Asp.Net Core: How to json serialize and deserialize IFormCollection? - asp.net

Question

In a controller I serialized form data to json and saved to database:
[HttpPost]
[ValidateAntiForgeryToken]
public IActionResult Create(IFormCollection formData)
{
var json = JsonConvert.SerializeObject(formData);
var doc = new Doc()
{
Subject = formData["subject"],
Content = json
};
_context.Docs.Add(doc);
_context.SaveChanges();
return RedirectToAction("Edit", new { Id = doc.Id });
}
Now, I'd like to deserialize form data and reconstruct the form:
public IActionResult Edit(int id)
{
var doc = _context.Docs
.Where(o => o.Id == id).FirstOrDefault();
if (doc == null)
{
ViewData["ErrorMessage"] = "Not found";
return View("Error");
}
var formData = JsonConvert.DeserializeObject<IFormCollection>(doc.Content);
ViewData["FormData"] = formData;
return View(doc);
}
The above will throw an exception at deserialization:
JsonSerializationException: Cannot create and populate list type Microsoft.AspNetCore.Http.IFormCollection. Path '', line 1, position 1.
If I do not specify type, then deserialization succeeds; but I prefer it
to be deserialized to IFormCollection. What is the proper way to deserialize IFormCollection?
Also, the reason I'm saving json is because, I'm dealing with 30 or so types of forms, and I do not want to create strongly typed model objects for each of them. Any advice is welcome.

Answer 1

The way I used to deal with json object in Database:
In your entity object add an other class to handle mapping with your json object :
public class Contact
{
public int Id { get; set; }
internal string _Data { get; set; }
[NotMapped]
public UserData Data
{
get { return _Data == null ? null : JsonConvert.DeserializeObject<UserData>(_Data); }
set { _Data = JsonConvert.SerializeObject(value); }
}
}
public class UserData
{
public string Name { get; set; }
//Add your json data here
}
And my controller look like
public IActionResult Add(AddContactViewModel model)
{
var contact = new Contact()
{
Data = JsonConvert.DeserializeObject<UserData>(model.Data.ToString())
};
_contactService.Add(contact);
return new OkObjectResult(contact);
}
public class AddContactViewModel
{
public JObject Data { get; set; }
}
Thank's to mapping, when you access the object data contained by the object contact you can access all your data préviously defined in the UserData object (Object names can change in your case)
var contact = new Contact()
{
Data = JsonConvert.DeserializeObject<UserData>(model.Data.ToString())
};
contact.Data.Name;