public void ConfigureServices(IServiceCollection services)
{
    // 添加FaceServiceClient用来调用Azure Face API
    // 第二个参数为Face API的终结点
    services.AddTransient(_ => new FaceServiceClient("Your Cognitive Service Key", "https://eastasia.api.cognitive.microsoft.com/face/v1.0/"));
    services.AddMvc();
}

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }

    app.UseMvc();
}

[Produces("application/json")]
[Route("api/[Controller]")]
public class FaceController : Controller
{
    private readonly FaceServiceClient _faceClient;
    private const string groupId = "Your Group Id";

    public FaceController(FaceServiceClient faceClient)
    {
        _faceClient = faceClient;
    }

    /// <summary>
    /// 上次图片获取Face Id
    /// </summary>
    /// <param name="image">待识别的图片</param>
    /// <returns></returns>
    [Route("[Action]")]
    [HttpPost]
    public async Task<JsonResult> Upload(IFormFile image)
    {
        // 启用图片压缩，提高传输速度
        var magickImage = new MagickImage(image.OpenReadStream())
        {
            Quality = 50
        };
        var faces = await _faceClient.DetectAsync(new MemoryStream(magickImage.ToByteArray()));
        // 返回Face Id以及人脸位置信息
        return Json(faces.Select(face => new
        {
            Id = face.FaceId,
            Rect = face.FaceRectangle
        }));
    }

    /// <summary>
    /// 根据Face Id识别人脸
    /// </summary>
    /// <param name="model"></param>
    /// <returns></returns>
    [Route("[Action]")]
    [HttpPost]
    public async Task<JsonResult> Identify([FromBody]IdentifyModel model)
    {
        // 识别人脸
        var identifyResults = await _faceClient.IdentifyAsync(groupId, model.Faces, 0.6f);
        List<IdentifyResult> result = new List<IdentifyResult>();
        foreach (var item in identifyResults)
        {
            // 跳过无识别结果的人脸
            if (item.Candidates.Length == 0)
            {
                continue;
            }
            // 获取第一个识别结果的对应实体
            var person = await _faceClient.GetPersonAsync(groupId, item.Candidates.First().PersonId);
            result.Add(new IdentifyResult
            {
                Name = person.Name,
                StudentId = person.UserData
            });
        }
        return Json(result);
    }
}

<!--pages/index/index.wxml-->
<!-- 调用Camera组件来捕捉图像 -->
<camera device-position="front" flash="off" binderror="error" style="width: 750rpx; height: 750rpx;">
  <!-- 由于Camera是原生组件，只能通过cover-view才能覆盖在其上方 -->
  <block wx:for="{{faces}}" wx:key="id">
    <!-- 通过CSS实现矩形框 -->
    <cover-view class="box" style="left:{{item.rect.left}}px;top:{{item.rect.top}}px;width:{{item.rect.width}}px;height:{{item.rect.height}}px;">
    </cover-view>
  </block>
</camera>

<button type="primary" bindtap="takePhoto">识别</button>
<!-- 显示人脸数据 -->
<view wx:for="{{faces}}" wx:key="id">
  <view>Face {{index}}:</view>
  <view>{{item.id}}</view>
</view>
<view wx:for="{{results}}" wx:key="studentId">
  <view>Name: {{item.name}}</view>
  <view>StudentId: {{item.studentId}}</view>
</view>

/* pages/index/index.wxss */
/*
* 用于标出人脸位置
*/
.box {
  border: 5rpx solid green;
  position: relative;
}

// pages/index/index.js
// 定义API终结点
const baseUrl = "http://localhost:5000";

Page({
  // 页面的初始数据
  data: {
    // 保存FaceId和人脸位置信息
    faces: [],
    // 保存识别到的实体信息
    results: []
  },
  // 步骤图像，并上传到UploadAPI
  takePhoto() {
    let that = this;
    // 获取Camera上下文
    const ctx = wx.createCameraContext();
    // 捕捉图像
    ctx.takePhoto({
      quality: "low",
      success: res => {
        // 在捕捉成功后将图片直接上传到Upload API
        wx.uploadFile({
          url: baseUrl + "/api/Face/Upload",
          filePath: res.tempImagePath,
          name: "Image",
          success: function(res) {
            let obj = JSON.parse(res.data);
            // 保存检测到的人脸数据
            that.setData({
              faces: obj,
              results: []
            });
            // 若检测到人脸就就进一步调用识别API
            if (obj.length > 0) {
              that.identifyFace(obj.map(face => face.id));
            }
          }
        });
      }
    });
  },
  // 输出错误信息
  error(e) {
    console.log(e.detail);
  },
  // 调用Identify API
  identifyFace(faceIds) {
    let that = this;
    wx.request({
      url: baseUrl + "/api/Face/Identify",
      method: "POST",
      data: {
        faces: faceIds
      },
      dataType: "json",
      success: function(res) {
        that.setData({
          results: res.data
        });
      }
    });
  }
});