I am developing a web-based java application where the user inputs some data and then the servlets return a value after processing it. It's working fine on a single tab, but on the same laptop or from two different laptops and browsers, if I open the website i.e. on two tabs then the data is being shared on the second tab as well.
To further illustrate, let's say I enter the word "hi" in chrome Tab A, and then enter the word "hello" in Safari Tab A, and then I hit the button(to pass it to servlet) at the same time on both tabs. I can see the word "hi" as well as "hello" on Safari Tab A, even though I entered this word "hi" on chrome and not on Safari, whereas the Chrome Tab returns no result as if I had sent a blank input.
I am using IntelliJ idea's Java EE application module. So far I have already tried some answers which I quite did not understand mentioned below, but I think these problems are not matching mine.
1) Prevent shared session between tabs or same browser windows
2) The Scope and the life time of Session attribute in Servlet in my web application get me confused when using more than 2 tabs of the same browser
my index.jsp code:
<%# page contentType="text/html;charset=UTF-8" language="java" %>
<%# taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%# taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn" %>
<%# page import="Analyser.Repetition" %>
<html>
<% //GET & SET DATA FROM SERVLET
pageContext.setAttribute("data", session.getAttribute("raw"));
session.invalidate();
%>
<form action="/Analyse" method="POST" id="sourceInput">
<textarea name="message" id="msg" cols="63" rows="15" required title="Input Text"></textarea>
<br/>
<input type="submit" value="Analyse"/>
<div id="error"></div>
</form>
My servlet code:
#WebServlet(name = "Analyser", urlPatterns = {"/Analyser"})
public class Analyser extends HttpServlet {
HttpSession session;
private String text; // TEXT STRING
private String[] trimmedArray;
private List<WordsList> words;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
words = new ArrayList<>();
session = request.getSession();
text = request.getParameter("message");
if (text.equals("") || text.isEmpty() || text.equals(",") || text.equals("?")) {
response.sendRedirect("index.jsp");
return;
}
session.setAttribute("raw", text);
response.sendRedirect("index.jsp");
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
}
each user input should be processed separately, while it's being exposed to the second tab eve from two different laptops.
Sometimes it just shares the value, and sometimes it gives the following error.
StandardWrapperValve[Analyser]: Servlet.service() for servlet Analyser threw exception
java.lang.NullPointerException
But it does not have anything to do with the entered word, as it never gives this error when accessed only from a single tab.
Related
The ASP.NET function ClientScript.RegisterClientScriptBlock can be used to register a chunk of JavaScript code that will be added to the page when it's rendered. The idea here is that you could have multiple instances of various user controls trying to register the same script over and over, but this ensures that it will only be included once.
The problem is, you don't really have any control over where the code is added to the page. This will insert the code inside the BODY tag of your page, but I need to add something (not limited to JavaScript code) into the HEAD block.
I'm well aware of various methods of adding something to the HEAD block via a ContentPlaceHolder block or by "Head.Controls.Add but these options do not address the problem of the same thing being added multiple times.
Is there an existing way to do this, or do I have to write a class that does something similar to ClientScript.RegisterClientScriptBlock except targeting the HEAD block?
I threw together a user control. There's nothing in the markup at all, so you can just add a new Web Forms User Control to your project and put this in the code behind:
public partial class ScriptControl : System.Web.UI.UserControl
{
private Dictionary<string, string> _scripts = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
public void RegisterScript(string key, string script)
{
if(!_scripts.ContainsKey(key)) _scripts.Add(key, script);
}
protected override void Render(HtmlTextWriter writer)
{
writer.WriteFullBeginTag("script");
foreach(var script in _scripts.Values) writer.Write(script);
writer.WriteEndTag("script");
}
}
Just add the directive to your page markup:
<%# Register TagPrefix="uc" TagName="ScriptControl"
Src="ScriptControl.ascx" %>
(where "ScriptControl.ascx" is whatever you've named the control)
and then you can add it wherever you need to, including in the header.
<head runat="server">
<uc:ScriptControl id="HeaderScriptControl" runat="server"/>
</head>
The usage is pretty much the same:
HeaderScriptControl.RegisterScript("myScript",
#"alert(""hello, world!"")");
I have to move my UI page from a .cshtml file to an .aspx file. Now I'm having a couple of compiling errors.
First is that 'ViewBag' does not exist in the current context. Can I not use it in .aspx? If not, what is a good substitute?
