1.添加表单和文件输入组件到页面：

    
    上传文件

2.在服务器端创建一个控制器并处理文件上传请求：

[ApiController]
[Route("[controller]")]
public class FileUploadController : ControllerBase
{
    private readonly string _uploadFolder;

    public FileUploadController(IWebHostEnvironment webHostEnvironment)
    {
        _uploadFolder = Path.Combine(webHostEnvironment.WebRootPath, "uploads");
    }

    [HttpPost]
    public async Task Upload(IFormFile file)
    {
        if (file.Length != 0)
        {
            var fileName = DateTime.Now.ToString("yyyyMMddHHmmss_") + file.FileName;
            var filePath = Path.Combine(_uploadFolder, fileName);
            using (var stream = new FileStream(filePath, FileMode.Create))
            {
                await file.CopyToAsync(stream);
            }
            return Ok(new { fileName });
        }
        return BadRequest();
    }
}

3.使用 jQuery 和 Ajax 在客户端处理文件上传和显示文件：

$(function () {
    $("#uploadButton").click(function (event) {
        event.preventDefault();
        var fileInput = document.getElementById('fileInput');
        var file = fileInput.files[0];
        var formData = new FormData();
        formData.append('file', file);
        $.ajax({
            url: '/FileUpload',
            data: formData,
            processData: false,
            contentType: false,
            type: 'POST',
            success: function (data, textStatus, jqXHR) {
                $("#fileList").append(`
${data.fileName}
`);
            }
        });
    });
});

4.在页面上添加一个列表框来显示上传的文件：

这样就可以将文件上传到服务器并在页面上显示它，同时不需要刷新整个网站。