如何在不使用JS FormData的情况下将文件上载到ASP.NET MVC控制器操作

<input type="file" id="fileInput" />

var fileInput = document.getElementById('fileInput');
var file = fileInput.files[0];

var reader = new FileReader();
reader.onload = function(e) {
  var base64Data = e.target.result;
  // 将base64Data发送给后端
};
reader.readAsDataURL(file);

[HttpPost]
public ActionResult UploadFile(string base64Data)
{
    byte[] fileData = Convert.FromBase64String(base64Data);
    // 处理文件数据
    return View();
}

[HttpPost]
public ActionResult UploadFile(string base64Data)
{
    byte[] fileData = Convert.FromBase64String(base64Data);
    
    string filePath = "path/to/save/file.ext";
    using (FileStream fs = new FileStream(filePath, FileMode.Create))
    {
        fs.Write(fileData, 0, fileData.Length);
    }
    
    // 文件上传成功
    return View();
}