interface IAsela

My Favorite Project

2008-12-07T16:17:00.000+05:30

I have been working mostly as a software developer for the last 10 years. But my favorite project which I got involved during my carrier is NOT a software project. Of course it had coding involved with it, but it was a digital profile.

Year – 2006 / 2007

Client – ODEL (through Leo Burnett)

Project – ODEL wanted to have a virtual tour of their departmental store to be created and stored in a mini CD. They wanted to give that mini CD’s to participants of an international fashion show. As ODEL’s advertising agency, Leo Burnett approached us to design and develop the digital profile. What made this project much more interesting is we had only 5 days to complete this project; So we worked almost 24/7 for 5 days.

Technology – Profile was totally done using macromedia Flash.

Project Team
Duminda Perera – Art Director
Asela – Software Architect, ActionScript Coding (Main Auto Navigation)
Chathuranga Neminda –UI Design
Anjana Wijerathne – ActionScript Coding (Manual Navigation)
Chaminda Prasad – ActionScript Coding (Music Player)
And also Marsh Dodanwala from Leo Burnett was the project coordinator and Ranil Gunawardene from HPH studios composed some awesome background music for the profile.

My First Web Application Project

2008-12-03T14:16:00.004+05:30

I was really bored and wondering what happened to the people I used to work with in previous companies. Then I remembered the first ever web application project I was involved in. This is a tribute to all the wonderful / talented people I worked with, in that project.

Year – 2000 / 2001

Client – HighQ (Israel / Singapore)

Project – HighQ wanted to develop a full pledged Learning Management System. As the first step the wanted to have a web based question management system which will generate question papers according to predefined criteria. When a student go through the test, web application will measure various things such as how much time spent on a question, the pattern of answering etc. After completion of a paper, web application used rule based logic to identify the “illnesses” of the student and provided ‘prescriptions” (which were flash based games) to overcome their illnesses.

Technology – Flash front end communicates with classic ASP via JavaScript. Classic ASP invoke methods in the DLL stored in COM+ and after applying the business rules COM+ DLL access the PL SQL stored procedures resides within the Oracle 8i Database Server.

Project Team
Kolitha de Silva – Project Manager, Project Leader, Technical Consultant (Classic ASP)
Chanura Rajakaruna – Software Architect
Asela (yeah that’s me) – COM+ middle tire Development
Janaka Shavantha – Component / User Controls Development
Sandaruwan Disanayaka – Database Administrator (DB Management)
Sandun Abeweera – Database Administrator (PL SQL)
Manjuma Salgadu – Classic ASP (Reporting)
Suwath – Classic ASP (Communication)
Roshan Vijaya Pradeep – Classic ASP
Gayan Dias – Classic ASP
Duminda Perera – Graphic / UI Design
Mahesh Thilakshana – ActionScript / Lingo
Nilam Zawath – Flash UI / Animations
Aslam Ameen – HTML

Got ripped off by a scam - iqquizapp.com

2008-11-28T07:22:00.003+05:30

Unfortunately I couldn’t post anything for months because I was very busy with work related assignments (2 project releases). Now I am in Sydney for one month assignment. This post is not to boast about how good (or bad) Sydney is.

I got ripped off by a website. Believe it or not, I am not the average web user who falls in to these kinds of traps. Anyway here goes the story.

While I was surfing through Facebook, it recommended me to take a quiz called “How Australian are you?” Just for fun I went through that quiz. I accidently pushed Next button under the questioner which was actually a button related to an advert on the page, and it opened up an IQ quiz (outside of Facebook).

Being curious, I completed that IQ quiz which was walk in the park (that was bit strange, because IQ quiz are supposed to be hard). The URL was http://www.iqquizapp.com/au-1/ (and later I found that they have au-1 to au-5 questioners).

After completion of the quiz, it prompted me for phone number as a verification.

I entered my aussie phone number and got a pin code via SMS.

