Control Class (System.Web.UI)

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Control Class

Defines the properties, methods, and events that are shared by all ASP.NET server controls.

Inheritance Hierarchy

SystemObject
System.Web.UIControl
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Namespace: System.Web.UI
Assembly: System.Web (in System.Web.dll)

Syntax

<[%$TOPIC/983zwx2h_en-us_VS_110_2_0_0_0_0%](False)> _
<[%$TOPIC/983zwx2h_en-us_VS_110_2_0_0_0_1%](True)> _
Public Class Control _
	Implements [%$TOPIC/983zwx2h_en-us_VS_110_2_0_0_0_2%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_0_0_3%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_0_0_4%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_0_0_5%],  _
	[%$TOPIC/983zwx2h_en-us_VS_110_2_0_0_0_6%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_0_0_7%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_0_0_8%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_0_0_9%]

[[%$TOPIC/983zwx2h_en-us_VS_110_2_0_1_0_0%](false)]
[[%$TOPIC/983zwx2h_en-us_VS_110_2_0_1_0_1%](true)]
public class Control : [%$TOPIC/983zwx2h_en-us_VS_110_2_0_1_0_2%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_1_0_3%], 
	[%$TOPIC/983zwx2h_en-us_VS_110_2_0_1_0_4%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_1_0_5%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_1_0_6%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_1_0_7%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_1_0_8%], 
	[%$TOPIC/983zwx2h_en-us_VS_110_2_0_1_0_9%]

[[%$TOPIC/983zwx2h_en-us_VS_110_2_0_2_0_0%](false)]
[[%$TOPIC/983zwx2h_en-us_VS_110_2_0_2_0_1%](true)]
public ref class Control : [%$TOPIC/983zwx2h_en-us_VS_110_2_0_2_0_2%], 
	[%$TOPIC/983zwx2h_en-us_VS_110_2_0_2_0_3%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_2_0_4%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_2_0_5%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_2_0_6%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_2_0_7%], 
	[%$TOPIC/983zwx2h_en-us_VS_110_2_0_2_0_8%], [%$TOPIC/983zwx2h_en-us_VS_110_2_0_2_0_9%]

[<[%$TOPIC/983zwx2h_en-us_VS_110_2_0_3_0_0%](false)>]
[<[%$TOPIC/983zwx2h_en-us_VS_110_2_0_3_0_1%](true)>]
type Control =  
    class 
        interface [%$TOPIC/983zwx2h_en-us_VS_110_2_0_3_0_2%] 
        interface [%$TOPIC/983zwx2h_en-us_VS_110_2_0_3_0_3%] 
        interface [%$TOPIC/983zwx2h_en-us_VS_110_2_0_3_0_4%] 
        interface [%$TOPIC/983zwx2h_en-us_VS_110_2_0_3_0_5%] 
        interface [%$TOPIC/983zwx2h_en-us_VS_110_2_0_3_0_6%] 
        interface [%$TOPIC/983zwx2h_en-us_VS_110_2_0_3_0_7%] 
        interface [%$TOPIC/983zwx2h_en-us_VS_110_2_0_3_0_8%] 
        interface [%$TOPIC/983zwx2h_en-us_VS_110_2_0_3_0_9%] 
    end

The Control type exposes the following members.

Constructors

	Name	Description
	Control	Initializes a new instance of the Control class.

