将文件从邮递员上传到 Web API 时，IFormFile 为空值答案

【问题标题】：IFormFile is null value when uploading file from postman to web API将文件从邮递员上传到 Web API 时，IFormFile 为空值
【发布时间】：2019-06-07 13:09:16
【问题描述】：

我尝试通过邮递员测试将 IFormFile 上传到 Web API，错误显示 IFormFile 为空值。

    [HttpPost("upload")]
    public async Task<string> Post(IFormFile photo)
    {
        try
        {
            // Full path to file in  location
            string fname = DoPhotoUpload(photo);
            string filePath = Path.Combine(_env.WebRootPath, "photos/" + fname);

            if (photo.Length > 0)
                using (var stream = new FileStream(filePath, FileMode.Create))
                    await photo.CopyToAsync(stream);
            //return Ok(new { count = 1, path = filePath });
            return fname;
        } catch (Exception ex)
        {
            return ex.Message;
        }

响应显示我的 IFromFile 是一个空值，但我无法找出我错过了哪里。

【问题讨论】：

标签： c# post asp.net-web-api postman nullreferenceexception

【解决方案1】：

[HttpPost("upload")]
public async Task<string> Post([FromBody] IFormFile photo)
{
    try
    {
        // Full path to file in  location
        string fname = DoPhotoUpload(photo);
        string filePath = Path.Combine(_env.WebRootPath, "photos/" + fname);

        if (photo.Length > 0)
            using (var stream = new FileStream(filePath, FileMode.Create))
                await photo.CopyToAsync(stream);
            //return Ok(new { count = 1, path = filePath });
        return fname;
    } catch (Exception ex)
    {
        return ex.Message;
    }
}

【讨论】：