Sanjivani Kumar

Blog has been moved

2010-05-27T14:21:00.002+08:00

My blog has been moved to http://sanjivanipant.com. Please visit new link for blogs.

Accessing and Setting Properties via Reflection

2010-05-11T13:38:00.005+08:00

.NET gives us a cool feature called Reflection using that we can access object’s properties and methods at run time. The classes which help us in using this feature are all in System.Reflection namespace. That means you will have to add this namespace in the class where you will be writing reflection code. So basically, when object type is unknown at design time, we can’t access its properties until we don’t know what properties object possesses. In such situation we can access object properties at runtime using Reflection.

Let’s head towards building a small example,

I have Red and Blue forms in my project and for both the forms I want to show a label on the form when form is in focus and make that label invisible when form is not in focus.

I have a common library where I have ShowBusy() method. Red and Blue form calls this method to get label visible and invisible on Enter and Leave events respectively.

Both forms also have two more properties:

1. GetProgressLabel: It is a read only property which will return progress label.

2. IsInProgress: This property will possess form’s status whether form is in progress or not. Once ShowBusy is done for a form, it can update this property for a form.

So Blue and Red form’s code looks like below:

Blue Form:

public partial class frmBlue : Form

{

private bool _isInProgress;

clsProgress objprog = new clsProgress();

public frmBlue()

{

InitializeComponent();

}

private void frmBlue_Enter(object sender, EventArgs e)

{

objprog.ShowBusy(this, true);

}

public Label GetProgressLabel

{

get { return lblProgress; }

}

public bool IsInProgress

{

get { return _isInProgress; }

set { _isInProgress = value; }

}

private void frmBlue_Leave(object sender, EventArgs e)

{

objprog.ShowBusy(this, false);

}

Red Form:

public partial class frmRed : Form

{

private bool _isInProgress;

clsProgress objprog = new clsProgress();

public frmRed()

{

InitializeComponent();

}

private void frmRed_Enter(object sender, EventArgs e)

{

objprog.ShowBusy(this, true);

}

public Label GetProgressLabel

{

get { return lblProgress; }

}

public bool IsInProgress

{

get { return _isInProgress; }

set { _isInProgress = value; }

}

private void frmRed_Leave(object sender, EventArgs e)

{

objprog.ShowBusy(this, false );

}

In the common Library, I have a class clsProgress in which I have defined ShowBusy as below:

public class clsProgress

{

public void ShowBusy(object sender, bool busy)

{

//Make Progress Label Visible/Invisible

#1 Type SenderType = sender.GetType();

#2 PropertyInfo pi = (PropertyInfo)SenderType.GetProperty("GetProgressLabel");

#3 MethodInfo mi = pi.GetGetMethod();

#4 System.Windows.Forms.Label lbl = (System.Windows.Forms.Label)mi.Invoke(sender, null);

#5 lbl.Visible = busy;

//Set IsInProgress property of the form

#6 PropertyInfo pi1 = (PropertyInfo)SenderType.GetProperty("IsInProgress");

#7 pi1.SetValue(sender, busy, null);

}

In the ShowBusy method, we have code to make form’s progress label visible/invisible. It also has logic to set IsInProgress property of the form.

In this case, it would have been difficult to access sender’s property directly because at design time it is not known for which form ShowBusy is called. Another point to be noted is, Common Library project does not have reference of Red and Blue form project, so if you are thinking of having alternate way of achieving this by adding if conditions then casting to red and blue form then it won’t be possible. To cast it to Red and Blue form, you will need to have Blue/Red form project reference added in Common Library. So we adopted the Reflection here to access and modify object’s properties.

Let’s understand what we have done in ShowBusy:

#1 : We are extracting the type out of sender object

#2 : Using the extracted type we are extracting GetProgressLabel property and storing the property information in PropertyInfo object.

#3 : It returns the “Get” accessor of the GetProcessLabel property.

#4 : Invoke method on MethodInfo object will invoke the get property and return its value.

#5 : At line #4 we got the form’s label, so accessing Visible property and setting it.

#6 : Like step #2, extracting IsInProgress property.