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Properties

	Name	Description
	Adapter	Gets the browser-specific adapter for the control.
	AppRelativeTemplateSourceDirectory	Gets or sets the application-relative virtual directory of the Page or UserControl object that contains this control.
	BindingContainer	Infrastructure. Gets the control that contains this control's data binding.
	ChildControlsCreated	Gets a value that indicates whether the server control's child controls have been created.
	ClientID	Gets the control ID for HTML markup that is generated by ASP.NET.
	ClientIDMode	Gets or sets the algorithm that is used to generate the value of the ClientID property.
	ClientIDSeparator	Gets a character value representing the separator character used in the ClientID property.
	Context	Gets the HttpContext object associated with the server control for the current Web request.
	Controls	Gets a ControlCollection object that represents the child controls for a specified server control in the UI hierarchy.
	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	Gets a value indicating whether a control is being used on a design surface.
	EnableTheming	Gets or sets a value indicating whether themes apply to this control.
	EnableViewState	Gets or sets a value indicating whether the server control persists its view state, and the view state of any child controls it contains, to the requesting client.
	Events	Gets a list of event handler delegates for the control. This property is read-only.
	HasChildViewState	Gets a value indicating whether the current server control's child controls have any saved view-state settings.
	ID	Gets or sets the programmatic identifier assigned to the server control.
	IdSeparator	Infrastructure. Gets the character used to separate control identifiers.
	IsChildControlStateCleared	Gets a value indicating whether controls contained within this control have control state.
	IsTrackingViewState	Gets a value that indicates whether the server control is saving changes to its view state.
	IsViewStateEnabled	Gets a value indicating whether view state is enabled for this control.
	LoadViewStateByID	Gets a value indicating whether the control participates in loading its view state by ID instead of index.
	NamingContainer	Gets a reference to the server control's naming container, which creates a unique namespace for differentiating between server controls with the same ControlID property value.
	Page	Gets a reference to the Page instance that contains the server control.
	Parent	Gets a reference to the server control's parent control in the page control hierarchy.
	RenderingCompatibility	Gets a value that specifies the ASP.NET version that rendered HTML will be compatible with.
	Site	Gets information about the container that hosts the current control when rendered on a design surface.
	SkinID	Gets or sets the skin to apply to the control.
	TemplateControl	Gets or sets a reference to the template that contains this control.
	TemplateSourceDirectory	Gets the virtual directory of the Page or UserControl that contains the current server control.
	UniqueID	Gets the unique, hierarchically qualified identifier for the server control.
	ValidateRequestMode	Gets or sets a value that indicates whether the control checks client input from the browser for potentially dangerous values.
	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.
	ViewStateIgnoresCase	Gets a value that indicates whether the StateBag object is case-insensitive.
	ViewStateMode	Gets or sets the view-state mode of this control.
	Visible	Gets or sets a value that indicates whether a server control is rendered as UI on the page.

