基于ASP.NET使用C#实现简单人脸识别功能

(博客园对Markdown的排版也太不友好了吧(小声逼逼))

案例概述

本案例基于ASP.NET和百度云人脸库，主要实现静态人脸添加和静态人脸检测的功能，是笔者一个练习的小Demo

使用的工具

主要使用了VS 2017、MS SQL Server数据库和百度云人脸库

实现的功能

• 人脸注册
• 人脸搜索

功能及代码展示

知识背景

百度人脸库的创建

1.打开浏览器登录百度智能云，（百度账号即可登录）

2.应用列表|创建应用


3.人脸库管理|选择刚刚创建好的应用

4.在这个应用中创建新分组（这个分组将在之后上传图片信息中用到）

本项目中用到的类

1.AccessToken.cs

主要功能：将创建人脸库时获取的API Key和Sercet Key，放入json字符串中传给百度云人脸识别接口，与自己创建的人脸库建立连接，并获取连接凭证。
返回回来的json字符串中含有的Access_Token就是这个凭证。

这个类不是笔者写的，是百度云提供的api调用方式文档(点此访问)，在这个文档的基础上，笔者进行了一些修改，形成了下面的类。

using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Web.Script.Serialization;

namespace com.baidu.ai
{
    public static class AccessToken

    {
        // 调用getAccessToken()获取的 access_token建议根据expires_in 时间 设置缓存
        // 返回token示例
        public static String TOKEN = "24.adda70c11b9786206253ddb70affdc46.2592000.1493524354.282335-1234567";

        // 百度云中开通对应服务应用的 API Key 建议开通应用的时候多选服务
        private static String clientId = "*********";
        // 百度云中开通对应服务应用的 Secret Key
        private static String clientSecret = "**********";

        public static String getAccessToken()
        {
            String authHost = "https://aip.baidubce.com/oauth/2.0/token";
            HttpClient client = new HttpClient();
            List<KeyValuePair<String, String>> paraList = new List<KeyValuePair<string, string>>();
            paraList.Add(new KeyValuePair<string, string>("grant_type", "client_credentials"));
            paraList.Add(new KeyValuePair<string, string>("client_id", clientId));
            paraList.Add(new KeyValuePair<string, string>("client_secret", clientSecret));

            HttpResponseMessage response = client.PostAsync(authHost, new FormUrlEncodedContent(paraList)).Result;
            String result = response.Content.ReadAsStringAsync().Result;
            Console.WriteLine(result);


            //获取返回的字符串
            //string test = AccessToken.getAccessToken();
            //Response.Write(test + "<br/>");


            //获取返回的Access_Token
            string Access_Token = "";
            JavaScriptSerializer Jss = new JavaScriptSerializer();
            Dictionary<string, object> DicText = (Dictionary<string, object>)Jss.DeserializeObject(result);
            //如果返回值中含有access_token，则将其值赋予Access_Token，不存在则说明获取失败。
            if (!DicText.ContainsKey("access_token"))
            {
                Access_Token = "获取Access_Token失败";
            }
            else
            {
                Access_Token = DicText["access_token"].ToString();
            }

            //Session["Token"] = Access_Token;
            //Response.Write(Access_Token);
            return Access_Token;
        }
    }
}

2.FaceAdd.cs

主要功能：在人脸库中新建人脸,并设置这个人脸的编号和分组，这个类也是基于百度云的开发文档

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Text;
using System.Web;
using System.Web.Script.Serialization;

namespace com.baidu.ai
{
    public class FaceAdd
    {
        // 人脸注册
		///参数说明：token->之前获取的Access_Token，base64->图片数据，tel->人脸编号
        public static string add(string token,string base64,string tel)
        {
            //string token = "[调用鉴权接口获取的token]";
            string host = "https://aip.baidubce.com/rest/2.0/face/v3/faceset/user/add?access_token=" + token;
            Encoding encoding = Encoding.Default;
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(host);
            request.Method = "post";
            request.KeepAlive = true;

