Polymorphism means same method/function can perform completely different task or can show completely different behavior in different classes or same  class, in case if methods are in different classes then they are related with each other by base and drive class relationships. There are two types of polymorphism: Compile time  polymorphism (Method overloading) Run time  polymor... [More]

Run time polymorphism allows us to invoke derived class methods through a base class reference during run-time. This is also called runtime  binding. An example is shown below. namespace TestApp { public class DrawingBaseClass { public virtual void Draw() { Console.WriteLine("I am a Base Class drawing object."); } } public cla... [More]

Sometime we get requirement to trigger an event like button click event from JavaScript code. This we can achieve through "__doPostBack(eventTarget, eventArgument)" function. __doPostBack is not new to ASP.Net, if we see view source of the asp.net page then we can see this __doPostBack function in our asp.net generated HTML code. Whenever asp.net page posted back to the server, as... [More]

Here are important SQL Server questions part -2 interviews: Part -1: http://www.expertsblog.in/post/Important-SQL-Interview-Questions.aspx   Q. Select all employees who does not have phone? SELECT emp_name FROM Employee WHERE (emp_id NOT IN (SELECT DISTINCT emp_id FROM Phone)) Q. Select the employee name who is having more than one phone number. SELECT emp_name FROM Employee WHER... [More]

Here are some important SQL Server questions which often ask in interviews: Q. What are the benefits of views and stored procedures instead of large and heavy duty queries? These can reduce network traffic, because client will send to server only store procedure or view name perhaps with some parameters instead of large queries. Views can be used to facilitate permission management also, cause... [More]

Often .Net developers in the initial years of their programming careers faces some questions regarding coding practices and way of programming that minimize the chances of Bugs/Errors. Following are some guideline which might be helpful to achieve some good programming practices: Clarity and Consistency Always ensure that you are applying all coding standards consistently in your project. And d... [More]

.NET Framework provides a class specifically to create XML documents, the System.Xml.XmlTextWriter class. By using this class we can create XML documents with easy. In this article we'll look at using the XmlTextWriter class to create XML documents. The XmlTextWriter class contains following important methods:  WriteStartDocument() - we should use this m... [More]

We often need client side JavaScript validation for validate email address. Below is example for validating email address. function validateEmail() {         var email = document.getElementById("txtemail").value;         var Isvalid=1;         var emailRegex = new RegExp(/^[a-zA-Z0-9._-]+@gmail\.com$/); // This is for specific d... [More]

In web development we often need client side JavaScript validation for checking only characters. Below is example for checking any non-alphabets characters, and no spaces or special characters.  function validateName() {       var valid=1, checkchar;       var name = document.getElementById('txtName').value;       name = name.toLower... [More]

In web development we often need client side JavaScript validation for checking non-numeric characters. Below is example for checking any non-numeric characters, and the length is not null. function validateEmpId() {       var empid = document.getElementById("txtempid").value;       var IsempValid=1;       if(isNaN(empid) || empid.length==0) ... [More]