Here is my code:
partial void OnisApprovedChanging(bool value)
{
this.dateApproved = DateTime.Now;
}
'dateApproved' is updated in the business logic, but this change is not being applied to the database table. I've seen some examples where DateUpdated columns are updated whenever any edit to a table is made, but I'm only interested in updating the time-stamp when this field is updated and I'm not sure of the best way to access the DataContext from this scope.
Do I need to instantiate the Data-context and update it manually?
EDIT Did some more research, and found that some blogs suggested adding business logic on update like this:
public partial class DataContext : System.Data.Linq.DataContext
{
partial void Updateaccount(account instance)
{
//business logic here
}
}
However, I cannot determine any way to find out if particular fields have changed. Any ideas?
Found this is the way to get the original entity and do comparisons.
partial void Updateaccount(account instance)
{
account acctPriorToUpdate = accounts.GetOriginalEntityState(instance);
if (instance.isApproved != acctPriorToUpdate.isApproved)
{
//Do Stuff
}
this.ExecuteDynamicUpdate(instance);
}
Related
I’m trying save some entities using breeze.js. Breeze is working fine and it saves all the changes as required. However, I have trouble validating and ensuring authorization is the server side. From what I’ve gather so far I guess the only way to do this is via examining the JObject passed into save bundles and constructing corresponding objects on the server side. I have to do this (instead of relying Breeze.SaveChanges as I have some logic on the server side). How do I do this? And how do I construct the Breeze.WebApi. SaveResult?
Idea of any other way of solving this problem is also very welcome
This should be done by implementing a custom EFContextProvider.
The code below implements a custom EFContextProvider for the Northwind database and was taken directly from the documentation on the breeze.com website .
public class NorthwindContextProvider: EFContextProvider<NorthwindIBContext> {
public NorthwindContextProvider() : base() { }
protected override bool BeforeSaveEntity(EntityInfo entityInfo) {
// return false if we don’t want the entity saved.
// prohibit any additions of entities of type 'Role'
if (entityInfo.Entity.GetType() == typeof(Role)
&& entityInfo.EntityState == EntityState.Added) {
return false;
} else {
return true;
}
}
protected override Dictionary<Type, List<EntityInfo>> BeforeSaveEntities(Dictionary<Type, List<EntityInfo>> saveMap) {
// return a map of those entities we want saved.
return saveMap;
}
}
#jaq316 is correct: a custom EFContextProvider is the place to intercept changes coming from the client. It is the place to both authorize and validate them . The documentation has more details. The essence of it is that you scrutinize the proposed changes within your overrides of the BeforeSaveEntity and BeforeSaveEntities virtual methods; alternatively you can attach handlers to the BeforeSaveEntityDelegate and BeforeSaveEntitiesDelegate.
So here is my thought on this one, since I am not using a ContextProvider at all. I am utilizing a SQL back-end and Ninject to inject a repository dependency into each controller I have. I have more items than the demo for "Todos" and want separate controllers out there and repositories as well. If I created the ContextProvider as shown by the breeze docs I would have one ContextProvider file with all the entities in it. This would be huge. If I separated them into separate contexts I would duplicating code in all the overrides.
Here is my Save Changes method in ContactFormController.cs :
[HttpPost]
public SaveResult SaveChanges(JObject saveBundle)
{
var sr = new SaveResult() { KeyMappings = new List<KeyMapping>(), Entities = new List<object>()};
dynamic entity = saveBundle["entities"][0];
ContactForm form = entity.ToObject<ContactForm>();
EntityState state = entity.entityAspect.entityState;
switch (state)
{
case EntityState.Added:
KeyMapping mapping = new KeyMapping(){EntityTypeName = typeof(ContactForm).ToString(), TempValue = form.Id };
var validationErrors = _contactFormService.ProcessContactForm(ref form).Cast<object>().ToList();
//if we succeed then update the mappings
if (validationErrors.Count == 0)
{
//setup the new mappings
mapping.RealValue = form.Id;
sr.KeyMappings.Add(mapping);
//link the entity
sr.Entities.Add(form);
}
else
{
sr.Errors = validationErrors;
}
break;
}
return sr;
}
I dynamically change the endpoints before saves on the client side so that each controller in my webapi has a SaveChanges() method. I then call into the appropriate repository to process the backend functions as needed. This way I can run mock code or actual SQL changes depending on the repo injected.
