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ASP.NET: Pulling ServerSide Variables Into ClientSide Code

kwilliams

By kwilliams
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kwilliams Member

kwilliams

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I'm trying to pull a server-side variable (VB) into client-side code (JavaScript). I can do this successfully using a regular ASP.NET page, but when I try to implement the same thing using the MasterPage method, I receive an error. I've included the working and non-working code below, along with the results of each. If anyone can please let me know what I'm doing wrong, that would be greatly appreciated. Thanks.SAMPLE #1: WORKING CODE (SINGLE ASP.NET PAGE)

<%@ Page Language="VB" Explicit="True" %><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><script runat="server">	'Like MasterPage.master.vb	Dim CurrentState As String = "Colorado"</script><html><head><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><title>Current State</title><script language="JavaScript"><!--	//Like MasterPage.js	var currentState = "<% Response.Write(CurrentState) %>";// --></script></head><script language="JavaScript">	//Like MasterPage.master	document.write(currentState);</script></body></html>

SAMPLE #1 RESULT: (works properly)ColoradoSAMPLE #2 NON-WORKING ASP.NET MASTERPAGE:MasterPage.master.vb

Partial Class MasterPage	Inherits System.Web.UI.MasterPage	Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)		Dim CurrentState As String = "Colorado"	End SubEnd Class

MasterPage.master

<%@ Master Language="VB" CodeFile="MasterPageAlerts.master.vb" Inherits="MasterPageAlerts" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" ><head runat="server">	<title>Untitled Page</title>	<script language="JavaScript">		<!--		//Like MasterPage.js		var currentState = "<% Response.Write(CurrentState) %>";		// -->	</script></head><body>	<form id="form1" runat="server">	<div>	<script language="JavaScript">	//Like MasterPage.master	document.write(currentState);</script>		<asp:contentplaceholder id="ContentPlaceHolder1" runat="server">		</asp:contentplaceholder>	</div>	</form></body></html>

SAMPLE #2 RESULT: (error)Compiler Error Message: BC30451: Name 'CurrentState' is not declared.Line 9: <!--Line 10: //Like MasterPage.jsLine 11: var currentState = "<% Response.Write(CurrentState) %>";<<<------THIS IS THE ERRORLine 12: // -->Line 13: </script>

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jesh Devoted Member

jesh

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I'm not much of a VB expert, but it looks like you are declaring the CurrentState variable inside the scope of your Page_Load handler. So, once control has left the page load stage and entered into the render stage, "'CurrentState' is not declared."Try moving declaration of that variable outside the Page_Load and then set it in Page_Load.In C#

public partial MyMasterPage : MasterPage{	public string CurrentState;	protected void Page_Load(object sender, EventArgs e)	{		CurrentState = "Colorado";	}}

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kwilliams Member

kwilliams

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Thanks for replying so quickly Jesh.When I moved the variable declaration outside the Page_Load handler, like this:

Partial Class MasterPage	Inherits System.Web.UI.MasterPage	Dim CurrentState As String = "Colorado"End Class

I now receive a different error:Compiler Error Message: BC30390: 'MasterPage.CurrentState' is not accessible in this context because it is 'Private'.Do I need to add some other code around the variable declaration to make this work?

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kwilliams Member

kwilliams

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Yeah, you need to make it public.According to this page, in VB you do that like so:
Public CurrentState As String

Hi Jesh,I had just received that suggestion from someone in another forum, so I guess great minds *do* think alike:)Here is the complete solution:Change this:Partial Class MasterPage Inherits System.Web.UI.MasterPage Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Dim CurrentState As String = "Colorado" End SubEnd ClasstoPartial Class MasterPage Inherits System.Web.UI.MasterPage Public CurrentState as String Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) CurrentState = "Colorado" End SubEnd Classand thisvar currentState = "<% Response.Write(CurrentState) %>";tovar currentState = "<%= CurrentState %>";"I probably should explain why you need to do that! >< When you declare your variable CurrentState inside of your method like that, it is in scope only to that method and to nothing else. By declaring it as a Public member of the class it is aviable to all methods in your class and thus allows you to use the value on your page."Thanks again Jesh:)
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