Is it possible to use a Javascript variable within C# code inside HTML?

Question

I have a collection that I would like to iterate over, which is held in a C# variable.

I would like to iterate over this using a for loop from within Javascript; is this possible?

For example:

@{ int questionCount = 0;
foreach(var q in Model.Questions){ 
questionCount++;
}

...do some HTML...

<script type="text/javascript">
jQuery(function () {


for (var i=1;i<=@questionCount;i++)
{        

    var d1 = @Model.Questions[i].Answers.Where(m => m.Answer == 1).Count(); 
    <-- this is where it breaks -->
}

});

The error I get says that the index is out of range. I guess this means that it doesn't understand 'i' once I've put the @ symbol into the line. How can I delimit the string correctly to use the variable i (from Javascript) to iterate over my C# collection?

Roy Dictus · Accepted Answer · 2012-10-22 09:47:32Z

1

This does not work. You cannot access client-side variables in a server-side code block.

answered Oct 22, 2012 at 9:47

Roy Dictus

33.3k9 gold badges64 silver badges77 bronze badges

Sign up to request clarification or add additional context in comments.

9 Comments

user1711233 Over a year ago

As I thought, thanks for the confirmation. Since I can ask for something like var d1 = @Model.Questions[0].Answers.Where(m => m.Answer == 1).Count(); (i.e. set the index to zero), and since I know the value of that index (from within the loop), is there a way to construct this single line dynamically?

Roy Dictus Over a year ago

You can create some code to run on the server that generates JavaScript (i.e., code that will then run on the client) in a string, then you output that string in your .CSHTML.

user1711233 Over a year ago

That sounds promising. I'm a bit of a newbie to this stuff, would it be C# code that generates Javascript?

Roy Dictus Over a year ago

Yes, C# that generates a string that contains JavaScript. You then output that string in your HTML, for instance by displaying a property @Model.GeneratedCode or whatever you wish to call it.

user1711233 Over a year ago

Looks like I spoke too soon. I'm just getting the script printing in plain text on screen. If I paste this into the .cshtml file then reload, it works. Any ideas why the javascript is just printing in plain text?

|

Asif Mushtaq · Accepted Answer · 2012-10-22 09:47:44Z

0

You can not use server side models in your javascript, These models are relevant only on server side for generating HTML.

If you really need a value in your javascript code then you can put the model's value in some hidden html element.

answered Oct 22, 2012 at 9:47

Asif Mushtaq

13.1k3 gold badges36 silver badges43 bronze badges

1 Comment

user1711233 Over a year ago

Thanks @Asif; can you elaborate on your second sentence? Also, Since I can ask for something like var d1 = @Model.Questions[0].Answers.Where(m => m.Answer == 1).Count(); (i.e. set the index to zero), and since I know the value of that index (from within the loop), is there a way to construct this single line dynamically?

Collectives™ on Stack Overflow

Is it possible to use a Javascript variable within C# code inside HTML?

2 Answers 2

9 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

9 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related