If their are errors on the Processing of the form then we cast our custom List list to a List and assign it to the Errors property of the SaveResult. If there are no errors we send back the new key mappings to be updated on the client.
Ideally I want to reduce all the code in this controller and perhaps abstract it out to a utility method so there is less repeat in every controller. I like this method because then I can create normal repositories and not have them depend on a ContextProvider. Breeze independent at that point.
I'm a bit confused if saving the information to session code below, belongs in the controller action as shown below or should it be part of my Model?
I would add that I have other controller methods that will read this session value later.
public ActionResult AddFriend(FriendsContext viewModel)
{
if (!ModelState.IsValid)
{
return View(viewModel);
}
// Start - Confused if the code block below belongs in Controller?
Friend friend = new Friend();
friend.FirstName = viewModel.FirstName;
friend.LastName = viewModel.LastName;
friend.Email = viewModel.UserEmail;
httpContext.Session["latest-friend"] = friend;
// End Confusion
return RedirectToAction("Home");
}
I thought about adding a static utility class in my Model which does something like below, but it just seems stupid to add 2 lines of code in another file.
public static void SaveLatestFriend(Friend friend, HttpContextBase httpContext)
{
httpContext.Session["latest-friend"] = friend;
}
public static Friend GetLatestFriend(HttpContextBase httpContext)
{
return httpContext.Session["latest-friend"] as Friend;
}
I wouldn't worry too much about where you put your code to save the model to session. It's one line of code so you are not saving anything or making anything clearer by extracting it out.
For creating your Friend object, I personally would either use something like Automapper, or have a populate method on my view model.
var friend = viewModel.Populate(new Friend());
public void Populate(Friend friend)
{
friend.FirstName = this.FirstName;
}
As for saving the friend to session, if you do want to extract it, I would do something similar to your static methods but as session extension methods. Just because it makes it immediately clear where it's being stored.
// set
Session.LatestFriend(friend);
// get
var latestFriend = Session.LatestFriend();
Controller is the right place to store and get data, and populate models with that Data.
Models are used as support for that data to be shown within views.
So what you're doing is pretty correct.
No need for the static class that will just get or store from Session, as it is about only one line of code.
+1 for the advice of Bigfellahull when dealing with multiple fields initialization.
I've been trying to find a good way to handle the Models of our Asp.net MVC websites when having common properties for all the pages. These properties are to be displayed in the Layout (Master Page). I'm using a "BaseModel" class that holds those properties and my Layout use this BaseModel as its model.
Every other model inherits from that BaseModel and each has specific properties relative to the view it represents. As you might have guessed, my Models are actually View Models even if that's not quite relevant here.
I have tried different ways to initialize the BaseModel values
By "hand" in every view
Having a base controller that has an Initialize virtual method to do it (so specific controller can implement specific common behavior for exemple)
Having a base controlelr that override OnActionExecuting to call the Initialize method
Using a helper class to do it outside of the controller
Using a Model Factory
But none of those really appeal to me:
Seems obvious to me, but DRY is one reason enough to justify that (actually I never tried that solution at all, I'm just putting it to be able to loop on that point in the last point).
I don't like that one because it means that whenever a new Controller is added, you need to know that it has to inherit from the BaseController and that you need to call the Initialize method, not to mention that if your controller has overriden the base one, to call the base anyway to maintain the values.
see next point
and 3. are a variation on the same topic but that doesn't really help with the issues of the second solution.
