上传大文件，取消内存缓存：

GlobalConfiguration.Configuration.Services.Replace(typeof(IHostBufferPolicySelector), new CustomPolicy());

public class CustomPolicy : WebHostBufferPolicySelector    {        #region Public Methods and Operators        public override bool UseBufferedInputStream(object hostContext)        {            return false;        }        #endregion    }

上传代码：

[HttpPost]        [Route("api/upload")]        public async Task
     
       PostFormData() {            // Check if the request contains multipart/form-data.            if(!Request.Content.IsMimeMultipartContent()) {                throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);            }                    string root = HttpContext.Current.Server.MapPath("~/Uploads/");            MyStreamProvider streamProvider = new MyStreamProvider(root);            //var provider = new MultipartFormDataStreamProvider(root);            try {                // Read the form data.                await Request.Content.ReadAsMultipartAsync(streamProvider);                // This illustrates how to get the file names.                //foreach(MultipartFileData file in streamProvider.FileData) {                //    Trace.WriteLine(file.Headers.ContentDisposition.Size);                //    Trace.WriteLine("Server file path: " + file.LocalFileName);                //}                FileInfo fileInfo = new FileInfo(streamProvider.FileData[0].LocalFileName);                            } catch(System.Exception e) {                throw e;            }        }
     

经测试上传：大文件，内存消耗不多，CPU有点上浮，上传速度有点慢，但比较稳定