#7 : To set property value, we have SetValue method. Please have a look onto http://msdn.microsoft.com/en-us/library/xb5dd1f1.aspx to understand SetValue method’s parameters.

You can download the example from here.

Introduction to C# 3.0 features – Part I

2010-04-29T13:56:00.005+08:00

There are many cool features available in C# 3.0 vis

Extension Methods
Implicitly Typed Local Variables
Lambda expressions
Object Initializers
Anonymous types
Implicitly typed arrays
Query expressions
Expression trees

Out of these cool features, I would like to write about Extension Methods first. I would write about C# 3.0 features in my subsequent articles.

Most of the times we tend to code in our traditional way and ignore such a cool features which are available to make developer’s life easy. For example, a developer like me who mostly worked on Framework 2.0 will hardly dare to spend more time in trying new alternate available way, in care of dead line J I would suggest be familiar with new features, trying it in dummy samples and be ready to use in your real projects.

Before heading towards Extension methods… let’s consider we have to create a method to reverse a string. So our usual approach would be to write a method accepting a string parameter, writing logic to reverse a string and returning a reversed string. Below is the code, we might have coded for this requirement.

class Program

{

static void Main(string[] args)

{

String myString = "Sanjivani";

Program obj = new Program();

String reverseString =obj.Reverse(myString);

Console.Write(reverseString);

Console.ReadKey();

}

string Reverse(string str)

{

char[] arr = str.ToCharArray();

Array.Reverse(arr);

return new string(arr);

}

Well, now heading towards Extension Methods…

Like name suggest, Extension Methods are extensions to typed instances. Extension Methods are static methods that can be invoked using instance method. For example when we have string type variable we get many built in methods and properties like...

strObj.Replace()

strObj.Split()

strObj.SubString()

ect

In the same way we can make our Reverse method available like strObj.Reverse(). So Reverse method will be available for all instances which are of string type.

Like we have Utility or common classes for our projects, we can have extension library having methods which works on a type.

Implementing Extension Methods:

Let’s convert same Reverse method into an extension method. I created new class for all extension methods as below:

public static class ExtensionLib

{

public static string Reverse(this string str)

{

char[] arr = str.ToCharArray();

Array.Reverse(arr);

return new string(arr);

}

If you notice, the changes I have method to the function are:

1) Introduced this before first parameter. First parameter’s type will always tell compiler that, that extension method is going to operate on the type used for first parameter.

2) Added public and static modifiers to Reverse method

3) Note that new class also has public and static modifiers

You are ready to use this extension method now:

class Program

{

static void Main(string[] args)

{

String myString = "Sanjivani";

Console.Write(myString.Reverse());

Console.ReadKey();

}

Please note that, my Extension method class and the program where I wanted to use this extension method were in same namespace, so I did not add extension method namespace in my Program class. But if both are in different namespaces, you will have to add extension method class namespace in your client program.

Your comments and knowledge on the topic are always welcome. I will appreciate your contribution :)

Shantaram

2010-03-28T10:45:00.009+08:00

I recently completed “Shantaram” book and picked up new book in my hand “Superstar India” by Shobha De and I realized I should write my feelings for Shantaram before getting involved in another book. It took approximately six months to me to complete Shantaram, there were many gaps in between though. Now after completing this book, definitely I am going to miss Shantaram reading in my daily life...

I came to know about the book from my husband. I was not much involved into reading books before marriage. After marriage I started getting more time in MRT (local trains) so I took these opportunities to read books from my ever dreamed list. But Shantaram was not in my list. I took time to pick up that book to read, thinking this is so big book and I was afraid that I won’t complete the book. I thought to read other books first and I did so and after 3-4 books I picked up Shantaram in my hand. I heard so much praise about this book from my husband that I could not wait any more and finally picked up the book.

The impression I was having before reading this book was, this is a true story (non fiction), my husband told that to me intentionally. And I was expecting a lot from this book then, I was curious to know how was Shantaram/Lin’s (author and main character in the book) in India. Most of the people definitely take bad and good experiences in their life. Few can be very serious and critical which the person might feel, it can only happen with him. I do also have faced many realities in my life and I was just thinking, will my any of experiences matches with him (I know that is crazy to think like that :D). But even there might have been same experience; definitely a foreigner will perceive that in different way. I haven’t been to any WAR or worked for any MAFIA.. but the common thing I found in Lin’s life experience is to live in slum with no option in hand. Seeing slum’s life so closely and observing people there. I never told this to anybody in my life, but my best and close friends know this.