My favorite so far, but now I have to pass a few more variables to set those values. I like it for the inversion of dependence. But then if I want to provide values from the session, I need to pass them explicitly for exemple, then I'm back to square one as I have to provide them by hand (being references or through an interface of any kind)
Of course, (almost) all of those solutions work, but I'm looking for a better way to do it.
While typing this question, I found maybe a new path, the builder pattern that might also do, but implementations can become quickly a burden too, as we can have dozens of views and controllers.
I'll gladly take any serious recommandation/hint/advice/patterns/suggestion !
Update
Thanks to #EBarr I came up with another solution, using an ActionFilterAttribute (not production code, did it in 5 minutes):
public class ModelAttribute : ActionFilterAttribute
{
public Type ModelType { get; private set; }
public ModelAttribute(string typeName) : this(Type.GetType(typeName)) { }
public ModelAttribute(Type modelType)
{
if(modelType == null) { throw new ArgumentNullException("modelType"); }
ModelType = modelType;
if (!typeof(BaseModel).IsAssignableFrom(ModelType))
{
throw new ArgumentException("model type should inherit BaseModel");
}
}
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
var model = ModelFactory.GetModel(ModelType);
var foo = filterContext.RequestContext.HttpContext.Session["foo"] as Foo;
model.Foo = foo;
model.Bar = somevalue;
filterContext.Controller.TempData["model"] = model;
}
}
Calling it is then really simple:
[Model(typeof(HomeModel))]
public ActionResult Index()
{
var homeModel = TempData["model"] as HomeModel;
// Add View Specific stuff
return View(homeModel);
}
And it gives me the best of every world. The only drawback is to find a proper way to passe the model back to the action.
Here it's done using the TempData object, but I also consider updating the model that one can find in the ActionParameters.
I'm still taking any serious recommandation/hint/advice/patterns/suggestion for that, or the previous points.
I went through almost exactly the same process as I dove into MVC. And you're right, none of the solutions feel that great.
In the end I used a series of base models. For various reasons I had a few different types of base models, but the logic should apply to a single base type. The majority of my view models then inherited from one of the bases. Then, depending on need/timing i fill the base portion of the model in ActionExecuting or OnActionExecuted.
A snippet of my code that should make the process clear:
if (filterContext.ActionParameters.ContainsKey("model")) {
var tempModel = (System.Object)filterContext.ActionParameters["model"];
if (typeof(BaseModel_SuperLight).IsAssignableFrom(tempModel.GetType())) {
//do stuff required by light weight model
}
if (typeof(BaseModel_RegularWeight).IsAssignableFrom(tempModel.GetType())) {
//do more costly stuff for regular weight model here
}
}
In the end my pattern didn't feel too satisfying. It was, however, practical, flexible and easy to implement varying levels of inheritance. I was also able to inject pre or post controller execution, which mattered a lot in my case. Hope this helps.
The idea that gave me #EBarr to use an action filter was actually working but felt wrong in the end, because there was no clean way to retrieve the model without passing through a viewbag, or the httpcontext items, or something alike. Also, it made mandatory to decorate every action with its model. It also made the postback more difficult to handle. I still believe that this solution has merits and might be useful in some specific scenarios.
So I was back to square one and started looking more into that topic. I came to the following. First the problem has two aspects
Initializing the data for the views
Rendering the data
While looking for more idea, I realized that I was not looking at the problem from the right perspective. I was looking at it from a "Controller" POV, whereas the final client for the model is the view. I was also reminded that the Layout/Master page is not a view and should not have a model associated with it. That insight put me on what feels the right path for me. Because it meant that every "dynamic" part of the Layout should be handled outside of it. Of course, sections seems the perfect fit for that, because of their flexibility.
