Single-Value, or "Simple," Data Binding

You can use single-value data binding to add information anywhere on an ASP.NET page. You can even place information into a control property or as plain text inside as HTML tag. Single-value data binding allows you to take a variable, a property, or an expression and insert it dynamically into a page.

Types of ASP.NET Data Binding

Two types of ASP.NET data binding exist: single-value binding and repeated-value binding.
Single-value data binding is by far the simpler of the two, whereas repeated-value binding provides the foundation for the most advanced ASP.NET data controls.

Data Binding

The basic principle of data binding is this: you tell a control where to find your data and how you want it display, and the control handle the rest of the details. Data binding in ASP.NET is superficially similar to data binding in the world of desktop or client/server application, but in truth, it's fundamentally different.In those environment, data binding involves creating a direct connection between a data source and a control in an application window.if a user change a value in the on-screen control, the data in the linked database is modified automatically. Similarly, if the database changes while the user is working with it (for example, another user commits a change), the display can be refreshed automatically.

Featues of ASP.NET 2.0

ASP.NET 2.0 improves ASP.NET by adding several new features.
Design goals for ASP.NET 2.0:

• Increase productivity by removing 70% of the code
• Use the same controls for all types of devices
• Provides a faster and better web server platform
• Simplify the administration of web applications

Some of the features in ASP.NET 2.0 are:

• Master Pages, Themes, and Web Parts
• Standard controls for navigation
• Standard controls for security
• Roles, personalization and internationalization services
• Improved and simplified data access controls
• Full support for XML standard like , XHTML, XML, and WSDL
• Improved compilation and deployment(installation)
• Improved site management
• New and improved development tools
  

Client Side Validation

ASP.NET automatically adds JavaScript code for client side validation.In this case, when the user clicks a CausesValidation button, the same error message will appear without the page needing to be submitted and returned from the server.This increase the representation of your web page.
However, even if the page validates successfully on the client side,ASP.NET still revalidates it when it's received at the server.This is because it's easy for an experienced user to circumvent client side validation. For example, a malicious user might delete the block of JavaScript validation. For example, a malicious user might delete the block of JavaScript validation code and continue working with the page.By performing the validation at both ends,ASP.NET makes sure your application can be responsive as possible while also remaining secure.

Server Side Validation

You can use the validator controls to verify a page automatically when the user submits it or manually in your code.The first approach is the most common.
When using automatic validation,the user receive a normal page and begins to fill in the input controls. When finished, the user clicks a button to submit the page.Every button has a causes Validation property, which can be set to true or false.What happens when the user clicks the button depends on the value of the CausesValidation property.

• If CausesValidation is false, ASP.NET will ignore the validation controls,the page will be posted back,and your event-handling code will run normally.
• If CausesValidation is true(the default), ASP.NET will automatically validate the page when the user clicks the button. It does this by performing the validation for each control on the page. If any control fails to validate, ASP.NET will return the page with some error information,depending on your setting.Your click event-handling code may or may not be executed-meaning you'll have to specifically check in the event handler whether the page is valid.
  

What is methods?

Methods are the most basic building block you can use to organize your code. Essentially,a method is a named grouping of one or more lines of code.Ideally,each method will perform a distinct,logical task.By breaking your code down into methods, you not only simplify your life,but you also make it easier to organize your code into classes and step into the world of object oriented programming.
When you declare a method in C#,the first part of the declaration specifies the data type of the return value,and the second part indicates the method name.If your method doesn't return any information,you should use the void keyword instead of a data type at the beginning of the declaration.
Here are two examples-one method that doesn't return anything and one that does:

// This method doesn't return any information.
void MyMethodNoReturnedData()
{
// Code goes here.
}

// This method returns an integer.
int MyMethodReturnsData()
{
// Return the number 10.
return 10;
}