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ASP.Net directives are instructions to specify optional settings, such as registering a custom control and page language. These settings describe how the web forms (.aspx) or user controls (.ascx) pages are processed by the .Net framework.
The syntax for declaring a directive is:
<%@ directive_name attribute=value [attribute=value] %> |
In this section, we will just introduce the ASP.Net directives and we will use most of these directives throughout the tutorials.
The Application directive defines application-specific attributes. It is provided at the top of the global.aspx file.
The basic syntax for a sample Application directive is:
<%@ Application Language="C#" %> |
The attributes of the Application directive are:
Attributes | Description |
---|---|
Inherits | the name of the class from which to inherit |
Description | text description of the application. Parsers and compilers ignore this |
Language | language used in code blocks |
The Assembly directive links an assembly to the page or the application at parse time. This could appear either in the global.asax file for application-wide linking or in the page file or a user control file for linking to a page or user control.
The basic syntax for a sample Assembly directive is:
<%@ Assembly Name ="myassembly" %> |
The attributes of the Assembly directive are:
Attributes | Description |
---|---|
Name | the name of the assembly to be linked |
Src | the path to the source file to be linked and compiled dynamically |
The Control directive is used with the user controls and appears in the user control (.ascx) files.
The basic syntax for a sample Control directive is:
<%@ Control Language="C#" EnableViewState="false" %> |
The attributes of the Control directive are:
Attributes | Description |
---|---|
AutoEventWireup | the Boolean value that enables or disables automatic association of events to handlers |
ClassName | file name for the control |
Debug | the Boolean value that enables or disables compiling with debug symbols |
Description | text description of the control page, ignored by compiler |
EnableViewState | the Boolean value that indicates whether view state is maintained across page requests |
Explicit | for VB language, tells the compiler to use Option Explicit mode |
Inherits | the class from which the control page inherits |
Language | language for code and script |
Src | the filename for the code-behind class |
Strict | for VB language, tells the compiler to use the Option Strict mode |
The Implement directive indicates that the web page, master page or user control page must implement the specified .Net framework interface.
The basic syntax for an Implements directive is:
<%@ Implements Interface="interface_name" %> |
The Import directive imports a namespace into a web page, user control pate of application. If the Import directive is specified in the global.asax, then it will apply to the entire application. If it is in a page of user control page, then it would apply to that page or control.
The basic syntax for an Import directive is:
<%@ namespace="System.Drawing" %> |
The Master directive specifies a page file as being the mater page.
The basic syntax for a sample MasterPage directive is:
<%@ MasterPage Language="C#" AutoEventWireup="true" CodeFile="SiteMater.master.cs" Inherits="SiteMaster" %> |
The MasterType directive assigns a class name to the Master property of a page, to make it strongly typed.
The basic syntax for a MasterType directive is:
<%@ MasterType attribute="value"[attribute="value" ...] %> |
The OutputCache directive controls the output caching policies of a web page or a user control. We will discuss this directive in details, in data caching.
The basic syntax for a OutputCache directive is:
<%@ OutputCache Duration="15" VaryByParam="None" %> |
The Page directive defines the attributes specific to the page file for the page parser and the compiler.
The basic syntax for a Page directive is:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" Trace="true" %> |
The attributes of the Page directive are:
Attributes | Description |
---|---|
AutoEventWireup | the Boolean value that enables or disables Page events that are being automatically bound to methods; for example, Page_Load |
Buffer | the Boolean value that enables or disables HTTP response buffering |
ClassName | class name for the page |
ClientTarget | the browser for which server controls should render content |
CodeFile | name of the code behind file |
Debug | the Boolean value that enables or disables compilation with debug symbols |
Description | text description of the page, ignored by the parser |
EnableSessionState | enables, disables or makes session state read-only |
EnableViewState | the Boolean value that enables or disables view state across page requests |
ErrorPage | URL for redirection if an unhandled page exception occurs |
Inherits | the name of the code behind or other class |
Language | programming language for code |
Src | file name of the code behind class |
Trace | enables or disables tracing |
TraceMode | indicates how trace messages are to be displayed - sorted by time or category |
Transaction | indicates if transactions are supported |
ValidateRequest | the Boolean value that indicates whether all input data is validated against a hardcoded list of values |
The PreviousPageType directive assigns a class to a page, so that the page is strongly typed.
The basic syntax for a sample PreviousPagetype directive is:
<%@ PreviousPageType attribute="value"[attribute="value" ...] %> |
The Reference directive indicates that another page or user control should be compiled and linked to the current page.
The basic syntax for a sample Reference directive is:
<%@ Reference Page ="somepage.aspx" %> |
The Register derivative is used for registering the custom server controls and user controls.
The basic syntax for a sample Register directive is:
<%@ Register Src="~/footer.ascx" TagName="footer" TagPrefix="Tfooter" %> |
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