On the test solution I made, I had (only) 4 different sections, some mandatory, some not. The problem with sections, is that you need to add them on every page, which can quickly be a pain to update/modify. To solve that, I tried this:
public interface IViewModel
{
KeyValuePair<string, PartialViewData>[] Sections { get; }
}
public class PartialViewData
{
public string PartialViewName { get; set; }
public object PartialViewModel { get; set; }
public ViewDataDictionary ViewData { get; set; }
}
For exemple, my model for the view is this:
public class HomeViewModel : IViewModel
{
public Article[] Articles { get; set; } // Article is just a dummy class
public string QuickContactMessage { get; set; } // just here to try things
public HomeViewModel() { Articles = new Article[0]; }
private Dictionary<string, PartialViewData> _Sections = new Dictionary<string, PartialViewData>();
public KeyValuePair<string, PartialViewData>[] Sections
{
get { return _Sections.ToArray(); }
set { _Sections = value.ToDictionary(item => item.Key, item => item.Value); }
}
}
This get initialized in the action:
public ActionResult Index()
{
var hvm = ModelFactory.Get<HomeViewModel>(); // Does not much, basicaly a new HomeViewModel();
hvm.Sections = LayoutHelper.GetCommonSections().ToArray(); // more on this just after
hvm.Articles = ArticlesProvider.GetArticles(); // ArticlesProvider could support DI
return View(hvm);
}
LayoutHelper is a property on the controller (which could be DI'ed if needed):
public class DefaultLayoutHelper
{
private Controller Controller;
public DefaultLayoutHelper(Controller controller) { Controller = controller; }
public Dictionary<string, PartialViewData> GetCommonSections(QuickContactModel quickContactModel = null)
{
var sections = new Dictionary<string, PartialViewData>();
// those calls were made in methods in the solution, I removed it to reduce the length of the answer
sections.Add("header",
Controller.UserLoggedIn() // simple extension that check if there is a user logged in
? new PartialViewData { PartialViewName = "HeaderLoggedIn", PartialViewModel = new HeaderLoggedInViewModel { Username = "Bishop" } }
: new PartialViewData { PartialViewName = "HeaderNotLoggedIn", PartialViewModel = new HeaderLoggedOutViewModel() });
sections.Add("quotes", new PartialViewData { PartialViewName = "Quotes" });
sections.Add("quickcontact", new PartialViewData { PartialViewName = "QuickContactForm", PartialViewModel = model ?? new QuickContactModel() });
return sections;
}
}
And in the views (.cshtml):
#section quotes { #{ Html.RenderPartial(Model.Sections.FirstOrDefault(s => s.Key == "quotes").Value); } }
#section login { #{ Html.RenderPartial(Model.Sections.FirstOrDefault(s => s.Key == "header").Value); } }
#section footer { #{ Html.RenderPartial(Model.Sections.FirstOrDefault(s => s.Key == "footer").Value); } }
The actual solution has more code, I tried to simplify to just get the idea here. It's still a bit raw and need polishing/error handling, but with that I can define in my action, what the sections will be, what model they will use and so on. It can be easily tested and setting up DI should not be an issue.
I still have to duplicate the #section lines in every view, which seems a bit painful (especialy because we can't put the sections in a partial view).
I'm looking into the templated razor delegates to see if that could not replace the sections.
Forgive me if this has been asked before; I couldn't find anything close after a few searches:
I'm trying to write an ActionFilter in MVC that will "intercept" an IQueryable and nullify all the parent-child relationships at runtime. I'm doing this because Linq does not serialize objects properly if they have parent-child relationships (it throws a circular reference error because the parent refers to the child, which refers back to the parent and so on), and I need the object serialized to Json for an Ajax call. I have tried marking the child relationship in the DBML file with a privacy status of internal, and while this fixes the serialization problem, it also hides the child members from the view engine when the page renders, causing another error to be thrown. So, by fixing one problem, I cause another.
The only thing that fixes both problems is to manually set the child members to null just before returning the serialization, but I'm trying to avoid doing that because it's cumbersome, not reusable, etc. I'd rather use an ActionFilter to inspect the IQueryable that is being serialized and nullify any members with a Type of EntitySet (how Foreign Keys/Associations are represented). However, I don't have much experience with Reflection and can't find any examples that illustrate how to do something like this. So... is this possible with Reflection? Is there a better way to accomplish the same thing? I'll post the relevant code tomorrow when I'm back at my work computer.