Anyway, one of the thing which was responsible towards my curiosity was, after I started this book, many people came to me and were asking me, oh you are reading Shantaram.. and they were curious to know how I am finding that. So they may get their answer here :)

When I started with first chapter, I realized I have to definitely keep dictionary with me if I really want picture author’s story, though I was getting its meaning from its context, I was so excited to grabs each and every aspect of the book.. indeed I was so excited to read that book with my full heart dedicated to that book. At the beginning I did refer to dictionary and obviously that I did not find it that interesting that I was thinking. I took a break of few days and again started the book with full determination. This time I did not care about adverbs author used and just went on.. I did grab all the context from the book.. may be I might missed few of the true meaning but I got its meaning, whole meaning of the book and I am thinking I may read this book again after few years.

Initial few chapters are not of just introduction of characters and author has excellently described those characters in his book. In fact I can imagine those characters. In my office, I have a team mate, and I found character of Prabhakar exactly matches with him. So whenever I see my team mate it reminds me of Prabhakar. So even there would be years after reading this book, character s of Shantaram book will remain always in my mind. Not only Prabhakar, but I found a girl in my office, and she reminds me of Karla :) I imagine, if Karla would be in real life, she must have to be like her (in appearance).

I enjoyed the book, especially when suspense’s started coming in the story. And I was so eager to read next pages to know what I am thinking as an answer to that suspense is true or not :)

Shantaram, is not of one type of book, which we can say it is a romantic book or it is a suspense or thriller book. I found it is ALL. It has thriller, suspense, romance, comedy, action (lot of actions :)) And just imagine when you are reading the book, and you know it is a true story how interesting that would be. But then I got to know not the entire book is true. I watched Gregory David Robert’s video on You Tube and got to know all events in this book are real and characters are friction. But when you will read the book, it is unbelievable that those character’s descriptions are fiction. Hats off to Gregory David Roberts and congratulations too! He has succeeded in describing characters as real ones.

I did not enjoy Afghanistan War part much because I was just curious to know suspense’s. And in my thoughts those long Afghanistan chapters were not related to the suspense’s which answers I was looking for. But ending of Afghanistan gives you more pleasure because there you will discover something important :), So then I realized it has also a meaning to read those Afghanistan war chapters. But you know it really need patience to complete those Afghanistan war chapters.

In many of the points, I was feeling like crying and sad however most of the moments were so romantic. I wish I could describe those moments here but it will reveal surprises involved in the book so I won’t write about any of the moments here.
Since it has all Mafia and Underworld related stories, be ready to get familiar with abusing language. But it also gives a decent society an idea how underworld people think and live and this language is part of their life, I think without those that languages they can’t survive or express themselves :)

I like all characters of the book, but if they were real characters I would definitely like to meet Prabhakar, Karla, of couse the king Kadar Khan, Dadier, Lisa.

I don’t want to reveal any of the event of the book because I don’t want to spoil your reading and give you presumptions.. go for the book and discover your own perceptions.

So, I found the book very good and after completing the book I still miss the book, I wish there would be more chapters to that :)

Using statement/keyword in C#

2010-03-22T13:47:00.004+08:00

I came across a question “What is use of using in C#” and I decided to write on it. I hope this blog will help you in knowing “using” statement/keyword better.

The Basic Syntax:

1) For one object

using (MyClass objMyClass = new MyClass())

{

//Use objMyClass

}

2) For Multiple objects

using (MyClass objMyClass = new MyClass(),

objMyClass1 = new MyClass())

{

//Use objMyClass and objMyClass1

}

3) Syntax 3 (Not recommended)

MyClass objMyClass = new MyClass()

using (objMyClass)

{

//Use objMyClass

}

// objMyClass can be used out of using block as well

We will see why it is not recommended in this blog later. If I explain it here then you may not follow it without knowing its main use first.

“using” statement can be used in following scenarios.

