Check out example codes for "asp.net core razor pages upload file". It will help you in understanding the concepts better.

Code Example 1

Upload and save to folder link
The following code features a very simple page called UploadFile.cshtml with a form for uploading a file:

@page
@model UploadFileModel
@{
}
<form method="post" enctype="multipart/form-data">
    <input type="file" asp-for="Upload" />
    <input type="submit" />
</form>

using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using System.IO;
using System.Threading.Tasks;
namespace RazorPagesForms.Pages
{
    public class UploadFileModel : PageModel
    {
        private IHostingEnvironment _environment;
        public UploadFileModel(IHostingEnvironment environment)
        {
            _environment = environment;
        }
        [BindProperty]
        public IFormFile Upload { get; set; }
        public async Task OnPostAsync()
        {
            var file = Path.Combine(_environment.ContentRootPath, "uploads", Upload.FileName);
            using (var fileStream = new FileStream(file, FileMode.Create))
            {
                await Upload.CopyToAsync(fileStream);
            }
        }
    }
}

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