Types of Server Controls ASP.NET Web Server Controls HTML Server Controls Creating Server Controls Dynamically
Session iii(server controls)
Aug 09, 2015
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Types of Server Controls
ASP.NET Web Server Controls
HTML Server Controls
Creating Server Controls Dynamically
With ASP. Net, these are any controls that run in the server space.
o Handled by ASP. Net runtimeo Must have runt=“server” attribute within the ASP. Net web formo Always identified with the “ID” attribute (also mandatory with
ASP. Net web controls)
Properties, events, etc. can all be handled by server-side code
• Label• Textbox• Button• Link• Link Button• Dropdown List• List Box• Checkbox• Radio Button• Image• File Upload• Panel
• <span />• <input type=“text” />• <input type=“submit” />• <a href=[#|page] />• <a href=[postback] />• <select />• <select [size=x] />• <input type=“checkbox” />• <input type=“radio” />• <img />• <input type=“file” />• <div />
• Like the ASP. Net Page object (System.Web.UI.Page), web controls maintain the same event processing– Init, PreRender, Load, etc
• If AutoPostBack is set on the control, the event will be fired immediately (causes an automatic postback), otherwise, the event will fire upon next page postback• Checkbox
– Check Changed()• Button
– Click(), Command()• Dropdown List
– Text Changed(), SelectedIndexChanged()
• System.Web.UI.HtmlControls– Ex: HtmlButton, HtmlTable, HtmlInputText
• These are ASP. Net HTML server controls– Rendered as:– <button />, <table />, <input type=“text” />
• The HtmlControls collection allows the programmer access to HTML elements (and their properties, etc.) from server-side code
– Hence, page content (HTML elements) can also be dynamically generated in the code behind or classes
• All controls in this collection inherit from the HtmlControl class
• HtmlAnchor• HtmlButton• HtmlInputButton• HtmlInputHidden• HtmlInputText• HtmlImage• HtmlSelect• HtmlTable• HtmlTextArea• HtmlGenericControl
<a /><button /><input type=“button” /><input type=“hidden” /><input type=“text” /><img /><select /><table /><text area /><span />, <body />, <h1 />,
<div />…
• Properties and Events can be managed efficiently in
the code behind
• Any server control can be referenced by its ID
property
Example:
txtTextBox.Text = “Hello!”;
• Code is written by the event handler that is
defined by the control
– <asp: Button On Click=“bttnGo_Click”... />
bttnGo_Click(object sender, …) { … }
• This is the key to maintaining clean, efficient
code for processing form data and UI
interaction
• It is good practice to prefix the name of control ID to text that indicates its “Type”
o Textbox txtNameo Checkbox chkCorrecto Dropdown List ddlProductTypeso Panel pnlCustInfo
• This will make it easier when referring to the controls at runtime in code
• Data– GridView– DataList– SqlDataSource– etc.
• Validation (server-side)– RequiredFieldValidator– RangeValidator– RegularExpressionValidator
• Navigation– SiteMapPath– Menu– TreeView– etc.
• Login– Login– LoginView– etc.
• Everything in VB/C# is an object, therefore
ASP. Net server controls are objects as well
• Controls can be dynamically created using
server side code (VB/C#)
Control Name Properties
RequiredFieldValidator
CompareValidator
RangeValidator
RegularExpressionValidator
CustomValidator
ValidationSummary
ControlToValidate, Display , ErrorMessage,ValidationGroup,ControlToCompare,
MaximumValue,MinimumValue
Validation Expression
Text,ClientValidationFunction, OnServerValidateHeader Text
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