AdRotator in ASP.NET.

The ASP.NET AdRotator web server control is a useful control to randomly display clickable ad banners / advertisements from a list on a web page, which is specified in an external XML schedule file. This external XML schedule file is called the advertisement file.

The XML file must begin and end with an <Advertisements> tag. Inside the <Advertisements> tag there may be several <Ad> tags which defines each ad.

The advertisement file needs to be a structured text file with well-defined tags delineating the data. There are the following standard XML elements that are commonly used in the advertisement file.

The predefined elements inside the <Ad> tag are listed below:

Element	Description
<ImageUrl>	Optional. The path to the image file
<NavigateUrl>	Optional. The URL to link to if the user clicks the ad
<AlternateText>	Optional. An alternate text for the image
<Keyword>	Optional. A category for the ad
<Impressions>	Optional. The display rates in percent of the hits

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Properties:

The AdRotator class is derived from the WebControl class and inherits its properties. Apart from those the AdRotator class has the following properties:

Property	Description
AdvertisementFile	Specifies the path to the XML file that contains ad information
AlternateTextField	Specifies a data field to be used instead of the Alt text for an ad
DataMember	The name of the specific list of data to be bound when advertisement file is not used.
DataSource	Control from where it would retrieve data.
DataSourceID	Id of the control from where it would retrieve data.
Font	Specifies the font properties associated with the advertisement banner control.
ImageUrlField	Specifies a data field to be used instead of the ImageURL attribute for an ad
KeywordFilter	Specifies a filter to limit ads after categories
NavigateUrlField	Specifies a data field to be used instead of the NavigateUrl attribute for an ad
runat	Specifies that the control is a server control. Must be set to "server"
Target	Specifies where to open the URL
UniqueID	Obtains the unique, hierarchically qualified identifier for the AdRotator control.

Following are the important events of the AdRotator Class:

Events	Description
AdCreated	It is raised once per round trip to the server after creation of the control, but before the page is rendered
DataBinding	Occurs when the server control binds to a data source.
DataBound	Occurs after the server control binds to a data source.
Disposed	Occurs when a server control is released from memory, which is the last stage of the server control lifecycle when an ASP.NET page is requested
Init	Occurs when the server control is initialized, which is the first step in its lifecycle.
Load	Occurs when the server control is loaded into the Page object.
PreRender	Occurs after the Control object is loaded but prior to rendering.
Unload	Occurs when the server control is unloaded from memory.