js上传文件 c#写代码

<input type="file" id="fileInput">
<button onclick="uploadFile()">上传文件</button>

function uploadFile() {
    const fileInput = document.getElementById('fileInput');
    const file = fileInput.files[0];
    if (file) {
        const formData = new FormData();
        formData.append('file', file);

        fetch('/api/upload', {
            method: 'POST',
            body: formData
        })
        .then(response => response.json())
        .then(data => console.log(data))
        .catch(error => console.error('Error:', error));
    }
}

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using System.IO;
using System.Threading.Tasks;

[Route("api/[controller]")]
[ApiController]
public class UploadController : ControllerBase
{
    [HttpPost]
    public async Task<IActionResult> UploadFile(IFormFile file)
    {
        if (file == null || file.Length == 0)
            return BadRequest("No file uploaded.");

        var path = Path.Combine(Directory.GetCurrentDirectory(), "uploads", file.FileName);

        using (var stream = new FileStream(path, FileMode.Create))
        {
            await file.CopyToAsync(stream);
        }

        return Ok(new { message = "File uploaded successfully." });
    }
}