Scenario 1: Importing namespace

A well known use of “using” keyword is for importing namespace into classes.

Examples:

using System.Collections.Generic;

using System.Linq;

using System.Text;

Scenario 2: Disposing object automatically

If object is delcared in using statement (like shown in syntax 1), that object becomes out of scope and get destroyed as soon as it leaves using block.

In the syntax 1, the care has to be taken that MyClass should implement IDisposable interface. That means, we can’t declare object of the class which do no implement IDisposable.

My MyClass class looks like below:

class MyClass:IDisposable

{

// Track whether Dispose has been called.

private bool disposed = false;

// Pointer to an external unmanaged resource.

private IntPtr handle;

// The class constructor.

public MyClass(IntPtr handle)

{

this.handle = handle;

}

public MyClass()

{

}

public void DisplayName()

{

Console.WriteLine("MyClass\n");

Console.ReadKey();

}

#region IDisposable Members

public void Dispose()

{

// throw new NotImplementedException();

Dispose(true);

// This object will be cleaned up by the Dispose method.

// Therefore, you should call GC.SupressFinalize to

// take this object off the finalization queue

// and prevent finalization code for this object

// from executing a second time.

GC.SuppressFinalize(this);

}

#endregion

// Dispose(bool disposing) executes in two distinct scenarios.

// If disposing equals true, the method has been called directly

// or indirectly by a user's code. Managed and unmanaged resources

// can be disposed.

// If disposing equals false, the method has been called by the

// runtime from inside the finalizer and you should not reference

// other objects. Only unmanaged resources can be disposed.

private void Dispose(bool disposing)

{

// Check to see if Dispose has already been called.

if (!this.disposed)

{

// If disposing equals true, dispose all managed

// and unmanaged resources.

if (disposing)

{

// Dispose managed resources.

// component.Dispose();

}

// Call the appropriate methods to clean up

// unmanaged resources here.

// If disposing is false,

// only the following code is executed.

CloseHandle(handle);

handle = IntPtr.Zero;

}

disposed = true;

}

// Use interop to call the method necessary

// to clean up the unmanaged resource.

[System.Runtime.InteropServices.DllImport("Kernel32")]

private extern static Boolean CloseHandle(IntPtr handle);

// Use C# destructor syntax for finalization code.

// This destructor will run only if the Dispose method

// does not get called.

// It gives your base class the opportunity to finalize.

// Do not provide destructors in types derived from this class.

~MyClass()

{

// Do not re-create Dispose clean-up code here.

// Calling Dispose(false) is optimal in terms of

// readability and maintainability.

Dispose(false);

}

To just test if we can declare object of class without having IDisposable interface, try to execute following code:

using (MyClass1 objMyClass1 = new MyClass1())

{

objMyClass1.DisplayName();

}

And here MyClass1 looks like:

class MyClass1

{

public void DisplayName()

{

Console.WriteLine("MyClass\n");

Console.ReadKey();

}

You will get following error:

'UsingKeyword.MyClass1': type used in a using statement must be implicitly convertible to 'System.IDisposable'

The reason for not allowing classes without IDisposable interface is:

“using” statement is shotcut to try/catch/finally block, having Dispose method call in finally block.

Thus,

using (MyClass objMyClass = new MyClass())

{

//Use objMyClass

objMyClass.DisplayName();

}

is similar to

MyClass objMyClass = new MyClass();

try

{

objMyClass.DisplayName();

}

finally

{

if (objMyClass != null)

((IDisposable)objMyClass).Dispose();

}

Thus, we get following benefits from “using”:

1. It ensures that using statement calls the Dispose method on the object in the correct way.

2. Within the using block, the object is read-only and cannot be modified or reassigned.

3. The using statement ensures that Dispose is called even if an exception occurs while you are calling methods on the object.

4. If you declare any un-managed object in using block, you don't need to explicitly dispose that object. Once the block execution is over, the Dispose will be called automatically.