Thanks,
Daniel
As promised, the code:
[GridAction]
public ActionResult _GetGrid()
{
IQueryable<Form> result = formRepository.GetAll();
foreach (Form f in result)
{
f.LineItems = null;
f.Notes = null;
}
return View(new GridModel<Form> { Data = result });
}
An added wrinkle is that I'm using the new Telerik MVC Extensions, so I'm not actually serializing the Json myself -- I'm just returning the IQueryable in an IGridModel, and the action filter [GridAction] does the rest.
So, just in case anyone's curious, here's how I finally solved this problem: I modified Damien Guard's T4 template to include the attribute [ScriptIgnore] above entities of type Association. This lets the JSON serializer know to not bother serializing these, thus preventing the circular reference problem I was getting. The generated code ends up looking like this:
private EntitySet<LineItem> _LineItems;
[ScriptIgnore]
[Association(Name=#"Form_LineItem", Storage=#"_LineItems", ThisKey=#"Id", OtherKey=#"FormId")]
public EntitySet<LineItem> LineItems
{
get {
return _LineItems;
}
set {
_LineItems.Assign(value);
}
}
This fixes the serialization problem I was having without disabling the use of child tables through LINQ. The grid action on the controller ends up looking like this:
[GridAction]
public ActionResult _GetGrid()
{
return View(new GridModel<Form> { Data = formRepository.GetAll() });
}
There are two options, one is to ignore those properties during serialization using [XmlIgnore]. The other one is to nullify the properties using reflection.
Ignore in serialization, simple usage sample that shows how to use default value in serialization:
[Serializable]
public class MyClass
{
[XmlIgnore]
public int IgnoredVal { get; set; }
public int Val { get; set; }
}
public void UsageSample()
{
var xmlSerializer = new XmlSerializer(typeof(MyClass));
var memoryStream = new MemoryStream();
var toSerialize = new MyClass { IgnoredVal = 1, Val = 2 };
xmlSerializer.Serialize(memoryStream, toSerialize);
memoryStream.Position = 0;
var deserialize = (MyClass)xmlSerializer.Deserialize(memoryStream);
Assert.AreEqual(0, deserialize.IgnoredVal);
Assert.AreEqual(2, deserialize.Val);
}
Nullify with reflection, code sample:
public void NullifyEntitySetProperties(object obj)
{
var entitySetProperties = obj.GetType().GetProperties()
.Where(property => property.PropertyType == typeof(EntitySet));
foreach (var property in entitySetProperties)
{
property.SetValue(obj, null, null);
}
}
In my opinion, if the first option can be done used in your code it's better. This option is more direct and economic.
I have an ASP.NET MVC app which depends on a lot of settings (name-value pairs), I am planning to store this information in a database table called SiteSettings. Is there an easy way in which I can get these settings using NHibernate. And what are the best practices when saving settings for a web application. And by settings I mean the settings which control the flow of processes in the web application and which are governed by business rules. These are not the typical connection string kind of settings. I was unable to get much information on the web on this topic. Maybe I am not searching on the right keywords, Any help will be greatly appreciated.
I can't answer in the context of nhibernate (which I'm not using) or best practices (I came up with this on my own recently). However, it works well for me, and will probably work for you.
I have a table (Biz_Config) in the database to store business preferences. (I've created a web.config section for what I call IT preferences.)
I have a class that is in charge of managing the biz preferences. The constructor grabs the entire table (one row per setting) and copies these into a dictionary, and it has methods to access (such as bizconfig.get("key")) and update this dictionary, also updating the table at the same time. It also has a few shortcut properties for specific dictionary values, especially where the value has to be cast (I have a few important numbers). It works quite well.
