deepak.MyBlog()

Win7 Style Messagebox Control for ASP.NET

2011-03-02T01:23:00.001+05:30

In my previous post - Asp.Net PopUp Message Box UserControl

it was implemented by using the ModalPopupExtender control from the AjaxControlToolkit as well as some additional CSS and images.
Now I have tried to implement it using jQuery and CSS,am hoping you will like it too.

Returning a practical and easily recognizable message to a user is critical to a positive user experience on a website. In this article we'll create a simple ASP.net user control to display a message back to the user. The user control we will make can easily be drag and dropped onto any section of an aspx page or master page. After that, it just takes one line of code to display a message.

Sprite for the Icons

The Html
Our html source code for the message box control is simply a wrapping container with an inner message type logo and the message to display.

<asp:Panel ID="pnlMessage" Runat="server" Visible="False">
<div id="divMessagesLogo" runat="server" class="messages-logo"></div>
<div class="messages-text"><asp:Literal id="litMessage" runat="server"></asp:Literal></div>
</asp:Panel>
<asp:Literal ID="litSpace" Runat="server"></asp:Literal>

The Code

public enum MessageType : int

{

Error = 0,

Warning = 1,

Success = 2

}

protected void Page_Load(object sender, EventArgs e)

{

}

public void SetMessage(string sMessage)

{

SetMessage(sMessage, MessageType.Error);

}

public void SetMessage(string sMessage, MessageType messageType)

{

pnlMessage.CssClass = "messages messages-error";

if (messageType == MessageType.Warning) {

pnlMessage.CssClass = "messages messages-warning";

}

else if (messageType == MessageType.Success) {

pnlMessage.CssClass = "messages messages-success";

}

pnlMessage.Visible = (sMessage.Length > 0);

litMessage.Text = sMessage;

litMessage.Visible = true;

litSpace.Text = "<br />";

}

public void ClearMessage()

{

litMessage.Text = "";

litSpace.Text = "";

pnlMessage.Visible = false;

}

You can style the MessageBox control however you want, but here is the styling I'll use for this example.

The CSS

.messages {width:75%; padding:5px; margin-left:3px}

.messages-logo {height:32px; width:32px; float:left; background:url(message_logos.png)}

.messages-text {margin-left:40px; padding:6px 0}

.messages-error {background-color:#fbe3e4; color:#d12f19; border:solid 1px #fbc2c4}

.messages-error .messages-logo {background-position:-64px 0}

.messages-warning {background-color:#faffcf; color:#5e5f00; border:solid 1px #edef00}

.messages-warning .messages-logo {background-position:-32px 0}

.messages-success {background-color:#e0efd1; color:#003300; border:solid 1px #a5cc7a}

.messages-success .messages-logo {background-position:0 0}

How-to Use It

Now that we have the control build. Simply add the control to the page like in the example below.

<%@ Register src="Messages.ascx" tagname="Messages" tagprefix="uc1" %>
<!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>Messagebox Example</title>
<link href="messages.css" rel="Stylesheet" type="text/css" />
</head>
<body>
<form id="form1" runat="server">
<uc1:Messages ID="MessageBox" runat="server" />
</form>
</body>
</html>

It just takes 1 line of code now to add your message.

MessageBox.SetMessage("ERROR: An example of an error message!");

That's it, hope you enjoy this control. :)

Prevent Session Timeout in ASP.NET

2011-03-02T00:05:00.000+05:30

What is an ASP.NET Session Timeout?

One of the biggest issues I've dealt with in ASP.NET over the years is session timeouts. A session timeout occurs after a user is inactive for a set period of time. The purpose of timeouts is to lock out unauthorized users when a system is unattended or when someone forgets to log out of an application. The only way to prevent a session from timing out is to keep activity between the browser and the server.

For anyone who has edited web content or filled out a really long form has probably lost a significant amount of data to a session timeout. In this article, I will tackle how-to prevent a session timeout in ASP.NET and when it is appropriate to use this method for keeping a session alive.

How-to prevent session timeout

To prevent our session from timing out, we simply need to maintain contact with the server.

Step 1: Create a .NET web service

The web services doesn't really need to do anything, the call to the web service is enough to keep the session alive.

[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.Web.Script.Services.ScriptService]
public class webservice : System.Web.Services.WebService
{
public webservice()
{
}
[WebMethod(Description = "Keeps your current session alive", EnableSession = true)]
public void PingSession()
{
}
}

Step 2: Leverage ajax to call the web service

A simple call to the web service using jQuery.

