Control Class

Definition

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

public ref class Control : IDisposable, System::ComponentModel::IComponent, System::Web::UI::IControlBuilderAccessor, System::Web::UI::IControlDesignerAccessor, System::Web::UI::IDataBindingsAccessor, System::Web::UI::IExpressionsAccessor, System::Web::UI::IParserAccessor, System::Web::UI::IUrlResolutionService
[System.ComponentModel.Bindable(true)]
[System.Web.UI.Themeable(false)]
public class Control : IDisposable, System.ComponentModel.IComponent, System.Web.UI.IControlBuilderAccessor, System.Web.UI.IControlDesignerAccessor, System.Web.UI.IDataBindingsAccessor, System.Web.UI.IExpressionsAccessor, System.Web.UI.IParserAccessor, System.Web.UI.IUrlResolutionService
type Control = class
    interface IComponent
    interface IDisposable
    interface IParserAccessor
    interface IUrlResolutionService
    interface IDataBindingsAccessor
    interface IControlBuilderAccessor
    interface IControlDesignerAccessor
    interface IExpressionsAccessor
Public Class Control
Implements IComponent, IControlBuilderAccessor, IControlDesignerAccessor, IDataBindingsAccessor, IDisposable, IExpressionsAccessor, IParserAccessor, IUrlResolutionService
Inheritance
Control
Derived
Attributes
Implements

Examples

The following example demonstrates a custom server control that derives from the Control class. The InnerContent class overrides the Control.Render 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.

Important

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.

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>");
           }
       }
    }    
}
   
Option Explicit
Option Strict

Imports System.Web
Imports System.Web.UI

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
    End Class
End Namespace 'SimpleControlSamples

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.

Constructors

Control()

Initializes a new instance of the Control class.

Properties

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

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

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 ID 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.

Methods

AddedControl(Control, Int32)

Called after a child control is added to the Controls collection of the Control object.

AddParsedSubObject(Object)

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(Page)

Applies the style properties defined in the page style sheet to the control.

BeginRenderTracing(TextWriter, Object)

Begins design-time tracing of rendering data.

BuildProfileTree(String, Boolean)

Gathers information about the server control and delivers it to the Trace property to be displayed when tracing is enabled for the page.

ClearCachedClientID()

Sets the cached ClientID value to null.

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()

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(TextWriter, Object)

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)
FindControl(String)

Searches the current naming container for a server control with the specified id parameter.

FindControl(String, Int32)

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()

Gets design-time data for a control.

GetHashCode()

Serves as the default hash function.

(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(Control)

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()

Determines if the server control holds only literal content.

LoadControlState(Object)

Restores control-state information from a previous page request that was saved by the SaveControlState() method.

LoadViewState(Object)

Restores view-state information from a previous page request that was saved by the SaveViewState() method.

MapPathSecure(String)

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(Object, EventArgs)

Determines whether the event for the server control is passed up the page's UI server control hierarchy.

OnDataBinding(EventArgs)

Raises the DataBinding event.

OnInit(EventArgs)

Raises the Init event.

OnLoad(EventArgs)

Raises the Load event.

OnPreRender(EventArgs)

Raises the PreRender event.

OnUnload(EventArgs)

Raises the Unload event.

OpenFile(String)

Gets a Stream used to read a file.

RaiseBubbleEvent(Object, EventArgs)

Assigns any sources of the event and its information to the control's parent.

RemovedControl(Control)

Called after a child control is removed from the Controls collection of the Control object.

Render(HtmlTextWriter)

Sends server control content to a provided HtmlTextWriter object, which writes the content to be rendered on the client.

RenderChildren(HtmlTextWriter)

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(String)

Gets a URL that can be used by the browser.

ResolveUrl(String)

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(IDictionary)

Sets design-time data for a control.

SetRenderMethodDelegate(RenderMethod)

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 ViewState property.

Events

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.

Explicit Interface Implementations

IControlBuilderAccessor.ControlBuilder

For a description of this member, see ControlBuilder.

IControlDesignerAccessor.GetDesignModeState()

For a description of this member, see GetDesignModeState().

IControlDesignerAccessor.SetDesignModeState(IDictionary)

For a description of this member, see SetDesignModeState(IDictionary).

IControlDesignerAccessor.SetOwnerControl(Control)

For a description of this member, see SetOwnerControl(Control).

IControlDesignerAccessor.UserData

For a description of this member, see UserData.

IDataBindingsAccessor.DataBindings

For a description of this member, see DataBindings.

IDataBindingsAccessor.HasDataBindings

For a description of this member, see HasDataBindings.

IExpressionsAccessor.Expressions

For a description of this member, see Expressions.

IExpressionsAccessor.HasExpressions

For a description of this member, see HasExpressions.

IParserAccessor.AddParsedSubObject(Object)

For a description of this member, see AddParsedSubObject(Object).

Extension Methods

FindDataSourceControl(Control)

Returns the data source that is associated with the data control for the specified control.

FindFieldTemplate(Control, String)

Returns the field template for the specified column in the specified control's naming container.

FindMetaTable(Control)

Returns the metatable object for the containing data control.

Applies to

See also