Say I have an User (mapped to a User table) and the Edit view (in MVC) displays a multiselectlist of Modules (mapped to a Modules table) that user can access, with the Modules pre-selected based on the User's EntitySet of Modules.
I have tried saving the User then deleting all User_Modules manually and adding them back based on what's selected on submit, but the User has a null EntitySet for User.User_Modules.
I cannot find the correct way to handle this scenario anywhere online. Can anyone help?
Edit: adding my EntitySet code
private EntitySet<UserModule> _UserModules;
[Association(Storage = "_UserModules", ThisKey="UserId", OtherKey = "UserId")]
public EntitySet<UserModule> UserModules
{
get { return this._UserModules; }
set { this._UserModules.Assign(value); }
}
Try checking if the set is loaded first
Linq to SQL
DataLoadOptions options = new DataLoadOptions();
options.LoadWith<User>(c => c.User_Modules);
context.LoadOptions = options;
//Do query and then see if your EntitySet is still null.
Linq to entities way...
if(!User.User_ModulesReference.IsLoaded){
User.User_ModulesReference.Load();
}
//Insert delete logic here...
Related
I am using Entity Framework's code-first approach to create tables, and I need to check if there are any entities in the database that I need to delete:
class MyDocument
{
public string Id { get; set; }
public string Text { get; set; }
}
class MyContext : DbContext
{
public DbSet<MyDocument> Documents { get; set; }
}
using (var data = new MyContext())
{
var present = from d in data.Documents
where d.Id == "some id" || d.Id == "other id"
select d;
// delete above documents
}
on first run, when there is no table yet, the LINQ expression above throws an exception:
Invalid object name 'dbo.Documents'
How do I check if the table is there and if it is not, then set present to the empty set, perhaps? Or maybe there is a way to force database/table creation before I issue the LINQ query?
EF will actually check the entire context against the DB it is attached to.
The DB can have more than the context. But not less.
So actually you check
Context.Database.CreateIfNotExists();
If the DB and context dont match and you are using automatic migrations, then you get specific object errors. But this can be misleading in terms of the how EF is handling the context to DB comparison.
You could of course try and access every DBSet in a context
Not sure how useful that is though.
EF Code first supports Migrations, either Automated or on demand.
See EF Code first migrations
Database.SetInitializer
use SetInitializer command to turn on automatic migrations for example.
The link will provide more info on the Manual/controlled approach to db migration for advanced db handling. The easier Automatic approach, is also described in the link.
I am new to MVC and EF and I have a question.
I have built a site with models views controllers etc.
On an edit view for a Case (pretty big model so I won't post it here) I have a FK to a Customer model using CustomerID. When a user selects a customer id from a drop down list, I would like to display CustomerName, CustomerPhone etc after the selection of the ID. I think I might need to do a post back for this to work?
Also, do I need to Include the related entities as part of the initial data "get"? I have read some detail on that but I dont fully understand how that needs to work.
Please let me know if I should post more info. Thanks!
Here is my ActionResult for Edit
public ActionResult Edit(int id)
{
Cases cases = db.Cases.Find(id);
//related data needs to loaded to show related data fields
//include related data entities
var v = db.Cases.Include("Customers");
ViewBag.TechnicianID = new SelectList(db.Technicians, "TechnicianID", "LastName", cases.TechnicianID);
ViewBag.BranchID = new SelectList(db.Branches, "BranchID", "BranchName", cases.BranchID);
ViewBag.EngineModelID = new SelectList(db.EngineModels, "EngineModelID", "EngineModelName", cases.EngineModelID);
ViewBag.CaseCategoryID = new SelectList(db.CaseCategories, "CaseCategoryID", "CategoryName",cases.CaseCategoryID);
ViewBag.Qualified = new SelectList(new[] { "YES", "NO", "PARTIALLY" });
ViewBag.CaseStatus = new SelectList(new[] { "OPEN/IN PROCESS", "CLOSED" });
return View(cases);
}
The line
var v = db.Cases.Include("Customers")
is what I am trying to use to load related customer data and then show in my edit view like this:
#Html.EditorFor(model => model.Customer.CustomerName)
Well it depends on what you are trying to do. You could include a model which holds all the required data and send it with every call on that page (initial empty ofcourse)
Once you selected the customer, do post-back and send the customerId to your application and return the same page with the desired model.
You could do that via AJAX too.
Also, do I need to Include the related entities as part of the initial data "get"?