$(function() {
setInterval('pingSession()', 60000); // keep session alive by pinging every 60 sec
});
function pingSession() {
$.ajax({
url: '/services/webservice.asmx/PingSession',
data: {},
type: "POST",
processData: false,
contentType: "application/json; charset=utf-8",
timeout: 10000,
dataType: "text",
success: function(obj) {
}
});
};

Usage

This method will prevent session timeout indefinitely, therefore, it should be used very conservatively. I only recommend using it on pages that you risk losing valuable data that was entered. For instance, if you are editing a large content in a WYSIWYG editor, you probably don't want the user losing an hours worth of work because of a session timeout. The purpose of a timeout is to allow the server to free up memory that was allocated for a user. If the session never ends, the memory is never free'd up.

Top Firefox Add-ons You Can't Live Without

2011-03-01T23:51:00.000+05:30

There are Firefox add-ons out there for developers, but which ones are the best of the best. The kind of add-on you use on a daily basis, and can't live without as a web developer. These are 5 add-ons you can't live without as a web developer.

1. Firebug

Firebug is hands down the best add-on out there for developers. It allows you to edit, debug, and monitor CSS, HTML, and Javascript live on any web page.

It also provides the ability to view all requests processed during pageload, warning you of any broken images or references.

Firebug also is an add-on for Google Chrome called Firebug Lite for Google Chrome.

2. Web Developer

Web Developer is an add-on that really does a great job of combining alot of helpful add-ons into one. Some of the features include: disabling cache, disabling javascript, disabling cookies, live css editing, window resizing, element outlining, and ruler measurements, to name a few.

The author also makes an add-on for Google Chrome: Web Developer for Google Chrome.

3. Pagespeed

Pagespeed is an add-on for evaluating the performance of a web page and offers suggestions on how to improve them. Pagespeed does require that you have Firebug installed.

I wrote a pretty lengthy post on this add-on called Speeding Up Your Website with Google Page Speed, which gives you a quick tour of the capabilities of PageSpeed and how to use it.

4. YSlow

YSlow, is very similar to Pagespeed in that it evaluates the performance of a web page and offers suggestions on how to improve them. However, YSlow considers a whole slew of criteria that PageSpeed does not, and vice versa. So I suggest using both add-ons.

5. ColorZilla

Colorzilla is a fancy add-on that lets you retrieve any color in your browser. Simply click the color tool and mouse over any color you want to retrieve in your browser window and click. It saves the color, so you can copy and paste the color into any other program. It also allows you to zoom the page you are viewing and measure distances between any two points on the page.

5. FireQuery

FireQuery is a Firefox extension integrated with Firebug.

jQuery expressions are intelligently presented in Firebug Console and DOM inspector
attached jQuery data are first class citizens
elements in jQuery collections are highlighted on hover
jQuerify: enables you to inject jQuery into any web page
jQuery Lint: enables you to automatically inject jQuery Lint into the page as it is loaded (great for ad-hoc code validation)

How to write good code ;-)

2011-01-11T00:15:00.002+05:30

Magic of CSS3 - Part 2

2010-07-14T13:42:00.001+05:30

Super Awesome Buttons with CSS3 and RGBA :

CSS3 is finally starting to see the light at the end of the tunnel as new browsers like Firefox and Safari continue to push its implementation.

One of our favorite things about CSS3 is the addition of RGBA, a color mode that adds alpha-blending to your favorite CSS properties. We've kicked the tires on it a bit with our own projects and have found that it helps streamline our CSS and makes scaling things like buttons very easy. To show you how, we've cooked up an example with some super awesome, scalable buttons.

View Tutorial : CSS3 Button

Magic of CSS3 Part I

2010-07-14T13:36:00.001+05:30

Border-radius: create rounded corners with CSS! :

W3C has offered some new options for borders in CSS3, of which one is border-radius. Both Mozila/Firefox and Safari 3 have implemented this function, which allows you to create round corners on box-items. This is an example

These different corners can also each be handled on their own, Mozilla has other names for the feature than the spec says it should have though, as it has

Mozilla/Firefox and Safari 3 users should see a box with a rounded left upper corner.
Mozilla/Firefox and Safari 3 users should see a box with a rounded right upper corner.
Mozilla/Firefox and Safari 3 users should see a box with a rounded left lower corner.
Mozilla/Firefox and Safari 3 users should see a box with a rounded right lower corner.