Second, the .cshtml page had a model declaration:
#model myProject.Models.Navigation
I changed it so that it would work in the .aspx page as follows:
<%# Import Namespace="myProject.Models" %>
I'm still not sure that's a correct substitute, because I could not include the word "Navigation" without getting an error. And now, in the code where I used to have:
#foreach (myProject.Models.Navigationitem item in Model.navigationItems){...
I've replaced it with:
<% foreach (myProject.Models.Navigationitem item in Model.navigationItems){...
And I get this error:
The name 'Model' does not exist in the current context
Apparently, I'm the only guy who has ever gone from razor to aspx, because there's exactly zilch about it online. Appreciate any help.
WebForms don't usually use a ViewBag, which is just a way to make data available to your View in ASP.Net MVC. With WebForms, a nice way to make data available to your "View" (the aspx page containing the HTML) is to expose a property containing that data.
The MVC way might be to set ViewBag.MyValue = "Some Value"; in your Controller, and reference it in your view with <h1>#ViewBag.MyValue</h1>. To do the equivalent in WebForms you would first define a property in your codebehind:
protected string MyValue { get; set; }
Then, set the value somewhere, perhaps in your Page_Load:
protected void Page_Load (object sender, EventArgs e)
{
this.MyValue = "Some Value";
}
And write the value on the page using WebForms syntax:
<h1><%= MyValue %></h1>
For your specific case, you don't seem to actually be using ViewBag. That's ok, you can make objects available as properties also:
protected MyProject.Models.Navigation Model { get; set; }
protected void Page_Load (object sender, EventArgs e)
{
this.Model = SomeMethodThatReturnsModel();
}
With the property defined and the value set, the code you have above for your ASPX should work just fine.
Your page should have
<%# Page Title="" Language="VB" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage(Of myProject.Models.Navigation)" %>
at the top to specify the model type.
Instead of ViewBag, you can use ViewState, as shown in the example below.
private List<TrimPackage> Packages
{
get
{
return (List<TrimPackage>)ViewState["Packages"];
}
set
{
ViewState["Packages"] = value;
}
}
I have a webusercontrol with a public int property SelectedCatID. I use this control on other pages and in other controls as follows:
<NewStore:LeftMenuLinks runat="server" SelectedCatID="<%#CatIDToSelect%>" />
How do I output cache this control based on SelectedCatID? Everything I've tried fails.
The closest I've gotten is getting it to cache, but it doesn't vary on SelectedCatID leaving the same menu item selected until the cache expires. Without caching, the control works as expected.
I figured out why the VaryByControls approach you used initially does not work. Sadly you edited it out of your question, so my research for this will just have to go into a blog post. Update: the blog post in question: http://tabeokatech.blogspot.be/2014/09/outputcache-on-user-controls.html .
The long and short of it though is that VaryByControls is kinda shorthand for VaryByParams, and does nothing for properties: it only looks at POST values. The fact that it ever worked for properties with a static value appears to be a bug - any string whatsoever in the VaryByControls would have made that part work. The accepted answer to this question is wrong: Vary by control properties using PartialCaching in ASP.NET .
There is no built-in way to vary by control property values.
That wouldn't make sense anyway, because user controls need to be created to have property values, and you want to avoid creating them, instead caching their rendered markup - cached user controls fields are null in code-behind if cached markup is served for them.
This works by injecting a PartialCachingControl into the page instead of the actual user control. This PartialCachingControl checks the cache, and only creates the control if no cached version exists.
As for making it work, I see two options:
If you only have 1 usercontrol per page, you could use the VaryByCustom approach. To make things easy you could write an interface that returns your property value for that page, and implement it on every page that hosts the user control, e.g.:
interface INumberProvider
{
int GetNumber();
}
// and the page:
public partial class _Default : Page, INumberProvider
{
public int GetNumber()
{
return this.SomeNumberPropertyOrWhatever;
}
...
In your Global.asax you cast the current handler to INumberProvider and get the number:
public override string GetVaryByCustomString(HttpContext context, string custom)
{
if (custom == "INumberProvider")
{
var page = context.CurrentHandler as INumberProvider;
if (page != null)
{
return page.GetNumber().ToString();
}
}
return base.GetVaryByCustomString(context, custom);
}
And in your control you obviously add:
OutputCache Duration="180" VaryByCustom="INumberProvider" VaryByParam="None" Shared="true"
That's if you only have one user control per page, and should be pretty straightforward. If you need more than one user control per page you're out of luck:
Build your own wrapper around your user control by writing a custom WebControl. Add the properties you need, capture the output of the rendered user control, and insert it into HttpContext.Current.Cache with a key that includes the SelectedCatID. Basically write your own custom PartialCachingControl.
