FormData + IFormFile is null

Question

I'm having a problem with IFormFile and FormData.

When I submit a file using FormData, the mapped Object returns a null value in the Backend.

I provide a code sample so that you may review my code.

Angular:

upload(prod: Product) {
let formData = new FormData();

formData.append("productName", prod.productName);
formData.append("productSku", prod.productSku);    

for(let i=0;i<prod.variants.length;i++){
  formData.append(`variants[${i}][variantName]`, prod.variants[i].variantName);
  formData.append(`variants[${i}][media][fileName]`, prod.variants[i].media.fileName);
  formData.append(`variants[${i}][media][mediaFile]`, prod.variants[i].media.mediaFile);
}
console.log(prod);
this.http.post('https://localhost:7255/api/products', formData)
.subscribe(res => {
  console.log(res);
  alert('Uploaded Successfully.');
})

}

ASP.Net Core

[Route("api/[controller]")]
[ApiController]
public class ProductsController : ControllerBase
{
    
    public ProductsController() {}
    
    [HttpPost]
    public IActionResult Post([FromForm] ProductCreateDto product )
    {
        return Ok();
    }

}
public class ProductCreateDto
{
    [JsonProperty("productName")]
    public string? ProductName { get; set; }
    [JsonProperty("productSku")]
    public string? ProductSku { get; set; }
    [JsonProperty("variants")]
    public IEnumerable<Variant> Variants { get; set; }
}

public class Media
{
    [JsonProperty("fileName")]
    public string? FileName { get; set; }
    public IFormFile? MediaFile { get; set; }
}

public class Variant
{
    [JsonProperty("variantName")]
    public string? VariantName { get; set; }
    [JsonProperty("media")]
    public Media? Media { get; set; }
}

What I got

When I update the code and I put a IFormFile in the DTO it works

    public class ProductCreateDto
{
    [JsonProperty("productName")]
    public string? ProductName { get; set; }
    [JsonProperty("productSku")]
    public string? ProductSku { get; set; }
    [JsonProperty("variants")]
    public IEnumerable<Variant> Variants { get; set; }
    
    public IFormFile TEST { get; set; }
}

What was the error with the first code?

ADO R · Accepted Answer · 2022-04-29 02:34:48Z

1

I find my error. The mapping was not good. I checked in Postman before. Here is the solution if someone is interrested.

upload(prod: Product) {
    let formData = new FormData();

    formData.append("productName", prod.productName);
    formData.append("productSku", prod.productSku);    

    for(let i=0;i<prod.variants.length;i++){
      formData.append(`variants[${i}].variantName`, prod.variants[i].variantName);
      formData.append(`variants[${i}].media.fileName`, prod.variants[i].media.fileName);
      formData.append(`variants[${i}].media.mediaFile`, prod.variants[i].media.mediaFile);
    }   
    this.http.post('https://localhost:7255/api/products', formData)
      .subscribe(res => {
        console.log(res);
        alert('Uploaded Successfully.');
      })
  }

answered Apr 29, 2022 at 2:34

ADO R

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