These are handled by / should be handled by:

-moz-border-radius-topleft / -webkit-border-top-left-radius
-moz-border-radius-topright / -webkit-border-top-right-radius
-moz-border-radius-bottomleft / -webkit-border-bottom-left-radius
-moz-border-radius-bottomright / -webkit-border-bottom-right-radius

How to debug your jquery code essential tools & tricks

2010-07-08T12:02:00.000+05:30

Not only are the JavaScript alert methods annoying, but until recently developers haven't had any really good tools to help them debug client-side code when they’re trying to re-create or resolve errors. Alert methods can also result in certain false assumptions about your code. For example, an alert dialog box waits to be closed before execution proceeds, so the timing of events can be off if you use this tool as a debugging mechanism.
In this article, I’ll describe some techniques to assist you in the debugging process when you are using jQuery in client-side Web development. Thankfully, we have much better tools and technologies than developers had even five years ago.

Ping this to get full article : How to debug your jquery code essential tools & tricks

Excellent Tips to improve UI using CSS3 and jquery

2010-07-08T11:55:00.000+05:30

CSS3 is getting a lot of attentions recently.  I'm absolutely in love with CSS3. Rounded corner, drop shadow and rotation couldn't be easier! The only drawback is, CSS3 standard is not fully implemented by most browsers and also, I believe you will get a lot of CSS validation errors as well. However, there are quite a lot of websites start using it already, for example, Twitter, it uses rounded border, and replace the rounded border with images if you viewed it with IE 7 or 8, and totally ignore IE6 users (*salute*, well done twitter).


And another great example with CSS3 and CSS3 animation: Neutron Creation
This post is all about CSS3 and Javascript. With all the new features that come with CSS3, there are whole lot of animation possibilites that can't be achieve before. So, Check this out and get inspired!

Excellent Tips to improve UI using CSS3 and jquery

Exception handling in AJAX (ASP.NET)

2010-07-04T10:50:00.002+05:30

Exception handling plays an important role in any application development. The way we present our exceptions to the user decides the quality of our software. The way we design a pattern for exception handling in C#, ASP.NET we should also design a similar pattern for implementing Ajax exceptions. If an Ajax exception is not caught, then it should as a pop-up directly on the screen showing the exact technical error message with a code. A layman/user will never know what went wrong behind the scene.

Different ways of handling exception in Ajax
1. Using the AsyncPostBackErrorMessage property of the Script Manager class
You can set the exception message that needs to be shown to the user to the AsyncPostBackErrorMessage property of the ScriptManager object. This can be achieved in the following way:

scriptManager.AsyncPostBackErrorMessage = "Oops..\nAn error occurred while processing";

Set the above exception message in the catch block of the method. When an exception occurs, this message will be shown to the user in a pop-up window.
2. Using the above method will show the exception message to the user as a pop-up window. It is not a good practice to show a pop-up on error. Better way to do is to add a Label field to the web page and set the text of that label field with the exception message. For more clarity to the user, the exception message can be shown in Red color. Ajax inherently exposes an event OnAsyncPostBackErrorHandler. This event is invoked when an exception occurs in your web page. It is better to set the exception message in this event as shown below:

protected void OnAsyncPostBackErrorHandler(object sender, AsyncPostBackErrorEventArgs e)
{
  scriptManager.AsyncPostBackErrorMessage = "Oops..\nAn error occurred while processing";
}

Is this going to suffice?
The answer it NO. Here we have just handled an event and set the required exception message to the AsyncPostBackErrorMessage property of the scriptManager class. We have to handle another event at client side to set this message to the Label control OR to some DIV as ModalPopupExtender of AjaxControlToolKit and inform the Ajax manager to not show the ugly pop-up:
The key to custom error handling in ASP.NET AJAX is the EndRequestEventArgs class, available when handling the endRequest event. It provides information on any error conditions that have resulted and exposes a method to let the framework know that we’ve handled the errors on our own.
I’m going to add a div, to serve as our replacement error message:


  An error has occured while trying to process your request.