            //将数据写入json字符串中
			Dictionary<String, String> dic = new Dictionary<string, string>();
            dic.Add("image", base64);
            dic.Add("image_type", "BASE64");
			//人脸库里的分组名
            dic.Add("group_id", "Users");
			//这个人脸的编号
            dic.Add("user_id", tel);
			//图片质量检测，Low表示可以接受较低画质的人脸数据
            dic.Add("quality_control", "LOW");
			//活体检测，这里只是一个小Demo，所以没有添加活体检测的功能
            dic.Add("liveness_control", "NONE");
            JavaScriptSerializer js = new JavaScriptSerializer();
            String str = js.Serialize(dic);
            
            byte[] buffer = encoding.GetBytes(str);
            request.ContentLength = buffer.Length;
            request.GetRequestStream().Write(buffer, 0, buffer.Length);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.Default);
            string result = reader.ReadToEnd();
            Console.WriteLine("人脸注册:");
            Console.WriteLine(result);
            return result;
        }
    }
}

3.FaceSearch.cs

主要功能：将从前端获取的Base64格式的人脸图片信息和人脸库中已有的人脸进行对比，匹配的编号和匹配程度（百分制），参考百度云人脸搜索。

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Text;
using System.Web;
using System.Web.Script.Serialization;

namespace com.baidu.ai
{
    public class FaceSearch
    {
        // 人脸搜索
        public static string Search(string token, string strbase64)
        {
            //服务器地址，Access_Token作为凭证
            string host = "https://aip.baidubce.com/rest/2.0/face/v3/search?access_token=" + token;
            Encoding encoding = Encoding.Default;
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(host);
            request.Method = "post";
            request.KeepAlive = true;
            //序列化，生成json字符串
            Dictionary<String, String> dic = new Dictionary<string, string>();
            dic.Add("image", strbase64);
            dic.Add("image_type", "BASE64");
            dic.Add("group_id_list", "Users");
            dic.Add("quality_control", "LOW");
            dic.Add("liveness_control", "NONE");
            JavaScriptSerializer js = new JavaScriptSerializer();
            String str = js.Serialize(dic);

            byte[] buffer = encoding.GetBytes(str);
            request.ContentLength = buffer.Length;
            request.GetRequestStream().Write(buffer, 0, buffer.Length);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.Default);
            string result = reader.ReadToEnd();
            Console.WriteLine("人脸搜索:");
            Console.WriteLine(result);
            return result;
        }
    }
}

主类其实就是上面三个类，但是为了方便从上面三个类返回的json字符串中取值和判断，笔者又添加了两个类

4.SearchReturn.cs

主要功能：实现json的反序列化，这个类文件中的几个类定义了一个数据类型，用于存放FaceSearch返回的json字符串转换成的变量。
其关系是 SearchReturn>Result>User_List

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

/// <summary>
/// SearchReturn 的摘要说明
/// </summary>
namespace com.baidu.ai
{
    public class SearchReturn
    {
        public int error_code { get; set; }
        public string error_msg { get; set; }
        public long log_id { get; set; }
        public int timestamp { get; set; }
        public int cached { get; set; }
        public Result result { get; set; }
    }

    public class Result
    {
        public string face_token { get; set; }
        public User_List[] user_list { get; set; }
    }

    public class User_List
    {
        public string group_id { get; set; }
        public string user_id { get; set; }
        public string user_info { get; set; }
        public float score { get; set; }
    }
}

5.ReturnResultDetect.cs

主要功能：基于FaceAdd和FaceSearch返回的json字符串，获取相应的值并返回相应的标记以帮助业务代码的实现。

（*需要在Nuget中添加Newtonsoft包）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Script.Serialization;
using Newtonsoft.Json.Linq;
using com.baidu.ai;
using Newtonsoft.Json;

