- In-line code is code that is embedded directly within the ASP.NET page.
- Code-behind refers to code for your ASP.NET page that is contained within a separate class file. This allows a clean separation of your HTML from your presentation logic.
When we use Microsoft Visual Studio .NET to create ASP.NET Web Forms, code-behind pages are the default method. In addition, Visual Studio .NET automatically performs precompilation for us when we build our solution.
A little bit of background
Directives in ASP.NET control the settings and properties of page and user control compilers. They can be included anywhere on a page, although it is standard to place them at the beginning. Directives are used in both .aspx files (ASP.NET pages) and .ascx files (user control pages). ASP.NET pages actually support eight different directives.
* @ Page
* @ Control
* @ Import
* @ Implements
* @ Register
* @ Assembly
* @ OutputCache
* @ Reference
Page directives are the most commonly used directives, and are used to edit a wide variety of settings that control how the page parser and page compiler work. The following is a list of some of the more commonly used page directive attributes in ASP.NET.
@ Page language=”c#” Codebehind=”WebForm1.aspx.cs”
AutoEventWireup=”false” Inherits=”TestWebApp.WebForm1″
- Language indicates the language in which the inline script code within the ASP.NET page is written (the code between tags). The value of this attribute can be C#, VB, or JS.
- Codebehind indicates the name of the file being used as the code supporting this ASP.NET page. This file should reflect the Language setting; that is, if the language being used is C#, the CodeBehind file should have a .cs extension and be written in C#.
- Inherits indicates a qualified class from which this ASP.NET page should inherit. Generally, this will be the name of the class described in the code-behind file.
- AutoEventWireup is a Boolean attribute that indicates whether the ASP.NET pages events are auto-wired.
Note: In the above case, ASP.NET compiles the code-behind page on the fly. We have to note that this compilation step only occurs when the code-behind file is updated. Whether the file has been updated or not, well this is detected through a timestamp change.
To get to the Real Thing
The AutoEventWireup attribute may have a value of true or false. When an ASP.NET Web Application is created by using Microsoft Visual Studio .NET, the value of the AutoEventWireup attribute is set as false.
We can specify the default value of the AutoEventWireup attribute in the following locations:
- The Machine.config file.
- The Web.config file.
- Individual Web Forms (.aspx files).
- Web User Controls (.ascx files)
The value of the AutoEventWireup attribute can be declared in the
section in the Machine.config file or the Web.config file.
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