I am writting an application with asp.net core 2.0 mvc.
Here is one of my controller's action:
[HttpPost]
public async Task<IActionResult> MyAction(long id, [Bind("id_person,name")] Person p)
{
ViewBag.message = "";
if (p.name == "")
{
ViewBag.message = "You need to set name.";
}
else if (ModelState.IsValid == false)
{
ViewBag.message = string.Join("; ", ModelState.Values.SelectMany(x => x.Errors).Select(x => x.ErrorMessage));
}
else
{
mydb_context.Update(p);
await mydb_context.SaveChangesAsync();
return RedirectToAction(nameof(Index));
}
return View(p);
}
And here is the associated cshtml razor view:
@model myproject.Person
<form asp-action="MyAction">
<div>@ViewBag.message</div>
<input type="hidden" asp-for="id_person" />
<input asp-for="name" />
<input type="submit">
</form>
Everything works fine: This action works great for insert and updating Persons.
Now, let's suppose i have a third field in my Person entity. For example "age".
I want this field to be secret. That's mean i do not want to user to see this information in his browser. I do not want too to put this information in an hidden field because the user may see or change the information.
My problem is if i keep MyAction and cshtml view as is, the age is set to null when a user updates a person. I want the age to keep its actual value in database.
Is there a basic way to do this ? I do not want to set by hand getters and setters in MyAction method, because i have a lot of fields. I want to work with Binding.
Thanks
I don't know if it's still available in EFCore but I used to do this in EF6.
If you only want to update the Name propoerty, you can use mydb_context.Entry()
.
var person = mydb_context.Person.FirstOrDefault(p => p.id_person == id);
if(person != null)
{
mydb_context.Entry(person).Property("name").CurrentValue = "Toto";
mydb_context.SaveChanges();
}
Read this for more details https://docs.microsoft.com/fr-fr/ef/ef6/saving/change-tracking/property-values