/// <summary>
/// ReturnResultDetect 的摘要说明
/// </summary>
namespace com.baidu.ai
{
    public static class ReturnResultDetect
    {
        public static int GetFaceAddReturnResult(string strjson)
        {
            int BackResult = 0;
            SearchReturn feedback = JsonConvert.DeserializeObject<SearchReturn>(strjson);
            if (feedback.result==null)
            {
                BackResult = 0;
            }
            else
            {
                BackResult = 1;
            }
            return BackResult;
        }
        public static string GetFaceSearchReturnResult(string strjson)
        {
            string BackResult ="";
            int score = 0;
            //将收到的json字符串转化成SearchReturn类型的变量，即反序列化
            SearchReturn feedback = JsonConvert.DeserializeObject<SearchReturn>(strjson);
            if (feedback.result==null)
            {
                BackResult = "_0";   //未检测到人脸
            }
            else
            {
                score = Convert.ToInt32(feedback.result.user_list[0].score);
                if (score<80)
                {
                    BackResult = "_1";   //人脸不匹配
                }
                else
                {
                    BackResult = feedback.result.user_list[0].user_id;
                }
            }
            return BackResult;
        }
    }
}

人脸注册

人脸注册的图像获取主要是通过HTML5的Video标签和Canvas标签，原理是将前置摄像头的视频内容放到video中显示，然后通过点击按钮获取点击时刻的video截图，将图片信息放入canvas中保存，并且将图片内容编码为Base64再通过Hiddenfield控件传给后端，实现后端对图片信息的获取。

前端代码

/*<%@ Page Language="C#" AutoEventWireup="true" CodeFile="User_Face_Signup.aspx.cs" Inherits="User_Face_Signup" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <meta charset='UTF-8' />
    <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0,user-scalable=no">
    <title>人脸注册</title>
    <meta name="renderer" content="webkit">
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
    <meta name="viewport" content="width=device-width,user-scalable=yes, minimum-scale=0.4, initial-scale=0.8,target-densitydpi=low-dpi" />
    <link rel="stylesheet" href="./css/font.css">
    <link rel="stylesheet" href="./css/xadmin.css">
    <script type="text/javascript" src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
    <script type="text/javascript" src="./lib/layui/layui.js" charset="utf-8"></script>
    <script type="text/javascript" src="./js/xadmin.js"></script>
    <script type="text/javascript" src="./js/cookie.js"></script>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>
    <form >
        <div>
            <div>
                <%--<div></div>--%>
                <div style="margin-top: 80px; margin-left: 20%;  30%; padding: 10px" class="layui-bg-green">人脸注册</div>
                <div style="margin-left: 20%; margin-top: 20px">
                    <video ></video>
                </div>
                <div style="margin-top: 10px; margin-left: 20%;  70%">
                    <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
                </div>
                    
                <div style="margin-top: 10px; margin-left: 20%;  30%">
                    <asp:Button ID="capture" runat="server" Text="提交并注册" OnClick="capture_Click" class="layui-btn" />
                </div>
                <%--<div style="margin-left: 20%;  70%">
                    <span style="color: #f00; font-size: smaller">
                        <asp:Label ID="Label1" runat="server" Text=""></asp:Label>
                    </span>
                </div>--%>

            </div>
           
        </div>*/
        <!-- 显示MediaStream视频流 -->
        <div>


            <asp:HiddenField ID="HiddenField1" runat="server" />
        </div>
        <div style="display: none">
            <canvas ></canvas>
        </div>

        <script type="text/javascript">


            // 访问用户媒体设备的兼容方法
            function getUserMedia(constraints, success, error) {
                if (navigator.mediaDevices.getUserMedia) {
                    // 最新的标准API
                    navigator.mediaDevices.getUserMedia(constraints)
                        .then(success).catch(error);
                } else if (navigator.webkitGetUserMedia) {
                    // Webkit核心浏览器
                    navigator.webkitGetUserMedia(constraints, success, error);
                } else
                    if (navigator.mozGetUserMedia) {
                        // Firefox浏览器
                        navigator.mozGetUserMedia(constraints, success, error);
                    } else if (navigator.getUserMedia) {
                        // 旧版API
                        navigator.getUserMedia(constraints, success, error);
                    }
            }
            var video = document.getElementById("video");// video元素
            var canvas = document.getElementById("canvas");// canvas元素
            var context = canvas.getContext("2d");

