Javascript从Web服务获取数据

Question

I am new to web app development I am trying to make a log in page and get the data of user from a local database using javascript. But I am having trouble finding where I did something wrong. Here is my javascript code

$(document).ready(function () {

$("#log-in-form").on("submit", function (e) {
    e.preventDefault();

    var username = $(this).find("input[type=text]").val();
    var password = $(this).find("input[type=password]").val();

    Authentication(username, password);

});

function Authentication(username,password){
    $.ajax({

        type: "GET",
        url: "../Web Service/LogIn.asmx/get_uinfos",
        data: "{'domain':" + username + "', 'accountpassword':'" + password + "'}",
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: function (response) {
            var result = response.d;
            var length = response.length;

            $.each(result, function (index, data) {
                var alias = data.alias;
                window.localStorage.replace("Main.aspx");
            });
        },
        error: function () {
            alert('Function Error "get_uinfos"')
        }
    });
}



});

and I am connecting to the local server using web service using these code

using Wishlist_2017;
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Web.Script.Services;
using System.Web.Services;


namespace Wishlist_2017.Web_Service
{
    /// <summary>
    /// Summary description for LogIn
    /// </summary>
    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
    // [System.Web.Script.Services.ScriptService]
    public class LogIn : System.Web.Services.WebService
    {
        dbconn dbcon = new dbconn();

        public class uinfos
        {
            public int id;
            public string alias;
            public string monito;
        }

        static List<uinfos> _get_uinfos = new List<uinfos> { };
        [ScriptMethod(ResponseFormat = ResponseFormat.Json)]
        [WebMethod]
        public List<uinfos> get_uinfos(string domain, string accountpassword)
        {
            DataTable table = null;
            SqlCommand cmd = new SqlCommand();

            cmd.CommandText = "Retrieve_UserInfo";

            cmd.Parameters.AddWithValue("@Domain", domain);
            cmd.Parameters.AddWithValue("@Password", accountpassword);

            cmd.CommandType = System.Data.CommandType.StoredProcedure;
            table = this.dbcon.ExecuteDataTable(cmd);

            _get_uinfos.Clear();

            foreach (DataRow row in table.Rows)
            {
                uinfos _list = new uinfos();

                _list.id = Convert.ToInt32(row["id"]);
                _list.alias = row["Alias"].ToString();
                _list.monito = row["Monito"].ToString();

                _get_uinfos.Add(_list);
            }

            return _get_uinfos;
        }
    }
}

but upon trying to log in by filling the username and password I encounter this error on the console

can someone help where to look it will be much appreciated

EDIT 1:

This is the code for the class of server

    using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Web;

namespace Wishlist_2017
{
    public class dbconn
    {
        string objConn = ConfigurationManager.ConnectionStrings["Server"].ToString();

        public dbconn()
        {
            //
            // TODO: Add constructor logic here
            //
        }

        public DataTable ExecuteDataTable(SqlCommand cmd)
        {
            DataTable dt = new DataTable();

            using (SqlConnection cn = new SqlConnection(objConn))
            {
                try
                {
                    cn.Open();
                    cmd.Connection = cn;
                    cmd.CommandTimeout = 1000;

                    SqlDataAdapter da = new SqlDataAdapter(cmd);

                    da.Fill(dt);
                }
                catch (Exception ex)
                {
                    throw ex;
                }
                finally
                {
                    if (cn.State != System.Data.ConnectionState.Closed)
                        cn.Close();
                }

                return dt;
            }
        }

        public void ExecuteNonQuery(SqlCommand cmd)
        {
            using (SqlConnection cn = new SqlConnection(objConn))
            {
                try
                {
                    cn.Open();
                    cmd.Connection = cn;
                    cmd.CommandTimeout = 1000;
                    cmd.ExecuteNonQuery();
                }
                catch (Exception ex)
                {
                    throw ex;
                }
                finally
                {
                    if (cn.State != System.Data.ConnectionState.Closed)
                        cn.Close();
                }
            }
        }


        public object ExecuteScalar(SqlCommand cmd)
        {
            object result = null;

            using (SqlConnection cn = new SqlConnection(objConn))
            {
                try
                {
                    cn.Open();
                    cmd.Connection = cn;
                    cmd.CommandTimeout = 1000;
                    result = cmd.ExecuteScalar();
                }
                catch (Exception ex)
                {
                    throw ex;
                }
                finally
                {
                    if (cn.State != System.Data.ConnectionState.Closed)
                        cn.Close();
                }
            }

            return result;
        }
    }
    }

the connection string is defined on my web.config

EDIT 2:

This is the connection string on my web.config

<connectionStrings>
  <add name="Server" connectionString="Data Source=(LocalDB)\ArnServer; initial Catalog=Wishlist; uid=sa; pwd=ordiz@2017!; Asynchronous Processing=true" providerName="System.Data.SqlClient"/>
</connectionStrings>

Answer 1

This is a tricky one. It took me some time to realize the issue. The error said it can't create an instance of the Wishlist_2017.Web_Service.LogIn . The files you supply seem to indicate it is there where it should be and the file seems okay.

However, in the constructor context, there is this call: dbconn dbcon = new dbconn(); . If that one fails, it might cause the type creation to fail in a not very specific way.

Analyzing further, it seems that the dbconn file has a similar way of initializing the connection:

string objConn = ConfigurationManager.ConnectionStrings["Server"].ToString();

If that one fails, the creation of dbconn will fail and the LogIn will fail subsequently. It seems the connection string has another name or there is some configuration invalid.

Try to see if removing the objConn initialization from dbconn solves the type creation problem.

Answer 2

Very subtle issue but your connection string line is the problem ie

string objConn = ConfigurationManager.ConnectionStrings["Server"].ToString();

ConnectionStrings['xxx'] returns an object and not the string itself, you want

string objConn = ConfigurationManager.ConnectionStrings["Server"].ConnectionString; 

Answer 3

Never ever manually create json. It is more time consuming and error prone than using a json serializer in whatever language you are working with.

What you are creating is invalid due to improper quotes!

Use JSON.stringify() on an object instead

data: JSON.stringify({'domain': username , 'accountpassword':  password }),