Scenario 3: Taking care of multiple objects at the same time (Syntax 2)

We can pass multiple object of the same type to using statement. We cannot create multiple objects of different types in one using block. Thus if I write syntax 2 as below, then it is invalid.

using (MyClass objMyClass = new MyClass(),

MyClass1 objMyClass1 = new MyClass1())

{

//Use objMyClass and objMyClass1

}

That is the reason, we don’t have to write type name from second object onwards. In below example, we cannot give type of the class name for second object since it is understood that, type will be same as used for first object.

using (MyClass objMyClass = new MyClass(),

MyClass objMyClass1 = new MyClass())

{

//Use objMyClass and objMyClass1

}

Scenario 5: Aliasing to namespaces

// Define an alias for the nested namespace.

    using Project = PC.MyCompany.Project;

Scenario 5: Aliasing to classes

Like aliases to Namespaces we can have aliases to classes as well.

// Using alias for a class.

using AliasToMyClass = NameSpace1.MyClass;

Answer to why Syntax 3 is not recommended

Wait! Don’t scroll to look at syntax 3, to help you to understand it better, I have put it below J

MyClass objMyClass = new MyClass()

using (objMyClass)

{

//Use objMyClass

}

// objMyClass can be used out of using block as well

As we know by now, unmanaged resources referenced/used by object get destroyed as soon as it leaves “using” block. So even object is accessible after using block, it may not have access to unmanaged resources and if we try to access object, it may be risky to use it because object may not be available in fully initialized state. For this reason, it is generally better to instantiate the object in the using statement and limits its scope to the using block.

References:

http://msdn.microsoft.com/en-us/library/yh598w02.aspx

http://msdn.microsoft.com/en-us/library/system.idisposable.dispose%28VS.71%29.aspx

BSNL keeps us busy!

2010-03-02T10:27:00.014+08:00

I read one of my friend’s blog yesterday. After enjoying those funny instances people faced dealing with BSNL officers, I am willing to share one more story.
We recently moved to new home which is just attached to Nagpur. It’s just geometrical boundary but we still feel living in Nagpur. Anyway, so there has to be an application for transferring our telephone and Internet line. I think my father logged an application on 22th Jan 2010. When my father logged the application, they assured phone will be transferred within 3-4 days knowing what area we were transferring to. After a week my father visited Nagpur BSNL office, there was no one in the office during office hours. Staff might have gone for tea party together: D After searching whole BSNL office, my father found one officer, and his response was, wait.. “chaparasi” (office boy) should come in sometime, he can guide you to whom to contact. : D Wasn’t that funny! My father waited and returned to home wasting his time there. Then again on next week, my father visited BSNL office and a lady told that your application had been entered in computer so other department would process it soon. But when nothing happened after another week, my father called to BSNL office, and that lady said, you contact Bootibori department, you will get your work done there. My father asked her Bootibori’s phone no, she said we don’t have, you will have to go there. One BSNL office does not have other BSNL office nos.. what a lie! These are government employer who meant to be there for public help but they just give unnecessary headaches. My father visited Bootibori office, and office man asked my father to inquire in the same Nagpur BSNL office from where my father got Bootibori’s reference. My father told them, you people are just diverting me from here and there. They asked to inquire here and you are asking to inquire there. After few more days, when my father visited BSNL department and talked to the same lady and told her that she should call Bootibori office and order them that why my telephone line was not transferred yet, those people does not listen.. they should listen to you. And off course a lady was glad to call them and ask them in bossy tone. You know, government employees never miss chance to show bossy nature on others :p So guys, this is also one more trick to handle them, put them on cloud no nine and ask them to do what you want to do . After hearing many excuses like "Cable cant reach till your home”, “Phone repairing man is not available now, call later" "I am on scooter now, call me later" from Bootibori BSNL office, in one of the visit to their office, Bootibori BSNL man told my father that they cannot transfer the line because new area comes under Gramin (village) area. Isn’t it clear that government employees are working to keep us busy… It took more than a month to get true response which they should give while applying for transfer itself. They should know to which areas they can transfer phone lines. And during this month when there was no service, they promptly sent phone and internet bill which is 1254.00. Finally we submitted the phone and canceled the line.
When I think of these government offices, I really wonder..Why people in government office take their job responsibilities for granted? Why don’t they bother to make the process smooth and efficient? Aren’t managers aware of corporate trainings? Why can’t they empathize others problem? Why can’t they think how much trouble they give before responding a lame response to public? I wish someone from government office visit this blog and answers me these questions.