There's also option 3:
Decide caching is not that important after all
<%# OutputCache Duration="60" VaryByParam="SelectedCatID" %>
Now store youre <%#CatIDToSelect%> as an a parameter ex ?SelectedCatID=12
Now you're Page or UserControl depending on what you want to cache will output the cache depending on what the Request.Param["SelectedCatID"] is equal to.
You can also do something like this (although not the easiest way)
This goes on the page/usercontrol you want cached:
<%# OutputCache duration="120" varybyparam="None" varybycustom="SelectedCatID" %>
This goes into the Gloabal.asax file:
public override string GetVaryByCustomString(HttpContext context, string custom)
{
if(custom == "SelectedCatID")
{
return CatIDToSelect;
}
return String.Empty;
}
I'm late to the party here what with an accepted answer and a 500 point bounty awarded. Still wanted to give my few cents on how this could be achieved.
It can be made to work in the control itself. You can have the control store it's own output in the cache and use the cached version in the Render method if found. I have made a really simple UserControl to test with. The markup looks like this:
<%# Control Language="C#" AutoEventWireup="true" CodeBehind="TestUC.ascx.cs"
Inherits="Webforms_Test.UserControls.TestUC" %>
<div>
<asp:Label ID="curTime" runat="server"></asp:Label>
</div>
It just contains a label that is set to DateTime.Now when it is initialized. The code behind looks like this:
public partial class TestUC : System.Web.UI.UserControl
{
private string cachedOutput = null;
public bool RenderFromCache = true; // set to false in containing page if this control needs to be re-rendered
protected void Page_Load(object sender, EventArgs e)
{
cachedOutput = HttpContext.Current.Cache["key"] as string;
if (cachedOutput == null)
{
// not found in cache, do the heavy lifting here to setup the control
curTime.Text = "UC:" + DateTime.Now.ToString("yy-MM-dd hh:mm:ss");
}
}
protected void Page_PreRender(object sender, EventArgs e)
{
if (cachedOutput == null || !RenderFromCache)
{
RenderFromCache = false;
StringBuilder b = new StringBuilder();
HtmlTextWriter h = new HtmlTextWriter(new StringWriter(b));
this.RenderControl(h);
cachedOutput = b.ToString();
HttpContext.Current.Cache.Insert("key", cachedOutput, null, DateTime.UtcNow.AddSeconds(10), TimeSpan.Zero);
RenderFromCache = true;
}
}
protected override void Render(HtmlTextWriter writer)
{
if (!RenderFromCache)
base.Render(writer);
else
writer.Write(cachedOutput);
}
}
In this sample, the control itself checks if its output is found in the cache, and if so the Render method will just write the cached output. If it is not found in the cache, the PreRender method will run the Render method normally and capture the output and store it in the cache.
In your case you would of course need a bit more logic which would check the relevant property on the control and use that to check if a cached version exists.
Disclaimer: This is an extremely simple test control. I have not tried to figure out how to make all of this work with controls that contain event handlers etc. So take it for what it's worth...
I saw on several web pages how to interface to a public method defined in a master file from a web page call behind code that uses that master file.
(I am using ASP.Net 4.0 on Visual Studio 2012.)
The procedure is (copied from article):
Make sure the function is accessible to the page (i.e. declared
public), and use the MasterType declaration in the ContentPage:
<%# Page .... %>
<%# MasterType VirtualPath="~/masterpage.master" %>
In the page, use Page.Master.MyFunction() to access the function.
*Note: before being able to access the function, you'll need to save & build.
The problem is that I do not see the method. Here is what I have:
Web Page (stored in /MyFolder, so /MyFolder):
<%# Page Language="C#" AutoEventWireup="true" CodeBehind="Logout.aspx.cs" Inherits="BvCorpMain.Candidates.Logout" %>
<%# MasterType VirtualPath="/SiteMasters/Site.Master" %>
Site.Master CS file (stored in /SiteMasters folder):
public void UpdateUserBlocksToCookie()
{
}
When I go into the code behind for the logout page and in a method I type in "Page.Master.", I do not see my method.
