HttpPostedFileBase could not be found Visual studio 2019 - asp.net-mvc

Question

hi,
i'm working on a asp.net core mvc with visual studio 2019,
(see attached for the mvc version (3.1.8).
i want to use HttpPostedFileBase, but getting error could not be found,
i've seen a solution suggesting to add using system.Web, and i did, but still getting this error,
Any ideas?
Edit:
Created the html :
<div class="col-md-6">
<div>
<input id="CSVFile" type="file">
</div>
<button onclick="Submit()">submit</button>
</div>
and javascript:
<script type="text/javascript">
function Submit() {
var pdata = new FormData();
var files = $("#CSVFile").get(0).files;
window.alert(files.Length);
pdata.append('CSVFile', files[0]);
$.ajax({
url: "Index",
type: "POST",
data: pdata,
processData: false,
contentType: false,
success: function (data) {
var input = $("#CSVFile");
input.replaceWith(input.val('').clone(true));
}
});
}
</script>
but the controller is not being called (it is defined HttpPost)
public ActionResult Index(IFormFile CSVFile)
{
return View();
}

Answer 1

.net core 3.1 doesn't contain HttpPostedFileBase.If you want to upload files,you can use IFormFile,here is an official tutorial.
Here is a simple demo to use IFormFile(from view to controller):
view:
<div class="row">
<div class="col-md-6">
<div>
<input id="CertImageFile" type="file">
</div>
<button onclick="Submit()">submit</button>
</div>
</div>
#section scripts{
<script type="text/javascript">
function Submit() {
var pdata = new FormData();
var files = $("#CertImageFile").get(0).files;
pdata.append('CertImageFile', files[0]);
$.ajax({
url: "Submit",
type: "POST",
data: pdata,
processData: false,
contentType: false,
success: function (data) {
var input = $("#CertImageFile");
input.replaceWith(input.val('').clone(true));
}
});
}
</script>
}
Controller:
[HttpGet]
public IActionResult TestIFormFile()
{
return View();
}
[HttpPost]
public IActionResult Submit(IFormFile CertImageFile)
{
return Ok();
}
result: