outside the bounds of the array when add new method to web service

Question

User2108892867 posted

Hello everyone, I have tested for a couple of hours now and still can't figure out why my web service.asmx is not working. I kept getting this error:

System.IndexOutOfRangeException: Index was outside the bounds of the array

Here is my service:

[WebMethod(EnableSession = true)]
        public void selectMyTest()
        {
            if (Session["user_id"] != null)
            {
                ....
                Context.Response.Write(JsonConvert.SerializeObject(events));
            }
        }

This is working but the moment I added method to my service, I got the above error.

[WebMethod(EnableSession = true)]
        public string addUser(MyUser pro)
        {
            string user_id = "";
            if (Session["user_id"] != null)
            {
                ....
            }

            return user_id;
        }

Any ideas why? I have other webservices which I can add as many methods as I want. But this one seems very odd. What did I do wrong? Thanks

Answer 1

User753101303 posted

Hi,

Where does it happen? The stack trace could help.

Not directly related but rather than having explicit serialization/deserialization code and writing to Response, you can write a web service method that gets object arguments and return object as done usually (and ASP.NET handles all that behind the scene for you).

Answer 2

User-1716253493 posted

to avoid error, when read an array check that array count greater than index

        if(arr.Count()>i)
        {
            string x = arr[i];
        }

Answer 3

User2108892867 posted

I did some research and found quite a lot of people having this issue. This is the error I got:

System.IndexOutOfRangeException: Index was outside the bounds of the array.
   at System.Web.Services.Protocols.HttpServerType..ctor(Type type)
   at System.Web.Services.Protocols.HttpServerProtocol.Initialize()
   at System.Web.Services.Protocols.ServerProtocolFactory.Create(Type type, HttpContext context, HttpRequest request, HttpResponse response, Boolean& abortProcessing)

This post has very similar issue

https://stackoverflow.com/questions/15772812/nullable-param-in-asmx-service-method-causes-other-method-to-fail

For me, it errors out when I added a service with a parameter which is a class I created. So this won't work.

[WebMethod(EnableSession = true)]
        public string addUser(MyUser pro)
        {
            string user_id = "";
            if (Session["user_id"] != null)
            {
                ....
            }

            return user_id;
        }

But if I changed it to this by changing the parameter to string 

[WebMethod(EnableSession = true)]
        public string addUser(String test)
        {
            string user_id = "";
            if (Session["user_id"] != null)
            {
                ....
            }

            return user_id;
        }

Then it will work. Or if I remove the parameter completely:

[WebMethod(EnableSession = true)]
        public string addUser()
        {
            string user_id = "";
            if (Session["user_id"] != null)
            {
                ....
            }

            return user_id;
        }

The weird thing is my js script is not even calling the addUser method. Why does this method matter? Secondly, I have other methods in a different asmx file that is using the class I created as parameter and it's working fine. So what is actually causing this?

Answer 4

User475983607 posted
The error is related to accessing an array or collection index that does not exist. There is no indication of an array or collection in the posted code. I assume you are not showing the code that is causing the error. Commonly the stack trace shows the file, class, and line of code that caused the error. Is there anyway you can post the relavent code?

Answer 5

User2108892867 posted

Hello mgebhard, thanks for your reply. I could actually put the code in there but the error is not in my code. Here is another post that has the same problem like mine. 

https://social.msdn.microsoft.com/Forums/en-US/a4918045-4d95-44c6-9b6f-03002028589c/index-out-of-range-when-trying-to-call-webservice?forum=asmxandxml

And one solution suggested in the post through this link http://rebelheart.squarespace.com/blog/2007/6/6/5-hours-later-and-hello-world-saves-the-day.html is put the hello function back in the webservice. Here is the function

  [WebMethod]
        public string HelloWorld()
        {
            return "Hello World";
        }

After I did that, it's working fine. 

So what is actually causing this behavior in the webservice? 

Thanks

Answer 6

User475983607 posted

If you can post code that reproduces the issue, someone will be able to provide an explanation.  I can only guess that you have some naming conflicts that causes an issue with the proxy code generator.  Like naming a return type or input type the same as a method or an object model that has a similar design issue.

Perhaps post your proxy "reference.cs" file so we can see what the code looks like.  

Answer 7

User-893317190 posted

Hi asplearning,

Don't know how you call your webserver.

As you said, if you have another method using customized class as  parameter.

The method returning void will not work.

One way is to change your method which returns void to a method returning string.

Another way is  to change the way you call your webmethod.

Below is my webservice.

  public class ArgumentTest : System.Web.Services.WebService
    {

        [WebMethod(EnableSession =true)]
        public void selectMyTest()
        {
           

          // do nothing
            
        }
        [WebMethod(EnableSession = true)]
        public string addUser(Student stu)
        {
            return "success";
        }

    }
    public class Student
    {
        public string Name { get; set; }
        public int Age { get; set; }
    }
}

If  I  call my method selectMyTest as follows. It will cause the error.

 $.ajax({

            url: ' /Services/ArgumentTest.asmx/selectMyTest',
            type: "post",
            dataType: "json",
          
           
    success: function (data) {
         console.log(data);
    }
              
                });

But if I change my method to  (just add  contentType: "application/json; charset=utf-8",)

 <script>
        $.ajax({

            url: ' /Services/ArgumentTest.asmx/selectMyTest',
            type: "post",
            dataType: "json",
           contentType: "application/json; charset=utf-8",
           
    success: function (data) {
         console.log(data);
    }
              
                });
    </script>

It could be called normally.

Best regards,

Ackerly Xu

Answer 8

User2108892867 posted

Thanks for your reply. This is how I called my webservice:

 return $http.get(
                   myWebServiceUrl,
                       {
                           params: { start: start, end: end }
                       }
                );

I tried by removing the hello function added the 

Ackerly Xu

contentType: "application/json; charset=utf-8",

But still the same error. After I put the hello function back, it's working fine. Can't really understand why it's doing that. Looks like naming conflict or something. 

Answer 9

User-893317190 posted

Hi asplearning,

It seems you are using angular.js.

Angular.js will deal with content-type in a special way.

So maybe the content type is still not set, you could open F12 to see the request header.

Please refer to the link below to learn how to set Conent-Type in angular.js.

https://stackoverflow.com/questions/16194442/angular-content-type-is-not-being-sent-with-http

Best regards,

Ackerly Xu

Answer 10

User-1716253493 posted

Im not sure, seem like the result need to be splited into an array

Can you provide user_id with valid value when session is null?

Maybe something like user_id =","