Should an input model for creating or updating entities have an ID field to identify the entity, or should your edit action accept an ID parameter?
Compare
Input Model
[HttpPost]
public ActionResult(EntityInputModel input)
{
var entity = _unitOfWork.CurrenSession.Get<MyEntity>(input.Id);
// do editing
// ...
}
Action Parameter
[HttpPost]
public ActionResult(Guid id, EntityInputModel input)
{
var entity = _unitOfWork.CurrenSession.Get<MyEntity>(id);
// ...
}
Personally I prefer the first. I always define a specific view model for each POST action. So if this action requires an id I include it as part of this specific view model.
Related
So in my mvc 5 app, I got this default 'Index' action, which simply redirects to the search action, with the default model values:
[Route]
public ActionResult Index()
{
var model = new T();
return RedirectToAction("Search", model);
}
What i got puzzled about is how i end up with the url like '.../search?xxx=xxx...'? Is there anything i can do to customize or at least inject/replace the url generation, especially the query string part? e.g. i might want to display 1/0 for bool properties in the search model, and customize query string key names etc?
and why would someone vote down for my question? psst...
The query string generated depend on the model property name and type + value you passed in.
For example, say if your pass in model is like
public class MyModel
{
bool IsSort{get;set;}
}
If your model is like this and IsSort value is true, then you will get url like /search?IsSort=true
Say you want to change your query string to 1/0 instead of true or false, then create viewModel which has property string then assing it properly like:
public class MyModel
{
string IsSort{get;set;}
}
var model = new MyModel();
model.IsSort = true? "1":"0";
same apply to querystring key (which correspond to property name)
How to add a query string from surface controller in umbraco mvc . This is my current code.
Initially I wrote a code like
public ActionResult Registration(RegisterModel model)
{
//Code to insert register details
ViewBag.Success="Registered Successfully"
return CurrentUmbracoPage();
}
with this I could successful persist my ViewBag and model properties value but I could not add a query string with it.
For certain requirement I have to change the code that returns a url with querystring.
which I did as below
public ActionResult Registration(RegisterModel model)
{
//Code to insert register details
ViewBag.Success="Registered Successfully"
pageToRedirect = AppendQueryString("success");
return new RedirectResult(pageToRedirect);
}
public string AppendQueryString(string queryparam)
{
var pageToRedirect = new DynamicNode(Node.getCurrentNodeId()).Url;
pageToRedirect += "?reg=" + queryparam;
return pageToRedirect;
}
and with this my values of the properties in model could not persist and the ViewBag returned with null value.
Can any one suggest me how to add query string by persisting the values in the model and ViewBag.
Data in ViewBag will not be available on the View when it redirects. Hence you have to add message in TempData which will be available in the View after the redirect like TempData.Add("CustomMessage", "message");
I am new to asp.net mvc. I have this controller that takes in a few parameters and then returns a view that gets data based on the input parameters.
I want to accept the input parameters as an object (for example instead of first name, last name and age, I want a person class that has these three parameters as its properties). Now my question is does the input parameter class (Person class) qualify to be called view model?
If yes. Do I make the return view model a part of this class?
In other words which of the bottom two approaches is preferred
Case 1: Same class for input and return
public ActionResult GetPersonDetails(Person p)
{
return View(new Person {....})
}
Case 2: Separate classes for input and return
public ActionResult GetPersonDetails(Person p)
{
return View(new PersonDetails {....})
}
Now my question is does the input parameter class (Person class)
qualify to be called view model?
Yes.
If yes. Do I make the return view model a part of this class?
Not necessarily. You could have different view model passed to the view as the one that your controller action is taking as parameter, although this is rare case scenario. It would really depend on your specific case but the general pattern is the following:
[HttpGet]
public ActionResult Index()
{
MyViewModel model = ...
return View(model);
}
[HttpPost]
public ActionResult Index(MyViewModel model)
{
if (!ModelState.IsValid)
{
// Some validation error occurred => redisplay the same view so
// that the user can fix his errors
return View(model);
}
// at this stage the view model has passed all validations =>
// here you could attempt to pass those values to your backend
// TODO: do something with the posted values like updating a database or something
// Finally redirect to a successful action Redirect-After-Post pattern
// http://en.wikipedia.org/wiki/Post/Redirect/Get
return RedirectToAction("Success");
}
I am trying to reuse the same form for adding and editing employee information. I am using knockout js and on my view I make the knockout model:
var koModel = new EmployeeModel(div);
and if I want to populate the fields from the server I want to do something like this:
var koModel = new EmployeeModel(unserializedModelFromController, div);
I was wondering what is the best way to distinguish if the request is for a new employee or if it is to edit an existing employee.