In order to be more efficient and not instantiate it every time I need a setting, and also to access it easily from my controllers and views, I created a static class, Globals, that is in charge of getting things out of the session or application variables. For the biz config object, it checks the application variable and, if null, creates a new one. Otherwise it just returns it. Globals is part of my helpers namespace, which is included in my web.config to be available to my views. So I can easily call:
<% Globals.Biz_Config.Get("key") %>
I hope this helps. If you'd like code, I can dig that up for you.
James
If you have a set of key/value pairs, you probably want to use a <map>. See the official NHibernate documentation or Ayende's post about 'NHibernate Mapping - <map/>'.
I have come up with a solution which is quite similar to the one suggested by James. I have an SiteSettingsService class which manages the settings for the whole site, it has a simple dependency on an interface called ISiteServiceRepository. This might not be the most elegant solution, But it is working perfectly for me. I have also configured the SiteSettingsService class as a Singleton using StructureMap. So, it saves me unnecessary instantiantion every time I need any settings.
//ISiteServiceRepository, an implementation of this uses NHibernate to do just two things
//i)Get all the settings, ii)Persist all the settings
using System.Collections.Generic;
using Cosmicvent.Mcwa.Core.Domain.Model;
namespace Cosmicvent.Mcwa.Core.Domain {
public interface ISiteServiceRepository {
IList<Setting> GetSettings();
void PersistSettings(IDictionary<string, string> settings);
}
}
//The main SiteSettingsService class depends on the ISiteServiceRepository
using System;
using System.Collections.Generic;
using Cosmicvent.Mcwa.Core.Domain;
using Cosmicvent.Mcwa.Core.Domain.Model;
namespace Cosmicvent.Mcwa.Core.Services {
public class SiteSettingsService : ISiteSettingsService {
private readonly ISiteServiceRepository _siteServiceRepository;
private IDictionary<string, string> _settings;
public SiteSettingsService(ISiteServiceRepository siteServiceRepository) {
_siteServiceRepository = siteServiceRepository;
//Fill up the settings
HydrateSettings();
}
public int ActiveDegreeId {
get {
return int.Parse(GetValue("Active_Degree_Id"));
}
}
public string SiteTitle {
get { return GetValue("Site_Title"); }
}
public decimal CounsellingFee {
get { return decimal.Parse(GetValue("Counselling_Fee")); }
}
public decimal TuitionFee {
get { return decimal.Parse(GetValue("Tuition_Fee")); }
}
public decimal RegistrationFee {
get { return decimal.Parse(GetValue("Registration_Fee")); }
}
public void UpdateSetting(string setting, string value) {
if (!string.IsNullOrEmpty(setting) && !string.IsNullOrEmpty(value)) {
SetValue(setting, value);
PersistSettings();
}
}
//Helper methods
private void HydrateSettings() {
_settings = new Dictionary<string, string>();
IList<Setting> siteRepoSettings = _siteServiceRepository.GetSettings();
if (siteRepoSettings == null) {
throw new ArgumentException("Site Settings Repository returned a null dictionary");
}
foreach (Setting setting in siteRepoSettings) {
_settings.Add(setting.Name.ToUpper(), setting.Value);
}
}
private string GetValue(string key) {
key = key.ToUpper();
if (_settings == null) {
throw new NullReferenceException("The Site Settings object is Null");
}
if (!_settings.ContainsKey(key)) {
throw new KeyNotFoundException(string.Format("The site setting {0} was not found", key));
}
return _settings[key];
}
private void SetValue(string key, string value) {
key = key.ToUpper();
if (_settings == null) {
throw new NullReferenceException("The Site Settings object is Null");
}
if (!_settings.ContainsKey(key)) {
throw new KeyNotFoundException(string.Format("The site setting {0} was not found", key));
}
_settings[key] = value;
}
private void PersistSettings() {
_siteServiceRepository.PersistSettings(_settings);
}
}
}
Hope this helps future developers facing similar problems. Any suggestions for improving this are more than welcome.