从 ajax 调用 WCF 并收到此错误，加载失败：服务器响应状态为 500 (System.ServiceModel.ServiceActivationException)

Question

I am new to WCF and got stuck and I am pretty sure that,error is in web.config,tried many changes in web.config file to get clear this issue, but it not work and failed to findout,i need help,thanks in advance................................................

web.config

    <configuration>
          <appSettings>
            <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true"/>
          </appSettings>
          <system.web>
<connectionStrings>
    <add name="DBCS" connectionString="server=ddcs; initial catalog=user;integrated security =SSPI"/>
  </connectionStrings>
            <compilation debug="true" targetFramework="4.7.2"/>
            <httpRuntime targetFramework="4.7.2"/>
          </system.web>
          <system.serviceModel>
            <behaviors>
              <serviceBehaviors>
                <behavior name="ServiceBehavior" >
                  <!-- To avoid disclosing metadata information, set the values below to false before deployment -->
                  <serviceMetadata httpGetEnabled="true" httpsGetEnabled="true"/>
                  <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->
                  <serviceDebug includeExceptionDetailInFaults="true"/>
                </behavior>
              </serviceBehaviors>
            <endpointBehaviors>
                <behavior name="ServiceAspNetAjaxBehavior">
                                <enableWebScript/>
                          </behavior>
            </endpointBehaviors>
            </behaviors>
              <services>
              <service name="Service" behaviorConfiguration="ServiceBehavior">
                    <endpoint address="" binding="webHttpBinding" contract="Service" behaviorConfiguration="ServiceAspNetAjaxBehavior">
                        <identity>
                            <dns value="localhost"/>
                        </identity>
                    </endpoint>
                   
                  </service>
                  </services>
            <serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true"/>
          </system.serviceModel>
          <system.webServer>
            <modules runAllManagedModulesForAllRequests="true"/>
            <!--
                To browse web app root directory during debugging, set the value below to true.
                Set to false before deployment to avoid disclosing web app folder information.
              -->
            <directoryBrowse enabled="true"/>
          </system.webServer>
        </configuration>

Service.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel.Activation;
using System.ServiceModel.Web;
using System.Text;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;

[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class Service : IService
{
    public Userdetails[] GetUserdetailsByEmailId(throughEmail e)
    {
        List<Userdetails> userdetails = new List<Userdetails>();

        string cs = ConfigurationManager.ConnectionStrings["DBCS"].ConnectionString;
        using (SqlConnection con = new SqlConnection(cs))
        {
            SqlCommand cmd = new SqlCommand("wcf_ajax_getdata", con);
            cmd.CommandType = CommandType.StoredProcedure;
            SqlParameter parameter = new SqlParameter();
            parameter.ParameterName = "@emailid";
            parameter.Value = e.email;
            cmd.Parameters.Add(parameter);
            con.Open();
            SqlDataAdapter rdr = new SqlDataAdapter(cmd);
            DataTable dtresult = new DataTable();
            rdr.Fill(dtresult);

            if (dtresult.Rows.Count > 0)
            {
                for (int i = 0; i < dtresult.Rows.Count; i++)
                {
                    Userdetails userInfo = new Userdetails();
                    userInfo.First_Name = dtresult.Rows[i]["First_Name"].ToString();
                    userInfo.Middle_Initial = dtresult.Rows[i]["Middle_Initial"].ToString();
                    userInfo.Last_Name = dtresult.Rows[i]["Last_Name"].ToString();
                    userInfo.Email_Id = dtresult.Rows[i]["Email_Id"].ToString();
                    userInfo.Emp_Id = Convert.ToInt32(dtresult.Rows[i]["Emp_Id"].ToString());
                    userInfo.Designation = dtresult.Rows[i]["Designation"].ToString();
                    userInfo.Joining_Date = dtresult.Rows[i]["Joining_Date"].ToString();
                    userInfo.Salary = dtresult.Rows[i]["Salary"].ToString();
                    userInfo.Address = dtresult.Rows[i]["Address"].ToString();
                    userdetails.Add(userInfo);
                }