Next, some CSS to style the div and close button:

#Error {
  top: 0px;
  right: 0px;
  width: 125px;
  background-color: yellow;
  border: solid 1px Black;
  padding: 10px;
  font-family: Sans-Serif;
  font-size: 10pt;
  position: absolute;
  margin: 5px;
}
#CloseButton {
  float: right;
  cursor: pointer; 
}

Finally, we need to add some JavaScript to tie it all together:

Sys.Application.add_load(AppLoad);

function AppLoad()
{  
 Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequest);
    Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(BeginRequest);
}

function BeginRequest(sender, args) 
{
  // Clear the error if it's visible from a previous request.
  if ($get('Error').style.visibility == "visible")
    CloseError();
}

function EndRequest(sender, args) 
{
  // Check to see if there's an error on this request.
  if (args.get_error() != undefined)
  {
    // If there is, show the custom error.
    $get('Error').style.visibility = "visible";
    // Let the framework know that the error is handled,
    //  so it doesn't throw the JavaScript alert.
    args.set_errorHandled(true);
  }
}

function CloseError() {
  // Hide the error div.
  $get('Error').style.visibility = "hidden";
}

The crux of this method is EndRequestEventArgs.set_errorHandled(). This tells the AJAX framework to call off the dogs and prevents the JavaScript alert from being displayed. Now, clicking Button1 results in this:

We have complete control over the error display. No JavaScript alert!

source: encosia.

Happy Coding :)

Simulate Slow Internet Connection while Testing your Apps

2010-07-03T23:33:00.000+05:30

So you have your Next-gen cool Web 2.0 application ready! You have tested it on your LAN environment and on your high speed internet connection – all seems ok and you are ready to deploy it in the ‘real world’. A few hours later, you get feedback that your application does not perform well on slower connections. That hurts!

Well the truth is that real world internet connections are much slower than you think. Your application end users may not always be broadband users but also people accessing your app through a dial-up connection, mobile sets, 3G or USB dongles. Most designers and developers forget to test their application on slower internet connections, resulting in a poor performing application.

Now there are many tools that let you simulate slow network connections. Out of them, what caught my attention is a nice Firefox browser plug-in that ‘effortlessly’ lets you simulate different speeds of Internet connection and lets you view the effects of slow speeds on your application. The plug-in is called Firefox Throttle.

Firefox Throttle is an extension that allows you to control download/upload rates and monitor current bandwidth utilization. Amongst other features, what I liked the most was that it lets you throttle localhost connections as well. Cool! Here’s a screenshot of the plugin in action.

The plug-in shows the current bandwidth utilization indicators in its Status panel as shown below and lets you quickly turn on/off throttling.

PingBack From this : DevCurry Atricle

Visual jQuery for jQuery 1.3.2

2010-05-05T11:16:00.000+05:30

Visual jQuery website, which is originally created by Yehuda Katz & updated by Remy Sharp, is very helpful & interactive to explore jQuery API. I'm using this website a lot more than jQuery documentation website

Update Version on : http://api.jquery.com/visual/

Test your jQuery code Online using jsFiddle

2010-05-05T11:05:00.000+05:30

Pingback from Test your jQuery code Online using jsFiddle Posted by Suprotim Agarwal

The ‘Works on My Machine’ is a common quote I often get to hear from fellow developers. When it comes to jQuery development, wouldn’t it be nice for developers to be able to see, test and edit each others code, using a common development environment. jsFiddle let’s you do that.

jsFiddle provides an online environment where you can preselect/add popular JavaScript frameworks and test your code. Here’s what the interface looks like:

As you can see, the interface is divided into an HTML editor, CSS Editor, JavaScript Editor and Output.

Observe the URL http://jsfiddle.net/ZqFp5/

Old Version - http://jsfiddle.net/ZqFp5/
New Version - http://jsfiddle.net/ZqFp5/1/
Slick, I must say!
Update: Check out Elijah’s post Tips using Firebug Lite and Full Screen with jsFiddle

Create PDF documents from .NET applications

2010-05-05T10:27:00.000+05:30

I have seen a very common question in the forums – How can I create PDF documents from my .NET application?

Here are some of the OpenSouce and Paid libraries that allow you to do so:

Open Source
PDFSharp - PDFsharp is the Open Source library that easily creates PDF documents from any .NET language
iTextSharp – Library to create/manipulate PDF documents on-the-fly
Report.NET - generate PDF documents in a simple and flexible manner
PDFjet for .NET - royalty-free PDF library

Paid Libraries
PDF4NET - .NET library for adding PDF capabilities your .NET application
ABCpdf - Dynamically create Adobe PDF documents on the fly
DynamicPDF™ Generator for .NET - real-time creation of PDF documents based on dynamic data

Simple tooltip apply on all Title attributes in Web App - jQuery plugin

2010-04-01T00:45:00.012+05:30

A few weeks ago I needed to display a tooltip for all fields having title attributes in web application. There are lots of jQuery plugins for that but I just needed a simple one which display a message on mouseover.
The text displayed in tooltip is the same as the TITLE attribute of the element.Either it become set as ToolTip on web controls in aspx page or on Resource Files(.resx)

