如何解决System.NullReferenceException

Question

I am calling a web service in my php page. The web services are in C#. When I try to call a method using soap client object, it displays me error like:

System.NullReferenceException: Object reference not set to an instance of an object.

The code I use to call Web service method is :

 $Username = "username";
 $Password = "password";
 $LifetimeRequest = 60*60*24;


$soap_data = array(
   'Username' => $Username,
   'Password' => $Password,
   'LifetimeRequest' => $LifetimeRequest
);
$client = new SoapClient('http://50.56.173.161:8502/AdomniService.svc?wsdl');
$response = $client->ClientLogin($soap_data);
var_dump($response);

When I use var_dump it shows output like:

object(stdClass)#2 (1) {
  ["ClientLoginResult"]=>
  object(stdClass)#3 (3) {
    ["Error"]=>
    object(stdClass)#4 (5) {
      ["Private"]=>
      float(2)
      ["Public"]=>
      int(1)
      ["Details"]=>
      string(284) "System.NullReferenceException: Object reference not set to an instance of an object.
   at Adomni.AdomniService.ClientLogin(ClientLoginRequest request) in C:\Users\megiddo\Documents\Visual Studio 2010\Projects\Adomni\AdOmniAPIService\AdomniService\AdomniClientService.svc.cs:line 107"
      ["ErrorCode"]=>
      int(0)
      ["ErrorMessage"]=>
      NULL
    }
    ["Status"]=>
    int(-1)
    ["Token"]=>
    object(stdClass)#5 (8) {
      ["Private"]=>
      float(2)
      ["Public"]=>
      int(1)
      ["EventNotificationUri"]=>
      NULL
      ["IsManager"]=>
      bool(false)
      ["LifetimeRequest"]=>
      int(0)
      ["Password"]=>
      NULL
      ["TokenId"]=>
      int(0)
      ["UserName"]=>
      NULL
    }
  }
}

Can anyone tell me what am I doing wrong here? Thanks in advance.

The code which was used in C# is like:

using System; 
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Web.Security;
using System.IO;
using System.Data;
using AdOmniWebPortal.AdOmniService;

namespace AdOmniWebPortal
{
    public partial class Login : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
        }

        protected void AdOmniLogin_Authenticate(object sender, AuthenticateEventArgs e)
        {
            AdomniServiceClient Client = new AdomniServiceClient();
            LoginRequest LoginRequest = new LoginRequest();
            LoginResponse LoginResponse = new LoginResponse();

            LoginRequest.Username = AdOmniLogin.UserName;
            LoginRequest.Password = AdOmniLogin.Password;
            LoginRequest.LifetimeRequest = 60*60*24;
            //This guy will be changed
            LoginRequest.EventNotificationURL = new Uri("http://herp-a-derp.com/awesome.html");

            LoginResponse = Client.Login(LoginRequest);

            if (LoginResponse.Status == 0)
            {
                System.Web.Security.FormsAuthentication.RedirectFromLoginPage(LoginResponse.Token.UserName, true);
                LifetimeToken token = LoginResponse.Token;
                Session["Token"] = token;

                GetUserRequest request = new GetUserRequest() { Token = token };
                GetUserResponse response = Client.GetUser(request);

                if (response.GetUser.Type == AdOmniService.UserType.Seller)
                {
                    Response.Redirect("~/Pages/Seller/SellerHomeDashboard.aspx");
                }

                if (response.GetUser.Type == AdOmniService.UserType.Client)
                {
                    Response.Redirect("~/Pages/Buyer/BuyerHomeDashboard.aspx");
                }

                if (response.GetUser.Type == AdOmniService.UserType.None)
                {
                    Response.Redirect("~/Pages/Buyer/BuyerHomeDashboard.aspx");
                }
            }
            else
            {
                Response.Redirect("~/Login.aspx");
                Response.Write(LoginResponse.Error.ErrorMessage);
            }
        }
    }
}

I have put the whole .cs page content in Edit.

Answer 1

Use Fiddler (a http debug proxy)

that will allow you to peak inside of the request being made to the web service (in xml format)

so you can see if you are missing anything.

channel your c# client through fiddler, and take a look

http://www.fiddler2.com/fiddler2/

Answer 2

Maybe in your PHP script, you should also set the EventNotificationURL variable.

Take a look at this section in the error response:

  ["EventNotificationUri"]=>
  NULL

Maybe the service expects you to pass in a EventNotificationUri value, just like you pass in the the Password , Username and LifetimeRequest .

[EDIT]

Try to change your variable name from Username to UserName . As far as I found out, PHP should be case sensitive in this matter, so "Username" != "UserName"