Your page is inheriting from System.Web.UI.Page, which only knows that its master page is of type System.Web.UI.MasterPage. If you are making modifications to a child class of MasterPage, then you need to cast the Page.Master property to your child class.
public class MyPage : System.Web.UI.Page
{
public new MyMaster Master { get { return base.Master as MyMaster; } }
public void Page_Load(object sender, EventArgs e)
{
Master.MyMasterPageFunction();
}
}
public class MyMaster : System.Web.UI.MasterPage
{
public void MyMasterPageFunction()
{
}
}
The previous answer did educate me, however I believe the resolution was to restart VS2012, maybe cleaning the solution and rebuilding did not hurt. Either way.
Microsoft adds in the following code automatically to the .aspx.designer.cs file.
/// <summary>
/// Master property.
/// </summary>
/// <remarks>
/// Auto-generated property.
/// </remarks>
public new MyNamespace.Site Master {
get {
return ((BvCorpMain.Site)(base.Master));
}
The previous answer conflicts with this definition. Also, the previous answer of MyMaster, although granting access does not give (automatically at least) to needed form information. I checked. Using the existing master file is the cleanest.
The definition for the master.cs file is:
namespace MyNamespace
{
public partial class Site : System.Web.UI.MasterPage
As you can see, Microsoft did give access to MyNamespace.Site, which is what I needed, with "Master.".
I did not think to check the .aspx.designer.cs file for that definition, when I was having the problems. Possibly the definition was lacking and got added later, when either I rebuilt or did a save, which I had previously done, or whatever.
Knowing the addition does simplify things, as I can add that in manually if it does not exist using that construct.
I have an app full of pages and user controls, many of which have one or more label controls on them for displaying various different messages to the user.
Example: the AddCompany.ascx user control, normally used on the Company.aspx page (with App.Master MasterPage) has a label on it called "OutOfCreditLabel" with Text="Error: You cannot create a new company, as you are out of credit". The code checks the credit and shows the label if needed.
I want to get rid of all these labels all over the place and just have a method I can call from anywhere like
ShowUserMessage("Text goes here");
In previous projects I've implemented this as a single label on the master page and public method in the .master.cs - as long as the page has the line
<%# MasterType VirtualPath="~/App.master" %>
in it, this works - but I can't get it to work on user controls (.ascx.cs). Is there a trick to this?
Or... Is there a better way?
What would you recommend for a "global" user message method that works from anywhere in the site?
Any nice jQuery solutions, perhaps?
Update
RPM1984 has asked for further clarification, so I'm trying to ask this a different way:
I need a method I can call from the code-behind (of a page or a user control) which will then display whatever text I specify to the user, like how stackoverflow tells you about new answers to your question when you next visit the site. It can be up the top of the window (like SO) or somewhere on the page, doesn't matter. What matters is that it's a "global" approach, rather than having various javascript alerts and asp:label's littered over every other page and user control in the project.
Something like this scenario:
A user clicks the "Create Widget" button on my "widget manager" user control on my page. In the event handler is:
if (User.IsOutOfCredit)
{
ShowUserMessage("Sorry, you cannot create widgets; you are out of credit.");
}
This results in the user seeing "Sorry, you cannot create widgets; you are out of credit." Either in a pop-up or red text in the page somewhere or at the top like StackOverflow, anything is fine
Does that make sense?
Why not a simple HTML "old-school" extension method? (i.e static method)
namespace Web.Helpers
{
public class HtmlHelpers
{
public static string Label(string target)
{
var dynamicText = SomeWhere.GetSomeCoolText();
return String.Format("<label for='{0}'>{1}</label>", target, dynamicText);
}
}
}
Then in your HTML:
<%= HtmlHelpers.Label("sometarget") =>
In your main master page, just import the namespace:
<%# Import Namespace="Web.Helpers" %>
EDIT after question updated
Ok, i see what you're trying to do now. I would recommend doing it all client-side.
That is, in your main master page, create an initially hidden <div> with a unique id:
<div id="message" style="display: none"></div>
Then create a helper method somewhere in your web project, rendering out some script.
public void DisplayMessage()
{
string message = SomeWhere.GetSomeCoolText();
StringBuilder script = new StringBuilder();
script.AppendFormat("$('message').show().append("<span>{0}</span>")", message);
Page.ClientScript.RegisterClientScriptBlock(this.GetType(), script.ToString(), true);
}
Of course, this is just a guideline. You dont have to use jQuery, you don't have to hardcode the script in the method. You could create a JavaScript function that accepts a string and modifies the HTML of the div, then just call the function.
