all.
I have following simple form in which I want to edit the entity. The problem is that I have some fields which I don't want to be edited. For example (Image file path).
As it is now, I have the service method -
public void addOrModifyLayout(Layout layout){
if(layout.getId() == null){
layoutRepository.save(layout);
}
else {
Layout modifiedLayout = new Layout();
modifiedLayout.setId(layout.getId());
modifiedLayout.setName(layout.getName());
modifiedLayout.setStatus(layout.getStatus());
modifiedLayout.setExhibitor(layout.getExhibitor());
layoutRepository.save(modifiedLayout);
}
}
As you can see, every field that I want to be able to be edited, I should explicitly put it in the service. Can I use some mapper or trick to update only some fields that are in the view (form) ? How you handle this kind of issues?
You can either
store all the entity fields in hidden inputs (e.g. imageFilePath hidden input). So you can store on UI all the entity fields and get them back to assign to the entity.
OR
Avoid new entity creation but retrieve existing one and fill only necessary fields.
Layout modifiedLayout = layoutRepository.getById(layout.getId());
modifiedLayout.setName(layout.getName());
modifiedLayout.setStatus(layout.getStatus());
modifiedLayout.setExhibitor(layout.getExhibitor());
layoutRepository.save(modifiedLayout);
Related
I have started a new project in Spring Boot after using Grails for 4 years.
In Grails I have used properties field of an instance of a domain class to update the associate row in a db table. The assignment of domain.properties was usually done inside a service.
The properties field was set with data coming from a web form.
This approach allows to update a domain instance with a single line, instead of writing n assignemnt, where n is the number of the attributes defined in the domain class.
Now the question.. there is something similar in Spring?
I would like to do something similar in Spring:
update(Long radioId,Map properties) {
// get the radio to be update from the db
Radio radio = getRadio(radioId)
radio.properties = properties
save(radio)
}
I add some detail,
My controller
public ModelAndView updateRadio(Radio radio) {
radioService.update(radio);
return new ModelAndView("redirect:/superadmin/radio/"+radio.getIdentifier()+"/zoom");
}
My Service
#Service
public class RadioService {
...
public void update(Radio radio) {
assert radio.getId() != null;
radioRepository.save(radio);
}
...
}
Now if the web form does not explicity send all the fields defined in Radio I have problem since I will loose the value of the field already stored.
If I could write somthing like that
public void update(Map radioProperties,Long radioId) {
Radio radio = radioRepository.findById(radioId);
radio.properties = radioProperties // only properties present in this map will be update (in grails)
radioRepository.save(radio);
}
it would be great.
In the latter method only the properties in the map (ence in the web form) will be updated, and the other store field of the radio instance will be untouched.
Take a look at Spring Data JPA, it can load domain objects by id, bind incoming request parameters to domain objects and also automagic you some CRUD repositories.
I am trying to accomplish the following:
I have a form that starts with a combo box, let's say that the user will have to pick either "Student" or "Teacher".
Both "Student" and "Teacher" will have the same fields displayed in the form, but if "Teacher" is checked, I will have more fields being displayed (that are hidden at first and that I will show with jQuery when the user select "Teacher").
The problem is that I want those fields to be mandatory only if "Teacher" is selected.
I have no idea to manage that, I don't think it's gonna be possible using annotations such as:
#NotBlank
private String teacherCourse;
since this field will always be blank when the user will have selected the "Student" radio button.
Any idea? Can I do a custom validation method and how?
I've taken two approaches with this in the past.
Use an enum field on the submission to determine which type of validation to perform. This is flexible and allows for any number of custom validation methods.
An alternative is to use a base command object which both student and teacher classes extend. This allows both types to extend and override validation and fields. This requires that separate methods are used to bind each type.
You could use validation groups to differentiate between constraints applying to both entities and those applying to only one of them:
public interface TeacherConstraints {}
#NotBlank(groups=TeacherConstraints.class)
private String teacherCourse;
When validating your object, specify the group to validate depending on the type selected in your combo box:
//teacher
Set<ConstraintViolation<Object>> violations = validator.validate(object, TeacherConstraints.class);
//student
Set<ConstraintViolation<Object>> violations = validator.validate(object, Default.class);
You can use javascript or JQuery for front side validation... depending upon your combo box value. If it's a teacher or student
function validate(){
var combox_value = document.getElementbyID("combo_box").value;
if(combox_value == "Teacher"){
//Validate for Teacher fields
var input_text1 = document.getElementbyID("input_text"2).value;
if(input_text1=="" || input_text1==null){
alert("Field cannot be empty");
return false;
}
return true;
}
else if(combox_value == "Student"){
//Validate for Student fields
var input_text2 = document.getElementbyID("input_text2").value;
if(input_text2=="" || input_text2==null){
alert("Field cannot be empty");
return false;
}
return true;
}
}
For JQuery try these links for live examples...
http://speckyboy.com/2009/12/17/10-useful-jquery-form-validation-techniques-and-tutorials-2/
http://www.jeasyui.com/tutorial/form/form3.php
http://www.camcloud.com/blog/jquery-form-validation-tutorial
Using ASP.NET MVC when I create my model, then a controller based on the model with CRUD operations, the CRUD views are generated. I added some code using Fluent API to require certain fields but for some reason the ModelState.IsValid passes even when these fields are not completed. What determines whether this passes or not? I thought it was based on your model property data types and other things like being required or maxlength, etc....
