Solved

How to return complex types like Generics(List<KeyValuePair<string,string>> or Dictionary<string,string>) from WebMethod

Posted on 2007-11-28
8
3,170 Views
Last Modified: 2013-11-19
I am currently working on ASP.NET Web Services and I want to return complex types like System.Collection.Generic class. I tried to return Dictionary<string,string> but this gave me exception. then I tried to return List<KeyValuePair<string,string> objKeyValuePair> but it didnt solve my problem. Can you tell me how can I return complex types. I dont want to serialize my data as this is not my requirement. Thanks in advance for any help or suggestion.
0
Comment
Question by:anwar ul haque
  • 4
  • 3
8 Comments
 
LVL 21

Expert Comment

by:MogalManic
ID: 20364708
Serialization IS a requirement for Web Services.  Every Web method is converted to XML to send across the wire.  So all of the classes have to be able to be represented as XML strings.  The only solution is to create serializable adapters that take the generic class and convert it into something that can be turned into XML strings.  For example This would be an adapter for a KeyValuePair<string, string>:
[Serializable]

public class KeyValuePairSerializable

{
 

     public KeyValuePairSerializable()

}

Open in new window

0
 
LVL 7

Expert Comment

by:Infinite_Recursion
ID: 20364715
As far as I can tell, response of a web service is always in XML, that is why they are called XML Web Services, that means types that are to be returned have to be serializable.
0
 
LVL 21

Expert Comment

by:MogalManic
ID: 20364730
Sorry submitted by mistake.  Here is it again:

Note:You could try to make it a Generic class so that it would work with all types of KeyValuePair<t1, t2>.  I'm not sure how it would work though.
[Serializable]

public class KeyValuePairSerializable

{

     private string _key,_value

     public KeyValuePairSerializable()  //Required for serialization

     {

     }

     public KeyValuePairSerializable(KeyValuePair<string, string> value)

     {

        this._key=value.Key;

        this._value=value.Value;

     }
 

     public string Key {

       get {return _key;}

       set {_key=value;}

     }

     public string Value {

       get {return _value;}

       set {_value=value;}

     }

     

}

Open in new window

0
 
LVL 21

Expert Comment

by:MogalManic
ID: 20364867
I just did a test and List<T> is serializable, but I could not get List<KeyValuePair<string,string>> to work.  Dictionary<string,string> is NOT XML serializable because it implements IDictionary.  But I got List<KeyValuePairSerializable> to work.
    [WebMethod]

    public List<KeyValuePairSerializable> HelloWorld()

    {

        Dictionary<string, string> hello = new Dictionary<string, string>();

        hello.Add("hello", "world");

        hello.Add("world", "hello");
 

        List<KeyValuePairSerializable> list=new List<KeyValuePairSerializable>();

        foreach (KeyValuePair<string, string> item in hello)

        {

            list.Add(new KeyValuePairSerializable(item));

        }

        return list;

    }

Open in new window

0
Enabling OSINT in Activity Based Intelligence

Activity based intelligence (ABI) requires access to all available sources of data. Recorded Future allows analysts to observe structured data on the open, deep, and dark web.

 
LVL 2

Author Comment

by:anwar ul haque
ID: 20365516
How can I use this class within my web service. My method's return value is List<KeyValuePair<string,string>>.
0
 
LVL 21

Accepted Solution

by:
MogalManic earned 500 total points
ID: 20365651
You will have to either create a new method or change the signature so that it returns List<KeyValuePairSerializable>.  Just like I did in my HelloWorld webmethod
0
 
LVL 2

Author Comment

by:anwar ul haque
ID: 20366253
Thank you mates, finally I got desired results.
0
 
LVL 2

Author Comment

by:anwar ul haque
ID: 20366332
while I was searching for the solution I could not find the answer so that's why I asked my question here.For me points are not issue I got solution and I'm very happy and thakful to these gentlemen.

Thanks.
0

Featured Post

Highfive + Dolby Voice = No More Audio Complaints!

Poor audio quality is one of the top reasons people don’t use video conferencing. Get the crispest, clearest audio powered by Dolby Voice in every meeting. Highfive and Dolby Voice deliver the best video conferencing and audio experience for every meeting and every room.

Join & Write a Comment

Preface This is the third article about the EE Collaborative Login Project. A Better Website Login System (http://www.experts-exchange.com/A_2902.html) introduces the Login System and shows how to implement a login page. The EE Collaborative Logi…
What is Node.js? Node.js is a server side scripting language much like PHP or ASP but is used to implement the complete package of HTTP webserver and application framework. The difference is that Node.js’s execution engine is asynchronous and event…
The viewer will learn how to create and use a small PHP class to apply a watermark to an image. This video shows the viewer the setup for the PHP watermark as well as important coding language. Continue to Part 2 to learn the core code used in creat…
The viewer will learn how to create a basic form using some HTML5 and PHP for later processing. Set up your basic HTML file. Open your form tag and set the method and action attributes.: (CODE) Set up your first few inputs one for the name and …

706 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

16 Experts available now in Live!

Get 1:1 Help Now