            }
            return userdetails.ToArray();
        }
    }
}

IService.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;

// NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IService" in both code and config file together.
[ServiceContract]
public interface IService
{    
    [OperationContract]
    [WebInvoke(Method = "POST", RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)]
    Userdetails[] GetUserdetailsByEmailId(throughEmail e);
}

Default.aspx

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body style="font-family:Arial">
    Email ID :
    <input id="txtId" type="text" style="width: 86px" />
    <input type="button" id="btnGetUser" value="Get User" />
    <br /><br />
    <table border="1" style="border-collapse: collapse">
        <tr>
            <td>First Name</td>
            <td><input id="txtName" type="text" /></td>
        </tr>
        <tr>
            <td>Middle Name</td>
            <td><input id="txtmname" type="text" /></td>
        </tr>
        <tr>
            <td>Last Name</td>
            <td><input id="txtlname" type="text" /></td>
        </tr>
    </table>
   
</body>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
      <script type="text/javascript">
      $(document).ready(function () {
          $('#btnGetUser').click(function () {
              throughEmail = {};
              throughEmail.email = $('#txtId').val();
                
                $.ajax({
                    type: "POST",
                    url: "/Service.svc/GetUserdetailsByEmailId",
                    data: JSON.stringify(throughEmail),
                    //contentType: "text/xml; charset=utf-8",
                    contentType: "application/json; charset=utf-8",
                    dataType: "json",                 
                    success: function (data) {
                        $('#txtName').val(data.d.First_Name);
                        $('#txtmname').val(data.d.Middle_Initial);
                        $('#txtlname').val(data.d.Last_Name);
                    },
                    error: function (err) {
                        alert(err);
                    }
                });
            });
        });
    </script>
</html>

Answer 1

According to the code you provided, I made a demo. This is the web.config of the demo:

<configuration>
<appSettings>
    <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true"/>
</appSettings>
<system.web>
    <compilation debug="true" targetFramework="4.7.2" />
    <httpRuntime targetFramework="4.7.2"/>
</system.web>
<system.serviceModel>
    <behaviors>
        <serviceBehaviors>
            <behavior name="ServiceBehavior" >
                <!-- To avoid disclosing metadata information, set the values below to false before deployment -->
                <serviceMetadata httpGetEnabled="true" httpsGetEnabled="true"/>
                <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->
                <serviceDebug includeExceptionDetailInFaults="true"/>
            </behavior>
        </serviceBehaviors>
        <endpointBehaviors>
            <behavior name="ServiceAspNetAjaxBehavior">
                <enableWebScript/>
            </behavior>
        </endpointBehaviors>
    </behaviors>
    <services>
        <service name="ServiceDemo.Service" behaviorConfiguration="ServiceBehavior">
            <endpoint address="" binding="webHttpBinding" contract="ServiceDemo.IService" behaviorConfiguration="ServiceAspNetAjaxBehavior">
                <identity>
                    <dns value="localhost"/>
                </identity>
            </endpoint>

        </service>
    </services>
    <serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true"/>
</system.serviceModel>
<system.webServer>
    <modules runAllManagedModulesForAllRequests="true"/>
    <!--
            To browse web app root directory during debugging, set the value below to true.
            Set to false before deployment to avoid disclosing web app folder information.
          -->
    <directoryBrowse enabled="true"/>
</system.webServer>

I used Postman to test this service, and it sent back data normally.

Answer 2

According to the information you provided, I found that you are using webhttpbinding, but I did not find in your configuration file. If you use webhttpbinding, you must configure in the configuration file.

           <endpointBehaviors>
                <behavior name="ESEndPointBehavior">
                    <webHttp/>
                </behavior>
            </endpointBehaviors>

We need to add to the endpointBehavior.