C# WebMethod retuen List

Question

I want to return List in my web method like below,

public List<Object> MyMethod(){

List<Object> list = new List<Object>();
myClass a = new myClass();
list.Add(a);

return list;

}

public class myClass{
public int StudetNumber {get; set;}
public string StudentName {get; set;}
public decimal average {get; set;}
}

But i get this error : System.InvalidOperationException : myClass is not expected. System.Xml.Serialization.XmlSerializationWriter.WriteTypedPrimitive(string name, string ns, Object o , Boolean xsiType);

I don't get the error when it returns List of myClass. It is possible to return List of System.Object or Do I have to return List of myClass ?

Thanks for advance.

I have just tested your code and seems to work fine... You are just missing a ";" next to "set" in your myClass class.. Take a look to this fiddle https://dotnetfiddle.net/dbaro4 — Brank Victoria, Oct 11 '18 at 07:48
Is your `myClass` class decorated with the `[Serializable]` attribute? — Matthew Watson, Oct 11 '18 at 07:51
Now it is unclear to me, you sid that you want to return a list. But then you just said "I don't get the error when it returns List. It is possible to return List or Do I have to return List ?" It is not that clear to me when the error appears. — Brank Victoria, Oct 11 '18 at 08:06
What error do you get then? The previous code would result in a compiler error.. — Tobias Moe Thorstensen, Oct 11 '18 at 08:07
@BrankVictoria Ok, I mean I want to return list of System.Object. When i try it, i get the error written in question. But when i return list of MyClass i don't get the error. It is possible to return List of System.Object or am i able to return a only specified type object like myClass in Webmethods ? — asyaben, Oct 11 '18 at 08:11

score 0 · Answer 1 · answered Oct 11 '18 at 07:48

0

you are missing the reserved word 'class' in your class definition you are missing a few ';'s

  public class myClass
    {
        public int StudetNumber { get; set; }
        public string StudentName { get; set; }
        public decimal average { get; set; }
    }

answered Oct 11 '18 at 07:48

jazb

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Hi, thanks for your answer but i wrote the question in mobile phone and i forgot the things you sad :) Normally in project myClass is the like you wrote above. – asyaben Oct 11 '18 at 07:56

score 0 · Accepted Answer · edited Oct 21 '18 at 13:26

It seems that I understand now your question. It seems that it is not compatible returning a generic type such as "Object" or List<Object> in a web method, because in a web method you'll have an XML definition (WSDL) and there is no way to define a generic type in that definition. So it seems that you need to always return a defined class, in your case "myClass".

Take a look to the following post where this topic was talked so it would be a little bit more clear for you:

How do I return a C# web service that has a generic property?

2 Answers2