(function($)
{
    $.fn.simpletooltip = function()
    {
        return this.each(function()
        {         
            if ($(this).attr("title").length > 0)
            {
                var text = $(this).attr("title");
                $(this).attr("title", "");             
                if (text != undefined)
                {
                    $(this).hover(function(e)
                    {
                        //alert("hover");
                        var tipX = e.pageX + 12; //set acc to ur need
                        var tipY = e.pageY + 12; //set acc to ur need
                        $(this).attr("title", "");
                        $("body").append("
");
                        if ($.browser.msie)
                            var tipWidth = $("#simpleTooltip").outerWidth(true)
                        else
                            var tipWidth = $("#simpleTooltip").width()
                        $("#simpleTooltip").width(tipWidth);
                        $("#simpleTooltip").css("left", tipX).css("top", tipY).fadeIn("medium");

                    },
   function()
   {
       $("#simpleTooltip").remove();
       $(this).attr("title", text);
   });
                    $(this).mousemove(function(e)
                    {                      
                        var tipX = e.pageX + 12;
                        var tipY = e.pageY + 12;
                        var tipWidth = $("#simpleTooltip").outerWidth(true);
                        var tipHeight = $("#simpleTooltip").outerHeight(true);
                        if (tipX + tipWidth > $(window).scrollLeft() + $(window).width()) tipX = e.pageX - tipWidth;
                        if ($(window).height() + $(window).scrollTop() < tipY + tipHeight) tipY = e.pageY - tipHeight;
                        $("#simpleTooltip").css("left", tipX).css("top", tipY).fadeIn("medium");
                    });
                }
            }
        });
    }
})(jQuery);

this.hidetooltip = function()
{
    $("#simpleTooltip").remove();
    $(this).attr("title", "");
};

CSS :

#simpleTooltip 
{
 position:absolute;
    border  :1px solid #333;  
 background:#f7f5d1;
 padding:5px;
 color:#333;
 cursor:pointer;
 font-weight:bolder;
 
 display:none;
 border-radius: 4px;
 -webkit-border-radius: 4px;
 -moz-border-radius: 4px;
 }

How to use :

$("#some-element").simpletooltip()
or
$("a.some-class").simpletooltip()
or
$("input[type='button']").simpletootip()

or Set it on Ajax PageLoad() to set back on async postback using updatePanel :

 function pageLoad()
         {
              // use to hide all tooltip on Async postback in updatepanel
              hidetooltip();
             //use when to apply on those elements having tooltip Css Class
             $(".tooltip").simpletooltip();
            //use to apply on whole input type fields on Web Application
             $("input").simpletooltip();
         }

Additional Info :

Tested with IE 6+, Firefox 3, Safari 4 and Opera 9
jQuery 1.3.2 (it should work with previous releases of jQuery, but I didn't test it)

Click here to download the simpletooltip jquery plugin.

Master Page - Content Page - Javascript Path problem

2010-03-09T00:00:00.001+05:30

Most of the developers who are using Master page and content pages in different folders, paths has faced a problem of reference of javascript file.

It was a nightmare and was a big headache to decide whether to use the masterfile concept or not. There are many advantages of using master pages and content pages.

We will not go in detail to find the advantage but will look to find the solution for the javascript path issue. One major advantage of using Masterpage is, if we are using single masterpages for the content pages irrespective of any path of content pages, the browser will cache the javascripts and css files, which optimizes the performance of the website.

* To show in real life we created a appllication where we saved all the javascripts in a folder

[ ApplicationName]/Common/Scripts

* Created a master page at [ ApplicationName]/Common/Usercontrols

and dragged the javascript files .

* Created two content pages one at

>> [ ApplicationName]/Common/Usercontrols/Test.aspx and

>> [ ApplicationName]/Test.aspx

refferring to the same master page.

