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c# - .NET WebApi - 如何接收带有附加参数的文件？

问题描述

这里的菜鸟问题，我正在尝试发送一个添加了字符串参数的文件。我的上传器类如下所示：

 public static void HttpUploadFile(string url, string file, string paramName, string contentType, NameValueCollection nvc)
        {
            string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
            byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");

            HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(url);
            wr.ContentType = "multipart/form-data; boundary=" + boundary;
            wr.Method = "POST";
            wr.KeepAlive = true;
            wr.Credentials = System.Net.CredentialCache.DefaultCredentials;
            Stream rs = wr.GetRequestStream();
            string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
            foreach (string key in nvc.Keys)
            {
                rs.Write(boundarybytes, 0, boundarybytes.Length);
                string formitem = string.Format(formdataTemplate, key, nvc[key]);
                byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);
                rs.Write(formitembytes, 0, formitembytes.Length);
            }
            rs.Write(boundarybytes, 0, boundarybytes.Length);
            string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n";
            string header = string.Format(headerTemplate, paramName, file, contentType);
            byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
            rs.Write(headerbytes, 0, headerbytes.Length);
            FileStream fileStream = new FileStream(file, FileMode.Open, FileAccess.Read);
            byte[] buffer = new byte[4096];
            int bytesRead = 0;
            while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
            {
                rs.Write(buffer, 0, bytesRead);
            }
            fileStream.Close();
            byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");
            rs.Write(trailer, 0, trailer.Length);
            rs.Close();
            WebResponse wresp = null;
            try
            {
                wresp = wr.GetResponse();
                Stream stream2 = wresp.GetResponseStream();
                StreamReader reader2 = new StreamReader(stream2);
               var result = reader2.ReadToEnd();
            }
            catch (Exception ex)
            {
                Program.log.Error(System.Reflection.MethodBase.GetCurrentMethod().Name + " Error occurred while converting file ", ex);
                if (wresp != null)
                {
                    wresp.Close();
                    wresp = null;
                }
            }
            finally
            {
                wr = null;
            }
        }

字符串参数位于 NameValueCollection 中。现在对方post方法应该怎么接收呢？

*此外，在这种情况下，我混合文件+字符串参数，内容类型应该是“应用程序/八位字节流”吗？

谢谢

标签： c#asp.net.netasp.net-web-apiasp.net-web-api2

解决方案

对于您的情况，您可以创建一个FileUploadViewModel以包含您的所有属性，包括IFormFile. 将此用作您的操作方法的参数类型。默认模型绑定器应该能够为您填充所有内容。

另请查看您是否需要自定义模型绑定器 - https://docs.microsoft.com/en-us/aspnet/core/mvc/advanced/custom-model-binding?view=aspnetcore-2.1

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