It all depends on how complicated your "message" is, if you need special server controls, internationalization, etc.
But this is certainly the easiest way to accomplish what you want (IMHO).
Personally, I'd prefer using the HttpContext.Current.Items dictionary with a custom control. Similar to Keith Bluestone's approach, but doesn't require an arbitrarily named control on the page; it makes it very clear what's going on. You could package it into one class as a server control easily enough, but here it is to drop into a standard web project.
To register a message in your code behind:
SiteMessageUtility.Add("Test message");
To display in your page, or master page, or wherever, really:
<%# Register TagPrefix="custom" TagName="SiteMessage" Src="~/Controls/SiteMessage.ascx" %>
<custom:SiteMessage runat="server" />
Here's the files you'll need:
~\App_Code\SiteMessageUtility.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
public static class SiteMessageUtility
{
public static void Add(string message)
{
string currMessage = HttpContext.Current.Items["message"] as string;
if (currMessage == null)
{
HttpContext.Current.Items["message"] = message;
}
else
{
HttpContext.Current.Items["message"] = currMessage + "<br/>" + message;
}
}
}
~\Controls\SiteMessage.aspx
<%# Control Language="C#" AutoEventWireup="true" CodeFile="SiteMessage.ascx.cs" Inherits="Controls_SiteMessage" %>
<asp:Literal runat="server" ID="message" />
~\Controls\SiteMessage.aspx.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class Controls_SiteMessage : System.Web.UI.UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected override void OnPreRender(EventArgs e)
{
message.Text = (string)HttpContext.Current.Items["message"];
base.OnPreRender(e);
}
}
On the master page add the following controls:
the hfMsg hidden field will hold the message that will be displayed
and the hfCtrl will hold the name of the html control that will display this message which will be in this example lblMsg.
<label id="lblMsg" style="background-color:Yellow; border:solid 1px; width:200px;height:100px;display:none;"></label>
<asp:HiddenField ID="hfMsg" runat="server" />
<asp:HiddenField ID="hfCtrl" runat="server" />
NOTE:you can add another html control with a different id on an ASCX control and use it to display the message instead of the lblMsg.
and the following script:
<script language="javascript" type="text/javascript">
var msg = $('#<%= hfMsg.ClientID %>').attr("value");
var ctrl = $('#<%= hfCtrl.ClientID %>').attr("value");
if (msg != undefined && msg != "") {
$("#" + ctrl).html(msg);
$("#" + ctrl).show();
}
else {
$("#" + ctrl).hide();
}
</script>
NOTE:the script simply checks to see if the hfMsg control has a message to display or not.
and add the following two methods to the master page:
public void ShowMessage(string control, string message)
{
this.hfCtrl.Value = control;
this.hfMsg.Value = message;
}
public void ClearMessage()
{
this.hfMsg.Value = string.Empty;
}
finally you can call the ShowMessage method from any page like this to display a message on the master page:
Master.ShowMessage("lblMsg","hello world!");
and if you have a user control that holds an html label (e.g lblUserMsg) to display the message you can simply call ShowMessage and pass it the name of the label:
Master.ShowMessage("lblUserMsg","hello world!");
Having a SetStatus method in the MasterPage is always the way I've done this, to access the MasterPage from inside a user control, just create a private property in the usercontrol (or create a baseControl class that all user controls inherit from):
private TheNameSpaceOfMyMasterPage.MyMasterPage Master
{
get { return (TheNameSpaceOfMyMasterPage.MyMasterPage)Page.Master; }
}
protected void btnSave_OnClick(object sender, EventArgs e)
{
// Do your stuff...
// Set the Status
this.Master.ShowStatus("blah blah blah");
}
Also if you're using a control to hold the status message remember to disable ViewState on it, otherwise you'll end up with the same status message across postbacks which you don't want.
Some good answers, but...
To Robert W: the master page impl works, but it does require strong coupling (knowledge of) with the master page type. Master pages should generally affect style only, right? E.g. I should be able to change master pages without breaking my app.
SubPortal: yes, very clever, but... too clever for me. Also has master page issue.
RPM1984: again, too clever for me!
MGOwen didn't mention any special DHTML requirements (e.g. update from client side). So why not just implement a simple server-side helper method as he mentioned, find the target control which displays the message, and display it?
