Chapter 2

ASP.NET Server Controls

Types of Server Control

• HTML Server Controls (Traditional HTML tags)
• Web Server Controls (New ASP. NET tags)
• Validation Controls
• User Define Controls

​

ASP.NET Server Controls (Cont..)

HTML server controls

• These controls are basically the original HTML controls but enhanced to enable server side processing.
• To make these elements programmable, add a runat="server" attribute to the HTML element. This attribute indicates that the element should be treated as a server control.
• All HTML server controls must be within a <form> tag with the runat="server" attribute. The runat="server" attribute indicates that the form should be processed on the server.
• You have all the HtmlControl class’s properties and methods available such as, ID, EnableViewState, Disabled, Style, and some more.

​

​

HTML server controls (Cont..)

HtmlControl Class

• The HtmlControl base class is used for those HTML classes that are focused on HTML elements that can be contained within a single node. Such as <img>, <input>, and <link> elements.

(These elements are derived from HtmlControl Class)

HtmlContainerControl Class

• A class specifically designed to work with HTML elements that require a closing tag.
• HTML elements such as <a>, <form>, and <select>, require an opening and closing set of tags.
• These controls have some extra properties like InnerText and InnerHtml.
• InnerHtml: Enables you to specify content that can include HTML elements to be placed between the opening and closing tags of the specified control.
• InnerText: Enables you to specify raw text to be placed between the opening and closing tags of the specified control.

(These elements are derived from HtmlContainerControl Class)

HtmlGenericControl Class

• Using the HtmlGenericControl class, you can get server-side access to the <meta>, <p>, <span>, or other elements that would otherwise be unreachable.

​

​

• Project Title

Manipulating Pages and Server Controls with JavaScript

• Apply JavaScript directly to the controls on your ASPX page.
• Using Page.ClientScript.RegisterClientScriptBlock
• The RegisterClientScriptBlock method allows you to place a JavaScript function at the top of the page.
• RegisterClientScriptBlock(type, key, script, script tag specification)
• Using Page.ClientScript.RegisterStartupScript
• RegisterStartupScript places the script at the bottom of the ASP.NET page instead of at the top.
• RegisterStartupScript(type, key, script, script tag specification)

Manipulating Pages and Server Controls with JavaScript (Cont..)

• Using Page.ClientScript.RegisterClientScriptInclude
• You can register the script files on your ASP.NET pages using the RegisterClientScriptInclude method.
• Page.ClientScript.RegisterClientScriptInclude(type, key, url)

​

Comparing a Typical Postback to a callback

• Postback
• A postback occurs when a request is sent from the client to the server for the same page as the one the user is currently viewing.
• When a postback occurs, the entire page is refreshed.
• Callback
• A callback occurs when a request is sent from the client to the server for which the page is not refreshed.
• Only a part of it is updated without any flickering occurring on the browser

Common Properties

• Access Key
• Alt + key.
• Attributes
• Enables you to define additional attributes for a Web server control that are not defined by a public property.
• Disabled
• Allows you to get or set whether the control is disabled using a Boolean value.
• Visible
• Specifies whether the control is visible on the generated page.