagate validation/error info. Maybe I should implement INotifyPropertyChanged on DTO and try to replay server side events on it ? And then bind ViewModel to it ? Would binding solve the problems with collection merges nice way ? Is EventAgregator from PRISM useful for that ? Is there any event record-replay component ? Is there better client side pattern for architecture with server side logic ?

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  • Using ARIMA to model and forecast stock prices using user-friendly stats program

    - by Brian
    Hi people, Can anyone please offer some insight into this for me? I'm coming from a functional magnetic resonance imaging research background where I analyzed a lot of time series data, and I'd like to analyze the time series of stock prices (or returns) by: 1) modeling a successful stock in a particular market sector and then cross-correlating the time series of this historically successful stock with that of other newer stocks to look for significant relationships; 2) model a stock's price time series and use forecasting (e.g., exponential smoothing) to predict future values of it. I'd like to use non-linear modeling methods (ARIMA and ARCH) to do this. Several questions: How often do ARIMA and ARCH modeling methods (given that the individual who implements them does so accurately) actually fit the stock time series data they target, and what is the optimal fit I can expect? Is the extent to which this model fits the data commensurate with the extent to which it predicts this stock time series' future values? Rather than randomly selecting stocks to compare or model, if profit is my goal, what is an efficient approach, if any, to selecting the stocks I'm going to analyze? Which stats program is the most user-friendly for this? Any thoughts on this would be great and would go a long way for me. Thanks, Brian

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  • Order in many to many relation in Django model

    - by Pietro Speroni
    I am writing a small website to store the papers I have written. The relation papers<- author is important, but the order of the name of the authors (which one is First Author, which one is second order, and so on) is also important. I am just learning Django so I don't know much. In any case so far I have done: from django.db import models class author(models.Model): Name = models.CharField(max_length=60) URLField = models.URLField(verify_exists=True, null=True, blank=True) def __unicode__(self): return self.Name class topic(models.Model): TopicName = models.CharField(max_length=60) def __unicode__(self): return self.TopicName class publication(models.Model): Title = models.CharField(max_length=100) Authors = models.ManyToManyField(author, null=True, blank=True) Content = models.TextField() Notes = models.TextField(blank=True) Abstract = models.TextField(blank=True) pub_date = models.DateField('date published') TimeInsertion = models.DateTimeField(auto_now=True) URLField = models.URLField(verify_exists=True,null=True, blank=True) Topic = models.ManyToManyField(topic, null=True, blank=True) def __unicode__(self): return self.Title This work fine in the sense that I now can define who the authors are. But I cannot order them. How should I do that? Of course I could add a series of relations: first author, second author,... but it would be ugly, and would not be flexible. Any better idea? Thanks

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  • Update "Properties" model when adding a new record in CakePHP

    - by Paul Willy
    Hi, I'm writing an application in CakePHP that, for now, is to be used to make quotes for customers. So Quote is a model. I want to have a separate model/table for something like "Property," which may be used by other models. Each time a user gets to the "Add Quote" action, I basically want to pull a Property called "nextQuoteNumber" or something along those lines, and then automatically increment that property, even if the new Quote isn't saved. So I don't think just using an autoincrement for Quote's id is appropriate here - also, the "quote number" could be different from the row's id. I know this is simple enough to do, but I'm trying to figure out the "proper" CakePHP way of doing it! I'm thinking that I should have a method inside the Property model, say "getProperty($property_name)", which would pull the value to return, and also increment the value... but I'm not sure what the best way of doing that is, or how to invoke this method from the Quotes controller. What should I do? Thanks in advance!

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  • best practice to persist classes model

    - by Yaron Naveh
    My application contains a set of model classes. e.g. Person, Department... The user changes values for instances of these classes in the UI and the classes are persisted to my "project" file. Next time the user can open and edit the project. Next version of my product may change the model classes drastically. It will still need to open existing projects files (I will know how to handle missing data). How is it best to persist my model classes to the project file? The easiest way to persist classes is Data contract serialization. However it will fail on breaking changes (I expect to have such). How to handle this? use some other persistence, e.g. name-value collection or db which is more tolerance ship a "project converter" application to migrate old projects. This requires to either ship with both old and new models or to manipulate xml, which is best?

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  • The mathematics of Schellings segregation model

    - by Bruce
    For those who don't know the model. You can read this pdf. I want to find what is the probability that 2 nodes are each others neighbors when the algorithm converges (i.e. when all nodes are happy). Here's the model in a gist. You have a grid (say 10x10). You have nodes of two kind (red and green) 45 each. So we have 10 empty spaces. We randomly place the nodes on the grid. Now we scan through this grid (Exact order does not matter according to Schelling). Each node wants a specific percentage of people of same kind in its Moore neighborhood (say b = 50% for each red and green). We calculate the happiness of each node (a = Number of neighbors of same kind/Number of neighbors of different kind). If a node is unhappy (a < b) it moves to an empty cell where it knows it will be happy. This movement can change the dynamics of old as well as new neighborhood. Algorithm converges when all nodes are happy. PS - I am looking for links for any mathematical analysis of the Schelling's model.

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  • Getting list of states/events from a model that AASM's

    - by Jason Nerer
    Hi, I successfully integrated the most recent AASM gem into an application, using it for the creation of a wizard. In my case I have a model order class Order < ActiveRecord::Base belongs_to :user has_one :billing_plan, :dependent => :destroy named_scope :with_user, ..... <snip> include AASM aasm_column :aasm_state aasm_initial_state :unauthenticated_user aasm_state :unauthenticated_user, :after_exit => [:set_state_completed] aasm_state : <snip> <and following the event definitions> end Now I would like to give an administrator the possibility to create his own graphs through the AASM states. Therefore I created two additional models called OrderFlow and Transition where there order_flow has many transitions and order belongs_to order_flow. No problem so far. Now I would like to give my admin the possibility to dynamically add existing transitions / events to an order_flow graph. The problem now is, that I do not find any possibility to get a list of all events / transitions out of my order model. aasm_states_for_select seems to be the correct candidate, but I cannot call it on my order model. Can anyone help? Thx in advance. J.

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