            // 成功的回调函数
            function success(stream) {
                var CompatibleURL = window.URL || window.webkitURL
                video.src = CompatibleURL.createObjectURL(stream);//将视频流设置为video元素的源
                video.play();// 播放视频
            }

            // 异常的回调函数
            function error(error) {
                console.log('访问用户媒体设备失败：', error.name, error.message);
            }

            if (navigator.mediaDevices.getUserMedia || navigator.getUserMedia ||
                navigator.webkitGetUserMedia || navigator.mozGetUserMedia) {
                // 调用用户媒体设备，访问摄像头
                getUserMedia({ video: {  480, height: 320 } }, success, error);
            } else {
                alert('您的浏览器不支持访问用户媒体设备！');
            }

            // 绑定拍照按钮的点击事件
            document.getElementById("capture").addEventListener("click", function () {
                context.drawImage(video, 0, 0, 480, 320);
                // 将video画面在canvas上绘制出来
                var data = canvas.toDataURL('image/png', 1);    
                //将当前显示的图像传到Base64编码的字符串里
                document.getElementById('HiddenField1').value = data;  
                //将上面转换好的Base64编码传到C#的HiddenField里，方便后端取值
            });
	        </script>

    </form>
</body>
</html>

后端代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using com.baidu.ai;
using System.Data;
using System.Data.Sql;
using System.Data.SqlClient;


public partial class User_Face_Signup : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Label1.Text= "<span style='color: #c2c2c2; font-size: x-small'>**请在光线充足的地方录入人脸以提高刷脸登录准确度！**<br />**准备好后点击下方按钮即可录入人脸！**</ span > ";
    }

    protected void capture_Click(object sender, EventArgs e)
    {
        //下面几个从session传过来的值是笔者这个项目里前一个页面的值，可以不看，但是为了保证程序完整性笔者还是将其放了上来
        string name = Session["UserName"].ToString();
        string tel = Session["UserTel"].ToString();
        string password = Session["UserPass"].ToString();
        string email = Session["UserMail"].ToString();

        string PreBase64 = HiddenField1.Value;
        string Base64 = "";
        
        //兼容各种不同的图片格式
        if (PreBase64.Contains("data:image/png;base64,"))
        {
            Base64 = PreBase64.Replace("data:image/png;base64,", "");
        }
        if(PreBase64.Contains("data:image/jpg; base64,"))
        {
            Base64 = PreBase64.Replace("data:image/jpg;base64,", "");
        }
        if (PreBase64.Contains("data:image/jpeg; base64,"))
        {
            Base64 = PreBase64.Replace("data:image/jpeg;base64,", "");
        }
        
        //调用类AccessToken中的getAccessToken方法，获取返回值Access_Token
        //注：Access_Token其实每次取值都可以保留一段时间，但是为了减少不必要的麻烦，笔者这里还是每次都获取新的Access_Token，代价是每次都要多连接一次人脸库，浪费时间
        string Access_Token = AccessToken.getAccessToken();
        //将图片信息和对应人脸编号传入，上传到服务器
        string Face_Add_Return = FaceAdd.add(Access_Token, Base64, tel);
        //获取人脸添加的返回值，1表示添加成功，否则为失败
        int Face_Add_Result = ReturnResultDetect.GetFaceAddReturnResult(Face_Add_Return);
        
        if (Face_Add_Result==1)
        {
            SqlConnection conn = new SqlConnection();
            conn.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionStringProManage"].ConnectionString;
            try
            {
                conn.Open();
                string SQL = "insert into Users (uername,password,usertype,name,tel,email) values (@tel,@password,2,@name,@tel,@email)";

                SqlCommand cmd = new SqlCommand();
                cmd.Connection = conn;
                cmd.CommandType = CommandType.Text;
                cmd.CommandText = SQL;

