passing variables from cs file to aspx file (to javascript) using visual studio 2012

Question

My website is on WPF project. I want to pass a string from my cs file:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page
{
    public string strHello = "Hello World!";
    protected void Page_Load(object sender, EventArgs e)
    {

    }
}

To my website:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html>

<html>
<head id="Head1" runat="server">
<script type="text/javascript">var jsstrHW = '<%=strHW%>'; alert("jsstrHW = " + jsstrHW);</script>
</head>
<body>
</body>
</html>

The output from alert method:

jsstrHW = <%=strHW%>

Please guide me how to do it right. Thanks a lot, Orian.

EDIT: I tried:

ScriptManager.RegisterStartupScript(this, this.GetType(), "someID", "alert('This pops up');", true);

and it didn't work as well. I copied only my aspx file and his cs file to other folder, then I closed my solution and created new one with those files. Everything worked on Google Chrome! So.. my code is probably right, but something in my solution ruin my website. what can it be? As I said before - I need that website for WPF app and not for Google Chrome (or Mozilla Firefox, etc.).

Thanks again, Orian.

Possible duplicate [passing variable values from c# to javascript](http://stackoverflow.com/questions/20849272/passing-variable-values-from-c-sharp-to-javascript) — Izzy, Nov 17 '14 at 09:55
dazzling kumar, I searched passing variables from cs to js and i found that. lzzy, i'm not using a seperate js file so it's not a duplicate, but i'll try to use the serialize way and RegisterClientScriptBlock way. — Orian Zinger, Nov 18 '14 at 10:37

yogi970 · Answer 1 · 2014-11-19T05:05:01.780

0

You access the c# variable in JS like this

<script>
     var jsstrHW = "<%=this.strHello %>";
     alert("jsstrHW = "+jsstrHW);
</script>

Here strHello is the variable name on cs page.

Suggestion you can use RegisterClientScriptBlock

Update you can try like this

 <script>
      var jsstrHW = <%= "'" + strHello + "'"%>;
     alert(jsstrHW);
</script>

edited Nov 19 '14 at 05:05

answered Nov 17 '14 at 10:00

yogi970

446
5
14

I tried your code, but the I got: jsstrHW = <%=this.strHello %> – Orian Zinger Nov 17 '14 at 11:47
what have tried from my code? can you change in your question with current problem? – yogi970 Nov 18 '14 at 05:17
The problem is the same. I just added "this." before "strHello". I'll try to use RegisterClientScriptBlock. Thanks. – Orian Zinger Nov 18 '14 at 10:39
i tested my code and it was working properly. So better if you check where you are doing some thing different. Thanks – yogi970 Nov 18 '14 at 10:58
I created new solution and new project and your code worked, but when I copied your code to my project I got jsstrHW = <%=this.strHello %>. – Orian Zinger Nov 18 '14 at 14:59

score 0 · Answer 2 · answered Nov 17 '14 at 11:15

You can use REGISTERCLIENTSCRIPTBLOCK to pass the value from C# to javascript.

C# code:

ScriptManager.RegisterClientScriptBlock(Me.Page, Me.Page.GetType(), "someID", 
                     "PassValue("+ strHW +");", True)

Javascript code:

function PassValue(value) 
{
    alert(value)
}

score 0 · Accepted Answer · answered Nov 25 '14 at 16:40

Well, Eventually I found another way to pass strings:

  this.WPFWindow.InvokeScript ("WriteFromExternal", new object [] {"this string is passed to  WriteFromExternal"});

and in JS:

function WriteFromExternal(message)
    {
        alert("Message from C#: " + message);
    }

And it worked :)

Thank you all.

passing variables from cs file to aspx file (to javascript) using visual studio 2012

3 Answers3