ASP.NET - Server Controls

Controls are small building blocks of the graphical user interface, which includes text boxes, buttons, check boxes, list boxes, labels and numerous other tools, using which users can enter data, make selections and indicate their preferences.

Controls are also used for structural jobs, like validation, data access, security, creating master pages, data manipulation.

ASP.Net uses five types of web controls, which are:

• HTML controls
• HTML Server controls
• ASP.Net Server controls
• ASP.Net Ajax Server controls
• User controls and custom controls

ASP.Net server controls are the primary controls used in ASP.Net. These controls again could be grouped into the following categories:

• Validation controls - these are used to validate user input and work by running client-side script
• Data source controls - these controls provides data binding to different data sources
• Data view controls - these are various lists and tables, which can bind to data from data sources for display
• Personalization controls - these are used for personalization of a page according to the user's preference, based on user information
• Login and security controls - these controls provide user authentication
• Master pages - these provides consistent layout and interface throughout the application
• Navigation controls - these helps in navigation, for example, the menus, tree view etc.
• Rich controls - these implements special features, for example, AdRotator control, FileUpload control, Calendar control etc.

The basic syntax for using server controls is:

<asp:controlType  ID ="ControlID"                      runat="server"                      Property1=value1  [Property2=value2] />

However, visual studio has the following features, which helps in error free coding:

• Dragging and dropping of controls in design view
• IntelliSense feature that displays and auto-completes the properties
• The properties window to set the property values directly

Properties of the Server Controls

The ASP.Net server controls with a visual aspect are derived from the WebControl class and inherit all the properties, events and methods of this class.

The WebControl class itself and some other server controls that are not visually rendered, e.g., the PlaceHolder control or XML control etc., are derived from the System.Web.UI.Control class.

ASP.Net server controls inherit all properties, events and methods of the WebControl and System.Web.UI.Control class.

The following table shows the inherited properties, which are common to all server controls:

Property	Description
AccessKey	Pressing this key with the Alt key moves focus to the control
Attributes	It's the collection of arbitrary attributes (for rendering only) that do not correspond to properties on the control.
BackColor	Background colour.
BindingContainer	The control that contains this control's data binding.
BorderColor	Border colour.
BorderStyle	Border style.
BorderWidth	Border width.
CausesValidation	Indicates if it causes validation.
ChildControlCreated	It indicates whether the server control's child controls have been created.
ClientID	Control ID for HTML markup.
Context	The HttpContext object associated with the server control.
Controls	Collection of all controls contained within the control
ControlStyle	The style of the Web server control.
CssClass	CSS class
DataItemContainer	Gets a reference to the naming container if the naming container implements IDataItemContainer.
DataKeysContainer	Gets a reference to the naming container if the naming container implements IDataKeysControl.
DesignMode	It indicates whether the control is being used on a design surface.
DisabledCssClass	Gets or sets the CSS class to apply to the rendered HTML element when the control is disabled.
Enabled	Indicates whether the control is grayed out
EnableTheming	Indicates whether theming applies to the control.
EnableViewState	Indicates whether the view state of the control is maintained.
Events	Gets a list of event handler delegates for the control.
Font	Font .
Forecolor	Foreground colour.
HasAttributes	Indicates whether the control has attributes set.
HasChildViewState	indicates whether the current server control's child controls have any saved view-state settings.
Height	Height in pixels or %.
ID	Identifier for the control.
IsChildControlStateCleared	Indicates whether controls contained within this control have control state.
IsEnabled	Gets a value indicating whether the control is enabled
IsTrackingViewState	It indicates whether the server control is saving changes to its view state.
IsViewStateEnabled	It indicates whether view state is enabled for this control.
LoadViewStateById	It indicates whether the control participates in loading its view state by ID instead of index.
Page	Page containing the control.
Parent	Parent control.
RenderingCompatibility	It specifies the ASP.NET version that rendered HTML will be compatible with.
Site	The container that hosts the current control when rendered on a design surface.
SkinID	Gets or sets the skin to apply to the control. (
Style	Gets a collection of text attributes that will be rendered as a style attribute on the outer tag of the Web server control.
TabIndex	Gets or sets the tab index of the Web server control.
TagKey	Gets the HtmlTextWriterTag value that corresponds to this Web server control.
TagName	Gets the name of the control tag.
TemplateControl	The template that contains this control.
TemplateSourceDirectory	Gets the virtual directory of the Page or control containing this control.
ToolTip	Gets or sets the text displayed when the mouse pointer hovers over the Web server control.
UniqueID	Unique identifier
ViewState	Gets a dictionary of state information that allows you to save and restore the view state of a server control across multiple requests for the same page.
ViewStateIgnoreCase	It indicates whether the StateBag object is case-insensitive.
ViewStateMode	Gets or sets the view-state mode of this control.
Visible	It indicates whether a server control is visible.
Width	Gets or sets the width of the Web server control.