                //依次添加每个字段的值
                SqlParameter ptel = new SqlParameter("@tel", SqlDbType.VarChar, 11);
                ptel.Value = tel;
                cmd.Parameters.Add(ptel);
                SqlParameter ppassword = new SqlParameter("@password", SqlDbType.VarChar, 20);
                ppassword.Value = password;
                cmd.Parameters.Add(ppassword);
                SqlParameter pname = new SqlParameter("@name", SqlDbType.NVarChar, 10);
                pname.Value = name;
                cmd.Parameters.Add(pname);
                SqlParameter pemail = new SqlParameter("@email", SqlDbType.NVarChar, 30);
                pemail.Value = email;
                cmd.Parameters.Add(pemail);

                int R = cmd.ExecuteNonQuery();  //R 的值就是返回影响表的行数
                if (R > 0)
                {
                    Session["ReturnPath"] = "Move_login.aspx";
                    Session["Message"] = "恭喜，注册成功！";
                    Response.Redirect("Success.aspx");
                }
                else
                {
                    Session["Message"] = "插入失败，请检查您的操作！";
                    Response.Redirect("Error.aspx");
                }
                //Session["ReturnPath"] = "Admin_Add.aspx";
                //Response.Redirect("Mid.aspx");
            }
            finally
            {
                conn.Close();
            }
        }
        else
        {
            Label1.Text = "<span style='color: #f00; font-size: smaller'>**未检测到人脸，请重试！**</span> ";
        }
        
    }
}

人脸搜索

人脸搜索和人脸注册的实现方式是类似的，只不过一个是写（注册），一个是读（搜索）。注册是把人脸信息录入人脸库，并给其分配一个唯一标识号——人脸编号，而搜索就是一个相反的过程，通过上传的人脸与数据库中的人脸对比，返回这个人脸编号和相似度。

前端代码

<%--和人脸注册的代码基本一致-->
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="User_Face_Login.aspx.cs" Inherits="User_Face_Login" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <meta charset='UTF-8' />
    <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0,user-scalable=no"/>
    <title>刷脸登录</title>
    <meta name="renderer" content="webkit"/>
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"/>
    <meta name="viewport" content="width=device-width,user-scalable=yes, minimum-scale=0.4, initial-scale=0.8,target-densitydpi=low-dpi" />
    <link rel="stylesheet" href="./css/font.css"/>
    <link rel="stylesheet" href="./css/xadmin.css"/>
    <script type="text/javascript" src="https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"></script>
    <script type="text/javascript" src="./lib/layui/layui.js" charset="utf-8"></script>
    <script type="text/javascript" src="./js/xadmin.js"></script>
    <script type="text/javascript" src="./js/cookie.js"></script>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>
    <form >
        <div>
            <div>
                <%--<div></div>--%>
                <div style="margin-top: 80px; margin-left: 20%;  30%; padding: 10px" class="layui-bg-green">刷脸登录</div>
                <div style="margin-left: 20%; margin-top: 20px">
                    <video ></video>
                </div>
                <div style="margin-top: 10px; margin-left: 20%;  70%">
                    <asp:Label ID="Label1" runat="server" Text=""></asp:Label>
                </div>
                    
                <div style="margin-top: 10px; margin-left: 20%;  30%">
                    <asp:Button ID="capture" runat="server" Text="登录" OnClick="capture_Click" class="layui-btn" />
                </div>
                <%--<div style="margin-left: 20%;  70%">
                    <span style="color: #f00; font-size: smaller">
                        <asp:Label ID="Label1" runat="server" Text=""></asp:Label>
                    </span>
                </div>--%>

            </div>
           
        </div>
        <!-- 显示MediaStream视频流 -->
        <div>


            <asp:HiddenField ID="HiddenField1" runat="server" />
        </div>
        <div style="display: none">
            <canvas ></canvas>
        </div>

