WEB API 使用MultipartFormDataStreamProvider上传文件（转）

在这简短的教程中，我们打算去看如何上传多个文件在 ASP.Net WebAPI 中使用 MultipartFormDataStreamProvider。这一概念基于多部分/格式数据我们可以在这里发布多个文件的内容不仅将 NameValueCollection 作为服务器端提供的常规表单字段。在本教程中我们还看到了如何重写默认行为的MultipartFormDataStreamProvider，将名称存储在一个独特的 BodyPart_ {GUID} 格式中。

适合手机端服务图片接口，支持多个文件（.NET Framework 4.5以上）笔记

[HttpPost]
        public async Task<HttpResponseMessage> PostSaveImg()
        {
            if (!Request.Content.IsMimeMultipartContent())
            {
                throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
            }

            // Prepare CustomMultipartFormDataStreamProvider in which our multipart form  
            // data will be loaded.  
            string fileSaveLocation = HttpContext.Current.Server.MapPath("~/UploadImages");
            CustomMultipartFormDataStreamProvider provider = new CustomMultipartFormDataStreamProvider(fileSaveLocation);
            List<string> files = new List<string>();
            try
            {
                // Read all contents of multipart message into CustomMultipartFormDataStreamProvider.  
                await Request.Content.ReadAsMultipartAsync(provider);

                foreach (MultipartFileData file in provider.FileData)
                {
                    //files.Add(Path.GetFileName(file.LocalFileName));
                    string orfilename = file.Headers.ContentDisposition.FileName.TrimStart('"').TrimEnd('"');
                    FileInfo fileinfo = new FileInfo(file.LocalFileName);
                    string fileExt = orfilename.Substring(orfilename.LastIndexOf('.'));
                    //定义允许上传的文件扩展名 
                    String fileTypes = "gif,jpg,jpeg,png,bmp";
                    if (String.IsNullOrEmpty(fileExt) || Array.IndexOf(fileTypes.Split(','), fileExt.Substring(1).ToLower()) == -1)
                    {
                        files.Add("Incorrect image format");
                    }
                    else
                    {
                        String ymd = DateTime.Now.ToString("yyyyMMdd", System.Globalization.DateTimeFormatInfo.InvariantInfo);
                        String newFileName = DateTime.Now.ToString("yyyyMMddHHmmss_ffff", System.Globalization.DateTimeFormatInfo.InvariantInfo);
                        fileinfo.CopyTo(Path.Combine(fileSaveLocation, newFileName + fileExt), true);
                        fileinfo.Delete();
                        files.Add("http://192.168.1.129/UploadImages/" + newFileName + fileExt);
                    } 
                }

                // Send OK Response along with saved file names to the client.  
                return Request.CreateResponse(HttpStatusCode.OK, files);
            }
            catch (System.Exception e)
            {
                return Request.CreateErrorResponse(HttpStatusCode.InternalServerError, e);
            }  
        }

        public class CustomMultipartFormDataStreamProvider : MultipartFormDataStreamProvider
        {
            public CustomMultipartFormDataStreamProvider(string path) : base(path) { }

            public override string GetLocalFileName(HttpContentHeaders headers)
            {
                return headers.ContentDisposition.FileName.Replace("\"", string.Empty);
            }
        }  

原文参考地址：http://blog.csdn.net/greystar/article/details/44562715