IT Experience!

2009-11-19T00:06:00.000+08:00

"Experience does not matter, only knowledge matters"...."There is no need of having yrs of experience to become a Team Lead"..."One does not know as per one's experience"... such sentences and many more similar sentences I hear from people. When I mulled over this, it is true in one sense that knowledge we gain from our experience matters. But what knowledge people mean here, writing code, learning new programming languages or new technology.. Is that the only knowledge qualified to call it as a real experience? I see many people who works very well, who have good command over technical skills but they lack in many things such as communication (not fluency but clarity in thinking and listening to others), team work, positive thinking, professionalism. What technical knowledge you gain over years that depend upon the project you have worked on so that is partially not in our hand to gain quality of technical experience (why partially because we can learn technical things on our interest).. but other experience which people automatically gains and which is not in their control to refuse not to gain is the professionalism, learning how to talk in team, how to communicate among team members, how to take things positively. If a person says he has so and so yrs of experience that means he has that much maturity and professionalism in him. So irrespective of technical knowledge gained over years and the quality of project one has worked on, we should give due respect to a person for his number of years experience.

I used to concentrate on my technical skills.. that time I was not knowing there are other important things also I have to concentrate upon. Sometimes I had misunderstood people and taken things wrongly. I thank to my last company (Infospectrum India Pvt Ltd), who made me realize this. We had been given trainings to know importance of team ethics, importance of punctuality, importance of listening to others and the way we should take others feedback into consideration rather considering it as criticized statements. I feel my Infospectrum experience was indeed quality experience for me. Now, I am in different country, Singapore… and here I am working in different surrounding so I am still learning new things day by day and helping myself to be better day by day.

So, if you want to make your work experience fully sensible and qualified, do notice and observe the things surrounding you, don’t just concentrate on your technical knowledge. Along with technical knowledge, team ethics and positive thinking also matters. Now, when we say technical knowledge depends on projects we work, in the same sense, team ethics and other things which I mentioned, depends upon the culture and surrounding you work in. It is better if we concentrate on self improvement along with our technical knowledge improvement. If you can analyze and think, you can gain from your surroundings. If you feel your surrounding can not give you as much as you wish, start reading self help books and be a better man ( you are already a good man), more positive thinker and a best team member which will help you in long run in your professional and personal life.

My first swimming in Singapore (2nd July 2009)

2009-07-03T12:43:00.000+08:00

Whooah Swimming! When I recall my India's days, one of the memorable things is my swimming classes. I can’t forget the feeling I had before joining the classes and while learning the swimming. The same feeling I was experiencing today in addition to my eagerness to know how swimming pools are here in Singapore. I was excited to know how the changing rooms here are. There was no doubt in swimming pool safeness but was eager to know how pools here are different than in Nagpur.

I brought new swim suit, goggles, and cap. And with my bag ready I reached at the swimming complex at 7.30 evening. Here we (Rajesh and I) saw few ticket accepting machines and which was allowing entering people after inserting ticket. We brought two tickets and were searching in which machine we have to insert the ticket because all machines were labeled as "Child". One of the children's tickets accepting machine accepted our ticket :D As soon as I entered inside the complex, I looked around. The scene was so colorful and beautiful. There were four pools. One for small children, one for average age kids, one was for adult learners and last one for professional swimmers.

I was so excited and little thrilled also. After almost a year I was going into the pool and I was not sure if I still remember the swimming that I learned in Nagpur.