        <script type="text/javascript">


            // 访问用户媒体设备的兼容方法
            function getUserMedia(constraints, success, error) {
                if (navigator.mediaDevices.getUserMedia) {
                    // 最新的标准API
                    navigator.mediaDevices.getUserMedia(constraints)
                        .then(success).catch(error);
                } else if (navigator.webkitGetUserMedia) {
                    // Webkit核心浏览器
                    navigator.webkitGetUserMedia(constraints, success, error);
                } else
                    if (navigator.mozGetUserMedia) {
                        // Firefox浏览器
                        navigator.mozGetUserMedia(constraints, success, error);
                    } else if (navigator.getUserMedia) {
                        // 旧版API
                        navigator.getUserMedia(constraints, success, error);
                    }
            }
            var video = document.getElementById("video");// video元素
            var canvas = document.getElementById("canvas");// canvas元素
            var context = canvas.getContext("2d");

            // 成功的回调函数
            function success(stream) {
                var CompatibleURL = window.URL || window.webkitURL
                video.src = CompatibleURL.createObjectURL(stream);//将视频流设置为video元素的源
                video.play();// 播放视频
            }

            // 异常的回调函数
            function error(error) {
                console.log('访问用户媒体设备失败：', error.name, error.message);
            }

            if (navigator.mediaDevices.getUserMedia || navigator.getUserMedia ||
                navigator.webkitGetUserMedia || navigator.mozGetUserMedia) {
                // 调用用户媒体设备，访问摄像头
                getUserMedia({ video: {  480, height: 320 } }, success, error);
            } else {
                alert('您的浏览器不支持访问用户媒体设备！');
            }

            // 绑定拍照按钮的点击事件
            document.getElementById("capture").addEventListener("click", function () {
                context.drawImage(video, 0, 0, 480, 320);// 将video画面在canvas上绘制出来
                var data = canvas.toDataURL('image/png', 1);
                document.getElementById('HiddenField1').value = data;
            });
	        </script>

    </form>
</body>
</html>

后端代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using com.baidu.ai;

public partial class User_Face_Login : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        Label1.Text = "<span style='color: #c2c2c2; font-size: x-small'>**请保持环境光线充足以提高刷脸登录准确度！**<br />**准备好后点击下方按钮即可登录！**</ span > ";
    }

    protected void capture_Click(object sender, EventArgs e)
    {
        //与上面类似的，获取前端传过来的Base64格式的图片编码
        string PreBase64 = HiddenField1.Value;
        string Base64 = "";
        if (PreBase64.Contains("data:image/png;base64,"))
        {
            Base64 = PreBase64.Replace("data:image/png;base64,", "");
        }
        if (PreBase64.Contains("data:image/jpg; base64,"))
        {
            Base64 = PreBase64.Replace("data:image/jpg;base64,", "");
        }
        if (PreBase64.Contains("data:image/jpeg; base64,"))
        {
            Base64 = PreBase64.Replace("data:image/jpeg;base64,", "");
        }
        //获取Access_Token，同上
        string Access_Token = AccessToken.getAccessToken();
        //获取返回的json字符串
        string feedback = FaceSearch.Search(Access_Token, Base64);
        //从返回的字符串中取值，并根据值给出相应的判断
        string backid = ReturnResultDetect.GetFaceSearchReturnResult(feedback);
        if (backid=="_0")
        {
            Label1.Text = "<span style='color: #f00; font-size: smaller'>**未检测到人脸，请重试！**</span> ";
        }
        else if (backid == "_1")
        {
            Label1.Text = "<span style='color: #f00; font-size: smaller'>**您尚未注册，请注册后登录**</span> ";
            Response.Redirect("Faca_Login_error.aspx");
        }
        else
        {
            Session["Move_Name"] = backid;
            Session["Move_Islogin"] = 2;
            Response.Redirect("Move_User.aspx");
        }
        
    }
}

本文是小弟在学习过程中做的一个小Demo，如有错误或者不当之处还请各位大佬斧正。

转载请注明原文链接。