Postman POST request Model binding not working with an IFormfile property

Question

I have a model like this.

    public class ClientDto
    {
       public string FirstName { get; set; }
       public string LastName { get; set; }
       public string PhoneNumber { get; set; }
       public string Address { get; set; }
       public IFormFile ProfilePicture { get; set; }
     }

And API controller like this:

    [HttpPost]
    public async Task<OperationResult> Post([FromForm] ClientDto c)
    {
        ImageHandler handler = new ImageHandler(env);
        Client client = new Client()
        {
            Address = c.Address,
            FirstName = c.FirstName,
            LastName = c.LastName,
            PhoneNumber = c.PhoneNumber,
            PhotoPath = await handler.UploadFile(c.ProfilePicture)
        };
        return await clientRepository.AddClient(client);
    }

Now if I make a Post request with postman after including a file with ProfilePicture as key (under Postman >> Body >> form-data section ), model binding works as expected. The api controller receives PofilePicture and rest of the properties null . But if I include json string for other properties like this ( under Postman >> Body >> raw section)

    {
     "c":{
          "FirstName": "XYZ",
          "LastName":"ABX"
         }
    }

OR

     {
          "FirstName": "XYZ",
          "LastName":"ABX"
     }

model binding no longer works. How do I hit the api controller with postman if i want to provide all properties?

Answer 1

You're mixing data sent to the controller - it's confused.

In your request with the image the content type is multipart/form-data as the body contains a file and potentially other form data fields. In the request with JSON the content type is application/json and you're not sending any file data.

You have to decide to either only send the JSON or the form data.

In this case, since you're sending a file, you need to use multipart/form-data and just set the missing fields in the form fields from Postman ( see how to set Postman form-data parameters here ).