I waited for my instructor almost 45 mins. I was getting energized looking others swimming and was not wanting to wait anymore and I headed towards changing room. But the same time my instructor reached there. It was totally new environment and I was going to swim with Chinese people around me. I was little nervous at the beginning and was little worried if I could understand my instructor's English :D

After changing I entered into the pool. I used to swim in 1.2 meter deep water but I was getting feeling like I entered into much deeper water. Water depth just intimidated me and I suddenly I got so nervous that my heartbeats went up. I was just trying to get comfortable in the water and all of sudden my instructor asked me to show her what I know. I took 1-2 mins to relax myself and I recalled how I used to do freestyle and showed her freestyle. She taught me few exercises and few leg movements of breaststroke which I have to practice till next class. I liked her way of teaching, systematic and professional way. I enjoyed my first swim class and am looking forward to today swimming :)

Using hyperlinks in ASP.NET

2009-06-24T16:15:00.000+08:00

Hello Techies,

Now a day I am working on a project, in which I used master page. Initially I used html hyperlink in the pages, and I found it is not as easy as it seems in the blog tile (“Using hyperlinks in ASP.NET”). I came across a problem in dealing with hyperlinks. I would like to share the problem and its solution with you all.

Problem:
If we use html hyperlink in asp.net, it creates problem.

Problem Replication:
1. Create an asp.net web application project, HyperLinkError. Choose the language of your preference.
2. Web application will have Default.aspx file by default. Delete it.
3. Add Master page to the application
4. Add new web form in the application, Default.aspx. Make sure you select master page for it.
5. Write “Default Page” in Default.aspx content place holder to recognize default page.
6. Create a folder inside the project, let’s say “User”
7. Add form in User folder, let’s say UserDefault.aspx. Make sure you select master page for it.
8. Write “User Default Page” in UserDefault.aspx content place holder to recognize user default page.
9. Put following html in the master page. It will create two hyperlinks in the master page

10. Set Default.aspx as start page by right clicking the page in solution explorer.
11. Run the web application.
12. Web application will look similar to this:

13. Notice web URL http://localhost:xxxx/HyperLinkError/Default.aspx
14. Click on Home hyperlink, the same page will get displayed Ok
15. Click on "Click Me" hyperlink

16. Notice web URL, http://localhost:xxxx/HyperLinkError/User/UserDefault.aspx
17. Now click on Home hyperlink, it throws following error

18. Notice web URL, it is http://localhost:xxxx/HyperLinkError/User/Default.aspx
19. Now if you go back and click on "click me" web URL changes to http://localhost:xxxx/HyperLinkError/User/User/UserDefault.aspx showing above error
20. That means, if URL is changed to some other folder, it assumes it as root folder and tries to find pages at that path.

Resolution:
Replace HTML hyperlinks with asp.net hyperlink controls. Assign its Navigation URL as below. All is set, try running the application again.

Since, here is the restriction for attaching files, I can not attach dummy application for you. If you need dummy application for understanding the problem, mail me. I will back you back with the source files.

Thanks
Sanjivani

My first morning out in Singapore

2009-06-04T13:04:00.000+08:00

3rd June 09 Morning

Surprising it may sound but, this was first time I saw and felt morning in the Singapore. I have been living in Singapore since Feb this year but I could never wake up in the morning and got out to feel its fresh air, its coolness, its peace and calm environment. I had woken up in the mornings earlier also, but this was the morning I got fascinated with and I got forced to go out to feel it. In the bed, I was hearing breeze's voice. I woke up and opened the window of my bedroom ,which gets opened toward main road of the apartment. And I was happy to feel nice and fresh air.. which was moving tree's branches heavily. I never saw such a windy in Singapore before. What I don't like here is probably the one thing, which is I don't see windy environment. And obviously when I saw wind, I could not restrict myself at home. I called my hubby who was on his way to home from night shift.. and told him my feelings after seeing such a refreshing environment. He invited me for breakfast at Mc D. It was not first time he asked for breakfast out in the morning but my laziness took priority always. I was more interested in walking on streets and enjoying weather than breakfast but I took a chance and took promise from Rajesh that we will walk back to home rather taking a cab.
I totally enjoyed my walk towards MRT. It was around 8.45 AM. I totally forgot that Rajesh was waiting for me.. I was just full of my thought while enjoying the walk. I was looking around, was observing people doing there daily routines.. a mom taking her son to school on bicycle. A man cutting grass.. cleaning streets.. People rushing to their offices... Finally I realised Rajesh is waiting for me when I saw MRT was just across the road. By the time I met Rajesh it was around 9 pm.. We did shopping in the Pasir Ris mall so early in the morning.. had breakfast in KFC and returned to home by walk. We spent our time in shopping so much that when we were on the way to return home, sun had risen and it had warmed up an environment.