Not sure if I understand what you are trying to say. You mean that you think you would have to send all customer's data down to the page and select the related data on client side?
would like to put fieldSets side-by-side on my “Edit” page because I have so many fields on the page. Since I couldn’t find an easy fix, I decided to put the fields in a table. This worked fine except for when I click on the “Save” button I get this error:
“Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries.”
Questions: How can I put my fieldsets side-by-side or make my table to work with the save button?
Thanks for any help.
Here's the edit methods of my controller:
public ActionResult Edit(int id)
{
CourseProgress courseprogress = db.CourseProgresses.Find(id);
ViewBag.CourseId = new SelectList(db.Courses, "CourseId", "Name", courseprogress.CourseId);
ViewBag.TeacherId = new SelectList(db.Teachers, "TeacherId", "Name", courseprogress.TeacherId);
var PdfReportProperties = new PdfReport();
return View(courseprogress);
}
//
// POST: /ProgressManager/Edit/5
[HttpPost]
public ActionResult Edit(CourseProgress courseprogress)
{
if (ModelState.IsValid)
{
db.Entry(courseprogress).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("ProgressRecord");
}
ViewBag.CourseId = new SelectList(db.Courses, "CourseId", "Name", courseprogress.CourseId);
ViewBag.TeacherId = new SelectList(db.Teachers, "TeacherId", "Name", courseprogress.TeacherId);
return View(courseprogress);
}
The most likely reason you are getting that error is that as you don't have a field for the ID of your model in the form, once you hit the SAVE button, the object you are editting has its ID property in null.
To solve it, use a hidden field holding the ID of the model, so that once the form post its fields it became mapped in your controller model object.
This problem has nothing to do with the position or layout of your fields.
I'm using ActiveRecord with NHibernate on the backend. I've set up a mapping for Users; I can create/retrieve/register users without any issues.
I now want to add an association called Role to my users (many users per role). I've created the appropriate Role class, tables, data, etc. and everything seems to be working on that end as well.
The problem is that when I save a user and associate a Role, that association does not persist to the database.
I've added a RoleId (int16) column to the aspnet_Users table to match the Role table's Id (int16) column. I've tried using Save and SaveAndFlush without success.
Here's some code:
Role superUser = Role.First(r => r.name == "Super User");
User me = User.First(r => r.UserName == myUserName);
me.Role = superUser;
me.Save(); // Or: SaveAndFlush
When debugging, I can see the association on the objects when they're saved (i.e. me.Role is not null and has the right attributes/properties/etc.) However, when I look at the database, the RoleId value for that user is still NULL. (SaveAndFlush doesn't make a difference.)
What am I missing?
I've read somewhere on SO that extending the users table is usually done by adding another table and linking the two by a foreign key; I assume the classes would then use inheritance by composition for the new ExtendedUser class. Assuming I don't want to go that route, why isn't this working? Is it because of the specific ASP.NET MVC stored procedures et. all?
Some relevant mapping:
[ActiveRecord("aspnet_Users", Mutable = false)]
public class User : ActiveRecordLinqBase<User>
{
[PrimaryKey(PrimaryKeyType.Assigned)]
public Guid UserId { get; set; }
// ...
[BelongsTo("RoleId", Cascade = CascadeEnum.SaveUpdate)]
public Role Role { get; set; }
}
[ActiveRecord]
public class Role : ActiveRecordLinqBase<Role>
{
[PrimaryKey]
public int Id { get; set; }
// ...
[HasMany(Inverse = true)]
public IList<User> Users { get; set; }
[Property]
public string Name { get; set; }
}
Edit: mutable="false" - this clearly stands that entity is read only, which is the source of your problem.
Immutable classes, mutable="false", may not be updated or deleted by the application. This allows NHibernate to make some minor
performance optimizations.
Also:
I believe that you need to have cascading defined. You are not saving just the entity itself but also reference to other entity. Use attributes, fluent config or hbml to define this the way you need. Here are the cascading options:
Here is what each cascade option means:
none - do not do any cascades, let the users handles them by
themselves.
save-update - when the object is saved/updated, check the assoications and save/update any object that require it (including
save/update the assoications in many-to-many scenario).
delete - when the object is deleted, delete all the objects in the assoication.
delete-orphan - when the object is deleted, delete all the objects in the assoication. In addition to that, when an object is
removed from the assoication and not assoicated with another object
(orphaned), also delete it.
all - when an object is save/update/delete, check the assoications and save/update/delete all the objects found.
all-delete-orphan - when an object is save/update/delete, check the assoications and save/update/delete all the objects found. In additional to that, when an object is removed from the assoication and not assoicated with another object (orphaned), also delete it.
