how to acces list object inside javascript funtion asp.net

Question

this is my list in c# view

@model SmartFeedBackModel.Models.Question;
@{
ViewData["Title"] = "Index";
}

@{
List<SmartFeedBackModel.Models.Question> list = ViewBag.Questions;

 }

this is my java script function

var i = 0;
    var qustid = 0 ;
    function aaa() {
        var a = @list[0].Answer1;
        alert(a);
        qustid = 22;
        i = i + 1;
    }

cannot assign value to variable a

both list and the js function are on the same view.so i need to get the list elements inside the js function and after that will display one by one manually by button click..if you have a better solution,let me know.thanks in advanced — sandun
– sandun, Commented Jan 18, 2018 at 6:00
if you able to show an alert this element "@list[0].Answer1" .its better — sandun
– sandun, Commented Jan 18, 2018 at 6:04
@NightOwl888 Not actually, the list value will be generated and inserted to html (if the script in same view). sandun If you open your browsers console, you should see there error, which will look something like this ReferenceError: <Answer1 value> is not defined. — SᴇM
– SᴇM, Commented Jan 18, 2018 at 6:06

Prajwal · Accepted Answer · 2018-01-18 07:25:13Z

2

You cannot use C# Objects directly in JavaScript. What you are trying to do is something like this.

On Server
--> Get the object & assign it to list.
--> create a script where line is var a = value of @list[0].Answer1

On Client 
--> Try to run  a = value of @list[0].Answer1

This doesn't work. Instead, you need to parse the list to JSON or JS Array. So, it will be something like this.

var jsList = JSON.parse('@Html.Raw(Json.Serialize(list))');
var i = 0;
var qustid = 0;
    function aaa() {
        var a = jsList[i].Answer1;
        alert(a);
        qustid = 22;
        i = i + 1;
    }

I'm assuming you need all the answers on client side and after calling aaa() you need to display next answer.

This is for converting C# array to JS Array.

How do I convert a C# List<string[]> to a Javascript array?

Edit: Json.Encode is not supported in .NET Core. Instead use Json.Serialize()updated the above code.

edited Jan 18, 2018 at 7:25

answered Jan 18, 2018 at 6:15

Prajwal

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7 Comments

SᴇM Over a year ago

You can use c# objects in JS, if he add quotes '' or "" it will work fine, but anyway, it is not the best way to achieve that.

Prajwal Over a year ago

@SeM I know, I think what he want is that entire object. Not just one value.

93Ramadan Over a year ago

I recommend this answer, its best to load the data to the client side then do whatever needs to be done on the JavaScript side. To be quiet frank, try reducing razor code to avoid slowness in rendering the page (since it is server side) - which is my biggest issue that I am facing with razor.

SᴇM Over a year ago

The best solution would be, if he will create a proper View Model, then use its values.

sandun Over a year ago

there is an error in Json.Encode .what should i do to avoid it

|

Anthony McGrath · Accepted Answer · 2018-01-18 06:03:58Z

0

Try changing @list[0].Answer1 to '@list[0].Answer1'

This will allow you to assign string razor values to a javascript variable.

answered Jan 18, 2018 at 6:03

Anthony McGrath

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1 Comment

sandun Over a year ago

var i =0 ; function aaa() { a = '@list[i].QuestionID'; alert(a); i = i + 1; } //here i need increment the i value..but error occurs saying name 'i' does not exist in the current context.plz hlp if you knok

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