Well, the most important difference between String and StringBuffer/StringBuilder in java is that String object is immutable whereas StringBuffer/StringBuilder objects are mutable.
By immutable, we mean that the value stored in the String object cannot be changed. Then the next question that comes to our mind is “If String is immutable then how am I able to change the contents of the object whenever I wish to?” . Well, to be precise it’s not the same String object that reflects the changes you do. Internally a new String object is created to do the changes.
So suppose you declare a String object:
String myString = “Hello”;
Next, you want to append “Guest” to the same String. What do you do?
myString = myString + ” Guest”;
When you print the contents of myString the output will be “Hello Guest”. Although we made use of the same object(myString), internally a new object was created in the process. So, if you were to do some string operation involving an append or trim or some other method call to modify your string object, you would really be creating those many new objects of class String.
Now isn’t that a performance issue?
Yes, it definitely is.
Then how do you make your string operations efficient?
By using StringBuffer or StringBuilder.
How would that help?
Well, since StringBuffer/StringBuilder objects are mutable, we can make changes to the value stored in the object. What this effectively means is that string operations such as append would be more efficient if performed using StringBuffer/StringBuilder objects than String objects.
Finally, whats the difference between StringBuffer and StringBuilder?
StringBuffer and StringBuilder have the same methods with one difference and that’s of synchronization. StringBuffer is synchronized( which means it is thread safe and hence you can use it when you implement threads for your methods) whereas StringBuilder is not synchronized( which implies it isn’t thread safe).
So, if you aren’t going to use threading then use the StringBuilder class as it’ll be more efficient than StringBuffer due to the absence of synchronization.
Incase you do not know – Here’s how you use StringBuilder
A simple Example to demonstrate that String object is Immutable
Incase you still have any doubts regarding String or StringBuilder then do leave a comment. I’ll be more than eager to help you out.
Note: StringBuilder was introduced in Java 1.5 (so if you happen to use versions 1.4 or below you’ll have to use StringBuffer)

Interview is your first impression on your dream company after your resume. From clothes to conduct to language to information to skill – everything is important. Employers don’t just want a skilled person, they want a complete package of skills and soft skills. Questions may differ from industry to industry, but some dos and don’ts remain the same. Here are a few tips for your next interview:
Know yourself
Though more important for first timers, but even those who have worked for a few years tend to short sell themselves. Know your strong, weak and saleable points. Understand the job profile thoroughly and articulate your words accordingly.
Know the interviewer
In times of social networking and professional networking it’s very easy to know the person you are scheduled to meet. Try to look up the profile of the interviewer, it will help you conduct yourself in the right way.
Identify saleable points and talk well about them
You know your job and your achievements more than anyone. Be prepared and prioritise them in your head. Depending on the profile state nice and crisp without sounding verbose.
Do not keep personals on the table
This includes everything from - bag, wallet, mobile and also your elbows. In terms of body language, this is a complete no. Don’t rest yourself o the table and keep your bag near the chair you are sitting on.
Informal formality
That’s the style for an interview these days. You have to be proper, without being stiff.
Dress smart
Your dress up may not be the only thing, but it’s the first thing to be noticed. Wearing formals is safe and best. Stay away from T-Shirts and torn jeans. Comfort and cleanliness should be the motto.
Ladies, be minimal
We are asking you to dress smart and not provocative. Stay away from plunging neck lines or short skirts. Heavy duppattas and too much jewelry will also be difficult to handle and will distract both the parties.
If you don't know the answer accept it
It’s not necessary that everyone knows everything. Please do not cook up, if you don't know the answer say so. Don't jump to answer a question, take time to think.
Don't try to be a wisecrack
Sense of humour is great, but in an interview you will be judged for things which matter to the company. Be light hearted but don’t be frivolous. For phone interviews, don’t let sarcasm make way through your voice.
Everyone wants a positive person
This may sound like a cliche, but be good human being. Employers are looking for more than skills. Be smart, don't criticise and don't accept criticism, tackle it.
Learn from every interaction
Every job profile has its own requirements. Don’t be disheartened if you are not called for the next round. Review it in your mind and do your learning and move to the next one.
Liked these tips?
Add your own super tips for an interview and help others win

• Calling validator controls from javascript.
• Hide/Show validator callout control using javascript.

Some other useful tab container control’ javascript functions

To make your Web application more efficient and easier to use, you need to remove any difficulty in web form navigation that your user could experience. User interface and web site navigation must be logical, easy to use and if possible: already well-known from other applications. Of course, nobody wants to learn some new complicated and unnecessary things and crawl through a large help files. Users wants self-explanatory interface that they can start to use immediately.
One of common standards is using a keyboard TAB key to move focus forward (or Tab + Shift key to move focus back) between controls on form, instead of forcing your Web site visitor to use a mouse click for changing a focus. Of course, your visitor still CAN use a mouse to set focus in some text box, but many of them, and they are usually experienced users like to use a tab key to move focus, because it is faster and more efficient way.