You may want to read this article.
I have a view model sent to the edit action of my controller. The ViewModel contains references to EntityObjects. (yea i'm fine with it and don't need to want to duplicate all the entities properties in the viewmodel).
I instantiate the view model and then call UpdateModel. I get an error that a property is "null" which is fine since it is a related model. I am trying to exclude the property from being bound during model binding. On debugging it I see in the entity where the model binder is trying to set the value of the property to null.
Here is my edit action:
var model = new SimplifiedCompanyViewModel(id);
var excludeProperties = new string[] {
"Entity.RetainedEarningsAccount.AccountNo"
,"Property.DiscountEarnedAccount.ExpenseCodeValue"
,"Entity.EntityAlternate.EntityID"
,"Property.BankAccount.BankAccountID"
,"Entity.PLSummaryAccount.AccountNo"
,"Property.RefundBank.BankAccountID"
,"Company.Transmitter.TCC"
};
try
{
UpdateModel<SimplifiedCompanyViewModel>(model, String.Empty, null, excludeProperties);
if (ModelState.IsValid)
{
//db.SaveChanges();
}
return RedirectToAction("Index");
}
catch
{
return View(model);
}
I have looked at a few other issues about specifying a "prefix" but I don't think that is the issue since I am telling it to bind to the viewmodel instance not just the entity object.
Am I excluding the properties correctly? Strange thing is is only seems to happen on this item. I suspect it may be an issue with the fact that there is actually no refund bank related to my entity. But I have other related items that don't exist and don't see the same issue.
More info... since I'm told me model isn't designed well.
The Company is related to a BankAccount. The Company view shows the currently related BankAccount.BankAccountId and there is a hidden field with the BankAccount.Key. I use jQueryUI autocomplete feature to provide a dropdown of bank account displaying the BankAccount.BankAccountId and when one is selected the jQuery code changes the hidden field to have the correct Key value. So, when this is posted I don't want the current bankaccounts BankAccountID modified, hence I want it to skip binding that field.
If I exclude BankAccountId in the model then on the BankAccount edit view the user would never be able to change the BankAccountId since it won't be bound. I'm not sure how this indicates a poor model design.
Use the Exclude property of the Bind attribute:
[Bind(Exclude="Id,SomeOtherProperty")]
public class SimplifiedCompanyViewModel
{
public int Id { get; set; }
// ...
}
This is part of the System.Web.Mvc namespace. It takes a comma-separated list of property names to exclude when binding.
Also you should consider using TryUpdateModel instead of UpdateModel. You can also just have the default model binder figure it out by passing it as an argument to the constructor:
public ActionResult Create([Bind(Exclude="Id")]SimplifiedCompanyViewModel model)
{
// ...
}
A very simple solution that I figured out.
try
{
UpdateModel<SimplifiedCompanyViewModel>(model, String.Empty, null, excludeProperties);
ModelState.Remove("Entity.RetainedEarningsAccount.AccountNo");
ModelState.Remove("Property.DiscountEarnedAccount.ExpenseCodeValue");
ModelState.Remove("Entity.EntityAlternate.EntityID");
ModelState.Remove("Property.BankAccount.BankAccountID");
ModelState.Remove("Entity.PLSummaryAccount.AccountNo");
ModelState.Remove("Property.RefundBank.BankAccountID");
ModelState.Remove("ompany.Transmitter.TCC");
if (ModelState.IsValid)
{
//db.SaveChanges();
}
return RedirectToAction("Index");
}
catch
{
return View(model);
}
Another option here is simply don't include this attribute in your view and it won't be bound. Yes - you are still open to model injection then if someone creates it on the page but it is another alternative. The default templates in MVC will create your EditorFor, etc as separate items so you can just remove them. This prevents you from using a single line view editor with EditorForModel, but the templates don't generate it that way for you anyways.
EDIT (adding above comment)
DRY generally applies to logic, not to view models. One view = one view model. Use automapper to easily map between them. Jimmy Bogard has a great attribute for this that makes it almost automatic - ie you create the view model, load up your Customer entity for example, and return it in the action method. The AutpMap attribute will then convert it to a ViewModel. See lostechies.com/jimmybogard/2009/06/30/how-we-do-mvc-view-models
Try the Exclude attribute.
I admit that I haven't ever used it.
[Exclude]
public Entity Name {get; set;}