I have a WebForms application in wich I store array of strings in Session object and I need to get this array in javascript code. Maybe someone can provide any solution, how should i do this?
Here is my code:
function loadAnswers() {
var answers = '<%=Session("answers")%>';
}
but is doesn't work and answerss variable contain simple string after assignment. ('System.String[]')
If you serialize the answers object to JSON, then you should be able to access it programatically from JavaScript.
var answers = <%= new System.Web.Script.Serialization.JavaScriptSerializer().Serialize(Session("answers")) %>;
UPDATE: Below is a working example using four different types of data (string, number, collection, object). This illustrates how JSON serialized from the server can be used as a JavaScript object literal client-side.
Code-behind:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebFormsTestApp
{
public partial class _Default : Page
{
protected string Name = "Alice Student";
protected decimal GPA = 3.84M;
protected List<string> Classes = new List<string>() { "World History", "Algebra II", "English", "Phys Ed", "Latin I", "Home Economics" };
protected School School = new School() { Name = "Jefferson High School", County = "Hamilton County", Ranking = 5 };
}
public class School
{
public string Name { get; set; }
public string County { get; set; }
public int Ranking { get; set; }
}
}
ASPX:
<%@ Page Title="Home Page" Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="WebFormsTestApp._Default" %>
<script type="text/javascript">
var name = <%= new System.Web.Script.Serialization.JavaScriptSerializer().Serialize(Name) %>;
var gpa = <%= new System.Web.Script.Serialization.JavaScriptSerializer().Serialize(GPA) %>;
var classes = <%= new System.Web.Script.Serialization.JavaScriptSerializer().Serialize(Classes) %>;
var school = <%= new System.Web.Script.Serialization.JavaScriptSerializer().Serialize(School) %>;
alert(name + ' goes to ' + school.Name + ', has a ' + gpa + ' GPA, and takes ' + classes.length + ' classes.');
</script>
(I assume u use VB) You can use a code like this:
function loadAnswers() {
var answers = ['<%= String.Join("','", CType(Session("answers"), String()))%>'];
}
It actually joins your array into a string, that is formatted into JS array representation.
So for example if you have an array like this
Session("answers") = New String() {"aaa", "bbb", "ccc"}
It will prodice a line like this
var answers = ['aaa','bbb','ccc'];
Which will be a real JS array. If you need a simple string instead, you can use
var answers = '<%= String.Join(",", CType(Session("answers"), String()))%>';
which will produce
var answers = 'aaa,bbb,ccc';
New String() {"Mixed O'quotes ""succeeded"""}. Generating correct JS/HTML/XML with string concatenation is major pain - try not to do so.