While testing both, [ ApplicationName]/Test.aspx was not reffered to the javascript, same will happen if any other pages which are in other path. This is the problem

The solution is simple:

Instead of

< script type="text/javascript" src='../Scripts/jQuery/jquery-1.3.2.min.js'>&lt/script>
make the reference as
< script type="text/javascript" src=''<%=ResolveUrl("../Scripts/jQuery/jquery-1.3.2.min.js")%> </script>

as shown below.

just add "ResolveUrl" for the src of the file

ASP.Net AJAX Control Toolkit’s New Release, AsyncFileUpload Control

2009-10-11T23:45:00.000+05:30

Ajax Control Toolkit is not new for every .NET developer. A new version of the AJAX Control Toolkit is now available for download from the CodePlex website. This new version of the AJAX Control Toolkit contains two new controls:

SeaDragon Java Script Code (SJC) - The SJC control allows SeaDragon scripts to be used to display an image, and to zoom in and out of that image using mouse button keys without resizing the window. I saw the demo and it's a really cool control.
AsyncFileUpload - Finally, we have a control which uploads file asynchronously. This new control enables you to perform file uploads without doing a postback. The control displays a throbber image during upload and raises client and server events when the upload is complete. Check the live demo here.

Note: This control will only work with .NET 3.5 or higher version.

PingBack From :Code Project

Difference between obj.ToString() vs Convert.ToString(obj) vs (string)obj vs obj as string

2009-10-11T23:27:00.000+05:30

obj.ToString()

.ToString() can be called from any object. It returns a string that represents the current Object. ToString() is a method of object, and it will always work on a non-null reference. For example:

object str = "test string";
string newTestString = str.ToString();

str.ToString() will return "test string" as string .But

object str = null;
string newTestString = str.ToString();

Will throw the exception:“Object reference not set to an instance of an object.”
The above exception came because str is null we can not perform any operation on any object that has null reference.

Convert.ToString(obj) :

Convert.ToString(obj) means we are calling a method and passing obj as argument.Internally it will call ToString(object value) method and then ToString(object value, IFormatProvider provider) method is called.

(string)obj :
First it should be clear that it is a cast operation, not a function (or method) call. We should use this if we are sure the object we are passing is of type string or it has an implicit or explicit operator that can convert the object to a string. This will return null if the object itself is null . See examples.

object str = "test string";
string newTestString = (string)str;

(string)str will return "test string" as string.But you cant do tht for Int.See below example:

object i = 2;
string str = (string)i;

The above code will throw this error:
Unable to cast object of type 'System.Int32' to type 'System.String'.Cannot cast expression of type int to string
Int doesn't have an explicit operator to string.When casting a number to a string, there is a "loss" in data. A string cannot perform mathematical operations, and it can't do number related things.

obj as string :
It is safe cast operation. It is similar like (string)obj but instead of throwing an exception it will return null if cast operation fails. For example:

object i = 2;
string str = i as string;

str will return null.

Code Translation for .Net c# < = > VB.Net

2009-10-11T23:20:00.000+05:30

This service will translate the code for you, just start typing the code or upload a file to convert it.

For now it only supports from VB.NET to C# and from C# to VB.NET.

VB.NET to C# and from C# to VB.NET Click Here

To use it you can either:
Start typing your code.
Copy and Paste the code in the Code Text Box.
Translate an entire file using the file upload.

Disclaimer:
No copy is done whatsoever of the code that you either type, or upload for translation. Everything is processed in the server in memory and returned immediately to the browser

How to control maxlength of multiline textbox in aspnet

2009-10-10T20:46:00.000+05:30

This is known issue in ASP.NET Standard Text box control when set its TextMode="MultiLine" the MaxLength property does not work.

There is a workaround to accomplish this using two ways :
1. RegularExpressionValidator : Following is the markup that will restrict the text box to maximum of 300 characters.

<asp:TextBox ID="txtComments" runat="server" TextMode="MultiLine" Height="100px"
Width="320"></asp:TextBox> 
<asp:RegularExpressionValidator
ID="regComments" runat="server" ControlToValidate="txtComments"
ValidationExpression="^[\s\S]{0,500}$" ErrorMessage="Maximum 300 characters are allowed in comments box." Text="Maximum 300 characters are allowed in comments
box." > 
</asp:RegularExpressionValidator>

2.By JavaScript :
The MaxLength property of textbox control works fine if Multiline mode is not set, but if TextMode='Multiline' is set in aspx page then this property is of no use and user can input any number of characters inspite of setting maxlength.
Single line textboxes render as an HTML input tag - which supports a max
length.

The Multiline Textbox, renders as an HTML TextArea which doesn't support a
length property.

So, one workaround is to roll your own by calling a JavaScript function that
checks the length of the text entered. The function gets called on every
keypress and denies further data entry when the max length is reached. Of
course the JavaScript function needs to ignore some keys. This one should
work.

This example requires just very basic knowledge of java script so don’t be scared I promise this will be one of the easiest java scripts that can solve a complex problem.

