视觉智能平台有没有C#调用SDK进行人脸表情识别的DEMO的？公司要迁移表情识别

是的，阿里云视觉智能平台提供了针对不同编程语言和平台的SDK，包括C#语言的SDK，可以用于快速访问平台提供的API接口。您可以前往阿里云官网，下载对应的C# SDK，并参考文档进行集成。

针对人脸表情识别，您可以调用平台提供的表情识别API来实现。下面提供一个C#示例代码供参考：

using System;
using System.IO;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using Newtonsoft.Json.Linq;

namespace FaceDemo
{
    class Program
    {
        static async Task Main(string[] args)
        {
            string url = "https://dtplus-cn-shanghai.data.aliyuncs.com/face/attribute";

            // 替换为您的AccessKey ID和AccessKey Secret
            string accessKeyId = "<Your AccessKey ID>";
            string accessKeySecret = "<Your AccessKey Secret>";

            string imageFilePath = "image.jpg";
            string imageBase64 = Convert.ToBase64String(File.ReadAllBytes(imageFilePath));

            string body = "{\"type\":\"1\", \"content\":\"" + imageBase64 + "\"}";

            string timestamp = DateTime.UtcNow.ToString("yyyy-MM-ddTHH:mm:ssZ");
            string signature = ComputeSignature(accessKeySecret, "POST\napplication/json\nUTF-8\n" + timestamp + "\n"+ "/face/attribute\n" + body);

            var request = new HttpRequestMessage(HttpMethod.Post, url);
            request.Headers.Add("Authorization", "Dataplus " + accessKeyId + ":" + signature);
            request.Headers.Add("accept", "application/json");
            request.Headers.Add("x-acs-region-id", "cn-shanghai");
            request.Headers.Add("date", timestamp);

            var content = new StringContent(body, System.Text.Encoding.UTF8, "application/json");
            request.Content = content;

            var client = new HttpClient();
            var response = await client.SendAsync(request);
            if (response.StatusCode == HttpStatusCode.OK)
            {
                var responseContent = await response.Content.ReadAsStringAsync();
                JObject jo = JObject.Parse(responseContent);
                var facesExpression = jo["faceList"][0]["attribute"]["emotion"];
                var anger = facesExpression["anger"].Value<float>();
                var disgust = facesExpression["disgust"].Value<float>();
                var fear = facesExpression["fear"].Value<float>();
                var happiness = facesExpression["happiness"].Value<float>();
                var sadness = facesExpression["sadness"].Value<float>();
                var surprise = facesExpression["surprise"].Value<float>();
            }
        }

        static string ComputeSignature(string accessKeySecret, string stringToSign)
        {
            var encoding = new System.Text.UTF8Encoding();
            var key = encoding.GetBytes(accessKeySecret);
            var hmacsha1 = new System.Security.Cryptography.HMACSHA1(key);
            var hashBytes = hmacsha1.ComputeHash(encoding.GetBytes(stringToSign));

            return Convert.ToBase64String(hashBytes);
        }
    }
}

该示例代码使用HttpClient发起了一个POST请求，将图片数据进行Base64编码后传给人脸属性分析接口（属性type为1代表分析表情），然后解析了json返回值中的表情信息。您需要自行替换您的AccessKey Id和AccessKey Secret，并修改图片路径和请求URL等信息。

这里：https://next.api.aliyun.com/api/facebody/2019-12-30/RecognizeExpression?spm=a2c4g.155004.0.i0&tab=DEMO&lang=CSHARP，此回答整理自钉群“阿里云视觉智能开放平台咨询1群”