I entered that PIN on the web and got some crappy results. As soon as I ended the pin I got an SMS saying I have subscribed to their service and they sent 3 SMS’s weekly which causes AUD 6.6 per message. And right after that I got 3 messages in a raw which reduced my pre-paid phone balance by AUD 20.

Later I managed to unsubscribe and then I went back to that page. When I scroll the page down it had their conditions in small letters saying about the $6.6 per message. Actually they had that on the top of the page as well. But when there’s a flash app on a page, the eye directly goes to the flash rather than other parts of the screen.

Moral of the story - Never put your Phone Number in a website unless you are really sure about that website and the website creators intentions.

Identity vs uniqueidentifier

2008-10-30T16:49:00.003+05:30

If you are a developer working with SQL server, you have used Identity columns more than once. With SQL 7 Microsoft introduced a new data type called “uniqueidentifier”. From a top level the usage of both are the same.

But there are differences as well…

Identity column contains numbers where uniqueidentifier contains a GUID.

If you use an identity column, when ever there is a new row added to a table which has an identity column, SQL server will assign the next identity number on the sequence (this will depend on the identity seed settings). You can easily retrieve this by using @@identity.

If you have a uniqueidentifier column in your table, system won’t automatically create a value to that column. You have to use “NEWID()” SQL function to create a new GUID and then assign it to the column which is uniqueidentifier type.

uniqueidentifier type is good since GUID’s are unique in space and time. So even if you merge two tables with uniqueidentifier columns, there won’t be any duplicate uniqueidentifier’s. But only constrain with uniqueidentifier is the size (16 bit).

C# Random Numbers

2008-10-22T13:31:00.000+05:30

C# random numbers are not random. According to Professor Charles Apps (or anyone who knows a little bit of maths) random numbers also has a pattern since it's developed using an algorithm.

Traditional way...

Random r = new Random();
string randomFlag = r.Next(0, 999999999).ToString("000000000");

Next time when you want to generate a random number try this code instead of the traditional way ...

public static int GetRandomNumber(int maxvalue)
{
System.Security.Cryptography.RandomNumberGenerator random =
System.Security.Cryptography.RandomNumberGenerator.Create();
byte[] r = new byte[1];
random.GetBytes(r);
double val = (double)r[0] / byte.MaxValue;
int i = (int)Math.Round(val * maxvalue, 0);
return i;
}

LUVNAME.COM is it a virus?

2008-09-30T10:15:00.000+05:30

Facebook has become the largest social networking website. When a site gets popular there are more people who’ll be trying to misuse it as well.

I have seen a message on my Facebook wall saying "FIND OUT WHO YOUR LOVE IS!! VISIT: LUVNAME .COM (remove spaces) HURRY BEFORE IT'S TOO LATE!"

I just ignored this message. But when the same message appeared on my wall several times on my wall (posted by different friends) I was bit concerned about this.

I did some digging and found that this is some sort of an automated script which post these messages without the user knowing.

There are several possibilities, how an automated script can achieve this task….

1. Somehow they have found your Facebook password using a phishing site (this is the most likely scenario)

Solution – Login to your Facebook account and change your password. Make sure not to put your Facebook password in any sites other than Facebook

2. You have downloaded a malicious script (virus, worm, Trojan, spy wear ) so it has recorded your password and sent back to the creator

Solution – Run a full virus scan and a spy wear scan on your computer and remove all the malicious files.

TransactionScope Timeout

2008-09-18T17:00:00.003+05:30

If you are using TransactionScope to handle transactions within your .NET code, you might find a scenario where your transactions get Timeout. The default value is 1 minute. If you want to change the transaction timeout, you can change it in either Web.Config or App.Config file.

The above code should be used within the Configuration section.

ViewState persists with ViewState disabled

2008-09-09T18:06:00.003+05:30

One of my developer friends who recently moved from Win Application development to web application development wanted to know what ViewState and the benefits of using ViewState.