Tab order in web form

So, you need to define a logical navigation through a web form using a Tab key. There is a TabIndex property of server controls. First control in form should get lowest TabIndex. With every next tab, focus will move to the control with next higher value of TabIndex. It is pretty simple to set tab order, you need only to care about few common problems:
Problem 1: When we run the page, we can see there is no control with focus when web page is loaded. Much better solution is to have a focus on the right place immediately after page is loaded. Research about how you can set a focus initially and other focus issues you can see in Focus in ASP.NET tutorial. One solution, which shows how you can set a focus to textbox named txtFirstName, when page is loaded, could be a code like this:

[VB.NET] Page.RegisterStartupScript("SetInitialFocus", _ "<script>document.getElementById('" & txtFirstName.ClientID & _ "').focus();</script>") [C#] Page.RegisterStartupScript("SetInitialFocus", "<script>document.getElementById('" + txtFirstName.ClientID + "').focus();</script>");

Problem 2: Focus moves through a web form, but also goes to Web browser address bar, Google or Yahoo toolbar etc. It is more expected that focus should move only inside the web form, instead to goes to browser's address bar.
Let say the last focus in on the button named "btnOK" and when user press tab key, we want to move focus again to the first control, textbox "txtFirstName" and skip focus in browser toolbars, address bars and other distraction things. You can do it with next piece of code:

[VB.NET] btnOK.Attributes.Add("onkeydown", _ "if(event.which || event.keyCode)" & _ "{if ((event.which == 9) || (event.keyCode == 9)) " & _ "{document.getElementById('" & txtFirstName.ClientID & _ "').focus();return false;}} else {return true}; ") [C#] btnOK.Attributes.Add("onkeydown", "if(event.which || event.keyCode)" + "{if ((event.which == 9) || (event.keyCode == 9)) " + "{document.getElementById('"+ txtFirstName.ClientID + "').focus();return false;}} else {return true}; ");

You don't want to move a focus to specific control?

For some reason, you don't want to some control receive a focus. That could be a case if, for example you have an invisible text box or some search text box on top of the web page, but you want to allow tab functionality only to few main controls on the web form. Simply set TabIndex property of server control, or tabindex attribute of HTML control to -1. When you run web page and hit tab key, controls with TabIndex = -1 will never get a focus. Although, user can click into this control with a mouse and set focus on that way.

Web form sample project of using TAB key

You can download sample "Contact form" Visual Studio 2003 or Visual Studio 2005 project which shows you how you can manage focus on page load and move the focus using the Tab key. The sample contains simple contact form. When you start web application, textbox named "txtFirstName" gets a focus when page is loaded. If you press Tab key, focus will move to the next control, depending of value of control's TabIndex property. When focus comes to the last control with the biggest TabIndex, it goes again to the first control, txtFirstName. There is also txtSearch textbox on the web form which never can be "tabbed" and can receive focus only with a mouse click in it.

How to type TAB key in textbox or textarea

Sometimes, you don't need to move cursor to the next control when hit Tab key. What if you need to type Tab character into text box or text area as a part of the text? Of course, your user can type tab in Notepad or some other text editor and simply do copy/paste to your form, but it is not so nice solution and users could say your application is not professional :). Instead of that, to type tab key in text box, you can use script like this (text box which accepts tab keys is named txtLongText):

[VB.NET] txtLongText.Attributes.Add("onkeydown", _ "if(event.which || event.keyCode){if ((event.which == 9)" & _ "|| (event.keyCode == 9)) {document.getElementById('" & _ txtLongText.ClientID + "').selection = " & _ document.selection.createRange();" & _ txtLongText.ClientID & ".selection.text = " & _ " String.fromCharCode(9);return false;}} else {return true}; ") [C#] txtLongText.Attributes.Add("onkeydown", "if(event.which || event.keyCode){if ((event.which == 9)" + "|| (event.keyCode == 9)) {document.getElementById('"+ txtLongText.ClientID + "').selection = document.selection.createRange();" + txtLongText.ClientID + ".selection.text = String.fromCharCode(9);return false;}} else {return true}; ");

Or better, to avoid hard coding, you can put this code to function named EnableTabType. Function has only one parameter, which specifies what is TextBox control where you need to enable typing of Tab characters.

[VB.NET] Public Sub EnableTabType(tb As TextBox)     tb.Attributes.Add("onkeydown", _     "if(event.which || event.keyCode){if((event.which == 9)" & _     "|| (event.keyCode == 9)) {document.getElementById('" & _     tb.ClientID & "').selection=document.selection.createRange();" & _     tb.ClientID & ".selection.text = " & _     " String.fromCharCode(9);return false;}}else{return true};") End Sub [C#] public void EnableTabType(TextBox tb) {     tb.Attributes.Add("onkeydown",     "if(event.which || event.keyCode){if ((event.which == 9)" +     "|| (event.keyCode == 9)) {document.getElementById('"+     tb.ClientID + "').selection = document.selection.createRange();" +     tb.ClientID + ".selection.text = String.fromCharCode(9);return false;}} else {return true}; "); }

Tab key endnote

Default value of TextBox AutoPostBack property is false. If you set it to true and if text in TextBox control is changed, tab key will cause form to submit. After submitting, it is possible to lose a focus on current control, especially if you used javascript on page load to set focus initially. In that specific case, you can register client script dynamically when Page.IsPostBack value is true.
With Bean Software Shortcut Controls you can use TAB key as a keyboard shortcut to call ASP.NET server side code. Also, with these controls, you can manipulate different keyboard shortcuts like simple Enter, Tab or placing a focus in specific text box, or more complicated e.g. Ctrl + Shift + O or similar, just like shortcuts used in Visual Studio or Microsoft Word. Source code is included.

have been asked zillion times that How to Send Bulk Emails using C# or VB.NET in ASP.NET.

Well, there are hundreds of tutorials all over the internet on sending bulk emails in ASP.NET using C# or VB.NET.

However, I decided to post a basic "how to" for beginners so that they can easily understand the functionality of send bulk emails in ASP.NET.

For this example I will be using Northwind Database.

Step 1:





ASPX Code:



This is simple form containing 3 TextBoxes

1. Recipient(s)
2. Email Subject
3. Email Body

Now, user has two options, either they can select multiple users from list and/or they can add recipients email address manually separated by ";"

Code Behind:
C#:



VB.NET:




Now you may type Email Subject, Email Body and press "Send Email" to send bulk emails!


Thats It!!

Was that so difficult??

I dont think so.
However, for any query, feel free to contact me!

Happy Coding!
Happy Shoding!