Add the following to your Multiline box in aspx page:

<asp:TextBox Rows="5" Columns="80" ID="txtCommentsForSearch" MaxLength='500' onkeyDown="checkTextAreaMaxLength(this,event,'500');"  TextMode="multiLine" runat="server"> </asp:TextBox>

*txtCommentsForSearch-This is asp.net control that is having multiline property set

I have used MaxLength='500', same property you have to use in underlying javascript file also. I have also passed this length to the calling javascript method, so that in case the MaxLength is not accessible then can be picked from parameters of javascript method.

Add the following to your javascript file:

function checkTextAreaMaxLength(textBox,e, length)
{
    
        var mLen = textBox["MaxLength"];
        if(null==mLen)
            mLen=length;
        
        var maxLength = parseInt(mLen);
        if(!checkSpecialKeys(e))
        {
         if(textBox.value.length > maxLength-1)
         {
            if(window.event)//IE
              e.returnValue = false;
            else//Firefox
                e.preventDefault();
         }
    }   
}

function checkSpecialKeys(e)
{
    if(e.keyCode !=8 && e.keyCode!=46 && e.keyCode!=37 && e.keyCode!=38 && e.keyCode!=39 && e.keyCode!=40)
        return false;
    else
        return true;
}

How to Generate Sequence Diagram online

2009-09-27T17:23:00.002+05:30

How to Generate Sequence Diagram online
Don't wast your time to create sequence diagram using visio or some
other tools.
Here I found very useful site that generates sequence diagram as per
your requirement.
You have to just type very smple script that should descripe the call
from one class to
another and On click of "Draw" button you can get your secquence diagram
in the form of picture or pdf.
Don't worry about script learning and script notation, it's
very,following site will give you all help and example
pink back from :
http://www.websequencediagrams.com/

Formatting numeric data types in .NET

2009-09-27T17:19:00.000+05:30

Formatting for decimal places.
Formatting numbers.
Formatting numbers using # symbol.
Formatting for thousand separator.
Formatting for positive and negative numbers.
Multiplying a number by 100 .
Appending currency symbol to a number.
Displaying numbers in exponential form.

Thanks to Sandeep for Sharing Such formatters......

Methods in Global.asax

2009-09-27T17:06:00.000+05:30

It’s very important to understand the methods in global.asax so that we as programmers can handle some application level events very efficiently. I said application level events and reason for using application word is that global.asax is an application level file and methods in it are used to handle application level events and these methods are not at all specific to any aspx page. Some of the common methods in the order in which they are executed are listed below

Application_Start
Application_BeginRequest
Application_AuthenticateRequest
Session_Start
Application_EndRequest
Session_End
Application_End
Application_Error

PingBack from Methods in Global.asax

Configuring Machine Key in ASP.NET 3.5 to tamper proof viewState

2009-09-27T16:49:00.001+05:30

Security is a major concern when it comes to online transactions like shopping. Today we will learn how to tamper proof your ASP.NET application using element in web.config file. How to protect your sensitive ViewState data and Forms authentication ticket.

By default, ViewState in ASP.NET is encoded and not encrypted as you might feel. ViewState is transmitted to server as a Base64 string and can be easily decoded.Take a look at this if you are interested in decoding stuff and read more about Base64 here.

Encrypting and protecting ViewState: For a tamper proof ViewState a hashed message authentication code (HMAC) is generated from ViewState data which is then compared on subsequent requests. We can make use of element and can encrypt our ViewState using desired encryption mechanisms. Eg, SHA1 , MD5, AES and 3DES. Here is how a element looks but before that we need to set enableViewStateMac=True in our asp.net page as shown below code segment.

<%@ Page  EnableViewStateMac="true" ViewStateEncryptionMode="Auto"  Language="C#" AutoEventWireup="true" CodeBehind="login.aspx.cs" Inherits="Using_SQL_Membership.login" %>

Or you can set it in web.config file as shown below.

enableViewState=True enables hashing of viewstate while you viewStateEncryptionMode takes 3 values. Auto, Always and Never. With viewStateEncryptionMode set to Auto, the page is only encrypted if a control has specifically asked for it by calling the Page.RegisterRequiresViewStateEncryption() method to request encryption. If it set to Always, this forces encryption even if a control does not request it. For performance reasons do not encrypt viewState unless and until it has sensitive data.

1. validationKey: This specifies the key that the HMAC algorithm uses to make ViewState tamper proof.

