ASP.NET Returning JSON with ASHX

Question

I am creating autocomplete functionality for my website. So far, the javascript part is over. Also, I can get the MembershipUser object of the user that matches.

I need to return JSON in the following format:

{
 query:'Li',
 suggestions:['Liberia','Libyan Arab Jamahiriya','Liechtenstein','Lithuania'],
 data:['LR','LY','LI','LT']
}

and this is the code in ashx:

public void ProcessRequest (HttpContext context) {
    System.Web.Script.Serialization.JavaScriptSerializer JsonSerializer;   
    string query = context.Request.QueryString["query"];
    System.Web.Security.MembershipUserCollection Users = System.Web.Security.Membership.GetAllUsers();
    context.Response.ContentType = "application/json";
    foreach (System.Web.Security.MembershipUser User in Users)
    {
        if (User.UserName.StartsWith(query.ToLower()))
        {
            context.Response.Write(query + Environment.NewLine);
            context.Response.Write(User.Email);
        }
    }
}

How can I return the json in the desired format? Thanks.

That is not valid JSON by the way. See: json.org

ChaosPandion
– ChaosPandion

2011-12-05 21:55:59 +00:00
Commented Dec 5, 2011 at 21:55 — ChaosPandion
– ChaosPandion, Commented Dec 5, 2011 at 21:55
ChaosPandion, the plugin requires this output... :/

user1027620
– user1027620

2011-12-05 22:06:39 +00:00
Commented Dec 5, 2011 at 22:06 — user1027620
– user1027620, Commented Dec 5, 2011 at 22:06

L.B · Accepted Answer · 2011-12-05 22:44:03Z

39

context.Response.Write(
    jsonSerializer.Serialize(
        new
        {
            query = "Li",
            suggestions = new[] { "Liberia", "Libyan Arab Jamahiriya", "Liechtenstein", "Lithuania" },
            data = new[] { "LR", "LY", "LI", "LT" }
        }
    )
);

answered Dec 5, 2011 at 22:44

L.B

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Comments

SWeko · Accepted Answer · 2013-10-02 09:57:57Z

28

This helps me:

using System;
using System.Data;
using System.Web;
using System.Linq;
using System.Collections;
using Newtonsoft.Json;

public class Handler : IHttpHandler {

public void ProcessRequest (HttpContext context) {
    context.Response.ContentType = "application/json";
    string quer = context.Request["query"];

    DataTable _t = AMC.Core.Logic.Root.Storage.ExecuteQuery("SELECT [tag_name] FROM [tags] Where [tag_name] like '%' + @ke + '%'", new System.Data.SqlClient.SqlParameter("ke", quer));

    DataRow[] list = new DataRow[_t.Rows.Count];
    _t.Rows.CopyTo(list, 0);

    var wapper = new { 
        query = quer
        , suggestions = (from row in list select row["tag_name"].ToString()).ToArray()
        //, data = new[] { "LR", "LY", "LI", "LT" } 
    };
    context.Response.Write(JsonConvert.SerializeObject(wapper));            
}

Newtonsoft.Json will be found here: http://json.codeplex.com/releases/

edited Oct 2, 2013 at 9:57

SWeko

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answered Feb 17, 2012 at 9:49

BigMan

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1 Comment

Mike Gledhill Over a year ago

Just to add, in IE8 (only?) this will fail when its called. A dialog will popup asking if you want to open or save the file "handler.ashx". To resolve this, change the line of code to return text: context.Response.ContentType = "text/html";

Tim Hoolihan · Accepted Answer · 2011-12-05 21:58:31Z

6

Create a class that has a contract based on the return you want, and then use the JSONSerializer on an instance of that class to create your return content

[DataContract]
public class YourReturnObject {
  [DataMember(Name="query")]
  public String Query { get;set;}

  [DataMember(Name="suggestions")]
  public String[] Suggestions { get;set;}  

  [DataMember(Name="data")]
  public String[] OtherData{ get;set;} 
}

answered Dec 5, 2011 at 21:58

Tim Hoolihan

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1 Comment

user1027620 Over a year ago

Hi, thanks for the answer. Could you please explain a bit how this is implemented in the for loop?

Al W · Accepted Answer · 2011-12-05 22:03:50Z

5

your json is a little awkward since you have to maintain an index into both of those array. might I suggest something more like this?

{
query: 'Li',
data: [{id:'LR', text:'Liberia'}, {id:'LY', text:'Libyan Arab Jamahiriya'}, ...]
}

answered Dec 5, 2011 at 22:03

Al W

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