I tried a simple example using a textbox , button and when user typed something and press the button it was persisted (default – viewState is enabled). I tried the same thing with ViewState disabled for the textbox and still got the same results.

When I was doing some digging I found that the example which I used doesn’t use ViewState at all. Following example explains how the persistence of data has been done during postback.

“One nice thing about ASP.NET is that the Web controls in a Web Form remember their values across postback. That is, if you have a TextBox Web control on a page and the user enters some value into the TextBox and posts back the page, the TextBox's Text property is automatically updated to the user's entered value. This happens because the TextBox Web control implements the IPostBackDataHandler interface, and the Page class hands off the appropriate value to the TextBox class, which then updates its Text property.

To concretize things, imagine that we have an ASP.NET Web page with a TextBox whose ID property is set to txtName. When the page is first visited, the following HTML will be rendered for the TextBox. When the user enters a value into this TextBox (such as, "Hello, World!") and submits the form, the browser will make a request to the same ASP.NET Web page, passing the form field values back in the HTTP POST headers. These include the hidden form field values (such as __VIEWSTATE), along with the value from the txtName TextBox.

When the ASP.NET Web page is posted back in the load postback data stage, the Page class sees that one of the posted back form fields corresponds to the IPostBackDataHandler interface. There is such a control in the hierarchy, so the TextBox's LoadPostData() method is invoked, passing in the value the user entered into the TextBox ("Hello, World!"). The TextBox's LoadPostData() method simply assigns this passed in value to its Text property.” - Source : MSDN

It’s a good example to try to understand things as much as you can rather than using it for granted.

Why drill down option is disabled in Crystal Reports

2008-09-02T15:41:00.004+05:30

If you have tried to create a drill down report using Crystal reports, you may end up with the following screen. Unfortunately, you can’t find a single article on web how to fix this little problem.

( Group Tab Disabled )

( Report part drill down option disabled )

The concept behind drill down is to summarize the data on the top and then drill down to the details. So when you are setting up your data connection, if you have setup summery field(s) the appropriate menu(s) and sections(s) will automatically get enabled.

Google Chrome - New Browser from Google

2008-09-02T11:03:00.004+05:30

I do not usually post news items. But this is BIG. Google is going to launch their own Browser called Google Chrome.

BBC

Google Blog

Google Books

More Info

More on Strategy Pattern

2008-08-22T16:17:00.002+05:30

I am not sure whether my previous blog post about Strategy Pattern had good practical examples. Since I am currently working on a module where I had to use Strategy pattern, I thought of explain more on that topic.

My current work involves invoicing module. Unfortunately I am not at liberty to explain the whole scenario. Let’s assume that there are several invoice types which uses different calculations and logics to calculate invoices.

For the example let’s use two simple invoice types. Fixed Invoice type has a fixed value for every month and RateBased Invoice type value always changes according to the services provided.

InvoiceJob object is the triggering point of all the invoices and Invoice Job has the type of Invoice as well.

Let’s start with the interface definition for the algorithm objects.

public abstract class JobType
{
public abstract void Run(int JobId);
}

And then lets create the algorithm Objects.

public class FixedInvoice:JobType
{

public override void Run(int JobId)
{
//TO DO - Implement Process
}
}

public class RateBasedInvoice:JobType
{

public override void Run(int JobId)
{
//TO DO - Implement Process
}
}

Now Let’s create an Invoice job Object which holds an Invoice job and which will also have a property to set which JobType Algorithm needs to be used.

public class InvoiceJob
{
private JobType jobType;

public void SetJobType(JobType newJobType)
{
this.jobType = newJobType;
}

public void Run(int JobId)
{
jobType.Run(JobId);
}

}

Now let’s have a look at how to consume this InvoiceJob class with different Algorithm objects…

public class InvoiceProcess
{

public void ProcessInvoices()
{

// TO DO - Get All Invoice Jobs in to Data Table “InvoiceJobs”

foreach (DataRow dataRow in InvoiceJobs.Rows)
{
//Get the Job Id to the Variable “InvoiceJobId”

