.Net Core WebAPI , Unable to post data with POSTMA

问题:

I am testing my first .net Core WebAPI with Postman

unknown media type error is occurring.

What am I missing?

This is my posting object

public class Country
{
    [Key]
    public int CountryID { get; set; }
    public string CountryName { get; set; }
    public string CountryShortName { get; set; }
    public string Description { get; set; }
}

This is the webapi controller

[HttpPost]
public async Task<IActionResult> PostCountry([FromBody] Country country)
{
    if (!ModelState.IsValid)
    {
        return BadRequest(ModelState);
    }

    _context.Country.Add(country);
    try
    {
        await _context.SaveChangesAsync();
    }
    catch (DbUpdateException)
    {
        if (CountryExists(country.CountryID))
        {
            return new StatusCodeResult(StatusCodes.Status409Conflict);
        }
        else
        {
            throw;
        }
    }

    return CreatedAtAction("GetCountry", new { id = country.CountryID }, country);
}

回答1:

You're not sending the Content-Type header. Choose JSON (application/json) in the dropdown near the mouse pointer on your first screenshot:

回答2:

This worked for me (I was using api in the route)

[Produces("application/json")]
[Route("api/Countries")]
public class CountriesController : Controller
{
    // POST: api/Countries
    [HttpPost]
    public async Task<IActionResult> PostCountry([FromBody] Country country)
    {
        if (!ModelState.IsValid)
        {
            return BadRequest(ModelState);
        }

        _context.Country.Add(country);
        try
        {
            await _context.SaveChangesAsync();
        }
        catch (DbUpdateException)
        {
            if (CountryExists(country.CountryID))
            {
                return new StatusCodeResult(StatusCodes.Status409Conflict);
            }
            else
            {
                throw;
            }
        }

        return CreatedAtAction("GetCountry", new { id = country.CountryID }, country);
    }
}