How append whole object to formData - asp.net

Question

I need to send image list and product data to ASP.net api via formData. I succesfully sended images but now i dont really know how to append whole object. I have seen some ways to do that in JS JSON.stringfy(object) or Object.keys(object).forEach(key => formData.append(key, object[key])); but it doesnt works for me.
angular http service
updateProduct(imageProductVM:ProductImageViewmodel): Observable<any> {
const formData = new FormData()
// imageProductVM.product ??
for (const photo of imageProductVM.files) {
console.log(photo)
formData.append('files', photo)
}
return this.http.post(this.apiURL + '/product/', formData, {headers:{"ContentType": "multipart/form-data"}})
}
asp.net api
[HttpPost]
public async Task<ActionResult> AddProduct([FromForm] ProductService ser)
{
return Ok();
}
public class ProductService
{
public Product? product { get; set; }
public List<IFormFile>? files { get; set; }
}

Answer 1

In fact, I forgot to say that my product object also has nested objects. Thanks W.S for sharing the info.
This answer helped me
to understand what an object should look like for ASP.net , Here's how it should look in my case:
product.id "*value*"
product.supplierId "*value*"
product.supplierName *value*
product.title "*value*"
product.description "*value*"
product.vendor "*value*"
product.vendorId "*value*"
product.documents[0].id *value*
product.documents[0].url
product.documents[0].keywords
product.attributes[0].attributeId *value*
product.attributes[0].attributeName *value*
product.attributes[0].type A
product.attributes[0].value 2
And then I used the following code to convert my object to a compatible view:
productEntriesIteration(object:object, j:number, nestedKey:string) {
Object.entries(object).forEach(([key, value], i)=> {
if (value) {
if (typeof value == "string") {
this.appendSingleField(key, nestedKey,j,value);
}
else if (typeof value == "number") {
if ( Number(value) === Number(value) && Number(value) !== (Number(value) | 0)) {
value = value.toString().replace(".", ',')
}
this.appendSingleField(key,nestedKey,j,value)
}
else if (typeof value.getMonth === 'function') {
this.appendSingleField(key, nestedKey, j, value.toISOString())
}
else if (Array.isArray(value)) {
for (let val in value) {
if (typeof value[val] == "object") {
this.productEntriesIteration(value[val], Number(val), key)
}
else if (typeof value[val] == "number"){
this.appendSingleField(key, nestedKey, j, value[val])
}
else {
this.appendSingleField(key, nestedKey, j, value[val])
}
}
} else if (typeof value == "object") {
this.productEntriesIteration(value, -1, key)
}
}
})
return this.formData
}
appendSingleField(key:string, nestedKey:string, i:number, value:any) {
if (i == null) {
this.formData.append('product.'+key+'',value)
} else if (i == -1) {
this.formData.append('product.'+nestedKey+'.'+key,value)
} else {
this.formData.append('product.'+nestedKey+'['+i+'].'+key,value)
}
}
I hope this helps someone