c# API接受图片文件以Base64格式上传图片

 /// base64上传图片
        /// </summary> 
        /// <returns>成功上传返回上传后的文件名</returns>
        [httppost]
        public async task<ihttpactionresult> uploadimagebase64()
        {
            httpcontextbase context = (httpcontextbase)request.properties["ms_httpcontext"];
            string text = context.request.form["file"];

            stream stream = new memorystream(convert.frombase64string(text.split(',')[1]));
            using (httpclient client = new httpclient())
            {
                var request = new httprequestmessage(httpmethod.post, configurationmanager.appsettings["imgaes"].tostring() + "/upload");
                var content = new multipartformdatacontent();

                //client.defaultrequestheaders.add("fileext", httpcontext.request.headers["fileext"]);
                content.add(new streamcontent(stream), "file", "file.jpg");
                request.content = content;
                var response = await client.sendasync(request);
                response.ensuresuccessstatuscode();
                var filenamestr = await response.content.readasstringasync();//返回结果
            }
            return ok();
        }