If you turn your parameters around you can write a single constructor function.
var EmployeeModel = function(div, model) {
if (model) {
// Existing model has been passed, it's an edit request
} else {
// No model has been passed, it's a new request
}
}
This can be called like:
new EmployeeModel(div);
or
new EmployeeModel(div, model);
You can send a parameter with a default value to the view.
If you are editing an employee, you can send the value of id, you're creating not send.
The function that receives a request to store or edit could have a default value.
public void SaveOrEditEmployee(int id=0, ...) //id=0 is a default value
{
if(id==0)
{
//SaveEmployee
}else
{
//EditEmployee
Employee empl = (x => employee.id == id);
...
}
}
Or you can do likewise, receive full model and assess whether the property 'id' already exists in your database
Say I have a bunch of boolean properties on my entity class public bool isActive etc. Values which will be manipulated by setting check boxes in a web application. I will ONLY be posting back the one changed name/value pair and the primary key at a time, say { isActive : true , NewsPageID: 34 } and the default model binder will create a NewsPage object with only those two properties set. Now if I run the below code it will not only update the values for the properties that have been set on the NewsPage object created by the model binder but of course also attempt to null all the other non set values for the existent entity object because they are not set on NewsPage object created by the model binder.
Is it possible to somehow tell entity framework not to look at the properties that are set to null and attempt to persist those changes back to the retrieved entity object and hence database ? Perhaps there's some code I can write that will only utilize the non-null values and their property names on the NewsPage object created by model binder and only attempt to update those particular properties ?
[HttpPost]
public PartialViewResult SaveNews(NewsPage Np)
{
Np.ModifyDate = DateTime.Now;
_db.NewsPages.Attach(Np);
_db.ObjectStateManager.ChangeObjectState(Np, System.Data.EntityState.Modified);
_db.SaveChanges();
_db.Dispose();
return PartialView("MonthNewsData");
}
I can of course do something like below, but I have a feeling it's not the optimal solution. Especially considering that I have like 6 boolean properties that I need to set.
[HttpPost]
public PartialViewResult SaveNews(int NewsPageID, bool isActive, bool isOnFrontPage)
{
if (isActive != null) { //Get entity and update this property }
if (isOnFontPage != null) { //Get entity and update this property }
}
API is not strongly typed but you can do it as follows. DbContext API has better support for this.
[HttpPost]
public PartialViewResult SaveNews(NewsPage Np)
{
Np.ModifyDate = DateTime.Now;
_db.NewsPages.Attach(Np);
var entry = _db.ObjectStateManager.GetObjectStateEntry(Np);
var cv = entry.CurrentValues;
if (isActive)
{
cv.SetBoolean(cv.GetOrdinal("isActive"), true);
}
_db.SaveChanges();
_db.Dispose();
return PartialView("MonthNewsData");
}
You can go for two options
Register a custom model binder for that action. In the custom model binder you have to get the complete object from the database and only update the POSTed properties.
Use a view model. Instead of directly having the NewsPage model as the action parameter. You can create a custom view model that wraps the necessary properties. Inside the action you have to make a call to db to get the complete NewsPage instance and update only the corresponding properties from the view model.
Somewhat ugly, but did the trick in my case without having to create and register custom model binder or using multiple if statements.
[HttpPost]
public void SaveNews(string propname, bool propvalue, int PageID)
{
var prop = typeof(NewsPage).GetProperties().FirstOrDefault(x => x.Name.ToLower() == propname.ToLower());
var Np = _db.NewsPages.FirstOrDefault(x => x.PageID == PageID);
prop.SetValue(Np, propvalue, null);
Np.ModifyDate = DateTime.Now;
_db.SaveChanges();
_db.Dispose();
}