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Methods

	Name	Description
	AddedControl	Called after a child control is added to the Controls collection of the Control object.
	AddParsedSubObject	Notifies the server control that an element, either XML or HTML, was parsed, and adds the element to the server control's ControlCollection object.
	ApplyStyleSheetSkin	Applies the style properties defined in the page style sheet to the control.
	BeginRenderTracing	Begins design-time tracing of rendering data.
	BuildProfileTree	Infrastructure. Gathers information about the server control and delivers it to the Trace property to be displayed when tracing is enabled for the page.
	ClearCachedClientID	Infrastructure. Sets the cached ClientID value to .
	ClearChildControlState	Deletes the control-state information for the server control's child controls.
	ClearChildState	Deletes the view-state and control-state information for all the server control's child controls.
	ClearChildViewState	Deletes the view-state information for all the server control's child controls.
	ClearEffectiveClientIDMode	Infrastructure. Sets the ClientIDMode property of the current control instance and of any child controls to Inherit.
	CreateChildControls	Called by the ASP.NET page framework to notify server controls that use composition-based implementation to create any child controls they contain in preparation for posting back or rendering.
	CreateControlCollection	Creates a new ControlCollection object to hold the child controls (both literal and server) of the server control.
	DataBind	Binds a data source to the invoked server control and all its child controls.
	DataBind(Boolean)	Binds a data source to the invoked server control and all its child controls with an option to raise the DataBinding event.
	DataBindChildren	Binds a data source to the server control's child controls.
	Dispose	Enables a server control to perform final clean up before it is released from memory.
	EndRenderTracing	Ends design-time tracing of rendering data.
	EnsureChildControls	Determines whether the server control contains child controls. If it does not, it creates child controls.
	EnsureID	Creates an identifier for controls that do not have an identifier assigned.
	Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	FindControl(String)	Searches the current naming container for a server control with the specified id parameter.
	FindControl(String, Int32)	Infrastructure. Searches the current naming container for a server control with the specified id and an integer, specified in the pathOffset parameter, which aids in the search. You should not override this version of the FindControl method.
	Focus	Sets input focus to a control.
	GetDesignModeState	Infrastructure. Gets design-time data for a control.
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetRouteUrl(Object)	Gets the URL that corresponds to a set of route parameters.
	GetRouteUrl(RouteValueDictionary)	Gets the URL that corresponds to a set of route parameters.
	GetRouteUrl(String, Object)	Gets the URL that corresponds to a set of route parameters and a route name.
	GetRouteUrl(String, RouteValueDictionary)	Gets the URL that corresponds to a set of route parameters and a route name.
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	GetUniqueIDRelativeTo	Returns the prefixed portion of the UniqueID property of the specified control.
	HasControls	Determines if the server control contains any child controls.
	HasEvents	Returns a value indicating whether events are registered for the control or any child controls.
	IsLiteralContent	Infrastructure. Determines if the server control holds only literal content.
	LoadControlState	Restores control-state information from a previous page request that was saved by the SaveControlState method.
	LoadViewState	Restores view-state information from a previous page request that was saved by the SaveViewState method.
	MapPathSecure	Retrieves the physical path that a virtual path, either absolute or relative, maps to.
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	OnBubbleEvent	Determines whether the event for the server control is passed up the page's UI server control hierarchy.
	OnDataBinding	Raises the DataBinding event.
	OnInit	Raises the Init event.
	OnLoad	Raises the Load event.
	OnPreRender	Raises the PreRender event.
	OnUnload	Raises the Unload event.
	OpenFile	Gets a Stream used to read a file.
	RaiseBubbleEvent	Assigns any sources of the event and its information to the control's parent.
	RemovedControl	Called after a child control is removed from the Controls collection of the Control object.
	Render	Sends server control content to a provided HtmlTextWriter object, which writes the content to be rendered on the client.
	RenderChildren	Outputs the content of a server control's children to a provided HtmlTextWriter object, which writes the content to be rendered on the client.
	RenderControl(HtmlTextWriter)	Outputs server control content to a provided HtmlTextWriter object and stores tracing information about the control if tracing is enabled.
	RenderControl(HtmlTextWriter, ControlAdapter)	Outputs server control content to a provided HtmlTextWriter object using a provided ControlAdapter object.
	ResolveAdapter	Gets the control adapter responsible for rendering the specified control.
	ResolveClientUrl	Gets a URL that can be used by the browser.
	ResolveUrl	Converts a URL into one that is usable on the requesting client.
	SaveControlState	Saves any server control state changes that have occurred since the time the page was posted back to the server.
	SaveViewState	Saves any server control view-state changes that have occurred since the time the page was posted back to the server.
	SetDesignModeState	Sets design-time data for a control.
	SetRenderMethodDelegate	Infrastructure. Assigns an event handler delegate to render the server control and its content into its parent control.
	SetTraceData(Object, Object)	Sets trace data for design-time tracing of rendering data, using the trace data key and the trace data value.
	SetTraceData(Object, Object, Object)	Sets trace data for design-time tracing of rendering data, using the traced object, the trace data key, and the trace data value.
	ToString	Returns a string that represents the current object. (Inherited from Object.)
	TrackViewState	Causes tracking of view-state changes to the server control so they can be stored in the server control's StateBag object. This object is accessible through the ControlViewState property.

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Events

	Name	Description
	DataBinding	Occurs when 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.

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Extension Methods

	Name	Description
	FindDataSourceControl	Returns the data source that is associated with the data control for the specified control. (Defined by DynamicDataExtensions.)
	FindFieldTemplate	Returns the field template for the specified column in the specified control's naming container. (Defined by DynamicDataExtensions.)
	FindMetaTable	Returns the metatable object for the containing data control. (Defined by DynamicDataExtensions.)