Thanks
Sanjivani

App_Data

2009-04-10T17:29:00.000+08:00

Hello Friends,
One of dotnetspider member raised a question on app_data in the forum, and that inspired me to write about this folder. I will explain why this folder resides in the web application. Its use and advantages.

Why App_Data folder:
App_Data folder reside in web application’s root folder. It is a reserved folder and it is there so that we can save our web site specific data related files such as database files (e.g. MS SQL Server, MS Access). You can have nested folders inside App_Data to organize your database files. One web site project can have only one App_Data folder.

To add database to App_Data, right click on the folder and select required data file. It provides you list of all possible data files.

To add existing database files, simply copy paste the files in App_Data and refresh the folder or go through Add existing files after right clicking the folder. Be aware of adding MS SQL server database files. You need to detach the database files first and then copy to the folder and reattach them.

Advantage of having App_Data folder:
1. It can be used for maintaining Membership(http://msdn.microsoft.com/en-us/library/yh26yfzy.aspx) and Roles managements(http://msdn.microsoft.com/en-us/library/5k850zwb.aspx)
2. If your web project is complicated enough like having *.cs and *.vb files, this folder will not get affected by that since it just saves your database files and to access database in all code behind files you can just use connection string of web.config file.
3. You can manage your database easily using server explorer

[The same article you can find here]

Cheers!
Sanjivani

After and Instead Of Triggers

2009-04-10T16:47:00.000+08:00

.NET Interview questions

After Triggers

“After triggers” are triggers which get fired after executing SQL statement. After triggers are also knows as “For triggers” or simple triggers. In the old version of SQL server (prior to version 2000), these are the only triggers available. After trigger fires after Insert, Update and Delete actions.

To understand After trigger in the real world, lets create a dummy table first on which a After trigger will be created.

To create a table, open Microsoft SQL Server Management Studio and click on the menu File->New->Query

Note: You will have to select a database in which you want table created.

Copy paste or type below SQL statement in query window and run the SQL.

Create table Mytable

( col1 int

)

Above Statement will create Mytable named table in the selected database.

Now let’s create After update trigger:

Create TRIGGER Mytable_trigger on Mytable After Update

Begin

Select * from Mytable;

Select * from inserted;

Select * from deleted;

Select '------------------------';

End

Above trigger is using “inserted” and” deleted” logical tables. This is the advantage we got in trigger. We can see new value updated or inserted in “inserted” logical table and old values which got replaced by new values in “deleted” logical table.

Now insert few rows into Mytable so that we can modify them and see how trigger react to them.

insert into Mytable values(1);

insert into Mytable values(2);

insert into Mytable values(3);

insert into Mytable values(4);

insert into Mytable values(5);

Now fire the following update statement in query window

Update Mytable set col1=col1 * 2

After firing the above SQL statement you will see following result in the result panel

Observe gthat Mytable values got updated already when trigger got fired.

As there can be multiple after trigger on a table, to set order of triggers, there is sp_settriggerorder standard stored procedure available.

Conclusion:

From above steps it is proved that After triggers are fired after Insert /Update/ Delete actions.

Instead Of Triggers

After triggers fire after update/insert/delete action whereas Instead Of triggers fire in place of insert/update/delete action.

There can be only one Instead of trigger of a type on a table.

To see how Instead If triggers works,

Change above created table using following SQL statements:

ALTER TRIGGER [dbo].[Mytable_trigger] on [dbo].[Mytable] Instead Of Update

Begin

Select * from Mytable;

print 'Not allowing to update values'

Rollback;

End

Now reset Mytable values by firing following statements:

delete from Mytable;

insert into Mytable values(1);

insert into Mytable values(2);

insert into Mytable values(3);

insert into Mytable values(4);

insert into Mytable values(5);

Now ready to see what happens if we update the values of Mytable. Fire following update statement and notice the result

Update Mytable set col1=col1 * 2

Conclusion:

Result shows value of Mytable which did not update . So instead of trigger give us option to implement other logic instead of actual action. We can still get updated values in inserted table in, in case we have to validate updated values and then commit those.

Happy Triggering!
Sanjivani Kumar