The following ShowMessage will find the target message control wherever it is on the page, as well as enable any page to override the default application's ShowMessage behavior if desired.
public static class ASPHelper {
// Defines something that shows a message
public interface IShowMessage
{
void ShowMessage(string msg);
}
// default implementation: finds a target message display control
// wherever it is on the page.
static void ShowMessage_Default(string msg)
{
const string SHOWMESSAGE_CONTROL_ID = "ctlShowMessage"; // or whatever
// find the control
Page currentPage = HttpContext.Current.CurrentHandler as Page;
Control ctlMessage = currentPage.FindControlRecursive(SHOWMESSAGE_CONTROL_ID);
if (ctlMessage == null)
throw new Exception("ShowMessage control not found!" );
Literal ctlMessageLiteral = ctlMessage as Literal;
if (ctlMessageLiteral == null)
throw new Exception("ShowMessage control must be a Literal!");
// Message control should not implement viewstate -- unneccesary
Debug.Assert(ctlMessageLiteral.EnableViewState == false);
// show it
ctlMessageLiteral.Text = msg;
ctlMessageLiteral.Visible = true;
}
// public version for use across app & in pages
static public void ShowMessage(string msg)
{
// Allow the current page to implement its own way of showing
// messages -- provides flexibility.
Page currentPage = HttpContext.Current.CurrentHandler as Page;
IShowMessage showMessageImpl = currentPage as IShowMessage;
if (showMessageImpl != null)
{
// Show using custom message displayer
showMessageImpl.ShowMessage(msg);
}
else
{
// static/global/default version
ShowMessage_Default(msg);
}
}
} // end ASPHelper
To use, simply place a literal control on the page, as in:
<div><asp:Literal
ID="ctlShowMessage" runat="server"
Visible="false"
EnableViewState="false"
/>
</div>
To use, simply call ShowMessage, as in ASPHelper.ShowMessage("insufficient credit"). Hope this is what you're looking for... Keith
Javascript safe popup. Works with Ajax/jQuery.
Namespace Utilities
''' <summary>
''' Utility class for injecting JavaScript into pages. Used primarily for throwing a JavaScript alert box, with correct focus.
''' </summary>
''' <remarks></remarks>
Public Class WriteJava
Region "Public Subs"
Public Shared Sub Script(ByVal script As String, ByRef p As Page, Optional ByVal scriptName As String = "")
If String.IsNullOrEmpty(scriptName) Then
scriptName = GetScriptName(p)
End If
If Not p.ClientScript.IsStartupScriptRegistered(scriptName) Then
ToolkitScriptManager.RegisterStartupScript(p, p.GetType, scriptName, script, True)
End If
End Sub
Public Overloads Shared Sub Alert(ByVal MyAlert As String, ByRef p As Page)
Script("alert('" & Format(MyAlert) & "');", p)
End Sub
Private Shared Function Format(ByVal value As String) As String
Return value.Replace("'", "\'").Replace(Chr(13), "\r").Replace(Chr(10), "\n")
End Function
Private Shared Function GetScriptName(ByVal p As Page) As String
Dim i As Integer = p.AppRelativeVirtualPath.LastIndexOf("/")
Dim pageName As String = p.AppRelativeVirtualPath.Substring(i + 1)
Return pageName
End Function
End Region
End Class
End Namespace
Use by calling:
Utilities.WriteJava.Alert("DANGER WILL ROBINSON", Me.Page)
I was looking for a site-wide way to display message to the user. I found jnotifica. It's similar to stackoverflow's bar at the top of the page.
The author's site appears to be down at the moment.
Raise an event in the user control, subscribe to the event from the page. The event handler updates your custom page property. Seems like the least amount of moving parts.
I would like to suggest to use a class for custom page(Inherited from System.Web.UI.Page) inside that add follwing as
protected void AlertError(string ErrorString)
{
StringBuilder scriptBuidler =
new StringBuilder(#"<script type='text/javascript' language='javascript'>");
scriptBuidler.Append(#"alert('");
scriptBuidler.Append(ErrorString);
scriptBuidler.Append(#"');");
scriptBuidler.Append(#"</script>");
AjaxControlToolkit.ToolkitScriptManager.RegisterClientScriptBlock
(this, typeof(Page),
"Patient Detail Not Found",
scriptBuidler.ToString(),
false
);
}
and inherit all your pages from this class instead of inherinting from system.web.ui.page
and use this function to to show your messages to your clients