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Explicit Interface Implementations

	Name	Description
	IControlBuilderAccessorControlBuilder	For a description of this member, see IControlBuilderAccessorControlBuilder.
	IControlDesignerAccessorGetDesignModeState	For a description of this member, see IControlDesignerAccessorGetDesignModeState.
	IControlDesignerAccessorSetDesignModeState	For a description of this member, see IControlDesignerAccessorSetDesignModeState.
	IControlDesignerAccessorSetOwnerControl	Infrastructure. For a description of this member, see IControlDesignerAccessorSetOwnerControl.
	IControlDesignerAccessorUserData	For a description of this member, see IControlDesignerAccessorUserData.
	IDataBindingsAccessorDataBindings	For a description of this member, see IDataBindingsAccessorDataBindings.
	IDataBindingsAccessorHasDataBindings	For a description of this member, see IDataBindingsAccessorHasDataBindings.
	IExpressionsAccessorExpressions	For a description of this member, see IExpressionsAccessorExpressions.
	IExpressionsAccessorHasExpressions	For a description of this member, see IExpressionsAccessorHasExpressions.
	IParserAccessorAddParsedSubObject	For a description of this member, see IParserAccessorAddParsedSubObject.

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Remarks

This is the primary class that you derive from when you develop custom ASP.NET server controls. Control does not have any user interface (UI) specific features. If you are authoring a control that does not have a UI, or combines other controls that render their own UI, derive from Control. If you are authoring a control that does have a UI, derive from WebControl or any control in the System.Web.UI.WebControls namespace that provides an appropriate starting point for your custom control.

The Control class is the base class for all ASP.NET server controls, including custom controls, user controls, and pages. ASP.NET pages are instances of the Page class, which inherits from the Control class, and that handle requests for files that have an .aspx extension.

The Control class can directly or indirectly be used as part of the user interface for your Web application, and as such should be scrutinized to make sure best practices for writing secure code and securing applications are followed.

For general information on these topics, see Overview of Web Application Security Threats, Security Policy Best Practices, and Key Security Concepts. For more specific information, see Securing Standard Controls, How to: Display Safe Error Messages, How to: Protect Against Script Exploits in a Web Application by Applying HTML Encoding to Strings, and Introduction to the Validation Controls.

Examples

The following example demonstrates a custom server control that derives from the Control class. The InnerContent class overrides the ControlRender method, checks to see if the class has any child controls on the page and determines whether the first child of the control is a literal control. If both of these conditions are met, the overridden method writes the HTML string <H2>Your Message:, the contents of the literal control, and a closing </H2> tag to the Web Forms page.

Security Note
This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview.

Option Explicit
Option Strict

Imports System
Imports System.Web
Imports System.Web.UI
Imports Microsoft.VisualBasic

Namespace SimpleControlSamples
    Public Class InnerContent
        Inherits Control
        <System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="Execution")> _
        Protected Overrides Sub Render(output As HtmlTextWriter)

            If HasControls() And TypeOf Controls(0) Is LiteralControl Then
                output.Write("<H2>Your message : ")
                Controls(0).RenderControl(output)
                output.Write("</H2>")
            End If 
        End Sub 'Render
    End Class 'InnerContent
End Namespace 'SimpleControlSamples

using System;
using System.Web;
using System.Web.UI;

namespace SimpleControlSamples {

    public class InnerContent : Control {
	[System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="Execution")] 
       protected override void Render(HtmlTextWriter output) {

           if ( (HasControls()) && (Controls[0] is LiteralControl) ) {
               output.Write("<H2>Your message : ");
               Controls[0].RenderControl(output);
               output.Write("</H2>");
           }
       }
    }    
}

Version Information

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

Platforms

Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Reference

System.Web.UI Namespace

Other Resources

Developing Custom ASP.NET Server Controls

Inheritance Hierarchy