Question
I've been looking for a proper way to mark a property to NOT be changed when updating a model in MVC.
For example, let's take this small model:
class Model
{
[Key]
public Guid Id {get; set;}
public Guid Token {get; set;}
//... lots of properties here ...
}
then the edit method MVC creates looks like this:
[HttpPost]
public ActionResult Edit(Model model)
{
if (ModelState.IsValid)
{
db.Entry(model).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
return View(model);
}
now if my View does not contain the Token, it will be nullified through that edit.
I'm looking for something like this:
db.Entry(model).State = EntityState.Modified;
db.Entry(model).Property(x => x.Token).State = PropertyState.Unmodified;
db.SaveChanges();
The best way so far I found is to be inclusive and set all properties I want included by hand, but I really only want to say which ones to be excluded.
Accepted Answer
we can use like this
db.Entry(model).State = EntityState.Modified;
db.Entry(model).Property(x => x.Token).IsModified = false;
db.SaveChanges();
it will update but without Token property
Popular Answer
Create new model that will have limited set of properties that you want to update.
I.e. if your entity model is:
public class User
{
public int Id {get;set;}
public string Name {get;set;}
public bool Enabled {get;set;}
}
You can create custom view model that will allow user to change Name, but not Enabled flag:
public class UserProfileModel
{
public int Id {get;set;}
public string Name {get;set;}
}
When you want to do database update, you do the following:
YourUpdateMethod(UserProfileModel model)
{
using(YourContext ctx = new YourContext())
{
User user = new User { Id = model.Id } ; /// stub model, only has Id
ctx.Users.Attach(user); /// track your stub model
ctx.Entry(user).CurrentValues.SetValues(model); /// reflection
ctx.SaveChanges();
}
}
When you call this method, you will update the Name, but Enabled property will remain unchanged. I used simple models, but I think you'll get the picture how to use it.
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