// TO DO - Get the Invoice type in to “InvoiceTypeId”

InvoiceJob invoiceJob = new InvoiceJob();

switch (InvoiceTypeId)
{
case 1:
//Type 1 means Fixed
invoiceJob.SetJobType(new FixedInvoice());
break;
case 2:
//Type 2 means Ratebased
invoiceJob.SetJobType(new RateBasedInvoice());
break;
}

invoiceJob.Run(InvoiceJobId);
}
}

}

How to enable Enable "clr enabled" configuration option

2008-08-06T16:58:00.001+05:30

If you are working with SQL server CLR objects there’s a higher possibility that you might encounter the following error.

“Msg 6263, Level 16, State 1, Line 1
Execution of user code in the .NET Framework is disabled. Enable "clr enabled" configuration option”

To overcome this, you have to reconfigure the SQL server to enable CLR objects. To do that, you can use the following commands…

exec sp_configure 'clr_enable','1'

RECONFIGURE

Note : - CLR objects only works with SQL server 2005 and later versions.

CLR Objects tutorial

More about MSN is-thatt-you.com and TST Management Inc

2008-08-05T17:23:00.003+05:30

I had enough spare time today to do a detailed research on is-thatt-you.com website. But unfortunately other than my previous post related to is-thatt-you.com there’s nothing much available in the web. But I found that Is-thatt-you.com has few other domain names as well.

datsyou.com
thatzyou.com
is-thatt-you.com
is-dat-u.com.

All those are phishing sites (“in computing, phishing is the criminally fraudulent process of attempting to acquire sensitive information such as usernames, passwords and credit card details, by masquerading as a trustworthy entity in an electronic communication.” - Wikipedia) which beg you to give your username and password to them. Fortunately Firefox 3 recognizes most of those as phishing sites.

A search on TST management Inc which claims who own the copyright of is-thatt-you.com reveal that so called TST management have done these sorts of scams before with MySpace as well.

So no matter whether you are a newbie or an elite user, next time when you are using your personal usernames and passwords make sure to check whether that is a legit site or a phishing site. Phishing filter will do 50% of the work, and the rest 50% is up to you.

Useful links

MySpace Scam details
More about Phishing

Suspicious website - http://is-thatt-you.com/

2008-08-04T16:57:00.008+05:30

Today I got an offline message from one of my friends through MSN. It was a URL for a site called is-thatt-you.com. The URL was http://myusername.is-thatt-you.com

When I go to that web site, it prompted me for sign in using my Windows LIVE ID and password.

I googled about is-thatt-you.com and it returned couple of results. All those said this domain looks suspicious, but none of those posts had any hardcore evidence. So I had a look at their terms and conditions of this so called is-thatt-you.com website.

"By filling out this form, you authorize TST Management, Inc to spread the word about this 100% real and upcomming Messenger Community Site.
You will receive your share of the credit in helping us spread the word. This is a harmless Community site which is offering users a platform to meet each other for free

We may temporarily access your MSN account to do a combination
of the following:
1. Send Instant Messages to your friends promoting this site.
2. Introduce new entertaining sites to your friends via Instant Messages.

You understand that this agreement shall prevail if there is any conflict between this
agreement and the terms of use you accepted when you signed up with MSN. You also understand that by temporarily accessing your msn account, TST Management, Inc is NOT agreeing to MSN's terms of use and therefore not bound by them. "

WTF? Are we insane to give out our MSN account details to a frigging 3rd party and let them send instant messages to our friends using our own accounts?

I am not sure either this is legal or ethical. But please be aware of these sort of sites.

Restore Active Desktop (Win XP) JavaScript Error

2008-08-01T11:26:00.002+05:30

Have you ever encountered Active Desktop Recovery screen while working with Win XP?

And the worst part is, sometimes when you try to restore, you get an ugly error saying there is a JavaScript error in "desktop.htt" file and you are stuck with Active Desktop recovery screen.