2.decryptionKey: specifies the key used to encrypt or decrypt data. Also, ASP.NET uses the key only if validation attribute is set to AES or 3DES.

3.validation: specifies the hashing algorithm used to generate HMACs to make ViewState encrypted.

In general, you should choose SHA1 over MD5 for tamper-proofing because this produces a larger hash than MD5 and is considered cryptographically stronger.

Encrypting and protecting Forms Authentication:

To ensure that forms authentication tickets are encrypted and protected against tampering, set the protection attribute of the element to All, as shown

Along with this make same settings to machineKey as shown above.

If you deploy your application in a Web farm, you must ensure that the configuration files on each server share the same value for validationKey and decryptionKey, which are used for hashing and decryption respectively. This is required because you cannot guarantee which server will handle successive requests.

Viewing ASP.NET viewstate with ViewState Decoder
Do you ever wonder what may be inside that asp.net viewstate? As a tester don't you think you should? It's a good thing to wonder about if you care about security. It's possible that the viewstate could contain sensitive user information that could be compromised in a man in the middle attack. For example: A user can input a credit card number into a textbox which would be passed to the next page via the viewstate. Not good... The viewstate is not encrypted by default its just simple Base64 encoding which can easily decoded with cool little tools like ViewState Decoder made by Fritz Onion.

ASP.NET View State

2009-09-27T15:20:00.010+05:30

What is a view state?
View state in simple terms can be defined as a way to maintain the state of an aspx page during postbacks. And this is the no 1 one liner answer I get from candidates during interviews. Viewstate is a technique which helps in retaining the values of the controls placed in a page during postback/roundtrip. With this blog, again, my aim is the same, to spread more light on what is view state all about.

What do you mean by state of an aspx page?
The state of an aspx page means the values of the controls in an aspx page. By default the view state is maintained for all the controls which are placed in an aspx page. The state of a control can be the text entered in a text box, the checked status of a radio button or check box, the content and selected item in a drop down control etc.

Where is view state stored?
View state is stored in the client in the form of a hidden control called “__VIEWSTATE”. Here by client I mean the rendered aspx pages in the browser. If view state property is set to true then ASP.NET automatically adds a hidden field/control by the name “__VIEWSTATE” and stores the information related to the state of the page in an encrypted format.

What is the encoding used in view state?
View state is stored in base64 format. The base64 format can generate huge amount of data on conversion and this is the reason we are adviced to use view state judiciously.

Which class handles view state?
StateBag class handles the view state and it implements a Dictionary to keep track of the changes in a form. The developer can add or remove items from this dictionary as you would from any dictionary object. You can access this class through the Control.ViewState property.

Can view state be stored in multiple hidden fields?
Yes, view state can be stored in multiple hidden fields. This can be achieved by setting the page’ “MaxPageStateFieldLength” property. If the property is set to a positive value then the view state is broken and sent to the client in multiple hidden field and each field’ size will be less than the value spedified in “MaxPageStateFieldLength”.

How to disable view state?
View state can be disabled in the following ways.

1. In machine.config – you can disable view state for all the application hosted in the server by modifying the following tag in machine.config as shown below.

2. Application/website level - if you want to disable view state for all the pages in your application then you can do that in web.config file as shown below.

3. Page level – you can use this option to switch off the view state for all the controls in a web page by setting the “EnableViewState” page attribute

4. Control level - you can switch off a control’ view state by setting the EnableViewState property of the control to false from property window or as shown below.

Hope the above details give a clearer picture on what view state is. There is more to view state than what is written here.

Microsoft Releases Charting Control as VS2008 Add-on

2009-09-27T01:03:00.001+05:30

As you may (or may not) know, a while back Microsoft purchased some charting functionality from Dundas, to be included as part of Reporting Services for SQL Server 2008. Well, now they have packaged up this functionality as a control for Visual Studio 2008! This is a fantastic add-on, as we now have the power, flexibility, and visual excellence of the old Dundas chart control as a free Visual Studio 2008 add-on!

Scott Guthrie has an excellent blog post discussing it, which can be found here.

Scott specifcially talks about ASP.NET, and a few of the commenters on his blog ask the obvious question: Can this be used for Winforms apps as well? I went ahead and installed the add-on, and the new Chart control can indeed be dropped into Winforms apps as well as ASP.NET!

Lastly, I got curious as to whether or not this control could be used from Visual Studio 2005. It doesn’t show up in the toolbox automatically, but it can be added and does indeed work in VS2005!

In addition to the above samples, you can download the Microsoft Chart Control Documentation