Also, I have manually added code to grab a list of Categories from the database and generate a checkbox for each one in the View. This is a navigation property for the Project model where there is a many-many relationship. To get the group of checked values in the Create(Project project) method in the controller I use:
var selected = Request["categories"].Split(',');
This however, throws the classic Object reference not set to an instance of an object error if no values are checked. So what I want to know is, how can I determine that this does not have any values so I can do something else once detected?
I added some code using Fluent API to require certain fields but for
some reason the ModelState.IsValid passes even when these fields are
not completed.
ASP.NET MVC doesn't know anything about the Fluent API of Entity Framework and doesn't evaluate this configuration. You only can use the data annotations which MVC will recognize:
[Required]
public string SomeProperty { get; set; }
...how can I determine that this does not have any values so I can do
something else once detected?
Not sure if I understand it correctly but I'd say:
var categories = Request["categories"];
if (categories != null)
{
var selected = categories.Split(',');
// ...
}
else
{
// do something else
}
A majority of the examples I see now are either using the Code First Approach or using an older version of MVC and the Entity Framework.
Assume I have a movie to update and I get to the Edit View, in the Edit method with the Post verb, what is the proper way to update a Movie? The first Edit Method below gets me to the Edit View with the populated Movie values and the second one is the one I want to use to update, I have tried some things, but nothing updates the data.
public ActionResult Edit(int id)
{
var movie = (from m in _db.Movies1
where m.Id == id
select m).First();
return View(movie);
}
[HttpPost]
public ActionResult Edit(Movie movie)
{
try
{
// TODO: Add update logic here
//What do I need to call to update the entity?
_db.SaveChanges();
return RedirectToAction("Index");
}
catch
{
return View();
}
}
Assuming that _db is derived from ObjectContext you have two options:
Change the state of the entity to Modified:
_db.Movies1.Attach(movie);
_db.ObjectStateManager.ChangeObjectState(movie, EntityState.Modified);
_db.SaveChanges();
This marks all properties of movie as modified and will send an UPDATE statement to the database which includes all column values, no matter if the values really changed or not.
Reload the original entity from the database and apply the changes to it:
var originalMovie = (from m in _db.Movies1
where m.Id == movie.Id
select m).First();
// You actually don't need to assign to a variable.
// Loading the entity into the context is sufficient.
_db.Movies1.ApplyCurrentValues(movie);
_db.SaveChanges();
ApplyCurrentValues will mark only those properties as modified which really did change compared to the original and the UPDATE statement which will be sent to the database only includes the changed column values. So, the UPDATE statement is potentially smaller than in the first example but you have to pay the price to reload the original entity from the database.
Edit
How does the second code example work?
When you run a query using the context (_db) Entity Framework does not only retrieve the entity from the database and assign it to the left side of the query (originalMovie) but it actually stores a second reference internally. You can think of this internal context "cache" as a dictionary of key-value pairs - the key is the entity primary key and the value is the entity itself, the same object as originalMovie refers to.
ApplyCurrentValues(movie) looks up this entity in the context's internal dictionary: It takes the key property value Id of the passed in movie, searches for an entity with that key in the internal dictionary and then copies property by property from the passed in ("detached") movie to the internal ("attached") entity with the same key. EF's change tracking mechanism marks the properties as Modified which were actually different to create later the appropriate UPDATE statement.
Because of this internal reference to the original entity you do not need to hold your own reference: That's the reason why originalEntity is not used in the code. You can in fact remove the assignment to the local variable altogether.
The example would not work if you disable change tracking when you load the original entity - for example by setting _db.Movies1.MergeOption = MergeOption.NoTracking;. The example relies on enabled change tracking (which is the default setting when entities are loaded from the database).
I cannot say which of the two examples has better performance. That might depend on details like size of the entities, number of properties which have been changed, etc.
It's worth to note though that both approaches do not work if related entities are involved (for example movie refers to a category entity) and if the relationship or the related entity itself could have been changed. Setting the state to Modified and using ApplyCurrentValues both affect only scalar and complex properties of movie but not navigation properties.
Your second edit method should look something like this:
[HttpPost]
public ActionResult Edit(int id, FormCollection collection)
{
var movie = (from m in _db.Movies1
where m.Id == id
select m).First();
if (TryUpdateModel(movie))
{
_db.SaveChanges();
return (RedirectToAction("Index"));
}
return View(movie);
}
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;}