IFormFile always return null in asp.net core 2.1

Question

Api method is looks like below

    [HttpPost]
    public async Task<BaseListResponse<MediaStorageModel>> MediaBrand(IFormFile file, int brandId)
    {
        var files = new List<IFormFile>();
        files.Add(file);

        var response = await this.Upload(files, "brand", brandId);

        return response;
    }

My postman configuration

Upgrade my dotnet core from 2.0 to 2.1 thie become not working, can anyone help about this. What going wrong

Answer 1

The below code should work

[HttpPost]
public async Task<BaseListResponse<MediaStorageModel>> MediaBrand([FromQuery] int brandId, IFormFile file)
{
    var files = new List<IFormFile>();
    files.Add(file);

    var response = await this.Upload(files, "brand", brandId);

    return response;
}

Answer 2

Update [FromForm] attribute, and don't put parameter into Headers, and put name of key is file and brandId.

I tested, It is Ok

Answer 3

Make sure the form is the correct enctype

<form asp-action="Edit" enctype="multipart/form-data">

I also had to change how the Model bind from the generated

public async Task<IActionResult> Edit([Bind("Text,Example")] Example example)

to

public async Task<IActionResult> Edit(Example example)

Answer 4

Change your method argument to take below model and add [FromForm], it should work.

public class FileUploadViewModel
{
    public IFormFile File { get; set; }
    public int BrandId { get; set; }
}

public async Task<BaseListResponse<MediaStorageModel>> MediaBrand([FromForm] FileUploadViewModel viewModel)

Answer 5

In your form use

enctype="multipart/form-data"

Answer 6

I have found a workaround to make it work:

Use HttpPut instead of HttPost on the controller action.

I was also surprised by this behavior. If someone can explain why it fixes the issue, it would help me.