Fix

Run Regedit

Navigate to: HKCU\Software\Microsoft\Internet Explorer\Desktop\SafeMode\Components

Change the DeskHTMLVersion key from 272 (Hex: 110) to 0 and reboot. The original desktop should now be back.

ASP.NET ImageButton form submission problem on Enter key press

2008-07-30T15:06:00.002+05:30

I am sure most of the developers have come across creating forms with multiple textboxes and corresponding buttons.

And if a user press enter on any of the textboxes in the form, the default button (unless not specified, it will be the first rendered button which will be the default button) on click event triggers.

But you can easily fix this by setting UseSubmitBehavior="false" on each and every button.

But what if you are using an imagebutton(s) in the form as well? Unfortunately imagebutton doesn’t have UseSubmitBehavior property.

One way of fixing this is use a normal ASPX button instead of an imagebutton and then set the image as background image for that particular button using CSS.

protected void Page_Load(object sender, EventArgs e)
{
btnMyButton.Attributes.Add("style", "position: relative; background:url(" + Request.ApplicationPath + "images/refresh.jpg) no-repeat; border:none 0px; width:25px; height:25px; vertical-align:top; cursor:pointer;");
}

Set ASP.NET session variables with JavaScript

2008-07-21T17:06:00.004+05:30

Is there any possible method to directly set ASP.NET session variable with JavaScript? NO. You cannot directly set a session variable via JavaScript. But there is a work around.

In the early days of classic ASP, we achieved this by using a hidden frame and use a server post back behind the scene.

But with AJAX, we no longer need hidden frames. All you have to do is, create a new page which accepts the parameters you need to set and then call that page with necessary parameters.

JavaScript

var url = "SetParams.aspx?ProjectCode= " + ProjectCode;
req = new ActiveXObject("Microsoft.XMLHTTP");
req.open("POST", url, true);
req.send();

SetParams.aspx

private void Page_Load(object sender, System.EventArgs e)
{
if(Request.QueryString["ProjectCode"] != null)
{
Session["ProjectCode"] =Request.QueryString["ProjectCode"].ToString();
}
}

How to get Perfect Achievement in Bowling Buddies

2008-07-11T10:33:00.007+05:30

I am sure most of you have seen the following video, and probably have tried it too.

When it comes to achieving a strike there are three obstacles.
1. Starting placement of the ball
2. If you move the mouse the ball will curve and take a different path
3. keeping the ball on an average speed

You can overcome the 2nd problem by reducing the size of the screen. To overcome the 3rd you have to use the mouse wheel to shoot the ball. First you have to find a starting position. This initial position always works for me.

Scroll your mouse wheel to the bottom of the page, then pick up the ball and line up for a strike (once you get a strike you'll know where) then hold the mouse steady in that position and simply scroll your mouse to the top of the page.. doing so will send the ball in a straight line down the alley every time from exactly where you line it up..once u get the hang of it u can constantly score perfect games all the time!

Good luck and good bowling:

Active Directory Authentication with Custom UI

2008-07-10T12:21:00.006+05:30

No matter whether you are working with a Win App or a web app, you can use the following class to authenticate a client using Active Directory and a custom User Interface.

Class

using System.Text;
using System.Collections;
using System.DirectoryServices;
using System;

public class LdapAuthentication
{

private string _path;
private string _filterAttribute;

public LdapAuthentication(string path)
{
_path = path;
}

public bool IsAuthenticated(string domain, string username, string pwd)
{
string domainAndUsername = domain + @"\" + username;
DirectoryEntry entry = new DirectoryEntry( _path,
domainAndUsername, pwd);
try
{
// Bind to the native AdsObject to force authentication.
object obj = entry.NativeObject;
DirectorySearcher search = new DirectorySearcher(entry);
search.Filter = "(SAMAccountName=" + username + ")";
search.PropertiesToLoad.Add("cn");
SearchResult result = search.FindOne();
if (null == result)
{
return false;
}
// Update the new path to the user in the directory
_path = result.Path;
_filterAttribute = (string)result.Properties["cn"][0];
return true;
}
catch (Exception ex)
{
throw new Exception("Error authenticating user. " + ex.Message);
}
}
}

Usage of Class

string adPath = "LDAP://DOMAINNAME";
LdapAuthentication adAuth = new LdapAuthentication(adPath);
if(adAuth.IsAuthenticated(txtDomain.Text,txtUser.Text,txtPassword.Text))
{
//This means the user has Authenticated
}

Strategy Design Pattern with C#

2008-07-10T10:26:00.006+05:30

As developers we all know the pros and cons of using design patterns. So I am not going to discuss those in my post. When I started learning design patterns one of the problems I faced was, design patterns samples were mostly for ultra geeks who lives within the code.

My objective here is to present Strategy design pattern with some real world cases where you can utilize it fully in your future coding endeavors.

Let’s imagine a case where you are supposed to build a simple payroll application, where there are three levels of employees (Worker, Executive and Manager). And also the company has three different methods (calculation logic) to calculate salary for these different types of employees.

So without any patterns our class will be like

public abstract class Employee
{
public virtual void CalculateSalary()
{

}
}

public class Manager : Employee
{
public override void CalculateSalary()
{
//Manager Salary Calculation goes here
Console.WriteLine("Manager's Salary is X");
}
}

public class Executive : Employee
{
public override void CalculateSalary()
{
//Executive Salary Calculation goes here
Console.WriteLine("Executive's Salary is Y");
}
}

With this we have to maintain separate codes for different version of the class. If the number of categories gets higher (which is the actual case in a real world scenario), code will be hard to maintain and for each and every deriving class you have to write your own code which is very tedious.

To overcome this, we can use Strategy design pattern. With Strategy pattern we can replace the overriding codes by an algorithm object.

With the usage of strategy pattern the code would be look like

public interface CalculateSalaryAlgorithm
{
void CalculateSalary ();
}

public class CalculateForManager : CalculateSalaryAlgorithm
{
public void CalculateSalary ()
{
//Manager Salary Calculation goes here
Console.WriteLine("Manager's Salary is X");
}
}

public class CalculateForExecutive: CalculateSalaryAlgorithm
{
public void CalculateSalary ()
{
//Executive Salary Calculation goes here
Console.WriteLine("Executive's Salary is X");
}
}

public abstract class Employee
{
private CalculateSalaryAlgorithm calculateSalaryAlgorithm;

public void SetAlgorithm(CalculateSalaryAlgorithm algorithm)
{
calculateSalaryAlgorithm = algorithm;
}

public virtual void CalculateSalary ()
{
calculateSalaryAlgorithm.CalculateSalary ();
}
}

public class Manager : Employee
{
public Manager()
{
SetAlgorithm(new CalculateForManager());
}

}

public class Executive : Vehicle
{
public Executive()
{
SetAlgorithm(new CalculateForExecutive());
}

}

class Program
{
static void Main(string[] args)
{
Manager myManager = new Manager ();
Executive myExecutive = new Executive ();
myManager.CalculateSalary ();
myManager.CalculateSalary ();
Console.Read();
}
}

Happy coding!

http://www.dofactory.com/Patterns/PatternStrategy.aspx

Visual Studio 2008 IDE crashes with Mouse Wheel

2008-07-08T15:11:00.008+05:30

While playing the Facebook game, Bowling Buddies, I reset the mouse scroll settings to one screen at a time.

And when I go back to Visual Studio and started to scroll through code view using the mouse Wheel, Visual Studio crashed. I tried several times, and the problem remained the same even after a reboot.

Then I googled, and found that it’s a known bug with Visual Studio IDE, that it doesn’t support One screen at a Time Scrolling. Now I reset the mouse wheel scroll settings to X number of lines at a time and Visual studio works perfectly.